JPH0936278A - Semiconductor device coated with metallic foil, its manufacture, and metallic foil material used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the separation of metallic foil materials, to improve the reliability of the materials during TCT tests, and to improve the cracking resistances of the materials at soldering time by providing adhesive layers which can be fixed temporarily to metallic cavity surfaces and are not shifted in position at molding time on one surfaces of the materials. SOLUTION: At the time of manufacturing a semiconductor device coated with metallic foil, metallic foil materials 7 are temporarily fixed to the cavity surfaces of metallic molds 1 and 2 with such adhesive forces that do not allow the materials 7 to shift in position. After a semiconductor element 4 positioned on a lead frame 5 is set to the metallic molds 1 and 2, the molds 1 and 2 are closed and a sealing resin 6 is injected into and molded and hardened in the molds 1 and 2. In order to temporarily fix the materials 7 to the cavities, adhesive layers 8 containing appropriate amounts of inorganic fillers are provided on one surfaces of the materials 7. Therefore, the temporarily fixing force of the materials 7 to and removing properties of the materials 7 from the cavity surfaces of the molds 1 and 2 after molding can be controlled and the semiconductor device can be manufactured stably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal foil material fixed to the surface of a semiconductor device obtained by sealing a semiconductor element with a resin, a semiconductor device provided with the same, and a method of manufacturing the semiconductor device.

[0002]

2. Description of the Related Art Conventionally, semiconductor elements such as transistors, ICs, and LSIs have been encapsulated with ceramics to be semiconductor devices, but resin encapsulation has become mainstream from the viewpoint of cost and mass productivity. Epoxy resin has been conventionally used for this resin encapsulation and has achieved good results. On the other hand, while technological innovation in the semiconductor field has led to an increase in the degree of integration and an increase in the size of semiconductor elements, there is a strong demand for miniaturization and thinning of semiconductor devices. However, higher reliability has been demanded for the sealing material. Particularly in recent years, with the increase in the size of semiconductor elements, there has been a demand for higher performance than before in a thermal cycle test (TCT test), which is an accelerated test for evaluating the performance of a semiconductor encapsulating resin. In addition, surface mounting is becoming the main method for mounting semiconductor devices on wiring boards.
It is required that the semiconductor device is not cracked or swollen when soldered while absorbing moisture.

To meet these demands, rubber fine particles have been conventionally added to a sealing resin or an epoxy resin has been modified with a silicone compound in order to improve heat stress resistance evaluated by a TCT test. It has been studied to reduce thermal stress. In addition, in order to improve the crack resistance during soldering, it has been studied to use a sealing resin with a small moisture absorption amount and to improve the adhesion with the lead frame, but the effect is still insufficient. It was

Therefore, the inventors of the present invention have to obtain a semiconductor device which is excellent in moisture resistance, heat stress resistance, and crack resistance during soldering and has high reliability even if the semiconductor device is made thin.
Japanese Patent Application No. 6-80158 proposes to coat the surface of a plastic package with a metal foil. As a method therefor, when molding a resin for sealing a semiconductor element using a mold, molding of the mold is performed. It proposes a method of directly fixing the metal foil material to the surface of the plastic package by temporarily fixing the metal foil material to the surface and then injecting and molding a resin. In that case, as a temporary fixing method to the die molding surface, a method of providing an adhesive layer for temporary fixing on the metal foil material surface and temporarily fixing it is proposed. Further, in Japanese Patent Application No. 7-33677, it was found that increasing the affinity between the metal foil material and the sealing material is effective in preventing peeling, and the surface of the metal foil material that comes into contact with the sealing resin during molding. Contact angle of water with water is 1
It has been proposed to use a metal foil composed of one that is 10 ° or less. Further, Japanese Patent Application Laid-Open No. 63-250846 proposes a method of temporarily fixing by a physical means such as vacuum adsorption, magnetic force or gravity without providing an adhesive layer.

[0005]

As described above, the metal foil material provided with the adhesive layer for temporary fixing is temporarily fixed to the mold through the adhesive layer, and then the sealing resin is injected and molded. In the manufacturing method, (1) when the sealing resin is molded or cured after molding because the adhesive force between the metal foil and the semiconductor device is insufficient, or when the semiconductor device is mounted on a wiring board, etc. The metal foil may peel off when a thermal stress is applied, and as a result, the effect that should be obtained by coating the surface of the semiconductor device with the metal foil, such as improvement of reliability in TCT test and crack resistance during soldering However, there has been a problem that some of the effects such as the improvement of (2) Further, regarding the metal foil material that is temporarily fixed and used on the surface of the mold cavity, depending on the type of the adhesive layer formed on the metal foil, the metal foil material may be misaligned on the cavity surface during molding. Mold stains were sometimes generated.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and when (1) a metal foil material is used to mold a resin for sealing a semiconductor element using a mold. And (2) a method of manufacturing a metal foil-covered semiconductor device, wherein a metal foil material is fixed to the surface of the semiconductor device by injecting and molding a sealing resin into the mold thereafter. The present invention provides a metal foil material and a semiconductor device obtained by using the manufacturing method.

The present invention will be described in detail below, but for reference, an example of the molding method will be described with reference to the drawings. First, as shown in FIG. 1A, the metal foil material 7 is temporarily fixed to the cavity surfaces of the opened molds 1 and 2 via the adhesive layer 8. Then, as shown in FIG.
The semiconductor element 4 to be sealed is supplied with the lead frame 5. Next, as shown in FIG.
After closing, the sealing resin 6 is injected into the mold to be molded and cured. After curing, the molds 1 and 2 are opened, and the semiconductor device in which the metal foil material 7 is fixed to the surface of the resin 6 is taken out as shown in FIG. In the above case, the term “temporary fixing” means that the mold does not fall off even when the mold is opened and closed, does not dislocate during molding, and can be easily separated from the mold after resin molding. Means

FIG. 2 schematically shows an enlarged structural example of the metal foil structural material 3. In the metal foil structural material 3 illustrated here, the adhesive layer 8 for temporarily fixing to the mold cavity surface is provided on one surface of the metal foil material 7. This is because the setting position of the metal foil structural material 3 changes when the resin 6 is injected into the cavities of the molds 1 and 2, or the resin 6 flows between the metal foil structural material 3 and the mold cavity surface. This is to prevent it from getting boring. At this time, when a metal foil material described later is temporarily fixed to the mold cavity surface, a semiconductor element is molded, and resin is sealed to manufacture a metal foil-covered semiconductor device, the surface roughness of the mold cavity surface (10-point average roughness; Rz;
JIS B0601-1982) is characterized in that a mold of 4 to 15 μm is used and a sealing resin is injected and molded. That is, in combination with various ideas of the adhesive layer formed on the metal foil material, a metal foil-covered semiconductor device can be manufactured with high productivity and a semiconductor device having a good surface appearance can be obtained. When the surface roughness of the mold cavity is less than 4 μm, the releasability of the metal foil uncovered portion is poor, and when it exceeds 15 μm, the fixing failure during temporary fixing of the metal foil occurs, which is not preferable.

Next, the metal foil material used in the present invention will be described. The metal foil material used here is not particularly limited as long as it is a metal having a melting point of 300 ° C. or higher so as to withstand the resin temperature and mold temperature during molding.
Examples of such materials include aluminum, stainless steel, copper, nickel and the like. The thickness of the metal foil material is set in the range of 1 μm to 300 μm, preferably 5 to 200 μm. Thickness is 1 μm
The following items are difficult to handle and have a thickness of 300 μm
If it exceeds, the thickness of the resin that wraps the semiconductor element decreases, and the fluidity of the resin during molding deteriorates. Further, an adhesive layer for temporarily fixing the metal foil material to the surface of the mold cavity is provided on one surface in advance.

The adhesive used in this adhesive layer can be temporarily fixed to a mold heated to a high temperature and does not cause the metal foil material to flow due to the pressure of the injected resin when the sealing resin is injected. Must. After molding, the semiconductor device can be released from the mold by the interface destruction between the mold and the adhesive layer without causing the cohesive failure at the adhesive layer or the interface failure at the interface between the metal foil and the adhesive layer. It must be able to be taken out well. To meet these requirements, adhesives that are adhesive even at high temperatures, for example,
It is possible to use an adhesive layer containing an inorganic filler based on a thermosetting resin such as a phenoxy resin, an ethylene vinyl acetate copolymer, a polyester resin, or an epoxy resin. The thickness of the adhesive layer is preferably 5 μm to 20 μm. In this case, since the inorganic filler increases the cohesive force of the adhesive layer, it exhibits an effect of preventing the adhesive from remaining on the mold cavity surface.

As the inorganic filler, silica, aluminum oxide, zirconium oxide, silver powder, aluminum powder or the like can be used. Examining the desired function expression range with the average particle size of the filler used at this time, it was found that there is a correlation with the thickness of the adhesive layer, and the average particle size of the inorganic filler is the thickness of the adhesive layer. It has been found that a value of 0.05 to 0.8 is suitable. If it is less than 0.05 times, the adhesive tends to remain on the mold cavity surface when releasing the semiconductor device after molding, and if it exceeds 0.8 times, the temporary fixing of the metal foil material to the mold becomes defective. Therefore, it is not preferable. Since the thickness of the adhesive layer is preferably 5 to 20 μm, the average particle diameter of the inorganic filler used in this case is generally 1 to 10 μm. It is preferable that the addition amount is 3 to 40 parts by weight with respect to 100 parts by weight of the adhesive layer, because the cohesive force and the adhesiveness to the mold cavity surface are balanced. If it is less than 3 parts by weight, the adhesive tends to remain on the mold cavity surface when the semiconductor device after molding is released from the mold, and if it exceeds 40 parts by weight, temporary fixing failure of the metal foil material to the mold tends to occur.

Further, as a result of confirming the effect on the maximum particle size of the inorganic filler used at this time, it was found that there is a situation where the average particle size alone cannot explain because the inorganic filler has its own particle size distribution. . In particular, when the inorganic filler is dispersed in a thin layer as in the present invention and used, the influence of the maximum particle size is likely to occur. As a result of the examination, by using the maximum particle size in the range of 1.5 to 3 times the thickness of the adhesive layer, the adhesive force with the mold cavity surface is maintained to withstand the shearing force during molding. It has been found to be effective in doing so. The maximum particle size as used herein means the particle size when the cumulative weight% is 90%. Probably because the inorganic filler particles, which are slightly larger than the thickness of the adhesive layer, jump out from the adhesive layer surface in an appropriate amount to reduce the adhesive force with the mold cavity surface and facilitate transfer of the metal foil material to the semiconductor device side. Be done. Further, as the inorganic filler used in the present invention, there are alumina, iron oxide, silver powder, etc. Among them, silica can be advantageously used. That is, there are amorphous silica and crystalline silica, and many of them have different particle size distributions, and since they contain few impurity ions, they can be suitably used for semiconductor devices.

As the organic material forming the adhesive layer using the filler as described above, a thermosetting resin is preferable. The reason is that thermosetting resins generally have excellent heat resistance and adhesiveness, so even if an inorganic filler is used, the extreme decrease in adhesive strength can be suppressed and the adhesive strength for temporary fixing can be controlled. Is. Typical thermosetting resins include epoxy resin, polyester resin, diallyl phthalate resin, and polyimide resin, and epoxy resin is preferably used. When an epoxy resin is used, it is preferable to add a rubber-based adhesive in an amount of 5 to 40% by weight based on the total amount of the adhesive in order to impart flexibility to the adhesive layer. The thickness of the adhesive layer is preferably in the range of 5 μm to 20 μm. Also,
A release agent such as silicone oil, waxes, fillers, etc. having a release effect on the mold is 0.01 to 0.01% of the total amount of the adhesive.
5% by weight can be contained.

In order to obtain a metal foil-covered semiconductor device by transferring the metal foil material temporarily fixed to the mold cavity surface to the surface of the semiconductor device with high productivity, the adhesive layer for temporary fixing and the mold cavity surface are separated. There is a need to solve the moldability and the problem of mold fouling due to the adhesive remaining on the mold cavity surface of the adhesive. Therefore, in order to deal with such a problem, the present invention improves the releasability between the temporary fixing adhesive layer and the mold cavity surface, and eliminates the adhesive residue of the adhesive on the mold forming surface. It is also an object to provide a metal foil material that can be reduced and also to provide a semiconductor device covered with the metal foil material with high productivity.

More specifically, the adhesive strength of the adhesive layer to the mold cavity surface at 175 ° C. is 0.3 to 5.0.
kgf / cm2, preferably 0.5 to 4.0 kgf / c
It is better to use an adhesive that is m2. 0.3 kgf / c
If it is less than m2, the metal foil material temporarily fixed to the mold cavity surface is apt to move, deform and peel off when the sealing resin is injected, and if it exceeds 5.0 kgf / cm2, the semiconductor after molding is molded. When the device is released from the mold, the semiconductor device is damaged, which is not preferable. Here, the tensile adhesive strength in the present invention means 100 kgf / 175 ° C.
What was adhered by applying a pressure of cm2 is JIS K
It is a value measured by a measuring method according to 6849 under an atmosphere of 175 ° C. and a pulling speed of 300 mm / min. In order to obtain the adhesive force in this range, any of the above-mentioned mold cavity surface roughness and metal foil material can be arbitrarily selected.

Further, an organic undercoating in which the contact angle of water on the surface of the metal foil material opposite to the surface on which the adhesive layer is formed and which contacts the sealing resin is 110 ° or less, preferably 100 to 25 °. It is also effective to provide a layer to improve the adhesiveness between the sealing resin and the metal foil material. If it is larger than 110 °, the wettability with the encapsulating resin is insufficient and air pockets are generated at the interface between the metal foil material and the encapsulating resin. As a result, at the time of molding, curing after molding, or mounting. This is because the metal foil material may peel off when the thermal stress is applied. As the organic undercoat layer used, materials such as a silane coupling agent layer, a polyimide resin, a polyetherimide resin, an epoxy resin, and a carbodiimide resin are usually used in a thickness range of 0.1 to 20 μm. Incidentally, the contact angle of the sealing resin with water is 60 to 100 °, and it can be seen that the influence of the affinity between the sealing resin and the metal foil material is obvious.

Next, the metal foil-covered semiconductor device will be described. The present invention relates to a semiconductor device in which a metal foil material corresponding to any of the above metal foil materials is fixed on the surface,
By coating with a metal foil, the reliability of the semiconductor device such as moisture resistance, heat stress resistance, and cracking during soldering is improved. At this time, when the semiconductor device is coated with the metal foil material, it is preferable to cover 20% or more of the surface area of the semiconductor device, and particularly 80% or more. This is because the coating of 20% or more improves the reliability of the obtained semiconductor device in the TCT test and the crack resistance during soldering, and particularly in the case of 80% or more, such a performance improving effect is remarkable.

FIG. 3 is a schematic sectional view of a metal foil-covered semiconductor device using an adhesive layer for temporary fixing. This feature is that the surface 9 of the metal foil material 7 is depressed from the surrounding sealing resin surface. Since the surfaces of the sealing resin and the adhesive layer are flush with each other, the metal foil material is embedded and fixed by the thickness of the adhesive layer. Therefore, as compared with the case where a metal foil is attached to the semiconductor device, there are advantages that the dimensions of the semiconductor device and the die size match and that the metal foil is less likely to be peeled from the semiconductor device. The adhesive layer on the metal foil has a hardness that does not hinder practical use when it is fixed to the surface of the semiconductor device through temporary fixing. Incidentally, FIG. 3 shows an example of the semiconductor device of the present invention, and it goes without saying that the semiconductor device of the present invention is not limited to this. For example, in the semiconductor device shown in the figure, the metal foil material 7 is fixed on both sides of the semiconductor device, but in the semiconductor device of the present invention, the metal foil material is fixed only on one side of the semiconductor device. Things are also included.

A thermosetting resin is used as the resin material for sealing the semiconductor element used at this time, and for example, an epoxy resin, a phenol resin, a urea resin, a melamine resin, a polyester resin, a diallyl phthalate resin, a cross-linking type resin is used. Examples include polyphenylene sulfide. Among these, it is preferable to use an epoxy resin. Examples of the epoxy resin include bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, cycloaliphatic type epoxy resin, naphthol type epoxy resin, biphenol type epoxy resin and dicyclopentadiene type epoxy resin. In this case, the epoxy resin is mixed with a conventionally known additive such as a curing agent, a curing accelerator, a filler, and a mold releasing agent, and used as an epoxy resin composition.

Furthermore, in the above semiconductor device, a semiconductor device in which solid identification information regarding the semiconductor device is recorded on an adhesive layer formed on a metal foil material is also an aspect of the present invention. The individual identification information such as the product name and manufacturing lot number of the semiconductor device is generally recorded on the surface of the semiconductor device after molding, but in the present invention, it is hardened or cured on the metal foil material covering the surface of the semiconductor device. It is preferably recorded on the surface of the adhesive layer having hardness after solidification. This individual identification information is laser marking, which is a common method.
It may be recorded by a method such as a stamp. In addition, in order to obtain more contrast, pigments and dyes such as carbon are usually added to the adhesive layer to color the adhesive layer to eliminate the effect of excess reflected light and accurately recognize solid identification information from a wide angle. You can enable it.

[0021]

The metal foil-covered semiconductor device of the present invention is such that the metal foil material is temporarily fixed to the mold cavity surface with an adhesive force that does not cause misalignment during molding, and then is placed on the lead frame. It is obtained by setting the element in a mold, then closing the mold, injecting a sealing resin, and molding and curing. To temporarily fix the metal foil material to the mold cavity, an adhesive layer is provided on the side of the metal foil material that comes into contact with the cavity, and the adhesive layer contains an appropriate amount of an inorganic filler,
Since the temporary fixing force of the metal foil material on the mold cavity surface and the releasability of the semiconductor device from the mold cavity after molding can be controlled, stable metal foil coating can be manufactured. At this time, if the constituent resin used for the adhesive layer is thermosetting, it is possible to cover the decrease in the adhesive strength due to the use of the inorganic filler, and thus it becomes easier to control the releasability. Furthermore, on the metal foil material side opposite to the adhesive layer on the metal foil material,
When an organic undercoat layer having a contact angle with water of 110 ° or less is provided, it is well compatible with the encapsulating resin, and the metal foil material is not affected by thermal stress during molding, curing after molding, or mounting. Peeling can be prevented. The mold cavities found through these processes and the adhesive layer on the metal foil 17
If the optimum range of the tensile adhesive strength at 5 ° C. is used, a metal foil coated semiconductor device can be obtained with good productivity. Further, when the metal foil material is temporarily fixed to the mold cavity, if the mold surface roughness is selected to be 4 to 15 μm, it is possible to obtain an adhesive layer provided on the metal foil material which has been devised for temporary fixing. By the combination, a metal foil-covered semiconductor device can be manufactured with good productivity and a semiconductor device having a good surface appearance can be obtained.
Since there is a hardened or solidified adhesive layer on the metal foil material of the obtained metal foil-covered semiconductor device, it is also possible to record the solid identification information of the semiconductor device by using this, and to prevent damage during thermal stress loading. A semiconductor device that is hard to receive can be provided.

[0022]

Embodiments of the present invention will be described below. The metal foil-covered semiconductor device was prepared as follows. (1) Temporary Fixing of Metal Foil to Mold Cavity Surface A metal foil having a size of 16 × 12 mm and a thickness of 40 μm was used, and the adhesive layer for temporary fixing having a thickness of 10 μm formed on the metal foil was An epoxy adhesive having the following composition was used. Epoxy resin (bisphenol A type); 5 parts by weight Rubber (carboxylated nitrile rubber); 2 parts by weight Curing agent (phenolic resin); 3 parts by weight Curing catalyst (phosphorus); 0.3 parts by weight (2) To mold Set of semiconductor element and frame of 80pinQFP (size 20 × 14 × 2mm), semiconductor element (size 6) on die pad (size 8 × 8mm)
Set the member with x6mm) adhered to the mold. (3) The mold was closed, the sealing resin was injected, and molding was performed at 175 ° C. for 2 minutes to obtain a metal foil-covered semiconductor device. The metal foil material 7 of the obtained metal foil-covered semiconductor device was recessed from the surface of the surrounding sealing resin as shown in FIG.

In Examples 1 and 2 of the present invention, an aluminum base material having a contact angle with water of 80 ° which constitutes the metal foil material was used, and the following adhesive layers were used.

Example 1 Fused silica having an average particle size of 0.8 μm and a maximum particle size of 20 μm was contained in an amount of 20 parts by weight based on 100 parts by weight of the adhesive, and the average particle size was 0.08 times the thickness of the adhesive layer. An adhesive layer having a particle diameter of 2.0 times the thickness of the adhesive layer was formed.

Example 2 20 parts by weight of crystalline silica having an average particle size of 3.0 μm and a maximum particle size of 25 μm was contained with respect to 100 parts by weight of the adhesive, and the average particle size was 0.30 times the thickness of the adhesive layer. An adhesive layer having a maximum particle diameter 2.5 times the thickness of the adhesive layer was formed.

In order to investigate the performance of the metal foil coated semiconductor devices of Examples 1 and 2 thus obtained, -50 ° C./5
Min-150 ° C / 5min TCT test and 85 ° C / 85%
The semiconductor device was left standing in a constant temperature layer of relative humidity to absorb moisture and then immersed in a solder bath at 260 ° C. for 10 seconds to perform a soldering resistance test, and the number of cracks generated in each case was measured. In addition, after molding the sealing resin, after curing, and after the TCT test, whether or not the aluminum material was peeled from the surface of the sealing resin (the surface of the semiconductor device) was observed using an ultrasonic probe. Table 1 shows the results. As is clear from Table 1, the metal foil is firmly adhered to the surface of the semiconductor device, so no peeling of the metal foil is observed even when heat stress is applied.
Almost no cracks were observed after the test or the solder resistance test. Further, the mold releasability from the mold was good, and the mold failure due to the adhesive layer and the poor adhesion to the mold did not occur.

As a comparative example corresponding to Examples 1 and 2, the same metal foil material as in Example 1 was used, but the following adhesive layer was used.

[Comparative Example 1] 20 parts by weight of fused silica having an average particle size of 0.2 μm and a maximum particle size of 10 μm was contained with respect to 100 parts by weight of the adhesive, and the average particle size was 0.02 times the thickness of the adhesive layer. An adhesive layer having a particle size 1.0 times the thickness of the adhesive layer was formed.

Comparative Example 2 20 parts by weight of fused silica having an average particle size of 10 μm and a maximum particle size of 40 μm was contained with respect to 100 parts by weight of the adhesive, and the average particle size was 1.0 times the thickness of the adhesive layer. Formed an adhesive layer 4.0 times the thickness of the adhesive layer. As shown in Table 1, as compared with Examples 1 and 2, in Comparative Example 1, mold stain was remarkable and mold releasability was poor, and in Comparative Example 2, many molding defects due to defective adhesion occurred.

In Examples 4 and 5 of the present invention, the average particle diameter of 7 μ was used in the temporary fixing adhesive layer constituting the metal foil structural material.
m, a maximum particle size of 28 μm, containing an appropriate amount of fused silica,
An adhesive layer having an average particle size of 0.7 times the adhesive layer thickness and a maximum particle size of 2.8 times the adhesive layer thickness was formed. The tensile adhesive strength at 175 ° C. with respect to the mold cavity surface was controlled by the content of the silica. At this time, the surface roughness of the mold cavity was also changed appropriately.

Example 4 Tensile bond strength at 175 ° C. of silica content of 20 parts by weight per 100 parts by weight of adhesive is 4.5.
The aluminum material used in Example 1 having an adhesive layer of kgf / cm 2 was used, and the surface roughness of the cavity was 5 μm.
It was molded using the mold.

Example 5 Tensile bond strength at 175 ° C. of silica content of 30 parts by weight per 100 parts by weight of adhesive is 2.0.
The aluminum material used in Example 2 having an adhesive layer of kgf / cm 2 was used, and the surface roughness of the cavity was 5 μm.
It was molded using the mold. As shown in Table 1, in Examples 4 and 5 of the present invention, the mold releasability from the mold was good, and the mold failure due to the dirt of the mold due to the adhesive layer and the poor adhesion to the mold did not occur, In Example 4, no crack was observed after the thermal stress was applied.

As a comparative example corresponding to Examples 4 and 5, the metal foil material used in Example 1 was used, and the adhesive force was controlled by appropriately changing the composition of the adhesive and the surface roughness of the mold cavity. Molded.

[Comparative Example 3] A mold having a cavity surface roughness of 20 μm was used, and the tensile adhesive strength at 175 ° C. was 0.1 kgf.
An adhesive layer of / cm 2 was molded using the metal foil constituent material formed on the aluminum material used in Example 1.

[Comparative Example 4] A mold having a cavity surface roughness of 2 μm was used, and the tensile adhesive strength at 175 ° C. was 7.5 kgf / c.
An adhesive layer of m2 was molded using the metal foil constituent material formed on the aluminum material used in Example 1. Comparative Example 3
However, since the temporary fixing adhesive strength of the metal foil material was low, the metal foil was misaligned during molding, and a good semiconductor device could not be obtained. Further, in Comparative Example 4, the adhesive force to the mold cavity portion was too strong, the mold was contaminated, and the mold release was also poor.
Probably because of this, cracks in the semiconductor device occurred under thermal stress.

[0028]

Example 6 An undercoat layer made of polycarbodiimide resin having a thickness of 10 μm (contact angle to water is 78 °) is provided on the side of the metal foil material used in Example 1 that comes into contact with the encapsulant, and adhesive for temporary fixing is provided. The agent layer used in Example 2 was used as it is in Example 2.
A semiconductor device was obtained by molding in the same manner as.

[Comparative Example 5] An adhesive layer for temporary fixing is provided by providing an undercoat layer (contact angle to water is 112 °) made of a silicone resin having a thickness of 10 µm on the side of the metal foil material used in Example 1 which comes into contact with the sealing material. A layer was formed in the same manner as in Example 2 using the layer of Example 2 as it was to obtain a semiconductor device. As shown in Table 1, in Example 6 in which the contact angle was 78 °, no peeling of the metal foil material was observed after the thermal stress was applied and no cracks were generated in the semiconductor device, but the contact angle was 112 °. In the case of the example, peeling of the metal foil material was observed after the thermal stress was applied, and some cracks in the semiconductor device were also observed.

[0029]

[Table 1]

[0030]

As described above, according to the present invention, when the metal foil material is adhered to the surface of the semiconductor device, the specific metal foil material which can protect the damage when the thermal stress is applied is used. When heat stress is applied by selecting the surface roughness of the mold cavity and the adhesive layer provided on the metal foil material, which is suitable for manufacturing semiconductor devices by temporarily fixing the material on the surface of the mold cavity. It is possible to manufacture a metal foil-covered semiconductor device which is less likely to be damaged by the above-mentioned method with high productivity.
Since the adhesive layer is present on the metal foil material, it is possible to record the solid identification information on the semiconductor device using the adhesive layer. Furthermore, the metal foil-covered semiconductor device obtained by the present invention,
Unlike the case where metal foil is attached to the finished semiconductor device, the metal foil material is recessed from the surface of the encapsulating resin around it, so the outer diameter becomes the same as that of a semiconductor device that does not use metal foil, and there is a problem during mounting. It also has the effect that it can be handled without using it.

[Brief description of drawings]

1 shows each step in an embodiment of the present invention,
With the mold open, a pair of metal foil materials were temporarily fixed (A), the lead frame on which the semiconductor element was mounted was set (B), the mold was closed and a sealing resin was injected to mold ( 3C is a cross-sectional view of the metal foil-covered semiconductor device (D) obtained by taking out from the mold after molding.

FIG. 2 shows a cross-sectional view of a metal foil structural material.

FIG. 3 shows a cross-sectional view of a metal foil-covered semiconductor device.

[Explanation of symbols]

 1, 2 ... Mold 3 ... Metal foil structural material 4 ... Semiconductor element 5 ... Lead frame 6 ... Sealing resin 7 ... Metal foil material 8 ... Adhesive layer 9 ... Metal foil material surface

Claims (12)

[Claims] 1. When molding a resin for sealing a semiconductor element by using a mold, the resin is temporarily fixed to a cavity surface of the mold,
An adhesive that is a metal foil material that is fixed to the surface of the semiconductor device by subsequent injection of molding resin into the mold and molding, and that can be temporarily fixed to the mold cavity surface and that does not cause misalignment during molding. A metal foil material for semiconductor device coating, wherein the layer is provided on one side of the metal foil material. 2. The metal foil material according to claim 1, wherein the adhesive layer contains an inorganic filler. 3. The metal foil material according to claim 2, wherein the inorganic filler contained in the adhesive layer has an average particle diameter of 0.05 to 0.8 times the thickness of the adhesive layer. 4. The metal foil material according to claim 2, wherein the maximum particle size of the inorganic filler contained in the adhesive layer is 1.5 to 3 times the thickness of the adhesive layer. 5. The metal foil material according to claim 2, wherein the inorganic filler is silica. 6. The metal foil material according to claim 2, wherein the adhesive layer contains a thermosetting resin and an inorganic filler as main components. 7. The adhesive layer with respect to the mold cavity surface 1
Tensile adhesive strength at 75 ℃ is 0.3-5.0kg
It is f / cm2, The metal foil material of Claims 1-6 characterized by the above-mentioned. 8. The metal foil material according to claim 1, further comprising an organic undercoat layer having a contact angle to water of 110 ° or less on the other surface of the metal foil material. 9. A semiconductor device, wherein the metal foil material according to claim 1 is fixed on the surface. 10. The semiconductor device according to claim 9, wherein the metal foil material is embedded and fixed by a thickness of the adhesive layer from a surface formed of the sealing resin and the adhesive layer. 11. The semiconductor device according to claim 9, wherein solid-state identification information regarding the semiconductor device is recorded on an adhesive layer on the metal foil material. 12. When molding a semiconductor element and sealing it with resin, the surface roughness (10-point average roughness;
Rz; JIS B 0601-1982) is 4 to 15 μ.
The metal foil material according to any one of claims 1 to 8 is temporarily fixed to the cavity surface of m, and then the sealing resin is injected and molded to fix the metal foil material to the surface of the semiconductor device. Of manufacturing a semiconductor device.