WO2017221613A1 - Heat bonding sheet, and heat bonding sheet with dicing tape - Google Patents

Abstract

A sheet for heat bonding which can provide sufficient bonding reliability for a power semiconductor device by suppressing inhibition of sintering of sinterable metal particles by an organic component, and a heat bonding sheet with a dicing tape which comprises said sheet for heat bonding are provided. The sheet for heat bonding has a precursor layer which becomes a sintered layer by heating, wherein the precursor layer contains sinterable metal particles and an organic component, the precursor layer is a phase-separated structure which is a sea-island structure or a co-continuous structure, and, in an SEM surface microscopy image of at least one surface of the precursor layer, the largest value of the diameters of the maximum inscribed circles in regions occupied by each phase of the phase-separated structure is 1-50μm.

Description

Heat bonding sheet and heating bonding sheet with dicing tape

The present invention relates to a heat bonding sheet and a heat bonding sheet with a dicing tape.

In the manufacture of semiconductor devices, the method of adhering a semiconductor element to an adherend such as a metal lead frame (so-called die bonding method) has started with conventional gold-silicon eutectic, and has shifted to a method using solder and resin paste. At present, a conductive resin paste is sometimes used.

However, in the method using the conductive resin paste, there are cases where the conductivity is reduced due to the generation of voids, the thickness of the paste is not uniform, the pad is contaminated due to protrusion, and the like.

On the other hand, in recent years, the spread of power semiconductor devices that control and supply electric power has become remarkable. Since current always flows through the power semiconductor device, the amount of heat generated is large. Therefore, it is desirable that the conductive adhesive used for the power semiconductor device has high heat dissipation and low electrical resistivity.

Power semiconductor devices are required to operate at high speed with low loss. Conventionally, semiconductors using Si such as IGBT (Insulated Gate Bipolar Transistor) and MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) are used for power semiconductor devices. In recent years, those using semiconductors such as SiC and GaN have been developed and are expected to expand in the future.

A semiconductor using SiC or GaN has features such as a large band gap and a high dielectric breakdown electric field, and can operate at low loss, high speed, and high temperature. High-temperature operation is advantageous in automobiles and small power conversion devices that have severe thermal environments. Semiconductor devices for applications with severe thermal environments are expected to operate at a high temperature of about 250 ° C., and solder and conductive adhesives, which are conventional bonding / adhesive materials, have problems in thermal characteristics and reliability. Therefore, a paste material containing sintered metal particles has been proposed (for example, Patent Document 1). The sintered metal particle-containing paste material contains nano-sized to micro-sized metal particles, and these metal particles are melted at a temperature lower than the normal melting point due to the nano-size effect, and sintering between the particles proceeds.

JP 2014-111800 A

However, since the paste material containing sintered metal particles is literally in a paste state, the thickness becomes non-uniform as in the case of the conductive resin paste, and as a result, uneven bonding occurs, resulting in a decrease in bonding reliability especially at high temperatures. There is a case. Therefore, in order to solve the non-uniformity of thickness and problems caused by this, a technique for forming a joining material containing sinterable metal particles into a sheet shape is being studied.

Addition of an organic binder, which is a relatively high molecular weight material, has been studied as one of the measures for imparting moldability to the bonding material. Sintering of the sheet-like bonding material proceeds by a process of sintering sinterable metal particles following decomposition and disappearance of organic components such as an organic binder.

However, when a polymer material typified by an organic binder and metal fine particles coexist, the decomposition temperature of the polymer material may shift to a high temperature side. If the degree of high temperature shift of the decomposition temperature becomes strong, the decomposition temperature of the polymer material may be the same as or higher than the sintering temperature of the sinterable metal particles. In this case, even when the sinterable metal particles are sintered, the polymer material remains without disappearing, and the undisappeared polymer material inhibits the sintering of the sinterable metal particles. There is a possibility that the sintering of the conductive metal particles becomes insufficient and the bonding reliability of the power semiconductor device is lowered.

The present invention has been made in view of the above-described problems, and its purpose is to perform heat bonding that can suppress the inhibition of sintering of sinterable metal particles by an organic component and can provide sufficient bonding reliability to a power semiconductor device. It is providing the sheet | seat for heating joining with a dicing tape which has a sheet | seat and the said sheet | seat for heat joining.

As a result of intensive studies to solve the conventional problems, the inventors of the present application have found that the above-described problems can be solved by adopting the following configuration, and have completed the present invention.

That is, the sheet for heat bonding according to one embodiment of the present invention has a precursor layer that becomes a sintered layer by heating,
The precursor layer includes sinterable metal particles and an organic component,
The precursor layer has a phase separation structure that is a sea-island structure or a co-continuous structure,
In the SEM surface observation image of at least one surface of the precursor layer, the maximum value of the diameters of the maximum inscribed circles in the region occupied by each phase of the phase separation structure is 1 μm or more and 50 μm or less.

The precursor layer of the heat bonding sheet has a phase separation structure in which the sinterable metal particles and the organic component have a sea-island structure or a co-continuous structure, and are separated into two or more phases. In the SEM surface observation image, when taking the maximum inscribed circle in the region occupied by each phase and comparing the diameters of the maximum inscribed circles, the maximum diameter is 1 μm or more and 50 μm or less. Yes. If each phase is finely dispersed or phase-separated, the diameter of the maximum inscribed circle in the region occupied by each phase is also reduced. On the other hand, when each phase aggregates or aggregates and the degree of dispersion or phase separation becomes sparse, the diameter of the maximum inscribed circle in the region occupied by each phase increases. That is, the maximum value of the diameter of the maximum inscribed circle obtained for each phase (hereinafter also referred to as “maximum diameter”) is significant as an index representing the degree of dispersion or aggregation of the phase separation structure in the precursor layer. Will have.

In the heat bonding sheet, the maximum diameter in the phase separation structure is in the above range, and the degree of aggregation (aggregation degree) of each phase is relatively high, in other words, the degree of phase separation is in a sparse state. A high degree of decomposition temperature of the organic component due to the coexistence of the organic component and the sinterable metal particles by forming an appropriate separation state between the phase in which the sinterable metal particles and the phase in which the organic component collects. The shift is suppressed and the decomposition and disappearance of the organic component can be promoted, and the penetration of the phase of the organic component into the phase of the sinterable metal particles is suppressed. As a result, inhibition of sintering of the sinterable metal particles by the organic component can be prevented, and the bonding reliability of the power semiconductor device can be improved.

If the maximum diameter is too small, each phase will be finely dispersed, resulting in a high temperature shift in the decomposition temperature of the organic component and an inhibition of sintering of the sinterable metal particles by the organic component, resulting in reduced bonding reliability. . On the other hand, if the maximum diameter is too large, the phase separation structure becomes too sparse, and each component is present in an uneven manner, which may impair the uniformity of the characteristics of the heat bonding sheet.

The organic component includes a low molecular component having a weight average molecular weight of 1000 or less and a polymer component having a weight average molecular weight of 5000 or more,
It is preferable that the maximum absolute value of the difference between the polarity term of the solubility parameter of the low molecular component and the polarity term of the solubility parameter of the polymer component is 3 or more and 15 or less.

By setting the maximum absolute value of the difference of the polar term within the above range, the high molecular component and the low molecular component are hardly dissolved in each other, and a phase separation structure is exhibited between the two components. Compared to the polymer component, the low-molecular component has more liquid components and has a higher affinity with the sinterable metal particles in terms of wettability and molecular mobility. Many stay in the component phase. That is, a phase separation structure between the sinterable metal particles and the polymer component can be efficiently formed using the phase separation action of the polymer component and the low molecular component. From a macro perspective, it promotes the formation of a phase-separated structure between the monolithic phase in which the sinterable metal particle phase and the low-molecular component phase are integrated, and the polymer component phase. A phase separation structure having a maximum diameter in a specific range can be efficiently formed.

When the SEM surface observation image is binarized to display in black and white, the area ratio of the black portion in the entire SEM surface observation image is 10 to 80%,
When the SEM central portion observation image of the central portion in the thickness direction of the precursor layer is binarized to display in black and white, the area ratio of the black portion in the entire SEM central portion observation image is 1 to 60%. preferable.

This makes it possible to achieve both the workability (flexibility and strength) of the heat-bonding sheet and good sintered bondability after sintering. When the area ratio of the black part when the SEM surface observation image is binarized is less than 10%, the workability may be deteriorated due to the poor flexibility of the heat bonding sheet, and the case is more than 80%. May be inferior in sintered bondability. When the area ratio of the black portion when the SEM central portion observation image is binarized is less than 1%, the strength (cohesive force) of the heat-bonding sheet may be inferior. There is a possibility that the number of pores in the sintered layer increases and the strength of the sintered layer is inferior.

The heat bonding sheet is used to heat bond a semiconductor chip and an adherend, and at least a part of each surface of the semiconductor chip and the adherend includes gold, silver, or copper. preferable. Since the heat bonding sheet has high bonding reliability, it can be suitably used for heat bonding between a semiconductor chip and an adherend such as a lead frame. In addition, since at least a part of each surface of the adherend and the chip contains gold, silver or copper, the affinity with the heat bonding sheet or bonding wire is increased, and the bonding reliability with them is further improved. Can do.

A sheet for heat bonding with a dicing tape according to another embodiment of the present invention, a dicing tape,
And the heat bonding sheet laminated on the dicing tape.

Since the heat bonding sheet with dicing tape is integrated with the dicing tape, the step of bonding to the dicing tape can be omitted. Moreover, since the said sheet | seat for heat joining is provided, sintering of a sinterable metal particle can be advanced by sufficient level, and favorable joining reliability can be acquired.

It is a cross-sectional schematic diagram which shows the sheet | seat for heat joining with a dicing tape which concerns on one Embodiment of this invention. It is a cross-sectional schematic diagram which shows the sheet | seat for heat joining with a dicing tape which concerns on other embodiment of this invention. It is a schematic diagram which shows the phase-separation structure of the precursor layer of the sheet | seat for heat joining which concerns on one Embodiment of this invention. It is a schematic diagram which shows the phase-separation structure of the precursor layer of the sheet | seat for heat joining which concerns on other embodiment of this invention. It is a cross-sectional schematic diagram which shows the sheet | seat for heat joining with a double-sided separator. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the semiconductor device which concerns on one Embodiment of this invention. 2 is an SEM surface observation image obtained for the heat bonding sheet of Example 1. FIG.

Embodiments of the heat bonding sheet and the heat bonding sheet with dicing tape of the present invention will be described below with reference to the drawings. However, in some or all of the drawings, parts unnecessary for the description are omitted, and there are parts shown enlarged or reduced for easy explanation. The terms indicating the positional relationship such as up and down are merely used for ease of explanation, and are not intended to limit the configuration of the present invention.

(Sheet bonding sheet with dicing tape)
Examples of the heat bonding sheet according to the present embodiment include a sheet in which the dicing tape is not bonded to the heat bonding sheet with dicing tape described below. Therefore, hereinafter, the heat bonding sheet with dicing tape will be described, and the heat bonding sheet will be described therein. FIG. 1 is a schematic cross-sectional view showing a heat bonding sheet with a dicing tape according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing another heat bonding sheet with dicing tape according to another embodiment of the present invention.

As shown in FIG. 1, a heat bonding sheet 10 with a dicing tape has a configuration in which a heat bonding sheet 3 is laminated on a dicing tape 11. The dicing tape 11 is configured by laminating the pressure-sensitive adhesive layer 2 on the substrate 1, and the heat bonding sheet 3 is provided on the pressure-sensitive adhesive layer 2. Moreover, the sheet | seat for heat joining with a dicing tape of this invention may be the structure which formed sheet | seat 3 'for heat joining only in the workpiece | work affixing part like the heat bonding sheet | seat 12 with a dicing tape shown in FIG. .

(Heat bonding sheet)
The heat bonding sheets 3 and 3 ′ have a sheet shape. Since it is not a paste but a sheet, good thickness uniformity and handling properties can be obtained.

Heat joining sheet | seats 3 and 3 'which concern on this embodiment consist of the precursor layer 31 used as a sintered layer by heating. In the present embodiment, a case where the heat bonding sheet includes a single precursor layer that becomes a sintered layer by heating will be described, but the present invention is not limited to this example. In the present invention, the precursor layer that becomes a sintered layer by heating may have a configuration in which a plurality of the precursor layers are laminated.
Moreover, although this embodiment demonstrates the case where the sheet | seat for heat joining consists of a precursor layer used as a sintered layer by heating, this invention is not limited to this example. Two or more layers may be sufficient as the sheet | seat for heat joining of this invention. For example, the structure which laminated | stacked the precursor layer which becomes a sintered layer by heating, and the other layer (layer which does not become a sintered layer by heating) may be sufficient.
That is, the heat-bonding sheet in the present invention is not particularly limited as long as it has at least a precursor layer that becomes a sintered layer by heating.

(Precursor layer that becomes a sintered layer by heating)
The precursor layer 31 (hereinafter also simply referred to as “precursor layer 31”) that becomes a sintered layer by heating contains sinterable metal particles and organic components (details of each component will be described later). As shown in FIGS. 3A and 3B, the precursor layer 31 has a phase separation structure resulting from phase separation between the sinterable metal particles and the organic component on at least one surface. FIG. 3A shows a mode in which the phase separation structure is a sea-island structure, and FIG. 3B shows a case where the phase separation structure is a co-continuous structure. The phase separation structure may be a sea-island structure or a co-continuous structure, and the sea-island structure and the co-continuous structure may coexist.

The sea-island structure shown in FIG. 3A is separated into two phases, a sea phase (for example, an organic component phase) Ps and an island phase (for example, a phase of sinterable metal particles) Pi. However, the number of phases included in the phase separation structure is not limited to 2, and may be separated into three or more phases according to the components included in the precursor layer 31. The sea phase and the island phase are not limited to the organic component phase and the sinterable metal particle phase, respectively, and the sea phase and island are included depending on the components contained in the precursor layer 31 and their blending ratio. These phases may be a phase of a sinterable metal particle and a phase of an organic component, respectively.

In the co-continuous structure shown in FIG. 3B, the sea-island structure shown in FIG. 3A is separated into two phases of a first phase P1 and a second phase P2 that are continuous to some extent. However, even in the co-continuous structure, the number of phases included in the phase separation structure is not limited to 2, and may be separated into three or more phases depending on the components included in the precursor layer 31 and the like. Further, the first phase and the second phase may be either a sinterable metal particle phase or an organic component phase, respectively.

In the SEM surface observation image of at least one surface of the precursor layer 31, the maximum value of the diameters of the maximum inscribed circles in the region occupied by each phase of the phase separation structure is 1 μm or more and 50 μm or less. Hereinafter, this feature will be described.

When FIG. 3A is viewed as a schematic diagram of an SEM surface observation image of at least one surface of the precursor layer 31, in the sea-island structure shown in FIG. 3A, the region occupied by the island phase Pi is in the region occupied by the sea phase Ps. Exists. In the observation field, the inscribed circle for the region occupied by the phase Pi of the island (for example, when looking at the region occupied by one island, the largest area of the circles in contact with the boundary line between the island phase and the sea phase) A plurality of circles) are obtained for each island, and the inscribed circle having the largest diameter among these inscribed circles is set as the maximum inscribed circle Ci for the region occupied by the phase Pi of the island. Similarly, in the observation field, the inscribed circle (for example, the largest area among the circles in contact with the boundary line between the region of the localized sea phase and the region of the island) occupies the region occupied by the sea phase Ps. A plurality of circles) are obtained for each limited region, and the inscribed circle having the largest diameter among these inscribed circles is defined as the maximum inscribed circle Cs for the region occupied by the sea phase Ps. The diameter Di of the maximum inscribed circle Ci for the region occupied by the island phase Pi is compared with the diameter Ds of the maximum inscribed circle Cs for the region occupied by the sea phase Ps, and the maximum value (ie, , Diameter Di) is the maximum diameter. Even if there are three or more phases in the phase separation structure, the maximum diameter can be obtained by obtaining the diameter of the maximum inscribed circle for each phase in the same manner as described above, and obtaining the maximum value of these diameters. it can.

In the co-continuous structure shown in FIG. 3B, the maximum diameter can be obtained similarly to the embodiment shown in FIG. 3A. In the co-continuous structure shown in FIG. 3B, the region occupied by the first phase P1 and the region occupied by the second phase P2 coexist. In the observation field, an inscribed circle for the region occupied by the first phase P1 (for example, when one continuous region of the regions occupied by the first phase P1 is viewed, the boundary between the phase and the second phase) A circle having the maximum area among circles in contact with the line) is obtained for each continuous region, and the maximum inscribed circle C1 for the region in which the first phase P1 occupies the inscribed circle having the maximum diameter among the plurality of inscribed circles. And Similarly, in the observation field, an inscribed circle (for example, when one continuous region of the region occupied by the second phase P2 is viewed in the region occupied by the second phase P2 is the phase and the first phase) A circle having the maximum area among the circles in contact with the boundary line with each other) is determined for each continuous region, and the maximum inner diameter of the region in which the second phase P2 occupies the inscribed circle having the maximum diameter among these inscribed circles. Let it be a tangent circle C2. Then, the diameter D1 of the maximum inscribed circle C1 for the region occupied by the first phase P1 is compared with the diameter D2 of the maximum inscribed circle C2 for the region occupied by the second phase P2, and the maximum value of these is compared. (That is, the diameter D1) is the maximum diameter. Even if there are three or more continuous phases in the phase separation structure, the maximum inscribed circle diameter is obtained for each continuous phase in the same manner as described above, and the maximum diameter is obtained by obtaining the maximum value of these diameters. be able to.

In the present embodiment, the maximum diameter is 1 μm or more and 50 μm or less, preferably 1.5 μm or more and 30 μm or less, and more preferably 2 μm or more and 10 μm or less. By setting the maximum diameter of the phase separation structure observed in the precursor layer 31 within the above range, the cohesion degree (aggregation degree) of each phase is set to a relatively high state, and the phase and the organic component in which the sinterable metal particles gather By forming an appropriate separation state between the phases that gather, the high-temperature shift of the decomposition temperature of the organic component due to the coexistence of the organic component and the sinterable metal particles is suppressed, and the decomposition disappearance of the organic component is promoted. be able to. In addition, the invasion of the organic component phase into the phase of the sinterable metal particles is suppressed, so that inhibition of sintering of the sinterable metal particles by the organic component can be prevented, and the bonding reliability of the power semiconductor device can be improved. Can be improved.

The average thickness of the precursor layer 31 is 5 μm to 200 μm, preferably 10 μm to 150 μm, more preferably 15 μm to 100 μm. By keeping the average thickness of the precursor layer 31 before heating in the above range, it is possible to ensure sheet shape maintenance and thickness uniformity.

The precursor layer 31 has a tensile modulus obtained by the following tensile test method of preferably 10 MPa to 3000 MPa, more preferably 12 MPa to 2900 MPa, and further preferably 15 MPa to 2500 MPa.

Tensile test method:
(1) As a test sample, a heat bonding sheet (thickness test heat bonding sheet) having a thickness of 200 μm, a width of 10 mm, and a length of 40 mm is prepared.
(2) A tensile test was performed under the conditions of a distance between chucks of 10 mm, a tensile speed of 50 mm / min, and 23 ° C.
(3) The slope of the straight line portion of the obtained stress-strain diagram is the tensile modulus.

When the tensile elastic modulus of the precursor layer 31 is 10 MPa or more, it is possible to further suppress the constituent material of the heat bonding sheet from protruding or creeping up to the chip surface during die attachment. Further, when the tensile elastic modulus is 3000 MPa or less, for example, the semiconductor wafer can be fixed during dicing.

The precursor layer 31 has a carbon concentration of 15% by weight or less obtained by energy dispersive X-ray analysis after heating from 23 ° C. to 400 ° C. under a nitrogen atmosphere under a temperature rising rate of 10 ° C./min. Preferably, it is 12% by weight or less, more preferably 10% by weight or less. When the carbon concentration is 15% by weight or less, the precursor layer 31 contains almost no organic matter after being heated to 400 ° C. As a result, after the heat bonding step, the heat resistance is excellent, and high reliability and thermal characteristics are obtained even in a high temperature environment.

(Sintering metal particles)
As the sinterable metal particles, an aggregate of metal fine particles can be suitably used. Examples of the metal fine particles include fine particles made of metal. Examples of the metal include gold, silver, copper, silver oxide, and copper oxide. Especially, it is preferable that it is at least 1 sort (s) chosen from the group which consists of silver, copper, silver oxide, and copper oxide. When the metal fine particles are at least one selected from the group consisting of silver, copper, silver oxide, and copper oxide, heat bonding can be more suitably performed.

The average particle size of the sinterable metal particles is preferably 0.0005 μm or more, more preferably 0.001 μm or more. Examples of the lower limit of the average particle diameter include 0.01 μm, 0.05 μm, and 0.1 μm. On the other hand, the average particle size of the sinterable metal particles is preferably 30 μm or less, more preferably 25 μm or less. Examples of the upper limit of the average particle diameter include 20 μm, 15 μm, 10 μm, and 5 μm.

The average particle size of the sinterable metal particles is measured by the following method. That is, the sinterable metal particles are observed with an SEM (scanning electron microscope), and the average particle diameter is measured. The SEM observation is, for example, observing at a magnification of 5000 when the sinterable metal particles are in a micro size, observing at a magnification of 50000 in the case of a submicron size, and observing at a magnification of 300000 in the case of a nano size. preferable.

The shape of the sinterable metal particles is not particularly limited, and may be, for example, a spherical shape, a rod shape, a scale shape, or an indefinite shape.

The precursor layer 31 preferably contains sinterable metal particles in the range of 60 to 98 wt% with respect to the entire precursor layer 31. The content of the sinterable metal particles is more preferably in the range of 65 to 97% by weight, and still more preferably in the range of 70 to 95% by weight. When the sinterable metal particles are included in the range of 60 to 98% by weight, the sinterable metal particles are sintered or melted to join two objects (for example, a semiconductor chip and a lead frame). it can.

(Organic component)
The organic component preferably includes a low molecular component having a weight average molecular weight of 1000 or less. Such a low molecular component preferably contains a low boiling point binder. The low boiling point binder is used to facilitate handling of the metal fine particles. Specifically, it can be used as a metal fine particle-containing paste in which the metal fine particles are dispersed in the low boiling point binder. In addition, it is preferable to contain the precursor layer of the sintered layer in order to adjust it to an arbitrary mechanical property.

Specific examples of the low boiling point binder include, for example, pentanol, hexanol, heptanol, octanol, 1-decanol, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, α-terpineol, 1,6-hexanediol, isobornyl. Monovalent and polyhydric alcohols such as cyclohexanol (MTPH), ethylene glycol butyl ether, ethylene glycol phenyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, diethylene glycol isobutyl ether, diethylene glycol hexyl ether, triethylene glycol methyl ether, diethylene glycol Dimethyl ether, diethylene glycol Cole diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, diethylene glycol isopropyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, propylene glycol propyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol Ethers such as propyl ether, dipropylene glycol butyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether, tripropylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol Examples thereof include coal ethyl ether acetate, diethylene glycol butyether acetate, dipropylene glycol methyl ether acetate (DPMA) and the like. Two or more of these may be used in combination. Among these, it is preferable to use two types having different boiling points. Use of two types having different boiling points is excellent in terms of maintaining the sheet shape.

It is preferable that the organic component includes a polymer component having a weight average molecular weight of 5000 or more. Such a polymer component preferably contains a thermally decomposable binder. When the thermally decomposable binder is contained, it is easy to maintain the sheet shape before the heat bonding step. Moreover, it is easy to thermally decompose at the time of a heat joining process.

In the present specification, the “thermally decomposable binder” refers to a binder that can be thermally decomposed in the heat bonding step. It is preferable that the thermally decomposable binder hardly remains in the sintered layer (precursor layer 31 after heating) after the heat bonding step. As the thermally decomposable binder, for example, even if included in the precursor layer 31, energy dispersion after heating from 23 ° C. to 400 ° C. under a nitrogen atmosphere under a temperature rising rate of 10 ° C./min. Examples thereof include materials whose carbon concentration obtained by the type X-ray analysis is 15% by weight or less. For example, if a material that is more easily thermally decomposed is used as the thermally decomposable binder, even if the content is relatively increased, it hardly remains in the sintered layer (preheated precursor layer 31) after the heat bonding step. Can be.

Examples of the thermally decomposable binder include polycarbonate, acrylic resin, ethyl cellulose, and polyvinyl alcohol. These materials can be used alone or in admixture of two or more. Of these, polycarbonate is preferable from the viewpoint of high thermal decomposability.

The polycarbonate is not particularly limited as long as it can be thermally decomposed in the heat bonding step, but an aromatic compound (for example, benzene) is interposed between the carbonic acid ester groups (—O—CO—O—) of the main chain. And an aliphatic polycarbonate having an aliphatic chain and an aromatic compound having an aromatic compound between carbonic acid ester groups (—O—CO—O—) of the main chain. Of these, aliphatic polycarbonate is preferable.
Examples of the aliphatic polycarbonate include polyethylene carbonate and polypropylene carbonate. Among these, polypropylene carbonate is preferable from the viewpoint of solubility in an organic solvent in producing a varnish for forming a sheet.
Examples of the aromatic polycarbonate include those containing a bisphenol A structure in the main chain.
The polycarbonate preferably has a weight average molecular weight in the range of 10,000 to 1,000,000.

In the present specification, the weight average molecular weight is a value measured by GPC (gel permeation chromatography, HLC-8320 GPC manufactured by TOSOH) and calculated in terms of polystyrene. The measurement conditions are as follows. Column: TSKgel SuperHZM-H / HZ4000 / HZ3000 / HZ2000, column size: 6.0 mm inner diameter × 150 mm, solvent: tetrahydrofuran (THF), solution concentration: 0.03-0.1 wt%, flow rate: 0.6 mL / min , Detector: differential refractometer (RI), column temperature: 40 ° C., injection volume: 20 μL

The acrylic resin is an ester of acrylic acid or methacrylic acid ester having a linear or branched alkyl group having 30 or less carbon atoms, particularly 4 to 18 carbon atoms, as long as it can be thermally decomposed in the heat bonding step. Polymers (acrylic copolymers) containing seeds or two or more kinds as components are listed. Examples of the alkyl group include a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, t-butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, heptyl group, cyclohexyl group, 2- Examples include ethylhexyl group, octyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, lauryl group, tridecyl group, tetradecyl group, stearyl group, octadecyl group, and dodecyl group.

In addition, the other monomer forming the polymer (acrylic copolymer) is not particularly limited, and for example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid Or a carboxyl group-containing monomer such as crotonic acid, an acid anhydride monomer such as maleic anhydride or itaconic anhydride, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth ) 4-hydroxybutyl acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate or (4 -Hydroxymethyl cycle Hexyl) -hydroxyl group-containing monomers such as methyl acrylate, styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate Alternatively, a sulfonic acid group-containing monomer such as (meth) acryloyloxynaphthalene sulfonic acid, or a phosphoric acid group-containing monomer such as 2-hydroxyethylacryloyl phosphate can be used.

Among the acrylic resins, those having a weight average molecular weight of 10,000 to 1,000,000 are more preferable, and those having a weight average molecular weight of 30,000 to 700,000 are more preferable. It is because it is excellent in the adhesiveness before a heat joining process and the thermal decomposability in the heat joining process as it is in the said numerical range. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.
Among acrylic resins, acrylic resins that thermally decompose at 200 ° C. to 400 ° C. are preferable.

The maximum absolute value of the difference between the polarity term of the solubility parameter of the high molecular component and the polarity term of the solubility parameter of the low molecular component is preferably 3 or more and 15 or less, and more preferably 5 or more and 12 or less. When one low molecular component and one high molecular component are present, the absolute value of the difference between the polar terms of the solubility parameters becomes the maximum value as it is. When multiple types of low-molecular components and multiple types of high-molecular components are included, there are combinations of differences in polar terms corresponding to the product of the number of types of low-molecular components and the number of types of high-molecular components. It is preferable that the maximum value of the absolute values of the differences be in the above range. By setting the maximum value of the absolute value of the difference between the polar terms within the above range, the high molecular component and the low molecular component are hardly dissolved from each other, and the formation of a phase separation structure is promoted between the two components. Compared to the polymer component, the low-molecular component has more liquid components and has a higher affinity with the sinterable metal particles in terms of wettability and molecular mobility. Many stay in the component phase. That is, a phase separation structure between the sinterable metal particles and the polymer component can be efficiently formed using the phase separation action of the polymer component and the low molecular component. From a macro perspective, it promotes the formation of a phase-separated structure between the monolithic phase in which the sinterable metal particle phase and the low-molecular component phase are integrated, and the polymer component phase. A phase separation structure having a maximum diameter in a specific range can be efficiently formed.

When the SEM surface observation image is binarized to display black and white, the area ratio of the black portion in the entire SEM surface observation image is preferably 10 to 80%, more preferably 15 to 70%. . In addition, when the SEM central portion observation image of the central portion in the thickness direction of the precursor layer is binarized to display black and white, the area ratio of the black portion in the entire SEM central portion observation image is 1 to 60%. It is preferably 5 to 50%. The method for measuring the area ratio of the black part when the SEM surface observation image and the SEM center part observation image are binarized is as described in the examples. For example, when a low molecular component and a high molecular component having the above-described solubility parameter relationship are included as an organic component, the integral phase in which the phase of the sinterable metal particles and the low molecular component phase are integrated is a white portion. The polymer component phase is displayed as a black part. By making the area ratio of the black part (the polymer component phase in the above example) when the SEM surface observation image and the SEM center part observation image are binarized into the above ranges, the workability of the sheet ( Both flexibility and strength) and good sintered bondability after sintering can be achieved.

The precursor layer 31 may contain, for example, a plasticizer as appropriate in addition to the above components.

The heat bonding sheets 3, 3 'can be manufactured by a usual method. For example, a varnish containing the above components for forming the precursor layer 31 is prepared, and the varnish is applied on the base separator so as to have a predetermined thickness to form a coating film, and then the coating film is dried. Thereby, the sheet | seat 3, 3 'for heat joining can be manufactured.

The solvent used in the varnish is not particularly limited, but an organic solvent or an alcohol solvent that can uniformly dissolve, knead, or disperse the above components is preferable. Examples of the organic solvent include ketone solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, acetone, methyl ethyl ketone, and cyclohexanone, toluene, xylene, and the like. Examples of the alcohol solvent include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2- Examples include butene-1,4-diol, 1,2,6-hexanetriol, glycerin, octanediol, 2-methyl-2,4-pentanediol, and terpineol.

The application method is not particularly limited. Examples of the solvent coating method include a die coater, a gravure coater, a roll coater, a reverse coater, a comma coater, a pipe doctor coater, and screen printing. Of these, a die coater is preferable in terms of high uniformity of coating thickness. The drying conditions for the coating film are not particularly limited, and for example, the drying can be performed at a drying temperature of 70 to 160 ° C. and a drying time of 1 to 5 minutes. Even after the coating film is dried, depending on the type of solvent, the entire solvent may remain in the coating film without being vaporized.

When the precursor layer 31 contains the low boiling point binder, a part of the low boiling point binder may volatilize depending on the drying conditions. Therefore, the ratio of each component constituting the precursor layer 31 changes according to the drying conditions. For example, even in the precursor layer 31 formed from the same varnish, the higher the drying temperature and the longer the drying time, the content of the metal fine particles in the entire precursor layer 31 and the content of the thermally decomposable binder Will be more. Therefore, it is preferable to set the drying conditions so that the content of the metal fine particles and the thermally decomposable binder in the precursor layer 31 is a desired amount.

As the base material separator, polyethylene terephthalate (PET), polyethylene, polypropylene, a plastic film or paper surface-coated with a release agent such as a fluorine-type release agent or a long-chain alkyl acrylate release agent can be used.

As a method for producing the heat-bonding sheets 3 and 3 ′, for example, a method for producing the heat-bonding sheets 3 and 3 ′ by mixing the respective components with a mixer and press-molding the obtained mixture is also suitable. It is. A planetary mixer etc. are mentioned as a mixer.

(Dicing tape)
The dicing tape 11 is configured by laminating an adhesive layer 2 on a substrate 1.

The base material 1 is a strength base of the heat bonding sheets 10 and 12 with a dicing tape, and preferably has ultraviolet transparency. Examples of the substrate 1 include low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolyprolene, polybutene, polymethylpentene, and the like. Polyolefin, ethylene-vinyl acetate copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene -Hexene copolymer, Polyester such as polyurethane, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyetheretherketone, polyetherimide, polyamide, wholly aromatic polyamide, polyphenyls Fuido, aramid (paper), glass, glass cloth, fluorine resin, polyvinyl chloride, polyvinylidene chloride, cellulose resin, silicone resin, metal (foil), paper, and the like.

Further, examples of the material of the substrate 1 include polymers such as a crosslinked body of the resin. The plastic film may be used unstretched or may be uniaxially or biaxially stretched as necessary. According to the resin sheet to which heat shrinkability is imparted by stretching treatment or the like, the adhesive area between the pressure-sensitive adhesive layer 2 and the heat bonding sheets 3 and 3 ′ is reduced by thermally shrinking the base material 1 after dicing, The collection of the semiconductor chip can be facilitated.

The surface of the substrate 1 is chemically treated by conventional surface treatments such as chromic acid treatment, ozone exposure, flame exposure, high piezoelectric impact exposure, ionizing radiation treatment, etc. in order to improve adhesion and retention with adjacent layers. Alternatively, a physical treatment or a coating treatment with a primer (for example, an adhesive substance described later) can be performed.

The thickness of the substrate 1 is not particularly limited and can be appropriately determined, but is generally about 5 to 200 μm.

The pressure-sensitive adhesive used for forming the pressure-sensitive adhesive layer 2 is not particularly limited, and for example, a general pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive or a rubber-based pressure-sensitive adhesive can be used. As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive having an acrylic polymer as a base polymer from the viewpoint of cleanability with an organic solvent such as ultrapure water or alcohol of an electronic component that is difficult to contaminate a semiconductor wafer or glass Is preferred.

Examples of the acrylic polymer include (meth) acrylic acid alkyl esters (for example, methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, Isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, tridecyl ester, tetradecyl ester, hexadecyl ester , Octadecyl esters, eicosyl esters, etc., alkyl groups having 1 to 30 carbon atoms, especially 4 to 18 carbon atoms, such as linear or branched alkyl esters) (Meth) acrylic acid cycloalkyl esters (e.g., cyclopentyl ester, cyclohexyl ester, etc.) acryl-based polymer such as one or more was used as a monomer component thereof. In addition, (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester, and (meth) of the present invention has the same meaning.

The acrylic polymer contains units corresponding to other monomer components copolymerizable with the (meth) acrylic acid alkyl ester or cycloalkyl ester, if necessary, for the purpose of modifying cohesive force, heat resistance and the like. You may go out. Examples of such monomer components include, for example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; maleic anhydride Acid anhydride monomers such as itaconic anhydride; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate Hydroxyl group-containing monomers such as 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; Styrene Contains sulfonic acid groups such as phonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid Monomers; Phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate; acrylamide, acrylonitrile and the like. One or more of these copolymerizable monomer components can be used. The amount of these copolymerizable monomers used is preferably 40% by weight or less based on the total monomer components.

Furthermore, since the acrylic polymer is crosslinked, a polyfunctional monomer or the like can be included as a monomer component for copolymerization as necessary. Examples of such polyfunctional monomers include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) An acrylate etc. are mentioned. These polyfunctional monomers can also be used alone or in combination of two or more. The amount of the polyfunctional monomer used is preferably 30% by weight or less of the total monomer components from the viewpoint of adhesive properties and the like.

The acrylic polymer can be obtained by subjecting a single monomer or a mixture of two or more monomers to polymerization. The polymerization can be performed by any method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization and the like. From the viewpoint of preventing contamination of a clean adherend, the content of the low molecular weight substance is preferably small. In this respect, the number average molecular weight of the acrylic polymer is preferably 100,000 or more, more preferably about 200,000 to 3,000,000, and particularly preferably about 300,000 to 1,000,000.

In addition, an external cross-linking agent can be appropriately employed for the pressure-sensitive adhesive in order to increase the number average molecular weight of an acrylic polymer as a base polymer. Specific examples of the external crosslinking method include a method of adding a so-called crosslinking agent such as a polyisocyanate compound, an epoxy compound, an aziridine compound, a melamine crosslinking agent, and reacting them. When using an external cross-linking agent, the amount used is appropriately determined depending on the balance with the base polymer to be cross-linked, and further depending on the intended use as an adhesive. In general, it is preferable to add about 5 parts by weight or less, and further 0.1 to 5 parts by weight with respect to 100 parts by weight of the base polymer. Furthermore, you may use additives, such as conventionally well-known various tackifiers and anti-aging agent, other than the said component as needed to an adhesive.

The pressure-sensitive adhesive layer 2 can be formed of a radiation curable pressure-sensitive adhesive. The radiation curable pressure-sensitive adhesive can increase the degree of cross-linking by irradiation with radiation such as ultraviolet rays, and can easily reduce its adhesive strength, and a portion 2a corresponding to the work pasting portion of the pressure-sensitive adhesive layer 2 shown in FIG. The difference in adhesive strength with the other part 2b can be provided by irradiating only with radiation.

Further, by curing the radiation-curing pressure-sensitive adhesive layer 2 in accordance with the heat-bonding sheet 3 ′ shown in FIG. 2, the portion 2 a having a significantly reduced adhesive force can be easily formed. Since the heat bonding sheet 3 ′ is attached to the portion 2 a that has been cured and has reduced adhesive strength, the interface between the portion 2 a of the pressure-sensitive adhesive layer 2 and the heat bonding sheet 3 ′ is easily peeled off during pick-up. Have. On the other hand, the portion not irradiated with radiation has a sufficient adhesive force, and forms the portion 2b. In addition, you may perform irradiation of the radiation to an adhesive layer after dicing and before pick-up.

As described above, in the pressure-sensitive adhesive layer 2 of the heat bonding sheet with dicing tape 10 shown in FIG. 1, the portion 2b formed of the uncured radiation-curing pressure-sensitive adhesive adheres to the heat bonding sheet 3, and dicing is performed. It is possible to secure a holding force when performing. In this way, the radiation curable pressure-sensitive adhesive can support the heat bonding sheet 3 for fixing a chip-like work (semiconductor chip or the like) to an adherend such as a substrate with a good balance of adhesion and peeling. In the pressure-sensitive adhesive layer 2 of the heat bonding sheet 11 with a dicing tape shown in FIG. 2, the portion 2b can fix the wafer ring.

As the radiation curable pressure-sensitive adhesive, those having a radiation curable functional group such as a carbon-carbon double bond and exhibiting adhesiveness can be used without particular limitation. As the radiation curable pressure sensitive adhesive, for example, an addition type radiation curable pressure sensitive adhesive in which a radiation curable monomer component or an oligomer component is blended with a general pressure sensitive pressure sensitive adhesive such as an acrylic pressure sensitive adhesive or a rubber pressure sensitive adhesive. An agent can be illustrated.

Examples of the radiation curable monomer component to be blended include urethane oligomer, urethane (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol. Examples include stall tetra (meth) acrylate, dipentaerystol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and 1,4-butanediol di (meth) acrylate. Examples of the radiation curable oligomer component include urethane, polyether, polyester, polycarbonate, and polybutadiene oligomers, and those having a molecular weight in the range of about 100 to 30000 are suitable. The compounding amount of the radiation-curable monomer component or oligomer component can be appropriately determined in accordance with the type of the pressure-sensitive adhesive layer, and the amount capable of reducing the adhesive strength of the pressure-sensitive adhesive layer. In general, the amount is, for example, about 5 to 500 parts by weight, preferably about 40 to 150 parts by weight with respect to 100 parts by weight of the base polymer such as an acrylic polymer constituting the pressure-sensitive adhesive.

In addition to the additive-type radiation-curable pressure-sensitive adhesive described above, the radiation-curable pressure-sensitive adhesive has a carbon-carbon double bond in the polymer side chain, main chain, or main chain terminal as a base polymer. Intrinsic radiation curable pressure sensitive adhesives using Intrinsic radiation curable pressure-sensitive adhesive does not need to contain an oligomer component, which is a low-molecular component, or does not contain much, so that the oligomer component or the like does not move in the pressure-sensitive adhesive over time and is stable. Since the adhesive layer of a layer structure can be formed, it is preferable.

As the base polymer having a carbon-carbon double bond, those having a carbon-carbon double bond and having adhesiveness can be used without particular limitation. As such a base polymer, those having an acrylic polymer as a basic skeleton are preferable. Examples of the basic skeleton of the acrylic polymer include the acrylic polymers exemplified above.

The method for introducing the carbon-carbon double bond into the acrylic polymer is not particularly limited, and various methods can be adopted. However, it is easy in terms of molecular design to introduce the carbon-carbon double bond into the polymer side chain. It is. For example, after a monomer having a functional group is copolymerized in advance with an acrylic polymer, a compound having a functional group capable of reacting with the functional group and a carbon-carbon double bond is converted into a radiation-curable carbon-carbon double bond. A method of performing condensation or addition reaction while maintaining the above.

Examples of combinations of these functional groups include carboxylic acid groups and epoxy groups, carboxylic acid groups and aziridyl groups, hydroxyl groups and isocyanate groups, and the like. Among these combinations of functional groups, a combination of a hydroxyl group and an isocyanate group is preferable because of easy tracking of the reaction. In addition, the functional group may be on either side of the acrylic polymer and the compound as long as the combination of these functional groups generates an acrylic polymer having the carbon-carbon double bond. In the preferable combination, it is preferable that the acrylic polymer has a hydroxyl group and the compound has an isocyanate group. In this case, examples of the isocyanate compound having a carbon-carbon double bond include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate, and the like. As the acrylic polymer, a copolymer obtained by copolymerizing the above-mentioned exemplified hydroxy group-containing monomers, ether compounds of 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, or the like is used.

As the intrinsic radiation curable pressure-sensitive adhesive, the base polymer (particularly acrylic polymer) having the carbon-carbon double bond can be used alone, but the radiation curable monomer does not deteriorate the characteristics. Components and oligomer components can also be blended. The radiation-curable oligomer component or the like is usually in the range of 30 parts by weight, preferably in the range of 0 to 10 parts by weight, with respect to 100 parts by weight of the base polymer.

The radiation curable pressure-sensitive adhesive contains a photopolymerization initiator when cured by ultraviolet rays or the like. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxypropio Α-ketol compounds such as phenone and 1-hydroxycyclohexyl phenyl ketone; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- ( Acetophenone compounds such as methylthio) -phenyl] -2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether and anisoin methyl ether; ketal compounds such as benzyldimethyl ketal; 2-naphthalenesulfonyl Black Aromatic sulfonyl chloride compounds such as 1; phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime and other photoactive oxime compounds; benzophenone, benzoylbenzoic acid, 3,3′-dimethyl Benzophenone compounds such as -4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2 Thioxanthone compounds such as 1,4-diethylthioxanthone and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketone; acyl phosphinoxide; acyl phosphonate and the like. The blending amount of the photopolymerization initiator is, for example, about 0.05 to 20 parts by weight with respect to 100 parts by weight of the base polymer such as an acrylic polymer constituting the pressure-sensitive adhesive.

Examples of the radiation curable pressure-sensitive adhesive include photopolymerizable compounds such as an addition polymerizable compound having two or more unsaturated bonds and an alkoxysilane having an epoxy group disclosed in JP-A-60-196956. And a rubber-based pressure-sensitive adhesive and an acrylic pressure-sensitive adhesive containing a photopolymerization initiator such as a carbonyl compound, an organic sulfur compound, a peroxide, an amine, and an onium salt-based compound.

In the radiation-curable pressure-sensitive adhesive layer 2, a compound that is colored by irradiation with radiation may be contained as necessary. By including a compound to be colored in the pressure-sensitive adhesive layer 2 by irradiation with radiation, only the irradiated portion can be colored. That is, the portion 2a corresponding to the workpiece pasting portion 3a shown in FIG. 1 can be colored. Accordingly, whether or not the pressure-sensitive adhesive layer 2 has been irradiated with radiation can be immediately determined by visual observation, the workpiece pasting portion 3a can be easily recognized, and workpieces can be easily pasted together. In addition, when detecting a semiconductor chip by an optical sensor or the like, the detection accuracy is increased, and no malfunction occurs when the semiconductor chip is picked up. The compound that is colored by irradiation with radiation is a colorless or light color compound before irradiation with radiation, but becomes a color by irradiation with radiation, and examples thereof include leuco dyes. The use ratio of the compound colored by radiation irradiation can be set as appropriate.

The thickness of the pressure-sensitive adhesive layer 2 is not particularly limited, but is preferably about 1 to 50 μm from the viewpoint of preventing chipping of the chip cut surface and compatibility of fixing and holding the heat bonding sheets 3 and 3 ′. The thickness is preferably 2 to 30 μm, more preferably 5 to 25 μm.

The dicing tape 11 according to the present embodiment is manufactured as follows, for example.
First, the base material 1 can be formed by a conventionally known film forming method. Examples of the film forming method include a calendar film forming method, a casting method in an organic solvent, an inflation extrusion method in a closed system, a T-die extrusion method, a co-extrusion method, and a dry lamination method.

Next, after a pressure-sensitive adhesive composition solution is applied onto the substrate 1 to form a coating film, the coating film is dried under predetermined conditions (heat-crosslinked as necessary), and the pressure-sensitive adhesive layer 2 is formed. Form. It does not specifically limit as a coating method, For example, roll coating, screen coating, gravure coating, etc. are mentioned. As drying conditions, for example, a drying temperature of 80 to 150 ° C. and a drying time of 0.5 to 5 minutes are performed. Moreover, after apply | coating an adhesive composition on a separator and forming a coating film, the coating film may be dried on the said drying conditions, and the adhesive layer 2 may be formed. Then, the adhesive layer 2 is bonded together with the separator on the base material 1. Thereby, the dicing tape 11 is produced.

The heat bonding sheets 10 and 12 with a dicing tape can be manufactured by a usual method. For example, the sheet | seat 10 for heat joining with a dicing tape can be manufactured by bonding the adhesive layer 2 of the dicing tape 11 and the sheet | seat 3 for heat joining.
In the heat bonding sheet 10 with dicing tape, the heat bonding sheet 3 is preferably covered with a separator. For example, after the dicing tape 11 and the heat bonding sheet 3 are bonded together, the base separator laminated on the heat bonding sheet 3 is peeled off, and the front base separator is peeled off, followed by heat joining with the dicing tape. The method of sticking a separator on the exposed surface of the heat bonding sheet 3 of the sheet 10 for use is mentioned. That is, it is preferable that the dicing tape 11, the heat bonding sheet 3, and the separator are stacked in this order.

In the embodiment described above, the heat bonding sheet with dicing tape in which the dicing tape and the heat bonding sheet are laminated has been described. However, the heat bonding sheet of the present invention may be provided in a state where it is not bonded to a dicing tape.
In the case where the dicing tape is not bonded, the heat bonding sheet is preferably a heat bonding sheet with a double-sided separator sandwiched between two separators. That is, it is preferable to use a heat bonding sheet with a double-sided separator in which the first separator, the heat bonding sheet, and the second separator are laminated in this order.
FIG. 4 is a schematic cross-sectional view showing an embodiment of a heat-bonding sheet with a double-sided separator.
The heat bonding sheet 30 with a double-sided separator shown in FIG. 4 has a configuration in which a first separator 32, a heat bonding sheet 3, and a second separator 34 are laminated in this order. As the 1st separator 32 and the 2nd separator 34, the same thing as the above-mentioned substrate separator can be used.
In addition, when it is set as the form by which the dicing tape is not bonded together, the sheet | seat for heat joining may be the form on which the separator was laminated | stacked only on one side of the sheet | seat for heat joining.

(Method for manufacturing semiconductor device)
The method of manufacturing a semiconductor device according to the present embodiment includes the step of preparing the heat bonding sheet;
A heat bonding step of heat bonding the semiconductor chip onto the adherend via the heat bonding sheet (hereinafter also referred to as a first manufacturing method).
Moreover, the method for manufacturing a semiconductor device according to the present embodiment includes the step of preparing the heat bonding sheet with dicing tape described above,
A bonding step of bonding the heat bonding sheet of the heat bonding sheet with the dicing tape and the back surface of the semiconductor wafer;
A dicing step of dicing the semiconductor wafer together with the heat bonding sheet to form a chip-like semiconductor chip;
Picking up the semiconductor chip together with the heat bonding sheet from the heat bonding sheet with the dicing tape;
A heat bonding step of heat bonding the semiconductor chip onto the adherend via the heat bonding sheet (hereinafter also referred to as a second manufacturing method).
The manufacturing method of the semiconductor device according to the first manufacturing method is the same as the manufacturing method of the semiconductor device according to the second manufacturing method, while the heating bonding sheet with dicing tape is used. Then, it differs in the point which uses the sheet | seat for heat joining alone, and is common in another point. In the manufacturing method of the semiconductor device according to the first manufacturing method, after preparing the heat-bonding sheet, the step of bonding the sheet to the dicing tape is performed, and thereafter the same as the manufacturing method of the semiconductor device according to the second manufacturing method. can do. Therefore, hereinafter, a method for manufacturing a semiconductor device according to the second manufacturing method will be described.

In the method of manufacturing a semiconductor device according to the present embodiment, first, the heat bonding sheets with dicing tape 10 and 12 are prepared (preparing step). The dicing tape-attached heat bonding sheets 10 and 12 are used in the following manner by appropriately separating the separator arbitrarily provided on the heat bonding sheets 3 and 3 ′. Hereinafter, a case where the heat bonding sheet with dicing tape 10 is used will be described as an example with reference to FIG.

First, the semiconductor wafer 4 is pressure-bonded onto the semiconductor wafer bonding portion 3a of the heat bonding sheet 3 in the heat bonding sheet 10 with dicing tape, and this is bonded and held (fixing step). This step is performed while pressing with a pressing means such as a pressure roll. The attaching temperature at the time of mounting is not particularly limited, and is preferably in the range of 23 ° C. to 90 ° C., for example.

The semiconductor wafer 4 is preferably one in which an electrode pad is formed on one surface and a gold thin film, a silver thin film, or a copper thin film is formed on the outermost surface of the other surface (hereinafter also referred to as the back surface). Moreover, it is preferable to form a thin film containing the same kind of metal as the sinterable metal fine particles contained in the precursor layer 31 on the outermost surface of the back surface of the semiconductor wafer 4. Examples of the thickness of the silver thin film include 10 nm to 1000 nm. Further, a titanium thin film may be further formed between the semiconductor wafer 4 and the silver thin film. Examples of the thickness of the titanium thin film include 10 nm to 1000 nm. When the gold thin film, the silver thin film, or the copper thin film is formed, the semiconductor chip 5 and the heat bonding sheet 3 can be strongly heat bonded in the heat bonding step described later. Further, when the titanium thin film is formed, the reliability of the electrode is improved. The silver thin film and the titanium thin film can be formed by vapor deposition, for example.

Next, the semiconductor wafer 4 is diced (dicing process). Thereby, the semiconductor wafer 4 is cut into a predetermined size and separated into individual pieces, and the semiconductor chip 5 is manufactured. Although the method of dicing is not particularly limited, for example, the dicing is performed from the circuit surface side of the semiconductor wafer 4 according to a conventional method. Further, in this step, for example, a cutting method called full cut in which cutting is performed up to the heat bonding sheet with dicing tape 10 can be adopted. It does not specifically limit as a dicing apparatus used at this process, A conventionally well-known thing can be used. Further, since the semiconductor wafer 4 is bonded and fixed by the heat bonding sheet 10 with a dicing tape, chip chipping and chip jumping can be suppressed, and damage to the semiconductor wafer 4 can also be suppressed.

Next, the semiconductor chip 5 is picked up in order to peel the semiconductor chip 5 adhered and fixed to the heat bonding sheet 10 with dicing tape (pickup process). The pickup method is not particularly limited, and various conventionally known methods can be employed. For example, there is a method in which each semiconductor chip 5 is pushed up by a needle from the heating bonding sheet 10 with dicing tape, and the pushed-up semiconductor chip 5 is picked up by a pickup device.

As the pick-up conditions, the needle push-up speed is preferably 0.5 to 100 mm / sec, more preferably 5 to 10 mm / sec in terms of preventing chipping.

Here, when the pressure-sensitive adhesive layer 2 is an ultraviolet curable type, the pickup is performed after the pressure-sensitive adhesive layer 2 is irradiated with ultraviolet rays. Thereby, the adhesive force with respect to the sheet | seat 3 for heat bonding of the adhesive layer 2 falls, and peeling of the semiconductor chip 5 becomes easy. As a result, the pickup can be performed without damaging the semiconductor chip 5. Conditions such as irradiation intensity and irradiation time at the time of ultraviolet irradiation are not particularly limited, and may be set as necessary. Moreover, a well-known thing can be used as a light source used for ultraviolet irradiation. When the adhesive layer is preliminarily irradiated with ultraviolet rays and cured, and the cured adhesive layer and the heat bonding sheet are bonded together, the ultraviolet irradiation here is not necessary.

Next, the picked-up semiconductor chip 5 is die-attached (heat bonded) to the adherend 6 via the heat bonding sheet 3 (heat bonding process). Examples of the adherend 6 include a lead frame, a TAB film, a substrate, and a separately manufactured semiconductor chip. The adherend 6 may be, for example, a deformable adherend that can be easily deformed or a non-deformable adherend (such as a semiconductor wafer) that is difficult to deform.

Examples of the lead frame include metal lead frames such as a Cu lead frame and a 42 Alloy lead frame. Moreover, a conventionally well-known thing can be used as said board | substrate. Examples thereof include organic substrates made of glass epoxy, BT (bismaleimide-triazine), polyimide, and the like. Especially, if a metal ream frame is used, it can be integrated with metal fine particles by heat bonding. The substrate may be an insulating circuit substrate in which a copper circuit substrate is laminated on an insulating substrate such as a ceramic plate. If an insulated circuit board is used, for example, a power semiconductor device that controls and supplies power can be manufactured.

It is preferable that at least a part of the surface of the adherend contains gold, silver, or copper. In this case, the surface of the adherend preferably contains the same type of metal as the sinterable metal fine particles contained in the precursor layer 31. When at least a part of the surface of the adherend contains gold, silver, or copper, the affinity with the heat bonding sheet or the bonding wire is increased, and the bonding reliability with them can be further improved. From the viewpoint of improving durability and weather resistance, gold or silver is preferred, and copper is preferred for cost reduction.

In the heat bonding step, the metal fine particles are sintered by heating, and the thermally decomposable binder is thermally decomposed as necessary. Further, the residual low boiling point binder that has not been volatilized by the drying step is volatilized. The heating temperature is preferably 180 to 400 ° C, more preferably 190 to 370 ° C, and further preferably 200 to 350 ° C. The heating time is preferably 0.3 to 300 minutes, more preferably 0.5 to 240 minutes, and still more preferably 1 to 180 minutes. Moreover, you may perform heat joining on pressurization conditions. The pressurizing condition is preferably in the range of 1 to 500 kg / cm ² , more preferably in the range of 5 to 400 kg / cm ² . The heat bonding under pressure can be performed with an apparatus capable of simultaneously performing heating and pressure, such as a flip chip bonder. Moreover, a parallel plate press may be used.

Next, if necessary, as shown in FIG. 5, the tip of the terminal portion (inner lead) of the adherend 6 and an electrode pad (not shown) on the semiconductor chip 5 are electrically connected by a bonding wire 7. (Wire bonding process). As the bonding wire 7, for example, a gold wire, an aluminum wire, a copper wire or the like is used. The temperature for wire bonding is 23 to 300 ° C., preferably 23 to 250 ° C. The heating time is several seconds to several minutes. The connection is performed by a combination of vibration energy by ultrasonic waves and crimping energy by applying pressure while being heated so as to be within the temperature range.

Next, as necessary, the semiconductor chip 5 is sealed with a sealing resin 8 as shown in FIG. 5 (sealing step). This step is performed to protect the semiconductor chip 5 and the bonding wire 7 mounted on the adherend 6. This step can be performed by molding a sealing resin with a mold. As the sealing resin 8, for example, an epoxy resin is used. The heating temperature at the time of resin sealing is usually 175 ° C. for 60 to 90 seconds, but the present invention is not limited to this. For example, it can be cured at 165 to 185 ° C. for several minutes. Thereby, the sealing resin 8 is cured. In this sealing step, a method of embedding the semiconductor chip 5 in a sheet-like sealing sheet (for example, see JP2013-7028A) can also be employed. In addition to molding the sealing resin with a mold, a gel sealing type in which silicone gel is poured into a case type container may be used.

Next, heating is performed as necessary to completely cure the insufficiently cured sealing resin 8 in the sealing process (post-curing process). The heating temperature in this step varies depending on the type of the sealing resin, but is in the range of 165 to 185 ° C., for example, and the heating time is about 0.5 to 8 hours.

In addition, the sheet | seat for heat joining of this invention and the sheet | seat for heat joining with a dicing tape can be used suitably also when laminating | stacking a some semiconductor chip and carrying out three-dimensional mounting. At this time, the heat bonding sheet and the spacer may be stacked between the semiconductor chips, or only the heat bonding sheet may be stacked between the semiconductor chips without stacking the spacer. It can be changed as appropriate.
In addition, the heat bonding sheet and the heat bonding sheet with dicing tape of the present invention are not limited to the applications exemplified above, and can be used for heat bonding two things.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

The components used in the examples were as follows.
Sinterable metal particle-containing paste: 6 parts by weight of isobornylcyclohexanol (MTPH, molecular weight 236), which is a low boiling point binder, per 100 parts by weight of copper powder (Mitsui Metal Mining Co., Ltd., average particle size 0.2 μm) Parts, 5 parts by weight of methyl ethyl ketone (MEK) added and stirred (each component was put into a rotation / revolution mixer (ARE-310, manufactured by Shinky Corporation) and stirred for 15 minutes at 2000 rpm).
Thermally decomposable binder A: PPC (polypropylene carbonate resin), manufactured by Empower, "QPAC40", weight average molecular weight 289,000
Thermally decomposable binder B: PiBMA (polyisobutyl methacrylate resin), manufactured by Fujikura Kasei Co., Ltd., “MM2002”, weight average molecular weight 170,000
Organic solvent: Methyl ethyl ketone (MEK)

<Examples 1 to 3 and Comparative Example 1>
100 parts by weight of a paste containing sinterable metal particles, 7 parts by weight of a thermally decomposable binder shown in Table 1, and 45 parts by weight of an organic solvent are put into a rotating / revolving mixer (ARE-310, manufactured by Sinky) and stirred at 2000 rpm for 8 minutes. And varnish was produced. The obtained varnish was applied and dried on a release treatment film (“MRA38” manufactured by Mitsubishi Resin Co., Ltd.). The application was performed using an applicator so that the thickness of the dried coating film was 70 μm. Drying was performed with an explosion-proof dryer. The drying conditions were 80 ° C. and 2 minutes. As a result, a heat bonding sheet having a thickness of 70 μm was obtained.

<Evaluation>
The sample of an Example and a comparative example was evaluated about the following items. The results are shown in Table 1.

(SEM observation of the phase separation structure and measurement of the maximum diameter of the maximum inscribed circle)
An image was taken with a scanning electron microscope (SEM) at an acceleration voltage of 5 kV and a magnification of 1000 times at the central portion of the exposed surface of the precursor layer of the heat bonding sheet. The measurement conditions were set so that the density histogram (256 divisions with a gradation of 0 to 255) of an image taken for later image analysis would not be extremely biased in the range of 0 to 255. For this purpose, for example, it is preferable to shoot after applying a command for automatically selecting the optimum contrast and brightness, such as “auto contrast” and “auto brightness” in the observation software. In FIG. 6, the SEM surface observation image obtained about the sheet | seat for heat joining of Example 1 is shown. Three regions of 50 μm × 50 μm were randomly cut out from the obtained SEM surface observation images as observation fields of view. FIG. 6 shows an observation visual field at one of them. Using the image analysis software (“imageJ”, an open source software developed at the National Institutes of Health, USA), the inscribed line that touches the boundary line of each phase that defines the phase separation in the phase separation structure of the observed field of view A circle is drawn about the area occupied by each phase.

Specifically, using the image analysis software, the bright phase and the dark phase of the SEM surface observation image are binarized to display black and white, and the boundary between the white portion and the black portion is defined for each phase that defines phase separation. A boundary line was used. The binarization of the bright part and the dark part was performed as follows. If the histogram displayed in the “B & C” window appears by selecting the commands in the menu bar of the image analysis software in the order of “Image”, “Adjust”, and “Brightness / Contrast”, it is the first. The lowest frequency between the most frequent peak and the second most frequent peak was used as the boundary, and less than that was binarized with black and more than that with white. If the above histogram does not consist of two or more peaks (when there is one peak), binarization is performed with 0 to 127 of the 0 to 255 gradations divided into 256 parts as black parts and 128 to 255 as white parts. did. In the phase separation structure shown in FIG. 6, an inscribed circle is drawn for the region occupied by each of the bright phase and the dark phase. The diameter of the maximum inscribed circle having the maximum diameter among the inscribed circles of each phase was read, and the maximum value among the diameters of the maximum inscribed circles for each phase was obtained and determined as the maximum diameter [μm].

The SEM central part observation image of the central part in the thickness direction of the sheet was obtained by the following procedure. A heat-bonding sheet is cut out along a plane perpendicular to the longitudinal direction of the sheet passing through the center of the sheet surface, and cryoion polish polishing (using Leica TIC-3X. Acceleration voltage: 6 kV, processing temperature: −20) ° C). It was obtained by taking an SEM observation image of the central portion of the obtained polished surface. The imaging conditions at the center in the thickness direction were an acceleration voltage of 2 kV and a magnification of 2000 times.

(Measurement of area ratio of black part in binarized SEM observation image)
For the SEM surface observation image, an image obtained by binarizing the bright phase and the dark phase and displaying in black and white was used, and the area ratio of the black portion in the entire observation field was obtained by image analysis. For the SEM central observation image, an image obtained by binarizing the bright phase and the dark phase and displaying in black and white is used. The central area (1 μm (thickness direction) × 20 μm (perpendicular to the thickness direction) of the black and white display image is used. The area ratio of the black portion in the direction)) was determined by image analysis.

(Calculation method of polarity term δp of solubility parameter (SP value))
The polar term δp of the SP value was determined by the following equation (from J. Appl. Polym. Sci., 1975, 19, 1163).
δp = 50.1 × {μ / (Vm) ^3/4 }
(In the formula, μ is a dipole moment of the target compound. When the target compound is a polymer, the μ of the polymer measures the dipole moment μ ′ of the main monomer of the polymer or searches for literature values. Vm is the molecular weight of the target compound (when the target compound is a polymer, the molecular weight of the main monomer) and the density of the target compound (when the target compound is a polymer, the main weight is obtained by multiplying μ ′ by 0.8). The main monomer is a monomer having the highest molar ratio in the target polymer component, and the monomer constituting the polymer component is extracted from the sheet by solvent extraction or the like. (The organic component is extracted, and after GPC fractionation, the polymer component can be identified by determining its structure by nuclear magnetic resonance (NMR).)

(Reliability evaluation-measurement of remaining joint area ratio)
A silicon chip (silicon chip thickness 350 μm, length 5 mm, width 5 mm) having a Ti layer (thickness 50 nm) and an Ag layer (thickness 100 nm) formed in this order on the back surface was prepared. The prepared heat bonding sheet was stacked on the Ag layer surface of the prepared silicon chip. In this state, I passed the laminator. The laminator conditions were a temperature of 70 ° C., a pressure of 0.3 MPa, and a speed of 10 mm / second.

Separately, a copper plate (copper plate thickness 3 mm) whose entire surface was covered with an Ag layer (thickness 5 μm) was prepared. A heat bonding sheet with a silicon chip (prepared above) was temporarily bonded onto the prepared copper plate. The pressure at the time of temporary adhesion was 0.1 MPa. In addition, the copper plate was preheated to 70 ° C. during the temporary bonding. This was used for evaluation of Example 1 and Comparative Example 1.

Further, a copper plate (copper plate thickness 3 mm) whose entire surface was covered with an Au layer (thickness 0.1 μm) was prepared. A heat bonding sheet with a silicon chip (prepared above) was temporarily bonded onto the prepared copper plate. The pressure at the time of temporary adhesion was 0.1 MPa. In addition, the copper plate was preheated to 70 ° C. during the temporary bonding. This was used for the evaluation of Example 2.

Furthermore, a copper plate (thickness of copper plate: 3 mm) with no surface coating was prepared. A heat bonding sheet with a silicon chip (prepared above) was temporarily bonded onto the prepared copper plate. The pressure at the time of temporary adhesion was 0.1 MPa. In addition, the copper plate was preheated to 70 ° C. during the temporary bonding. This was used for the evaluation of Example 3.

Subsequently, the heat bonding sheet temporarily bonded as described above was sintered under pressure and heating conditions to bond the silicon chip and the copper plate (pressure 10 MPa, temperature increase rate 90 ° C./min, sintering temperature). 300 ° C., sintering time 5 minutes). For the joining, a sintering apparatus (HTM-3000, manufactured by Hakutosha) was used. The pressurization was performed by a flat plate press, and the pressurization was always maintained during the temperature raising process and the sintering process. Moreover, the atmosphere at the time of temperature rising and sintering was a nitrogen atmosphere.

After heating (after completion of the sintering process), air cooling was performed until the temperature reached 170 ° C, and then water cooling was performed until the temperature reached 80 ° C. In addition, water cooling was based on the water-cooling type cooling plate provided in the pressure plate. Thereby, a sample for evaluation was obtained.

Next, the sample for evaluation was put into a thermal shock tester (Espec Corp., “TSE-103ES”) and subjected to 100 thermal shocks of −40 ° C. to 200 ° C. At this time, the temperature was kept at −40 ° C. and 200 ° C. for 15 minutes, respectively.

After 100 cycles, using an ultrasonic imaging device [SAT] (“FineSAT II” manufactured by Hitachi Construction Machinery Finetech), imaging was performed to confirm the portion where the silicon chip and the copper plate were joined by the sintered layer. Went. The transducer (probe) used was PQ-50-13: WD [frequency 50 MHz], and the imaging mode was “reflection”.

Using the image analysis software used in the SEM observation, the area (remaining bonding area) where the bonding remains in the obtained image is obtained, and the ratio of the remaining bonding area to the entire area (remaining bonding area ratio) Was calculated. In the image obtained by the ultrasonic imaging apparatus, the part where the silicon chip and the copper plate are peeled is displayed in white, and the part where the bonding remains is displayed in black (the threshold is 127. 0 to 255 floors). The binarization was performed with 0 to 127 among the 256 divided tones as black portions and 128 to 255 as white portions. The case where the remaining bonding area ratio was 70% or more was evaluated as “◯”, and the case where the remaining bonding area ratio was lower than 70% was evaluated as “X”.

(Results and discussion)
In Examples 1 to 3, the reliability evaluation was good. On the other hand, in Comparative Example 1, the reliability evaluation was inferior. In Comparative Example 1, the maximum value of the diameter of the maximum inscribed circle for the phase separation structure is less than 1 μm, the dispersibility of the sinterable metal particles and the organic component is high, and the decomposition temperature of the organic component is This is presumably due to the high temperature shift and the inhibition of sintering of the sinterable metal particles by the organic component.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Adhesive layer 3, 3 'Heat bonding sheet 4 Semiconductor wafer 5 Semiconductor chip 6 Substrate 7 Bonding wire 8 Sealing resin 10, 12 Heat bonding sheet with dicing tape 11 Dicing tape 30 Heating with double-sided separator Sheet for bonding 31 Precursor layer that becomes a sintered layer by heating 32 First separator 34 Second separator Pi (sea-island structure) island phase Ps (sea-island structure) sea phase Ci island maximum inscribed circle Cs Maximum inscribed circle of sea phase Di Diameter of maximum inscribed circle of island phase Ds Diameter of maximum inscribed circle of sea phase P1 (co-continuous structure) first phase P2 (co-continuous structure) Phase 2 C1 Maximum inscribed circle of the first phase C2 Maximum inscribed circle of the second phase D1 Diameter of the maximum inscribed circle of the first phase D2 Second phase The diameter of the maximum inscribed circle

Claims (5)

A heating bonding sheet having a precursor layer that becomes a sintered layer by heating,
The precursor layer includes sinterable metal particles and an organic component,
The precursor layer has a phase separation structure that is a sea-island structure or a co-continuous structure,
The SEM surface observation image of at least one surface of the precursor layer, wherein the maximum value of the diameters of the maximum inscribed circles in the region occupied by each phase of the phase separation structure is 1 μm or more and 50 μm or less. The organic component includes a low molecular component having a weight average molecular weight of 1000 or less and a polymer component having a weight average molecular weight of 5000 or more,
2. The heat bonding sheet according to claim 1, wherein the maximum absolute value of the difference between the polarity term of the solubility parameter of the low molecular component and the polarity term of the solubility parameter of the polymer component is 3 or more and 15 or less. When the SEM surface observation image is binarized to display in black and white, the area ratio of the black portion in the entire SEM surface observation image is 10 to 80%,
When the SEM central portion observation image of the central portion in the thickness direction of the precursor layer is binarized and displayed in black and white, the area ratio of the black portion in the entire SEM central portion observation image is 1 to 60%. The sheet for heat bonding according to 1 or 2. Used to heat-bond semiconductor chips and adherends,
The heat bonding sheet according to any one of claims 1 to 3, wherein at least a part of each surface of the semiconductor chip and the adherend includes gold, silver, or copper. Dicing tape,
A heat bonding sheet with a dicing tape comprising: the heat bonding sheet according to any one of claims 1 to 4 laminated on the dicing tape.

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