TWI879749B - Semiconductor device manufacturing method - Google Patents

Abstract

The present invention provides a method for efficiently and accurately supplying bonding materials to a micro area in a method for manufacturing a semiconductor device having a portion to be bonded using a bonding material containing sinterable particles. The semiconductor device manufacturing method of the present invention includes a transfer step, a pre-fixing step, and a bonding step. In the transfer step, the side of the bonding sheet 10 containing sinterable particles in the sheet body X is bonded to the bonding target portion 21 in the semiconductor element module 20, and then the portion of the bonding sheet 10 that has been pressed to the bonding target portion 21 is retained on the bonding target portion 21 as a bonding material layer 11, and the other portions are accompanied by the substrate B to perform the peeling of the substrate B. In the pre-fixing step, the bonding target portion 21 with the bonding material layer 11 is pre-fixed to the substrate via the bonding material layer 11. In the bonding step, the bonding material layer 11 interposed between the pre-fixed bonding target portion 21 and the substrate undergoes a heating process to form a bonding layer, and the bonding target portion 21 is bonded to the substrate.

Description

Semiconductor device manufacturing method

The present invention relates to a method for manufacturing a semiconductor device having semiconductor elements such as so-called micro LEDs (Light Emitting Diodes).

In the manufacture of semiconductor devices, as a method for bonding a semiconductor chip to a supporting substrate such as a lead frame or an insulating circuit board by electrically connecting one side of the semiconductor chip to the side of the supporting substrate, there are known methods of forming an Au-Si eutectic alloy layer between the supporting substrate and the chip to achieve a bonding state, or using solder or a resin containing conductive particles as a bonding material.

On the other hand, power semiconductor devices responsible for controlling the supply of electric power have become remarkably popular in recent years. Power semiconductor devices often generate a large amount of heat due to the large amount of current flowing during operation. Therefore, in the manufacture of power semiconductor devices, the method of electrically connecting one side of the semiconductor chip to the supporting substrate and bonding the chip to the supporting substrate at the same time requires a bonding state that has high reliability even during high-temperature operation. This requirement is particularly strong for power semiconductor devices that use SiC or GaN as semiconductor materials to achieve high-temperature operation. Therefore, in order to cope with this requirement, a technology using a solder paste material containing sinterable particles, a solvent, etc. has been proposed as a bonding method accompanied by electrical connection.

In the bonding process of semiconductor device manufacturing using a solder paste material containing sinterable particles, first, the solder paste material containing sinterable particles is applied to the predetermined chip bonding position in the supporting substrate or the predetermined bonding surface of the semiconductor chip to be bonded thereto. Then, the semiconductor chip is loaded on the predetermined chip bonding position of the supporting substrate through the solder paste material containing sinterable particles under specific temperature and load conditions. Thereafter, a heating step is performed under specific temperature and pressure conditions, so that the solvent in the solder paste material containing sinterable particles is volatilized between the supporting substrate and the semiconductor chip thereon, and bonding is performed between the sinterable particles. Thereby, a bonding layer is formed between the supporting substrate and the semiconductor chip, and the semiconductor chip is electrically connected and mechanically bonded to the supporting substrate. This technology is described in the following patent documents 1 and 2, for example. [Prior art document] [Patent document]

[Patent document 1] Japanese Patent Publication No. 2013-039580 [Patent document 2] Japanese Patent Publication No. 2014-111800

[The problem the invention is trying to solve]

In the above-mentioned bonding process using a solder paste material containing sinterable particles, the solder paste material containing sinterable particles is applied to each predetermined bonding location. However, this method is not efficient.

Furthermore, in the above-mentioned joining process using a solder paste material containing sinterable particles, there is a possibility that the solder paste material containing sinterable particles cannot be accurately applied to the intended joining position, and as a result, there is a possibility that the solder paste material overflows from between the joining objects, or the overflowed solder paste material spreads. After the solder paste material containing sinterable particles overflows from between the joining objects, it dries up and falls off from the overflowing portion during the process, collides with other portions of the manufacturing target object, i.e., the semiconductor device, and damages the quality of the device. The sintering of the solder paste material containing sinterable particles that has spread may cause a short circuit in the manufacturing target object, i.e., the semiconductor device. In the manufacturing process of semiconductor devices that involve the use of solder paste materials containing sinterable particles to bond parts, there is a tendency that the smaller the intended bonding part is, the more difficult it is to accurately apply the solder paste material containing sinterable particles to the intended bonding part, and these problems tend to become more prominent.

The present invention is conceived based on the above situation related to the bonding material containing sinterable particles, and its purpose is to provide a method suitable for efficiently and accurately supplying the bonding material to a micro area in a manufacturing method of a semiconductor device having a portion to be bonded using the bonding material containing sinterable particles. [Technical means for solving the problem]

The semiconductor device manufacturing method provided by the present invention includes the following transfer step, pre-fixation step, and bonding step, which is suitable for manufacturing semiconductor devices with micro semiconductor elements such as micro LEDs.

In the transfer step, first, the side of a bonding sheet (bonding material) in a sheet body having a layered structure including a bonding sheet containing sinterable particles and a substrate is bonded to a semiconductor element having at least two separated bonding objects or at least two bonding objects in a semiconductor element module. The bonding sheet may be a sheet-like sintering bonding composition (sintering bonding sheet) including at least sinterable particles containing a conductive metal and an adhesive component, or may be a sheet-like adhesive (adhesive sheet) including at least conductive particles and a resin component, wherein the conductive particles at least partially include sinterable particles containing a conductive metal. The so-called semiconductor element module refers to a plurality of semiconductor elements such as a micro LED module for a micro LED display integrated together. The separation distance of adjacent bonding objects in a semiconductor element or a semiconductor element module is, for example, 1 to 500 μm. The length of the adjacent bonding objects in the separation direction is, for example, less than 150 μm. In the separation direction of the adjacent bonding objects, the ratio of the length of each bonding object to the arrangement spacing of the bonding objects is, for example, 0.01 to 1. In the transfer step, the portion of the bonding sheet that has been pressed onto the bonding object portion is retained as a bonding material layer on the bonding object portion, and the other portions are accompanied by the sheet body substrate to peel off the substrate.

In the pre-fixing step, the bonding target portion to which the bonding material layer is attached is pre-fixed to the substrate by being pressed by the bonding material layer.

In the bonding step, the bonding material layer interposed between the pre-fixed bonding target portion and the substrate undergoes a heating process to form a bonding layer, and the bonding target portion is bonded to the substrate. For example, when a sintered bonding sheet is used in the above-mentioned transfer step, a sintered layer is formed as the bonding layer in the bonding step.

In the transfer step of the semiconductor device manufacturing method, as described above, the bonding sheet (bonding material) side of the sheet body is attached to at least two bonding target parts in the semiconductor element or semiconductor element module, and the portion of the bonding sheet that has been pressed to the bonding target part is retained on the bonding target part and the other portion is accompanied by the substrate to perform the peeling of the sheet body substrate. This structure is suitable for efficiently supplying bonding material to each of a plurality of bonding target parts at one time.

Furthermore, in the transfer step of the semiconductor device manufacturing method, the portion of the bonding sheet (bonding material) that has been pressed onto the bonding target portion is retained on the bonding target portion and transferred. This supply method that utilizes the pressing action of the bonding material on the bonding target portion is suitable for accurately supplying the bonding material to the bonding target portion. This method makes it easy to accurately supply the bonding material to the bonding target portion even if the bonding target portion is a micro area.

As described above, the semiconductor device manufacturing method of the present invention is suitable for efficiently and accurately supplying bonding materials to a micro area. The method suitable for accurately supplying bonding materials to the bonding object is suitable for preventing and suppressing the bonding materials from overflowing from the bonding objects or the overflowing bonding materials from spreading. Therefore, the method is suitable for manufacturing semiconductor devices with bonding parts with good yield.

FIG1 and FIG2 show a semiconductor device manufacturing method of an embodiment of the present invention. The semiconductor device manufacturing method of this embodiment is a method for manufacturing a semiconductor device having micro semiconductor elements such as micro LEDs through a specific bonding process, and includes the following preparation steps, transfer steps, pre-fixing steps, and bonding steps.

In the preparation step, as shown in FIG1(a), a sheet body X and a semiconductor element module 20 are prepared. The sheet body X has a laminated structure including a substrate B and a bonding sheet 10. The substrate B is, for example, a plastic film. The bonding sheet 10 is a sheet-like sintering bonding composition (sintering bonding sheet) including at least sintering particles containing a conductive metal and an adhesive component, or a sheet-like adhesive (adhesive sheet) including at least conductive particles and a resin component, wherein the conductive particles at least partially include sintering particles containing a conductive metal. In the present embodiment, the semiconductor element module 20 is a module in which a plurality of micro LEDs are arranged in an array and integrated, such as a micro LED module for a micro LED display. Each semiconductor element included in the semiconductor element module 20 has one or more bonding target parts 21 as a predetermined bonding position. In the micro-LED, the bonding target part 21 is an external electrode or a protrusion thereof. The separation distance D of adjacent bonding target parts 21 is, for example, 1 to 500 μm, preferably 1 to 300 μm, and more preferably 1 to 200 μm. The length L of the separation direction of adjacent bonding target parts 21 is, for example, less than 150 μm, preferably less than 100 μm, more preferably less than 50 μm, and more preferably less than 30 μm. The length L is, for example, more than 1 μm. In the separation direction of the adjacent bonding target portions 21, the ratio (L/P) of the length L of each bonding target portion 21 to the arrangement pitch P of the bonding target portions 21 is, for example, 0.01 to 1. From the viewpoint of reducing the loss of the bonding material constituting the bonding sheet 10 in the transfer step described later (the portion not transferred to the bonding target portion 21), the ratio (L/P) of the length L to the arrangement pitch P (=D+L) is preferably 0.05 or more, and more preferably 0.1 or more. From the perspective of ensuring the corresponding separation distance D for the length L of the bonding object portion 21 and ensuring the ease of transfer of the bonding material constituting the bonding sheet 10 in the transfer step described later, the ratio (L/P) of the length L to the arrangement spacing P (=D+L) is preferably less than 0.7, and more preferably less than 0.5.

In the transfer step, first, as shown in FIG. 1( b ), the sheet body X is bonded to the bonding target portion 21 in the semiconductor element module 20 or its semiconductor element. Specifically, the side of the bonding sheet 10 of the sheet body X is pressed and bonded to a plurality of bonding target portions 21. As a pressing mechanism for bonding, for example, a press roller can be cited. The bonding temperature is, for example, in the range of room temperature to 200° C., and the bonding load is, for example, 0.01 to 10 MPa.

In the transfer step, as shown in FIG. 1( c ), the portion of the bonding sheet 10 that has been pressed against the bonding target portion 21 is retained as the bonding material layer 11 on the bonding target portion 21 and the other portion is accompanied by the base material B to peel off the base material B. In this step, the bonding material can be supplied to each bonding target portion 21 at one time.

When the bonding sheet 10 is a sintering bonding sheet, the bonding sheet 10 is a sheet-shaped sintering bonding composition including at least sintering particles containing a conductive metal and a binder component as described above.

The sinterable particles used to constitute the sintered bonding sheet 10 are particles that contain conductive metal elements and are capable of sintering. As conductive metal elements, for example, gold, silver, copper, palladium, tin, and nickel can be listed. As constituent materials of such sinterable particles, for example, gold, silver, copper, palladium, tin, nickel, and alloys of two or more metals selected from the group thereof can be listed. As constituent materials of sinterable particles, metal oxides such as silver oxide, copper oxide, palladium oxide, and tin oxide can also be listed. In addition, the sinterable particles can also be particles having a core-shell structure. For example, the sinterable particles may also be core-shell structure particles having a core with copper as the main component and a shell with gold or silver as the main component and covering the core. In this embodiment, the sinterable particles are preferably at least one selected from the group consisting of silver particles, copper particles, silver oxide particles, and copper oxide particles. This structure is suitable for forming a strong sintered layer between the joining objects to be sintered using a sintering bonding sheet. In addition, from the viewpoint of achieving high electrical conductivity and high thermal conductivity in the formed sintered layer, silver particles and copper particles are preferred as sinterable particles. In addition, from the viewpoint of anti-oxidation, silver particles are easier to handle and are therefore preferred. For example, when a semiconductor device module is sintered and bonded to a copper substrate with a silver coating, when a sintering material containing copper particles as sinterable particles is used, the sintering process must be performed in an inert environment such as a nitrogen atmosphere, but when a sintering material containing silver particles as sinterable particles is used, the sintering process can be properly performed even in an air atmosphere. The sinterable particles as described above can have various shapes such as spherical, flat, needle-shaped, and flake-shaped. In addition, the bonding sheet 10 can contain one type of sinterable particles, or can contain two or more types of sinterable particles.

From the viewpoint of ensuring the flatness of the surface of the bonding sheet 10, the average particle size of the sinterable particles used is preferably 3000 nm or less, more preferably 1000 nm or less, and more preferably 500 nm or less. From the viewpoint of achieving good dispersibility of the sinterable particles in the sintered bonding sheet and the composition used to form the sinterable particles, the average particle size of the sinterable particles is preferably 1 nm or more, more preferably 10 nm or more, and more preferably 50 nm or more. The average particle size of the sinterable particles can be measured by observation using a scanning electron microscope (SEM).

From the viewpoint of realizing sinter bonding with higher reliability, the content ratio of the sinterable particles in the sinter bonding sheet is preferably 60 to 99 mass %, more preferably 65 to 98 mass %, and even more preferably 70 to 97 mass %.

The adhesive component of the sintering bonding sheet used to form the bonding sheet 10 in this embodiment includes at least a polymer adhesive and a low molecular adhesive, and may further include other components such as a plasticizer.

The polymer adhesive in the sheet for sintering bonding is preferably a thermally decomposable polymer adhesive. The thermally decomposable polymer adhesive is an adhesive component that can be thermally decomposed during the high-temperature heating process for sintering bonding, and is an element that helps to maintain the sheet shape of the sheet for sintering bonding before the heating process. In this embodiment, from the perspective of ensuring the function of maintaining the shape of the sheet, the thermally decomposable polymer adhesive is a material that is solid at room temperature (23°C). Examples of such thermally decomposable polymer adhesives include polycarbonate resins and acrylic resins. The sheet for sintering bonding preferably includes polycarbonate resins and/or acrylic resins as the polymer adhesive or the thermally decomposable polymer adhesive.

Examples of the polycarbonate resin include aliphatic polycarbonates containing an aliphatic chain without an aromatic compound such as a benzene ring between the carbonate groups (-O-CO-O-) of the main chain, and aromatic polycarbonates containing an aromatic compound between the carbonate groups (-O-CO-O-) of the main chain. Examples of aliphatic polycarbonates include polyethylene carbonate and polypropylene carbonate. Examples of aromatic polycarbonates include polycarbonates containing a bisphenol A structure in the main chain.

Examples of the acrylic resin include polymers of acrylic acid esters and/or methacrylic acid esters having a linear or branched alkyl group with 4 to 18 carbon atoms. Hereinafter, "(meth)acrylic acid" refers to "acrylic acid" and/or "methacrylic acid", and "(meth)acrylate" refers to "acrylate" and/or "methacrylate". Examples of the alkyl group of (meth)acrylate used to form the acrylic resin used as a thermally decomposable polymer adhesive include methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, isobutyl, pentyl, isopentyl, hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, lauryl, tridecyl, tetradecyl, stearyl, and octadecyl.

The acrylic resin may also be a polymer containing monomer units from other monomers other than the (meth)acrylate. Examples of such other monomers include monomers containing carboxyl groups, acid anhydride monomers, monomers containing hydroxyl groups, monomers containing sulfonic acid groups, and monomers containing phosphoric acid groups. Specifically, examples of monomers containing carboxyl groups include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of acid anhydride monomers include maleic anhydride and itaconic anhydride. Examples of monomers containing a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and 4-(hydroxymethyl)cyclohexylmethyl (meth)acrylate. Examples of monomers containing a sulfonic acid group include styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. Examples of monomers containing a phosphate group include 2-hydroxyethylacryloyl phosphate.

The weight average molecular weight of the polymer binder or the thermally decomposable polymer binder contained in the sintering bonding sheet is preferably not less than 10000. The weight average molecular weight of the thermally decomposable polymer binder is a value measured by gel permeation chromatography (GPC) and calculated by polystyrene conversion.

From the viewpoint of appropriately exerting the above-mentioned sheet shape-retaining function, the content ratio of the polymer binder or the thermally decomposable polymer binder contained in the sheet for sintering bonding is preferably 0.1 to 20 mass %, more preferably 0.5 to 18 mass %, and even more preferably 1 to 15 mass %.

The low molecular weight adhesive in the sheet for sintering bonding is preferably a low boiling point adhesive. The low boiling point adhesive is an adhesive component having a lower boiling point than the thermal decomposition starting temperature of a polymer adhesive such as a thermally decomposable polymer adhesive. In this embodiment, the low boiling point adhesive is a liquid or semi-liquid state having a viscosity of 1×10 ⁵ Pa･s or less at 23°C measured using a dynamic viscoelasticity measuring device (trade name "HAAKE MARS III", manufactured by Thermo Fisher Scientific). In this viscosity measurement, a parallel plate of 20 mmφ is used as a fixture, the plate spacing is set to 100 μm, and the shear rate in rotational shear is set to 1 s ^-1 .

Examples of the low-boiling point binder include terpene alcohols, alcohols other than terpene alcohols, alkylene glycol alkyl ethers, and ethers other than alkylene glycol alkyl ethers. Examples of terpene alcohols include isobutylcyclohexanol, citronellol, geraniol, nerol, geranyl alcohol, and α-terpineol. Examples of alcohols other than terpene alcohols include amyl alcohol, hexanol, heptanol, octanol, 1-decanol, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, and 2,4-dimethyl-1,5-pentanediol. Examples of the alkylene glycol alkyl ethers include ethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, diethylene glycol isobutyl ether, diethylene glycol hexyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, diethylene glycol isopropyl methyl ether, triethylene glycol 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 propyl ether, dipropylene glycol butyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether, and tripropylene glycol dimethyl ether. As ethers other than alkylene glycol alkyl ethers, for example, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, and dipropylene glycol methyl ether acetate can be listed. As a component of the bonding sheet 10, one low boiling point adhesive can be used, or two or more low boiling point adhesives can be used. From the viewpoint of stability at room temperature, the low boiling point adhesive in the bonding sheet 10 is preferably a terpene alcohol, and more preferably isobutylcyclohexanol.

From the viewpoint of ensuring good adhesion on the surface of the sheet, the content ratio of the low molecular weight adhesive such as the low boiling point adhesive in the sinter bonding sheet is, for example, 1 to 50 mass %.

The viscosity of the sinter-bonding sheet and the sinter-bonding composition forming the sinter-bonding sheet at 70° C. is, for example, 5×10 ³ to 1×10 ⁷ Pa·s, preferably 1×10 ⁴ to 1×10 ⁶ Pa·s.

The sintering bonding sheet can be produced, for example, by mixing the above-mentioned components in a solvent to prepare a varnish, applying the varnish on the substrate B to form a coating, and drying the coating. As the solvent for preparing the varnish, an organic solvent or an alcohol solvent can be used.

When the bonding sheet 10 is an adhesive sheet, the bonding sheet 10 is a sheet-shaped adhesive including at least conductive particles and a resin component as described above, and the conductive particles at least partially include sinterable particles containing a conductive metal.

As the sinterable particles in the bonding sheet, for example, the sinterable particles described above as the sinterable particles in the sintering bonding sheet can be used. As the conductive particles in the bonding sheet, in addition to the sinterable particles, carbon black and carbon nanotubes can also be listed. The content ratio of the conductive particles in the bonding sheet is, for example, 50 to 95 mass %.

In the present embodiment, the resin component of the connecting sheet used to form the bonding sheet 10 includes at least a thermosetting resin and a thermoplastic resin, and may further include other components such as a plasticizer.

Examples of the thermosetting resin include epoxy resins, phenol resins, amine resins, unsaturated polyester resins, polyurethane resins, polysilicone resins, and thermosetting polyimide resins. The bonding sheet may contain one thermosetting resin or two or more thermosetting resins.

Examples of the epoxy resin include bifunctional epoxy resins or polyfunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, brominated bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol AF type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, phenol novolac type epoxy resin, o-cresol novolac type epoxy resin, trihydroxyphenylmethane type epoxy resin, and tetraphenolethane type epoxy resin. The follower sheet may contain one epoxy resin or two or more epoxy resins.

From the viewpoint of appropriately expressing the function as a thermosetting adhesive in the adhesive sheet, the content ratio of the thermosetting resin in the adhesive sheet used to form the bonding sheet 10 is, for example, 1 to 50 mass %.

When epoxy resin is used as a thermosetting resin for bonding sheets, phenol resin is preferably used as a hardener for making the epoxy resin exhibit thermosetting properties.

Examples of phenolic resins that can function as a hardener for epoxy resins include novolac-type phenolic resins, resol-type phenolic resins, and polyhydroxystyrenes such as poly(p-hydroxystyrene). Examples of novolac-type phenolic resins include phenol novolac resins, phenol aralkyl resins, cresol novolac resins, tertiary butylphenol novolac resins, and nonylphenol novolac resins. The bonding sheet may contain one type of phenolic resin, or may contain two or more types of phenolic resins.

The thermoplastic resin in the bonding sheet is responsible for the function of an adhesive, and examples of the thermoplastic resin in the bonding sheet include acrylic resin, natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylate copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin such as 6-nylon or 6,6-nylon, phenoxy resin, saturated polyester resin such as polyethylene terephthalate or polybutylene terephthalate, polyamide imide resin, and fluororesin. The adhesive sheet may contain one thermoplastic resin or two or more thermoplastic resins. Acrylic resin has fewer ionic impurities and higher heat resistance, so it is preferably used as the thermoplastic resin in the adhesive sheet. The content ratio of the thermoplastic resin in the adhesive sheet is, for example, 1 to 50 mass %.

When the connecting sheet includes an acrylic resin as the thermoplastic resin, the acrylic resin preferably includes the largest amount of monomer units derived from (meth)acrylate in terms of mass ratio. "(Meth)acrylic" means "acrylic acid" and/or "methacrylic acid".

As the (meth)acrylate used as the monomer unit for forming the above-mentioned acrylic polymer, that is, as the (meth)acrylate as the constituent monomer of the acrylic polymer, for example, alkyl (meth)acrylate, cycloalkyl (meth)acrylate, and aryl (meth)acrylate can be listed. As the alkyl (meth)acrylate, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, and eicosyl (meth)acrylate can be listed. As the cycloalkyl (meth)acrylate, for example, cyclopentyl (meth)acrylate and cyclohexyl (meth)acrylate can be listed. Examples of the (meth)acrylic acid aryl ester include phenyl (meth)acrylate and benzyl (meth)acrylate. As the monomer constituting the acrylic polymer, one (meth)acrylate may be used, or two or more (meth)acrylates may be used. The acrylic polymer used to form the acrylic resin may be obtained by polymerizing the raw material monomers used to form the acrylic polymer. Examples of the polymerization method include solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization.

The acrylic polymers mentioned above may also contain one or more other monomers copolymerizable with (meth)acrylate as constituent monomers, for example, in order to improve their cohesive force or heat resistance. Examples of such monomers include carboxyl-containing monomers, acid anhydride monomers, hydroxyl-containing monomers, sulfonic acid-containing monomers, phosphoric acid-containing monomers, acrylamide, and acrylonitrile. Examples of carboxyl-containing monomers include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of acid anhydride monomers include maleic anhydride and itaconic anhydride. Examples of monomers containing a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. Examples of monomers containing a sulfonic acid group include styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, and (meth)acryloyloxynaphthalenesulfonic acid. Examples of monomers containing a phosphate group include 2-hydroxyethylacryloyl phosphate.

In the present embodiment, the thickness of the bonding sheet 10 at 23° C. is preferably 1 μm or more, more preferably 5 μm or more, and is preferably 100 μm or less, more preferably 50 μm or less.

In the present semiconductor device manufacturing method, as shown in FIG. 2(a) and FIG. 2(b), the bonding object portion 21 attached with the bonding material layer 11 is pre-fixed to the substrate S by pressing the bonding material layer 11 (pre-fixing step). In the present embodiment, the substrate S is a circuit substrate for a micro LED module having wiring (not shown) including an electrode pad on the surface. In this step, the bonding object portion 21 on the side of the semiconductor element module 20 is pre-fixed to the substrate S and its electrode pad via the bonding material layer 11. In this step, the temperature condition for pre-fixing is, for example, in the range of room temperature to 300°C, the pressing load is, for example, 0.01 to 50 MPa, and the bonding time is, for example, 0.01 to 300 seconds.

Next, as shown in FIG. 2( c ), the bonding material layer 11 interposed between the pre-fixed bonding target portion 21 and the substrate S is subjected to a heating process to form a bonding layer 12 , and the bonding target portion 21 is bonded to the substrate S (bonding step).

When the bonding sheet 10 is the above-mentioned sintering bonding sheet, in the bonding step, specifically, by undergoing a specific high-temperature heating process, the low molecular binder in the bonding material layer 11 (sintering bonding material layer) is volatilized, the high molecular binder is thermally decomposed and volatilized, and the conductive metal of the sintering particles is sintered. In this way, a sintering layer is formed as a bonding layer 12 between the substrate S and each bonding object 21, and the bonding object 21 is electrically connected to the substrate S side and bonded to the substrate S.

When the bonding sheet 10 is the above-mentioned bonding sheet, in the bonding step, a conductive adhesive layer is formed between the substrate S and the bonding target portion 21 as a bonding layer 12 by undergoing a specific heating process. In the bonding layer 12 formed when the bonding sheet 10 is a bonding sheet, a conductive path can be formed by sintering bonding between conductive particles, a conductive path can be formed by simple contact between conductive particles, or conductive particles can be placed in close proximity to each other so that electricity can be conducted through a tunneling effect to form a conductive path. A conductive adhesive layer is formed between the substrate S and each bonding target portion 21 as a bonding layer, and the bonding target portion 21 is electrically connected to the substrate S side and bonded to the substrate S.

In this step, the temperature condition for bonding is, for example, in the range of 150 to 400°C, preferably in the range of 250 to 350°C. The bonding pressure is, for example, less than 60 MPa, preferably less than 40 MPa. In addition, the bonding time is, for example, 0.3 to 300 minutes, preferably 0.5 to 240 minutes. For example, within the range of these conditions, the temperature distribution and pressure distribution for implementing the bonding step are appropriately set. The above bonding step can be implemented using a device that can perform heating and pressurization at the same time. As such a device, for example, a flip chip bonder and a parallel plate press can be listed. Furthermore, from the viewpoint of preventing oxidation of the metal involved in bonding, this step is preferably performed under a nitrogen atmosphere, under reduced pressure, or under a reducing gas atmosphere.

The semiconductor element module 20 and the substrate S can be assembled in the above manner to manufacture a semiconductor device having a portion joined using a joining material containing sinterable particles.

In the transfer step described above with reference to FIG. 1( b) and FIG. 1( c), the bonding sheet 10 (bonding material) side of the sheet body X is attached to the bonding target portion 21 of the semiconductor element module 20 or the semiconductor element contained therein, and the portion of the bonding sheet 10 that has been pressed against the bonding target portion 21 is retained on the bonding target portion 21 and the other portions are accompanied by the substrate B to perform the peeling of the substrate B. This configuration is suitable for efficiently supplying bonding material to each of a plurality of bonding target portions 21 at one time.

In addition, in the transfer step described above with reference to FIG. 1(b) and FIG. 1(c), the portion of the bonding sheet 10 (bonding material) that has been pressed onto the bonding target portion 21 is retained on the bonding target portion 21 and transferred. This supply method utilizing the pressing action of the bonding material on the bonding target portion 21 is suitable for accurately supplying the bonding material to the bonding target portion 21. This method makes it easy to accurately supply the bonding material to the bonding target portion 21 even if the bonding target portion 21 is a micro area.

As described above, the semiconductor device manufacturing method of this embodiment is suitable for efficiently and accurately supplying the bonding material to the tiny bonding target portion 21. This method suitable for accurately supplying the bonding material to the bonding target portion 21 is suitable for preventing and suppressing the bonding material from overflowing from the bonding target objects or the overflowing bonding material from spreading. Therefore, this method is suitable for manufacturing semiconductor devices with bonding parts with good yield.

10: Bonding sheet 11: Bonding material layer 12: Bonding layer 20: Semiconductor element module 21: Bonding object B: Substrate D: Separation distance (distance in the same direction as the arrangement pitch) L: Length (length in the same direction as the arrangement pitch) P: Arrangement pitch S: Substrate X: Sheet body

Figure 1(a)-(c) shows a part of the steps in a method for manufacturing a semiconductor device in an embodiment of the present invention. Figure 2(a)-(c) shows the steps after the steps shown in Figure 1.

10: Sheet for joining

11: Bonding material layer

20:Semiconductor component module

21: Joining object part

B: Base material

D: Separation distance (distance in the same direction as the arrangement spacing)

L: Length (length in the same direction as the arrangement spacing)

P: Arrangement spacing

X: Sheet body

Claims (2)

A method for manufacturing a semiconductor device comprises the following steps: a transfer step, wherein a side of a sheet body having a laminated structure including a sheet containing sinterable particles and a substrate is bonded to a semiconductor element having at least two separated bonding target portions or at least two bonding target portions in a semiconductor element module, and then the portion of the sheet that has been pressed to the bonding target portion is retained as a bonding material layer on the bonding target portion and the other portion is attached to the substrate to transfer the substrate to the substrate. The step of peeling off the bonding object part attached with the bonding material layer is pre-fixed on the substrate through the bonding material layer; and the bonding material layer interposed between the pre-fixed bonding object part and the substrate undergoes a heating process to form a bonding layer, and the bonding object part is bonded to the substrate; in the separation direction of adjacent bonding object parts, the ratio of the length of each bonding object part to the arrangement pitch of the bonding object parts is 0.01~0.7, and the length of the adjacent bonding object parts in the separation direction is 1~50μm. A method for manufacturing a semiconductor device as claimed in claim 1, wherein the separation distance between adjacent bonding objects is 1 to 500 μm.