JP2005005730A - Circuit device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that when an electrode or wiring is patterned as an insulating resin sheet onto both sides of an insulating resin in a semiconductor device that adopts, as a support substrate, a flexible sheet having a conductive pattern, mounts a semiconductor element onto it, and molds the whole, if the warp of this insulating resin sheet is noticeable, work efficiency is lowered, warping of a package is caused, etc. <P>SOLUTION: The front surface of an insulating resin 2 is so formed that a first conductive film 3 is formed all over its surface or that it is patterned onto it. However, the rear surface of the insulating resin is so formed that a second conductive film 4 formed thicker than the first conductive film 3 is formed. Thus, the fact that the rear surface of the insulating resin sheet 1 has the thickly formed second conductive film 4 can prevent the warp from being caused by a difference in the expansion coefficient. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

    The present invention relates to an insulating resin sheet and a method for manufacturing a semiconductor device, for example, a semiconductor that improves the workability of an insulating resin sheet having electrodes formed on at least the surface and seals semiconductor elements using the insulating resin sheet as a supporting substrate. The present invention relates to a device manufacturing method.

  In recent years, IC packages have been increasingly adopted for portable devices and small / high-density mounting devices, and the mounting concept of conventional IC packages is about to change significantly (Patent Document 1). This is a technology related to a semiconductor device that employs a polyimide resin sheet, which is a flexible sheet, as an example of an insulating resin sheet.

  14 to 16 employ a flexible sheet 50 as an interposer substrate. In addition, the drawing shown above each figure is a top view, and the drawing shown below is sectional drawing of an AA line.

  First, on the flexible sheet 50 shown in FIG. 14, a copper foil pattern 51 is prepared by being bonded via an adhesive. The copper foil pattern 51 differs in pattern depending on the semiconductor element to be mounted depending on the transistor and IC, but generally, a bonding pad 51A and an island 51B are formed. Reference numeral 52 denotes an opening for taking out an electrode from the back surface of the flexible sheet 50, and the copper foil pattern 51 is exposed.

  Subsequently, the flexible sheet 50 is conveyed to a die bonder, and a semiconductor element 53 is mounted as shown in FIG. Thereafter, the flexible sheet 50 is conveyed to a wire bonder, and the bonding pads 51A and the pads of the semiconductor element 53 are electrically connected by the fine metal wires 54.

  Finally, as shown in FIG. 16, a sealing resin 55 is provided on the surface of the flexible sheet 50 and sealed. Here, transfer molding is performed so as to cover the bonding pad 51A, the island 51B, the semiconductor element 53, and the fine metal wire 54. Thereafter, as shown in FIG. 16B, connecting means 56 such as solder or solder balls is provided, and a spherical solder 56 fused with the bonding pad 51A is formed through the opening 52 by passing through a solder reflow furnace. The Moreover, since the semiconductor elements 53 are formed in a matrix on the flexible sheet 50, they are diced and separated individually as shown in FIG.

In the cross-sectional view shown in FIG. 16C, 51 </ b> A and 51 </ b> D are formed as electrodes on both surfaces of the flexible sheet 50. In general, the flexible sheet 50 is supplied from a manufacturer with both sides patterned.
JP 2000-133678 A

  FIG. 17 shows a case where the flexible sheet 50 is transported and mounted on a part called a stage or a table in the above-described manufacturing apparatus such as a die bonder, a wire bonder, a transfer molding apparatus, a reflow furnace, or the like.

  However, the thickness of the insulating resin serving as the base of the flexible sheet 50 is as thin as about 50 μm, and the thickness of the copper foil pattern 51 formed on the surface is as thin as 9 to 35 μm. However, there was a disadvantage that the mounting property to the stage or table was poor. This may be due to warping due to the fact that the insulating resin itself is very thin, and warping due to the difference in thermal expansion coefficient between the copper foil pattern 51 and the insulating resin. In particular, when a hard insulating material is warped as shown in FIG. 18, there is a problem that it is easily broken by pressurization from above.

  In addition, since the portion of the opening 52 is pressed from above during molding, a force that warps the periphery of the bonding pad 51A upwards acts, which may deteriorate the adhesion of the bonding pad 51A.

  Further, the resin material constituting the flexible sheet 50 does not have flexibility or becomes hard when a filler is mixed in order to improve thermal conductivity. If bonding is performed with a wire bonder in this state, cracks may occur in the bonding portion. Also, in the case of transfer molding, a crack may occur at a portion where the mold abuts. This appears more prominently when there is a warp as shown in FIG.

  In the flexible sheet 50 described so far, no electrode is formed on the back surface, but as shown in FIG. 16C, the electrode 51D may be formed on the back surface of the flexible sheet 50 in some cases. At this time, since the electrode 51D is in contact with the manufacturing apparatus or in contact with the transport surface of the transport means between the manufacturing apparatuses, there is a problem in that the back surface of the electrode 51D is damaged. Since the electrode is formed with this damage, the electrode 51D itself has a problem of cracking due to heat applied later.

  Further, when the electrode 51D is provided on the back surface of the flexible sheet 50, there arises a problem that the surface cannot be brought into contact with the stage during transfer molding. In this case, as described above, when the flexible sheet 50 is made of a hard material, the electrode 51D serves as a fulcrum, and the periphery of the electrode 51D is pressed downward.

  The present invention has been made in view of the above problems. First, a first conductive film formed on the front surface and a second conductive film formed on the substantially entire back surface and formed thicker than the first conductive film. The problem is solved by an insulating resin sheet comprising a conductive film and a sheet-like insulating resin provided between the first conductive film and the second conductive film.

  Even if the first conductive film is substantially entirely covered with the first conductive film or patterned, the second conductive film is formed thick, so that the insulating resin sheet against the warp It becomes stronger and the transportability can be improved.

  Second, the first conductive film is 35 μm or less, the second conductive film is 70 μm or more, and the insulating resin is 100 μm or less.

  The thickness of the insulating resin is desired to be as thin as possible in order to reduce the thickness of the entire package. However, since the second conductive film is formed to be 70 μm or thicker than the first conductive film, warpage can be prevented.

  Thirdly, the insulating resin is solved by using a polyimide resin or an epoxy resin as a main component.

  Fourth, the first conductive film is provided over substantially the entire patterning region, and the second conductive film is formed over at least the entire surface corresponding to the sealing region of the lower mold. Is.

  Regardless of whether the insulating resin itself is hard or hardened by mixing a filler, an insulating resin sheet whose both surfaces are covered with a conductive film is obtained. Therefore, the crack which generate | occur | produces between supplying from a manufacturer and mounting in a manufacturing apparatus can be suppressed.

  Fifth, the first conductive film is patterned to be electrically connected to a semiconductor element, and the second conductive film is formed on the entire surface corresponding to at least the sealing region of the lower mold. It will be solved by.

  Since this insulating resin sheet is formed with a thick conductive film over the entire back surface, it can be used as a support substrate for chip die bonding, wire bonder, and semiconductor element sealing. In addition, when the insulating resin material itself is soft, it is difficult to transfer the energy at the time of wire bonding to the fine metal wire, but since the conductive film is formed on the back surface, the propagation of energy can be improved and the wire bonding property can be improved.

Sixth, a first conductive film formed on the front surface, a second conductive film provided on substantially the entire back surface and formed thicker than the first conductive film, and the first conductive film, Preparing an insulating resin sheet having a sheet-like insulating resin provided between the second conductive film,
Processing the first conductive film into a first electrode or / and a first wiring;
Fixing a semiconductor element electrically connected to the first electrode or / and the first wiring;
Transporting the insulating resin sheet to a sealing mold, contacting the second conductive film to the mold, and sealing the semiconductor element;
The problem is solved by patterning the second conductive film to form a second electrode or / and a second wiring electrically connected to the first electrode or / and the first wiring. .

  Since the conductive film is formed thick, the flatness of the insulating resin sheet can be maintained, and the surface can be brought into contact with the lower mold of the transfer mold apparatus, so that local pressurization is eliminated and cracking can be suppressed. Similarly, the energy applied at the time of the wire bonder is easily attached to the fine metal wire by adopting the second conductive film.

  Seventhly, the insulating resin sheet is solved by preparing the first conductive film in a state of being processed into the first electrode and / or the first wiring.

  Eighth, the second conductive film is made 70 μm or more, the transportability of the insulating resin sheet is improved, and the handleability is improved in the manufacturing process.

  Ninth, after the sealing, the second conductive film is thinned to form the second electrode or / and the second wiring.

  By thinning the second conductive film, the second electrode and / or the second wiring can be made into a fine pattern. In addition, since the back surface of the second conductive film can be thinned by etching or polishing / grinding, the damaged portion received in each manufacturing process can be removed. In particular, when thinning is performed in the polishing / grinding process, damage in this process may occur. At this time, light etching may be performed again.

Tenth, there is an insulating resin sheet having a first conductive film formed on the front surface and a second conductive film formed on the substantially entire back surface, and an insulating resin is provided between them.
Insulating at least one third wiring or / and third electrode provided between the first conductive film and the second conductive film from the third wiring or / third electrode. Having at least two layers of insulating resin, and the second conductive film is formed to be thicker than the first conductive film.
In Claims 1 to 9, the insulating resin sheet is provided with electrodes on the front and back sides. However, the claim 10 is generally provided with electrodes and wiring between the front and back electrodes. Is called a multilayer substrate.

  Also in this case, since the second conductive film is formed thick, the insulating resin sheet is strong against the warp, and the transportability can be improved.

  Eleventh, the first conductive film is 35 μm or less, the second conductive film is 70 μm or more, and the insulating resin is 100 μm or less.

  Twelfth, the insulating resin is solved by using a polyimide resin or an epoxy resin as a main component.

  Thirteenth, the first conductive film is provided over substantially the entire patterning region, and the second conductive film is formed at least in a portion corresponding to the sealing region of the lower mold. Is.

  Fourteenth, the first conductive film is patterned to be electrically connected to a semiconductor element, and the second conductive film is formed at least in a portion corresponding to the sealing region of the lower mold. It will be solved by.

  Fifteenth, the problem is solved by mixing a filler in the insulating resin.

  Generally, when a filler is mixed, rigidity is increased and cracks are easily generated. However, the formation of the conductive film on both surfaces makes it difficult for cracks to occur. Further, if the second conductive film is formed thick on the back surface, the flatness of the insulating resin sheet itself is increased, and the generation of cracks can be prevented.

Sixteenth, a first conductive film formed on the front surface and a second conductive film formed on the substantially entire back surface, and an insulating resin is provided between the first conductive film and the first conductive film At least one layer of third wiring or / and third electrode provided between the second conductive film and at least two layers of insulating resin for insulating the third wiring or / and third electrode And preparing an insulating resin sheet in which the second conductive film is thicker than the first conductive film,
The first conductive film is processed into a first electrode or / and a first wiring, and the first electrode or / and the first wiring and the second conductive film are electrically connected. Forming part,
Fixing a semiconductor element electrically connected to the first electrode or / and the first wiring;
Transporting the insulating resin sheet to a sealing mold, contacting the second conductive film to the mold, and sealing the semiconductor element;
The problem is solved by patterning the second conductive film to form a second electrode or / and a second wiring electrically connected to the first electrode or / and the first wiring. .

  Since the conductive film is formed thick, the flatness of the insulating resin sheet can be maintained, and the surface can be brought into contact with the lower mold of the transfer mold apparatus, so that local pressurization is eliminated and cracking can be suppressed. Similarly, the energy applied at the time of the wire bonder is easily attached to the fine metal wire by adopting the second conductive film.

  Seventeenth, the insulating resin sheet is solved by preparing the first conductive film in a state of being processed into the first electrode and / or the first wiring.

  Eighteenth, by making the second conductive film 70 μm or more, improving the transportability of the insulating resin sheet, and maintaining the flatness of the insulating resin sheet, the manufacturing process can be simplified and the yield factory can be realized. It is.

  Nineteenth, after the sealing, the second conductive film is thinned to form the second electrode or / and the second wiring.

  As described above, since the second conductive film is formed thick, it becomes strong against warping as an insulating resin sheet, and transportability can be improved.

  Moreover, even if the insulating resin itself is hard or hardened by mixing a filler, it becomes an insulating resin sheet whose both surfaces are covered with a conductive film. Therefore, the crack which generate | occur | produces between supplying from a manufacturer and mounting in a manufacturing apparatus can be suppressed.

  In addition, since the insulating resin sheet is formed with a thick conductive film over the entire back surface, the insulating resin sheet can be used as a support substrate for chip die bonding, wire bonder, and semiconductor element sealing. In addition, when the insulating resin material itself is soft, it is difficult to transfer the energy at the time of wire bonding to the fine metal wire, but since the conductive film is formed on the back surface, the propagation of energy can be improved and the wire bonding property can be improved.

  Furthermore, by thinning the second conductive film, the second electrode and / or the second wiring can be made into a fine pattern. In addition, since the back surface of the second conductive film can be thinned by etching or polishing / grinding, the damaged portion received in each manufacturing process can be removed.

  Finally, when a filler is mixed into the insulating resin, the rigidity is increased and cracks are likely to occur. However, the formation of the conductive film on both surfaces makes it difficult for cracks to occur. Further, if the second conductive film is formed thick on the back surface, the flatness of the insulating resin sheet itself is enhanced, and the generation of cracks can be further prevented.

First Embodiment Explaining Insulating Resin Sheet First, an insulating resin sheet will be described with reference to FIG. 1 and FIG. In both figures, conductive films are formed on the front and back.

  1A is an insulating resin sheet 1 as a whole, and an insulating resin 2 is provided in the middle. A first conductive film 3 is formed on the surface of the insulating resin 2, and a second conductive film 4 is formed on the back surface. The first conductive film 3 is formed over the entire surface of the insulating resin 2, and the bonding pad 5, the island 6, and the opening 7 indicated by dotted lines are formed by a subsequent process.

  That is, the surface of the insulating resin sheet 1 is formed with the first conductive film 3 over substantially the entire area, and the second conductive film 4 is formed over the entire area of the back surface. The material of the insulating resin 2 is an insulating material made of a polymer such as polyimide resin or epoxy resin. The first conductive film 3 and the second conductive film 4 are preferably made of Cu as a main material or a known lead frame material, and the insulating resin 2 is formed by a plating method, a vapor deposition method or a sputtering method. Or a metal foil formed by a rolling method or a plating method may be attached. When sticking, since the glue is used, the overall thickness increases.

  The insulating resin sheet 1 may be formed by a casting method. The manufacturing method will be briefly described below. First, paste-like polyimide is applied on the flat film-like first conductive film, and paste-like polyimide is also applied on the flat film-like second conductive film. When both polyimides are semi-cured and then bonded together, an insulating resin sheet is completed.

  Further, the first conductive film 3 may not be the entire region of the insulating resin sheet 1. This is shown in FIG. 1B. Three patterns are formed here. The left pattern shows the pattern processing region 8B and the sealing resin injection hole, that is, the gate 9. The central pattern indicates the contact area 10 between the upper mold and the insulating resin sheet 1. Here, when the upper mold is in contact with the first conductive film 3, the insulating resin 3 is not defective or cracked. Therefore, the 1st electrically conductive film 3 may be formed in the resin sealing area | region including a pattern process area | region or a contact area | region at least, and you may supply as the insulating resin sheet 1. FIG. The resin sealing region 8A is shown by the right pattern. In the present embodiment, the lower mold and the insulating resin sheet 1 are in contact with each other over the entire surface. Therefore, the second conductive film 4 is formed on the entire surface so that defects such as cracks do not occur in the insulating resin 2. However, as shown on the right side of FIG. 1B, the second conductive film 4 may be formed in the resin sealing region including the contact region and supplied as the insulating resin sheet 1.

  In any case, the first conductive film 3 is etched in a later process to form a pattern as shown in FIG. 2, and is completed as a semiconductor device through element mounting, electrical connection, and sealing processes. Reference numeral 11 denotes a guide hole.

Second Embodiment Explaining Insulating Resin Sheet FIG. 2 is an insulating resin sheet 1 as a whole, and a second conductive film 4 is entirely formed on the back surface of the insulating resin 2 as in the first embodiment. Is formed. However, the first conductive film is patterned in advance to form the bonding pad 5, the island 6, and the opening 7, and is supplied as the insulating resin sheet 1. The bonding pad 5 and the second conductive film 4 are electrically connected.

  The material of the insulating resin 2 is an insulating material made of a polymer such as polyimide resin or epoxy resin. The first conductive film 3 and the second conductive film 4 are preferably made of Cu as a main material, or a known lead frame material or the like, and the insulating resin 2 is formed by a plating method, a vapor deposition method or a sputtering method. Or a metal foil formed by a rolling method or a plating method may be attached. When sticking, since the glue is used, the overall thickness increases.

  An example of a specific insulating resin sheet 1 is shown in FIG. 1B. Three patterns are formed here. The pattern on the left shows a pattern processing area 8A and a gate 9. The central pattern shows the contact area 10 between the upper mold and the insulating resin sheet 1, the bonding pad 5, and the island 6. In other words, the first conductive film only needs to be formed by etching at least the first electrode and / or the first wiring as in the central pattern. As described above, the upper mold does not give defects or cracks to the insulating resin 3 when it is in contact with the first conductive film 3. Therefore, it is better that this contact area is also patterned. The second conductive film is formed on the entire surface of the insulating resin sheet 1 as in the first embodiment, but at least the resin sealing region or at least the contact region 10 as in the right pattern. You may form in the area | region included. Since the sealing region 8 is where an external force is applied during die bonding, wire bonding, and transfer molding, it is preferable that the second conductive film 4 be formed in a region including at least this portion.

  In this state, it is supplied from the manufacturer of the flexible sheet, and is completed as a semiconductor device through element mounting, electrical connection, and sealing processes.

  The feature of the present invention in both the first embodiment and the second embodiment is that the second conductive film 4 is formed thicker than the first conductive film 3.

  That is, by forming the second conductive film 4 thick, the flatness of the insulating resin sheet 1 can be maintained, the workability of the subsequent process is improved, and the induction of defects, cracks, etc. in the insulating resin 2 is prevented. Can do. Furthermore, the second conductive film 4 is damaged due to various processes. However, since the patterning is performed after the entire surface of the thick second conductive film 4 is thinned, this scratch can be removed. Further, since the sealing resin can be cured while maintaining flatness, the back surface of the package can be flattened, and the electrode formed on the back surface of the insulating resin sheet 1 can also be flatly arranged. Therefore, the electrode on the mounting substrate and the electrode on the back surface of the insulating resin sheet can be brought into contact with each other, and defective solder can be prevented. Furthermore, if the second conductive film 4 is thinned and then patterned, the etching can be reduced again, and a fine pattern becomes possible.

  Specifically, the thickness of the first conductive film 3 is preferably about 5 to 35 μm. This is because the first bonding pad 5 and the island 6 are formed by etching. Here, the bonding pads 5 and the islands 6 are shown, but as the number of IC pads increases, it is necessary to form them with a fine pattern. In addition, when a plurality of semiconductor elements are mounted in a planar manner, considering the case where a hybrid IC is configured by combining semiconductor elements and passive elements, wiring is required in addition to islands and bonding pads. An example of this is indicated by reference numeral 12 in FIGS. That is, at least one of electrodes or wirings is selected, and a conductive pattern is formed. Therefore, the denser the conductive pattern, the more necessary the fine pattern. However, when etching is performed until the insulating resin is completely exposed, side etching proceeds in the lateral direction regardless of whether it is anisotropic or isotropic. This is more conspicuous as the film thickness is larger, and as the film thickness is thinner, side etching is suppressed and a fine pattern becomes possible.

  In all the embodiments, the insulating resin 2 is preferably a polyimide resin, an epoxy resin, or the like. In the case of a casting method in which a paste is applied to form a sheet, the film thickness is about 10 μm to 100 μm. When formed as a sheet, a commercially available product has a minimum film thickness of 25 μm. In consideration of thermal conductivity, a filler may be mixed therein. As the material, glass, Si oxide, aluminum oxide, Al nitride, Si carbide, boron nitride or the like can be considered.

  The film thickness of the second conductive film 4 is preferably about 70 μm to 200 μm. Preferably, about 70-125 micrometers is good. If it is this thickness, even if the 1st electrically conductive film 3 is about 5-35 micrometers, flatness can be maintained.

  Thus, if the film thickness of the 2nd electrically conductive film 4 is formed thicker than the 1st electrically conductive film 3, the flatness of the insulating resin sheet 1 can be maintained.

  In particular, there is an advantage when an insulating resin sheet is arranged on the table of the die bonding apparatus, the table of the wire bonding apparatus, and the stage of the transfer molding apparatus.

The merits are described below.
First, the advantages of die bonding are described. For example, the back surface of a Si semiconductor element is generally coated with Au, and is fixed to Au formed on the surface of the island 6. At this time, it is heated to about 400 ° C. and pressurized. Then, the Au on the back surface of the chip and the island Au are fused, and simultaneously, an eutectic of Au and Si is formed. At this time, if the second conductive film 4 is thin, warping may occur due to this heat, and cracks may be formed in the electrodes, islands, or wirings formed on the surface of the insulating resin. However, since the second conductive film 4 itself is thick, warping can be suppressed and this crack can also be prevented. In addition, if the second conductive film 4 is thick, the function as a heat sink is enhanced. That is, since the second conductive film 4 absorbs the heat applied to the insulating resin 2, the deterioration of the insulating resin itself can be prevented. Furthermore, if the die bonding table is made of metal or the like, the heat is released to the outside. Is also possible.

  Next, the advantages of wire bond ink will be described. In general, at the time of wire bonding of Au wire, it is heated to 250 ° C. to 300 ° C. At this time, if the second conductive film is thin, the insulating resin sheet 1 warps, and the insulating resin sheet is pressurized through the bonding head in this state. Therefore, cracks may occur. This appears more prominently when the filler is mixed into the insulating resin, since the material itself becomes stiff and loses flexibility. In addition, since resin is softer than metal, it is difficult to transmit pressure or ultrasonic energy when bonding Au or Al. However, these problems can be solved by forming the second conductive film 4 to be thick.

  Finally, the advantages of transfer molding are described. For example, as shown in FIG. 5, after sealing with insulating resin, the resin is cooled. At this time, due to the difference in thermal expansion coefficient between the insulating resin and the conductive film, a difference in shrinkage ratio is generated, and the entire semiconductor device warps. However, since the second conductive film 4 itself is formed thick, the flatness of the entire package can be maintained until the temperature completely returns to room temperature. In particular, the electrodes formed on the back surface of the insulating resin sheet 1 cannot be positioned in the same plane due to warping. If it is placed on the mounting substrate in this state, a gap is generated between the electrode on the mounting substrate and the electrode on the back surface of the semiconductor device, resulting in a solder failure or the like. In the present invention, since the second conductive film 4 is formed thick, these problems can be prevented.

  Further, the second conductive film 4 is brought into contact with the above-described table or stage, or is rubbed by a transport device. Therefore, many scratches occur. However, when the second conductive film 4 is used as an electrode, and when a fine pattern is formed, the entire second conductive film 4 is etched, polished or ground to 35 μm or less to make the second conductive film 4 thin. Especially in the case of etching, this damage can be removed. Further, when polishing and grinding are performed, scratches are caused by this process, but thereafter, they can be removed by performing light etching.

  As described above, by making the second conductive film 4 thicker than the first conductive film, various merits as an insulating resin sheet are born, and even in a semiconductor device employing this insulating resin sheet. Generates excellent effects.

  Although not described as an embodiment, at least one conductive film may be provided between the first conductive film 3 and the second conductive film in FIG. 1 or FIG. This is generally called a multilayer substrate. In this case, the insulating resin has at least two layers. Currently, flexible sheets on which four-layer and five-layer metal wirings are formed are commercialized. Therefore, the through hole formation method and the like are omitted. Even in this case, the above-described merit is generated by forming a thick conductive film on the back surface.

Third Embodiment Explaining Method for Manufacturing Semiconductor Device Using Insulating Resin Sheet A method for manufacturing a semiconductor device using insulating resin sheet 1 will be described with reference to FIGS. . In addition, the figure shown by (A) is a top view, The figure shown by (B) is sectional drawing in the AA line.

  First, an insulating resin sheet 1 is prepared as shown in FIG. A second conductive film 4 is formed on the entire back surface of the insulating resin sheet 1 and a first conductive film 3 is formed on the entire surface.

  Subsequently, a photoresist from which only a portion corresponding to the opening 7 is removed is formed on the entire surface. Then, the first conductive film 3 is etched through this photoresist. The first conductive film 3 and the second conductive film 4 are both made mainly of Cu. Therefore, the etching solution is ferric chloride or cupric chloride. The opening diameter of the opening varies depending on the resolution of photolithography, but is about 50 μm here. In the etching, the second conductive film 4 is preferably covered with an adhesive sheet or the like. However, if the second conductive film 4 itself is sufficiently thick and has a film thickness that can maintain flatness even after etching, it is not covered with a sheet.

The conductive film may be Al, Fe, Fe-Ni, a known lead frame material, or the like. However, it is important that the second conductive film 4 has a thickness that can maintain flatness until it is sealed with resin and thermally cured. In consideration of workability, guide holes are provided on both sides of the insulating resin sheet. (See Figure 3 above)
Subsequently, after removing the photoresist, using the first conductive film 3 as a mask, the insulating resin 2 just below the opening 7 is removed by laser to expose the second conductive film 4 at the bottom of the opening 7. . As the laser, a carbon dioxide laser is preferable. In addition, after the insulating resin is evaporated by the laser, if there is a residue at the bottom of the opening, the residue is removed by wet etching with sodium permanganate or ammonium persulfate.

  Subsequently, plating is performed so that the second conductive film 4 and the first conductive film 3 are electrically connected through the opening 7. In general, both electroless plating and electrolytic plating are performed. Here, about 2 μm of Cu is formed at least on the entire surface of the opening by electroless plating. As a result, the first conductive film 3 and the second conductive film 4 are electrically connected, so electrolytic plating is performed again using the conductive films 3 and 4 as electrodes, and about 20 μm of Cu is plated. Thereby, the opening part 7 is embedded with Cu. In addition, when a plating solution called Ebara Eugelite is used as a trade name, it is possible to selectively embed only the opening. The plating film is Cu here, but Au, Ag, Pd or the like may be used. Alternatively, partial plating may be performed using a mask. In FIG. 4, the electroless plating film and the electrolytic plating film are illustrated integrally and denoted by reference numeral 13.

  In consideration of bonding properties and solderability, a film of Au, Ag, or the like is formed on the bonding pad 5 and the island 6.

  Subsequently, a photoresist is formed on the first conductive film 3 and patterned so that the photoresist remains on the bonding pad 5, the island 6, and the mold contact region 10. When the wiring 12 is formed as shown in FIGS. 12 and 13, a photoresist is also formed on the wiring. Then, using the photoresist as an etching mask, the first conductive film 3 is patterned to form the bonding pad 5, the island 6, and the contact region 10.

  Subsequently, the insulating resin sheet is conveyed and mounted on the table of the die bonding apparatus. Since the second conductive film 4 is formed thick, it is in contact with the table in a substantial surface. Here, the table becomes approximately 400 ° C., and the semiconductor element 14 and the island 6 are fixed. For example, if Au is formed on the surface of the island 6 and Au is formed on the back surface of the semiconductor element 14, eutectic bonding is possible at this temperature. Further, when Ag is formed on the island 6, generally, a brazing material such as solder is adopted and fixed.

  In this step, since heat of 400 ° C. is applied to the insulating resin sheet 1, warping may occur in a general insulating resin sheet. This phenomenon causes deterioration of the insulating resin and deterioration of die bonding properties. However, since the second conductive film 4 is thick, the warp can be prevented. Further, since the second conductive film is thick, it acts as a heat sink and can prevent deterioration of the insulating resin. Here, the semiconductor element may be mounted face-down. In this case, solder balls and bumps are provided on the surface of the semiconductor element. Electrodes are provided on the surface of the insulating resin sheet 1 at portions corresponding to the positions of the solder balls, and both are fixed. Further, although the island 6 is omitted, it may be left as an electrode for heat dissipation while being insulated from the semiconductor element.

  Subsequently, the insulating resin sheet 1 is transferred to a wire bonder and installed on the bonder table. Also at this time, since the second conductive film 4 is thick, the table and the insulating resin sheet 1 are substantially in contact with each other. When Au is adopted as the thin metal wire 15, it is heated to 250 ° C. to 300 ° C. In connection using Al wire, ultrasonic waves are applied at room temperature.

Also at this time, since the occurrence of warpage is suppressed in the insulating resin sheet 1, cracks due to impact during bonding can be suppressed. When the Au and Al fine metal wires 15 are employed, Au or Ag is formed on the surface of the bonding pad 5 on the outermost surface. (See Figure 4 above)
Subsequently, the insulating resin sheet 1 is conveyed to the molding apparatus and mounted on the stage. As a molding method, transfer molding, injection molding, coating, dipping and the like are also possible. However, when considering mass productivity, transfer molds and injection molds are suitable. In this case, it is mounted on the transfer mold apparatus 100 shown in FIG. 17, and the sealing resin 16 is melted by heat and molded. In FIG. 17, 100A is a lower mold, 100B is an upper mold, and 101 is a sealing region, which is generally called a cavity. Reference numeral 102 denotes a guide pin that passes through the guide hole 11, 103 is a pot, and 104 is a runner.

  Since the lower mold corresponding to at least the resin sealing region is flat as shown in the figure, the insulating resin sheet 1 needs to be abutted flat. That is, a high-temperature molten resin 16 is injected into the cavity 101, and then cooled to room temperature and cured. However, when the mold body is taken out from the mold, the shrinkage of the sealing resin 16 is generally not completely completed. Therefore, the flatness of the package is maintained by the second conductive film 4 until the shrinkage of the sealing resin 16 is completely completed.

In particular, the second conductive film 4 is later processed as a back electrode of the semiconductor device, and the plurality of electrodes can be arranged in substantially the same plane. (See Figure 5 above)
Subsequently, the insulating resin sheet 1 is conveyed to an etching apparatus, and is first etched until the entire second conductive film 4 is thinned to 35 μm or less. As a result, the scratches generated in the second conductive film 4 until now are removed. The film thickness of the remaining second conductive film 4 depends on the density of the pattern. It may be cut by polishing or grinding. However, it is better to perform light etching in order to finally remove the scratches generated in this process. Recently, CMP (Chemical Mechanical Polishing) has been adopted for the purpose of planarizing the wafer. This method can also be adopted in the present application.

  Then, the thinned second conductive film 4 is patterned. This can also be realized by photolithography employing a photoresist. Here, as shown in FIG. 6A, the second electrode 16A is formed at a position corresponding to the bonding pad 5, the second electrode 16B is formed at the solder ball forming position, and the wiring 12 that connects them together is formed. Provided. For example, it is the same as the rewiring pattern employed in BGA or the like. Since the second conductive film 4 is formed thin, this pattern can be realized finely.

  Further, with the sealing resin 16 as a supporting substrate, the back surface of the insulating resin sheet 1 is covered with an insulating resin 18 such as a solder resist, the second electrode 16B is opened, and the solder 17 is provided. A solder ball may be placed and melted.

Finally, since one unit to be a semiconductor device is formed in a matrix shape, it is separated individually. As a method, dicing, cutting, etc. can be considered. (See Figure 6 above)
FIG. 7 is a modification of FIG. Here, all of the second conductive film 4 is removed. A solder ball 17 is fixed to the plating film 13 exposed from the insulating resin 2.

  The semiconductor device 14 shown in FIGS. 8 to 9 is mounted face-down.

  An electrode 19, a land-shaped heat radiation electrode 20, or a wiring or the like is formed on the surface of the insulating resin 2. The steps up to here are the same as those described with reference to FIG.

Then, after a pattern is formed on the surface of the insulating resin 2, the semiconductor element 14 is mounted. A connection means 21 such as a solder ball or a bump is formed on the pad of the semiconductor element 14 and is electrically connected to the first electrode 19. The heat radiation electrode 20 may be omitted. (See Figure 8 above)
Subsequently, the insulating resin sheet 1 is transferred to a transfer mold apparatus and sealed with a sealing resin 16. If the gap between the semiconductor element 14 and the insulating resin sheet 1 is very narrow and the sealing resin 16 is difficult to enter, it may be molded after penetrating the underfill 22 having a low viscosity. (See Figure 9 above)
After that, as described with reference to FIGS. 6 and 7, the second conductive film 4 is thinned, patterned, and formed with solder and the like, and then individually separated as a semiconductor device.

Fourth Embodiment Explaining Semiconductor Device Next, a semiconductor device employing the insulating resin sheet of the present invention will be described with reference to FIG. 10A is a plan view of the semiconductor device, FIG. 10B is a cross-sectional view taken along line AA, and FIG. 10C is a cross-sectional view taken along line BB.

  As can be seen from the description up to the third embodiment, the second conductive film formed on the back surface of the insulating resin sheet is also formed thick and supplied as an insulating resin sheet, and this is used as a support substrate. Utilized, the semiconductor element 14 is fixed, filled with an underfill, and a sealing resin is formed by transfer molding.

  This semiconductor element is an IC having a large number of pads of 200 pins or more and a very large number of elements. For example, in FIG. 4, the bonding pad 5 can be formed around the semiconductor element. However, when the number of pins is 200 or more, there is a limit to the size of the bonding pad, and some bonding pads cannot be arranged in a ring shape even with the minimum size.

  In FIG. 10, solder and bumps are formed on pads on a semiconductor element, and these are connected to a first electrode formed on the surface of an insulating resin.

  The first first electrode 30 is connected to the bumps of the semiconductor element 31, extends outward along the surface of the insulating resin 32 via the first wiring 33, and is connected to the first electrode 34. The The first electrode 34 is connected to a second electrode 36 provided on the back surface of the insulating resin through a via hole 35 provided in the first electrode 34.

  The second first electrode 37 is connected to the bump of the semiconductor element 31, and the second electrode formed on the back surface of the insulating resin 32 through the via hole 35 formed on the back surface of the first electrode 37. 38, and is extended inwardly through the second wiring 39 from there, and is electrically connected to the second electrode 40 there.

  Since this structure has a large number of pins, the second electrodes 36 and 40 formed on the back surface of the insulating resin 32 are dispersed by utilizing the rewirings 33 and 39. That is, 200 or more electrodes are dispersed on the back surface of the package.

  By utilizing the thick second conductive film formed on the back surface of the insulating resin sheet, which is a feature of the present invention, the back surface of the package is formed flat. This places the first electrodes 36 and 40 substantially in one plane. Therefore, even if this semiconductor device is mounted on a mounting board, it can be brought into contact with the electrodes arranged on the mounting board side, and connection defects can be eliminated.

Fifth Embodiment Explaining Semiconductor Device Next, a semiconductor device employing the insulating resin sheet of the present invention will be described with reference to FIG. 11A is a plan view of the semiconductor device, FIG. 11 is a sectional view taken along line AA, and FIG. 11C is a sectional view taken along line BB.

  The present invention omits the sealing resin 41 in the fourth embodiment. If anything, when the semiconductor element 31 is mounted on the insulating resin sheet, the sealing resin is potted from the top or only the underfill material 42 is used. In this case, since the resin shrinkage that occurs when the sealing resin is cured is eliminated, the entire warp can be suppressed.

  In addition, since it is the same as that of previous embodiment except having eliminated sealing resin, the further description is abbreviate | omitted.

6. Sixth Embodiment Explaining Semiconductor Device Next, a semiconductor device employing the insulating resin sheet of the present invention will be described with reference to FIG. 12A is a plan view of the semiconductor device, FIG. 12B is a cross-sectional view taken along line AA, and FIG. 12C is a cross-sectional view taken along line BB.

  In the present invention, at least two semiconductor elements and passive elements are mounted, and the plurality of elements are electrically connected via the first wiring and the second wiring.

  When wiring is formed on the surface of the insulating resin 32, an intersecting portion is generated. Therefore, as shown by a dotted line, the second wiring 43 is provided on the back surface of the insulating resin 32 to realize crossover.

  A feature of the present invention is that, by forming the second conductive film thickly, the flatness of the back surface of the package is improved, and at the same time, the transportability and handling properties to various manufacturing processes are facilitated.

  However, the second conductive film itself can be patterned as the second electrode and the second wiring after the film thickness is finally reduced. That is, since two-layer wiring can be realized, such a crossover can be realized.

  Although it can be applied to all the embodiments, a more complicated circuit can be realized by a pattern of three or more layers in which a copper foil pattern is further added between the first conductive film and the second conductive film.

  Here, two semiconductor elements 44 and 45 are mounted, but a so-called hybrid circuit can be realized in one package by mounting passive elements such as a chip resistor and a chip capacitor in addition to the semiconductor elements.

  These are significantly different from mounting one element. That is, the planar mounting area increases. That is, the warpage of the package, which is one theme of the present invention, becomes a serious problem. However, if the second conductive film itself is formed thick, the flatness of the second conductive film can be maintained until the sealing resin is completely contracted. Therefore, the second electrode located on the back surface of the package is arranged in one plane, so that the mounting property on the mounting substrate is improved and the yield can be improved.

Seventh Embodiment Explaining Semiconductor Device Next, a semiconductor device employing the insulating resin sheet of the present invention will be described with reference to FIG. 13A is a plan view of the semiconductor device, FIG. 13B is a sectional view taken along line AA, and FIG. 13C is a sectional view taken along line BB.

  The present invention omits the sealing resin in the sixth embodiment. If anything, after mounting the semiconductor element on the support substrate, potting the sealing resin from the top or just using the underfill material. In this case, since the resin shrinkage that occurs when the sealing resin is cured is eliminated, the entire warp can be suppressed.

  In addition, since it is the same as that of previous embodiment except having eliminated sealing resin, the further description is abbreviate | omitted.

It is a figure explaining the insulating resin sheet of this invention. It is a figure explaining the insulating resin sheet of this invention. It is a figure explaining the manufacturing method of the semiconductor device of this invention. It is a figure explaining the manufacturing method of the semiconductor device of this invention. It is a figure explaining the manufacturing method of the semiconductor device of this invention. It is a figure explaining the manufacturing method of the semiconductor device of this invention. It is a figure explaining the manufacturing method of the semiconductor device of this invention. It is a figure explaining the manufacturing method of the semiconductor device of this invention. It is a figure explaining the manufacturing method of the semiconductor device of this invention. It is a figure explaining the semiconductor device of the present invention. It is a figure explaining the semiconductor device of the present invention. It is a figure explaining the semiconductor device of the present invention. It is a figure explaining the semiconductor device of the present invention. It is a figure explaining the manufacturing method of the conventional semiconductor device. It is a figure explaining the manufacturing method of the conventional semiconductor device. It is a figure explaining the manufacturing method of the conventional semiconductor device. It is a figure explaining a transfer mold device. It is a figure explaining the conventional flexible sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating resin sheet 2 Insulating resin 3 1st electrically conductive film 4 2nd electrically conductive film 5 Bonding pad 6 Island 7 Opening part 8 Resin sealing area | region 9 Gate 10 Contact area | region 11 Guide hole 12 Wiring 13 Plating film 14 Semiconductor element 15 Metal wire 16 Sealing resin 17 Solder

Claims (7)

Insulating sheet having a first conductive film, a second conductive film thicker than the first conductive film, and an insulating layer provided between the first conductive film and the second conductive film A process of preparing
Electrically connecting the first conductive film and the second conductive film through the insulating layer;
Forming a first conductive wiring layer by etching the first conductive film;
Placing a circuit element on the first conductive wiring layer;
Forming a sealing resin so that the circuit element and the first conductive wiring layer are sealed; and forming a second conductive wiring layer by etching the second conductive film. A method of manufacturing a circuit device.   The method of manufacturing a circuit device according to claim 1, wherein the second conductive wiring layer is formed after the sealing resin is formed. The back surface of the second conductive film is formed flat,
The method of manufacturing a circuit device according to claim 1, wherein the circuit elements are arranged in a state where a back surface of the second conductive film is in contact with a table. The back surface of the second conductive film is formed flat,
2. The circuit device according to claim 1, wherein a thin metal wire that connects the circuit element and the first conductive wiring layer is formed in a state in which the back surface of the second conductive film is in contact with a table. 3. Manufacturing method. The back surface of the second conductive film is formed flat,
The method of manufacturing a circuit device according to claim 1, wherein the sealing resin is formed in a state where the back surface of the second conductive film is in contact with a table.   2. The method of manufacturing a circuit device according to claim 1, wherein the formation of the second conductive wiring layer is performed after the second conductive film is thinned. A plurality of units comprising the first conductive wiring layer and the second conductive wiring layer constituting one circuit device are formed on the resin sheet,
The method of manufacturing a circuit device according to claim 1, wherein the sealing resin located at a boundary between the units is cut into individual circuit devices by cutting.

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