JP2006339226A - Semiconductor sealing tablet, its manufacturing method, and semiconductor device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor sealing tablet and its manufacturing method, and a semiconductor device using the semiconductor sealing tablet, capable of more reducing the formation of voids even in a semiconductor sealing tablet with the same high density. <P>SOLUTION: When a powdered semiconductor sealing material is pressurized and tableted along one axis from two directions, a movement distance of one pressurizing surface is set to fall within a range of 85 to 100% of that of the other pressurizing surface. By pressurizing the tablet such that the ratio of the density of the whole tablet to true specific gravity is 93% or more, there is obtained the semiconductor sealing tablet in which differences of ratios of densities of three divided pieces obtained by dividing the tablet into three perpendicularly to the direction of the pressurization with respect to true specific gravity falls within 3%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor sealing tablet used as a sealing material for a semiconductor device, a manufacturing method thereof, and a semiconductor device using the semiconductor sealing tablet.

  In a semiconductor device, elements (semiconductor chips) are mounted on a lead frame, and the elements and the lead frame are sealed with a sealing material such as an epoxy resin (see, for example, Patent Document 1). This sealing is usually performed by putting a sealing material formed in the form of a tablet into a pot of a molding die, heating it in the pot and making it flow, and then extruding it with a plunger. It is performed by flowing into the set cavity (by transfer molding).

  The defects at the time of sealing, which is the final step of manufacturing the semiconductor device, adversely affect the reliability of the semiconductor device and the productivity of the device incorporating the semiconductor device. There is a strong demand to reduce the generation of voids (cavities and holes generated due to air in the tablet) inside and on the surface.

Therefore, a higher-density tablet (having a smaller amount of air contained in the tablet) is used as the tablet made of the sealing material. This high-density tablet is manufactured as follows. That is, first, an epoxy resin and an inorganic filler are blended, melt-kneaded, and then rolled. And after cooling it, it grind | pulverizes and press-compresses the powdery material obtained in the metal mold | die of a desired shape only by the quantity required for sealing. By increasing the pressure during tableting, a high-density tablet can be produced.
JP 2004-55609 A

  However, even when a high-density tablet is used, there are cases where the number of voids increases, or even when a tablet with the same density is used, there is a difference in the number of voids generated. Thus, as a result of repeated studies on the cause by the present inventors, it was found that there is a deviation in density in one tablet, and the larger the deviation in density, the greater the variation in the number of voids generated. Moreover, the density deviation is various. For example, the density is higher as it is closer to the pressing surface (both end surfaces) when the tablet is manufactured, and the density is lower as the center portion is closer to one of the pressing surfaces. There are some having a high density and a low density in the vicinity of the central portion and the other pressing surface. And it is estimated that the part with the low density is the cause of generating many voids.

  The present invention has been made in view of such knowledge, and even with the same high-density semiconductor sealing tablet, a semiconductor sealing tablet that can further reduce the generation of voids, a manufacturing method thereof, and a semiconductor sealing An object is to provide a semiconductor device using a tablet.

  In order to achieve the above object, the present invention provides a semiconductor sealing tablet obtained by compressing a powdery semiconductor sealing material under pressure, and the ratio of the density of the entire tablet to the true specific gravity [(the entire tablet Density / true specific gravity) × 100] is 93% or more, and the density of the three divided pieces obtained by dividing the tablet into three equal parts at right angles to the pressing direction with respect to the true specific gravity. A semiconductor sealing tablet in which the difference in the ratio [(density of divided pieces / true specific gravity) × 100] is within 3% is taken as the first gist.

  Further, the present invention is a method for producing a semiconductor sealing tablet for producing a semiconductor sealing tablet by compressing and compressing a powdery semiconductor sealing material from two directions along one axis. When the pressure is applied from two directions, the moving distance of one pressing surface is set within the range of 85 to 100% of the moving distance of the other pressing surface, and the ratio of the density of the entire tablet to the true specific gravity [( The manufacturing method of the tablet for semiconductor sealing which pressurizes so that the density of the whole tablet / true specific gravity) × 100] may be 93% or more is a second gist.

  Furthermore, the present invention provides a semiconductor device in which a semiconductor chip is mounted on a lead frame, and the semiconductor chip and the lead frame are sealed with a semiconductor sealing material, wherein the semiconductor sealing material is used for the semiconductor sealing. A semiconductor device using a tablet is a third gist.

  Based on the above knowledge, the present inventors have found that the density deviation in one semiconductor sealing tablet is such that the generation of voids can be reduced even with the same high-density semiconductor sealing tablet. The idea was to make it smaller, and further research was conducted. As a result, when a tablet for semiconductor encapsulation is produced by compressing and compressing a powdery semiconductor encapsulation material from two directions along one axis, one of the pressures applied when pressing from the two directions is used. Pressing the tablet so that the moving distance of the pressing surface is within the range of 85 to 100% of the moving distance of the other pressing surface, and the density of the whole tablet (one tablet) is 93% or more of the true specific gravity. Then, it discovered that the tablet for semiconductor sealing with a small bias | inclination of density could be produced. That is, the difference in the ratio of the density of the three divided pieces obtained by dividing the produced semiconductor sealing tablet into three equal parts at right angles to the pressing direction is within 3%. I found out that I can do it. In such a semiconductor sealing tablet, the amount of air is uniformly reduced, and when the semiconductor sealing tablet is used for sealing, it has been found that generation of voids can be further reduced, and the present invention has been achieved. .

  The tablet for semiconductor encapsulation of the present invention is so dense that the ratio of the density of the whole tablet to the true specific gravity is 93% or more, and the tablet is divided into three equal parts perpendicular to the pressing direction. The density deviation is small enough that the difference in the ratio of the density of the three divided pieces obtained by the division to the true specific gravity is within 3%. Thereby, in the tablet for semiconductor sealing of the present invention, the amount of air is uniformly reduced. For this reason, when it seals using the tablet for semiconductor sealing of this invention, generation | occurrence | production of a void can be reduced more.

  In particular, among the above three divided pieces, when the number of divided pieces showing a value 2% or more lower than the value of the divided piece having the maximum density relative to the true specific gravity is less than two. Since the density deviation is further reduced, the generation of voids can be further reduced.

  Moreover, the manufacturing method of the tablet for semiconductor sealing of this invention is 85-85 of the movement distance of the other pressurization surface when the compression distance of one pressurization surface at the time of carrying out the press tableting from two directions along one axis | shaft. The pressure is set so as to be within a range of 100%, and the density of the whole tablet is 93% or more of the true specific gravity. Thereby, the tablet for semiconductor sealing of the present invention with the above high density and small density deviation can be produced. Furthermore, as described above, since the difference in the moving distance between the two pressing surfaces during pressure tableting is 0 or less, it is possible to apply pressure evenly or substantially uniformly on both pressing surfaces, and it is manufactured. Since the tablet for semiconductor encapsulation of the present invention does not partially become ultra-high density, it can be compressed and compressed at a relatively low pressure. As a result, the burden on the tableting machine can be reduced, and damage to the tableting machine can be prevented.

  Furthermore, since the semiconductor device of the present invention uses the above-described high density and low density deviation of the semiconductor sealing tablet of the present invention, the number of voids is very small and the reliability is high. .

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  The tablet for semiconductor encapsulation of the present invention is formed in a columnar shape, has a high density, and has a small density deviation in one tablet. Specifically, the ratio of the density of the whole tablet (one tablet) to the true specific gravity [(density of the whole tablet / true specific gravity) × 100, this ratio is hereinafter referred to as “density ratio of the whole tablet”] When it is 93% or more and the tablet is divided into three equal parts perpendicular to the columnar height direction (pressing direction when tableting into a tablet), the density of the three divided pieces , The difference in the ratio to the true specific gravity [(divided piece density / true specific gravity) × 100, which is hereinafter referred to as “(divided piece) density ratio”] is within 3%.

  In addition, although the magnitude | size of the tablet for semiconductor sealing in the said column shape is not specifically limited, Usually, it sets to the range of diameter 7-30mm and height 10-45mm.

  The above-mentioned semiconductor sealing tablet can be produced, for example, as follows. That is, first, a semiconductor sealing resin composition is dry blended with a mixer or the like, and then kneaded at a resin temperature of 90 to 130 ° C. using a biaxial kneader or the like. Next, the kneaded material discharged from the kneader is rolled into a sheet using a calendar roll or the like. The sheet is air-cooled and then pulverized using a mechanical pulverizer such as a hammer mill to obtain a powdery semiconductor sealing material. Next, using a tableting machine, the powdery semiconductor encapsulating material is compressed in two directions along one axis to form a cylindrical tablet. The pressurization from these two directions is set such that the moving distance of one pressing surface is within a range of 85 to 100% of the moving distance of the other pressing surface, and the density of the entire tablet is relative to the true specific gravity. The ratio (density ratio of the entire tablet) is 93% or more. This tableting method is a feature of the method for producing a semiconductor sealing tablet of the present invention. In this way, the above-mentioned semiconductor sealing tablet can be produced. In addition, the said pressurization pressure is normally set to the range of 245-784 MPa.

  More specifically, as the tableting machine, for example, as shown in FIG. 1, a machine capable of pressure tableting from the vertical direction is used. This includes a cylindrical die 1 for charging the powdery semiconductor sealing material A, and pressurizes and compresses the powdery semiconductor sealing material A in the hollow portion of the die 1. For this purpose, an upper punch 2a and a lower punch 2b are provided. The upper and lower punches 2a and 2b are connected to the hydraulic cylinders 3a and 3b, respectively, and can advance and retreat into and out of the hollow portion of the cylindrical die 1. The hydraulic cylinders 3a and 3b can control the pressurizing speeds and the like by the punches 2a and 2b connected to the hydraulic cylinders 3a and 3b, respectively. In FIG. 1, reference numerals 4a and 4b denote position indicating units indicating the positions of the respective punches 2a and 2b, 5a and 5b denote displacement sensors for detecting the displacement of the respective punches 2a and 2b by the respective position indicating units 4a and 4b, and 6 A die support base for supporting the die 1.

  Moreover, the particle size distribution of the powdery semiconductor sealing material A put into the die 1 of the tableting machine can be confirmed by a JIS standard sieve. In the present invention, the proportion of the pulverized particles remaining on the 1.0 mm sieve is preferably 50% by weight or less. The preferred lower limit is 7% by weight. That is, if the amount exceeds 50% by weight, even if the density ratio of the whole tablet is high, voids remain between the particles, and conversely, voids during molding tend to increase. Therefore, it is preferable that the particle | grains exceeding a particle size of 1.0 mm of the whole ground material are 50 weight% or less.

  Furthermore, it is preferable that the ratio of the pulverized particle | grains which pass a 0.125mm sieve is 10 to 40 weight% of the whole, Most preferably, it is 10 to 25 weight%. Fine particles such as pulverized particles that pass through a 0.125 mm sieve have the effect of filling the space between the large particle size and reducing the amount of air taken into the tablet when the tablet is formed. However, when the proportion exceeds 40% by weight, the bulk density is conversely lowered, the amount of air taken in increases, and the tablet tends to be difficult to mold. Therefore, it is particularly preferable that particles having a particle size of 0.125 mm or less be suppressed to 25% by weight or less from the relationship between the compression pressure by the punches 2a and 2b and the variation in tablet density. Thus, it is preferable that the particle | grains with a particle size of 0.125 mm or less of the whole ground material are 10 to 40 weight%, Especially preferably, it is 10 to 25 weight%.

  Thus obtained high density (the density ratio of the entire tablet is 93% or more) and small density deviation (the difference in density ratio of the three divided pieces obtained by dividing the tablet into three equal parts is 3%. Within) When the semiconductor chip and lead frame of a semiconductor device are sealed using a semiconductor sealing tablet, the amount of air in the semiconductor sealing tablet is uniformly reduced, thereby reducing the generation of voids. Can be made.

  Moreover, in the manufacturing method of the said tablet for semiconductor sealing, the movement distance of one pressurization surface at the time of press-compressing is set in the range of 85-100% of the movement distance of the other pressurization surface. Since the difference between the two moving distances is 0 or less, it is possible to pressurize evenly or substantially uniformly on both pressing surfaces. And since the tablet for semiconductor sealing produced does not become super-high density partially, it can be compressed and compressed by comparatively low pressure. As a result, the burden on the tableting machine can be reduced, and damage to the tableting machine can be prevented. In addition, the productivity of the semiconductor sealing tablet can be improved. Furthermore, it is possible to further increase the pressure at the time of compression tableting, and it becomes possible to produce a tablet for semiconductor sealing with higher density.

  In particular, in the manufacturing method of the above-mentioned tablet for semiconductor encapsulation, when the moving distance of one pressing surface is set to 100% of the moving distance of the other pressing surface when pressing with pressure (pressing in two directions) Of the pressure piece by the same), the divided piece having a density ratio that is 2% or more and 3% or less lower than the maximum density ratio of the divided piece having the maximum density ratio among the three divided pieces. The number can be less than two. That is, the density deviation in one tablet can be further reduced. And if it seals using such a tablet tablet for semiconductor sealing, generation | occurrence | production of a void can be reduced further.

  Next, the resin composition for semiconductor encapsulation, which is a material for forming the tablet for semiconductor encapsulation, will be described.

  The above-mentioned resin composition for encapsulating semiconductors usually contains an epoxy resin, a phenol resin, and an inorganic filler as essential components, and if necessary, a halogen-based flame retardant such as a curing accelerator and a brominated epoxy resin, antimony trioxide, etc. Flame retardant aids, pigments such as carbon black, silane coupling agents such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane, release agents such as carnauba wax Such additives are appropriately contained.

  The epoxy resin is not particularly limited, and various epoxy resins are used. Examples thereof include various epoxy resins such as a cresol novolac type, a phenol novolac type, a bisphenol A type, a biphenyl type, a triphenylmethane type, and a naphthalene type. These may be used alone or in combination of two or more.

  The phenol resin functions as a curing agent for the epoxy resin and is not particularly limited. Examples thereof include phenol novolak, cresol novolak, bisphenol A type novolak, naphthol novolak, and phenol aralkyl resin. It is done. These may be used alone or in combination of two or more.

  It is preferable to mix | blend the mixing ratio of the said epoxy resin and a phenol resin so that the hydroxyl group equivalent in a hardening | curing agent may be 0.5-2.0 equivalent per 1 equivalent of epoxy groups in an epoxy resin. More preferably, it is 0.8-1.2 equivalent.

  The inorganic filler is not particularly limited and includes various fillers such as quartz glass powder, talc, silica powder (such as fused silica powder and crystalline silica powder), alumina powder, aluminum nitride powder. And silicon nitride powder. These may be used alone or in combination of two or more. Among these, it is preferable to use the silica powder from the viewpoint that the linear expansion coefficient of the obtained cured product can be reduced, and it is particularly preferable from the viewpoint of high filling and high fluidity to use the fused silica powder among the silica powders. . Examples of the fused silica powder include spherical fused silica powder and crushed fused silica powder. From the viewpoint of fluidity, spherical fused silica powder is preferably used. Among them, it is preferable to use those having an average particle diameter in the range of 10 to 60 μm, particularly preferably in the range of 15 to 45 μm. In addition, the said average particle diameter can be measured using a laser diffraction scattering type particle size distribution measuring apparatus, for example.

  The content of the inorganic filler is preferably set in the range of 50 to 95% by weight, particularly preferably 70 to 90% by weight, based on the entire semiconductor sealing resin composition.

  The curing accelerator is not particularly limited, and examples thereof include imidazoles such as 2-methylimidazole, organic phosphorus compounds such as triethanolamine, tetraphenylphosphonium / tetraphenylborate and triphenylphosphine, And diazabicycloalkene compounds such as 8-diazabicyclo [5.4.0] undecene-7 and 1,5-diazabicyclo [4.3.0] nonene-5. These compounds may be used alone or in combination of two or more. And it is preferable to set the mixture ratio of this hardening accelerator to the ratio of 0.1 to 1.0 weight% of the whole resin composition for semiconductor sealing.

  In the above-described embodiment, the semiconductor sealing tablet has a cylindrical shape. However, the present invention is not limited to this. For example, the semiconductor sealing tablet may have a rectangular column shape such as a square column.

  Next, examples will be described together with comparative examples.

[Examples 1 to 5, Comparative Examples 1 to 4]
Each component shown in Table 1 below was put into a mixer at the ratio shown in the table and dry blended, and then the mixture was supplied to a biaxial kneader and melt-kneaded at a resin temperature of 110 ° C. Next, the kneaded material discharged from this kneader was rolled into a sheet (thickness 1 mm) by using a calender roll having a diameter of 150 mm. Next, the kneaded material formed into the sheet shape was air-cooled and then pulverized using a hammer mill to obtain a powdery semiconductor sealing material (true specific gravity 2.0). In this powdery semiconductor sealing material, the ratio of the bulk density after 1000 tappings to the true specific gravity (density ratio of the bulk density) was 65%.

[True specific gravity of tablet material]
In addition, the true specific gravity (2.0) of the powdery semiconductor encapsulating material is obtained by heating and press-molding the above kneaded product (175 ° C. × 2 minutes, 6.865 MPa, post-curing 175 ° C. × 5 hours). On the other hand, it measured according to JIS K6911 (specific gravity measuring method calculated | required from the weight in air and the weight in water).

[Preparation of tablets for semiconductor encapsulation]
And the powdery semiconductor sealing material was pressure-compressed so that it might become a desired density ratio as follows using the tableting machine shown in FIG. 1, and the tablet for semiconductor sealing was produced. That is, first, 6.0 g of the powdery semiconductor sealing material was weighed using a balance. Subsequently, after lowering the lower punch of the tableting machine in the die (inner diameter 14 mm), the above measured powdery semiconductor sealing material was put into the die. Next, the upper punch was lowered until it was in contact with the charged powdery semiconductor sealing material. Then, the upper punch and the lower punch are moved toward each other at a constant speed (5.0 mm / second) (compression direction) (distance between the pressing surface of the upper punch and the pressing surface of the lower punch: 30 mm), The density ratio of the bulk density of the powdery semiconductor sealing material in the die was set to 65%. Using this state as a pressing start point, the tableting was performed by pressurizing by the pressurizing method of each of the following Examples 1 to 5 and Comparative Examples 1 to 4 to form a semiconductor sealing tablet. In addition, the movement distance of each punch in the following Tables 2 and 3 is the movement distance from the pressurization start point. Then, the upper punch was raised and removed from the die, the lower punch was raised, and the formed semiconductor sealing tablet was pushed out of the die. However, in Comparative Example 4, when extruding the semiconductor sealing tablet from the die, cracks occurred in the circumferential direction, making it impossible to produce the tablet.

[Pressure method]
Example 1: The upper punch is moved at a speed of 2.5 mm / second and the lower punch is simultaneously moved at a speed of 5.0 mm / second, so that the density ratio of the whole tablet becomes 93% (the height of the whole tablet is 21.0 mm). Compressed as follows.
Example 2 In Example 1, the tablet was compressed so that the density ratio of the entire tablet was 96% (the height of the entire tablet was 20.3 mm). Other than that, it was the same as in Example 1 above.
Example 3: The upper punch and the lower punch were simultaneously moved at a speed of 5.0 mm / second, and compressed so that the density ratio of the entire tablet was 93%.
Example 4: In Example 3 above, the tablet was compressed so that the density ratio of the whole tablet was 96%. Other than that was carried out similarly to the said Example 3.
Example 5: In Example 3 above, the tablet was compressed so that the density ratio of the whole tablet was 98% (the height of the whole tablet was 19.9 mm). Other than that was carried out similarly to the said Example 3.
Comparative Example 1: In Example 3 above, the tablet was compressed so that the density ratio of the entire tablet was 92% (the height of the entire tablet was 21.2 mm). Other than that was carried out similarly to the said Example 3.
Comparative Example 2: Only the upper punch was moved at a speed of 5.0 mm / second and compressed so that the density ratio of the entire tablet was 93%.
Comparative Example 3: In Comparative Example 2, the tablet was compressed so that the density ratio of the whole tablet was 96%. Other than that, it was the same as in Comparative Example 2 above.
Comparative Example 4: In Comparative Example 2 above, the tablet was compressed so that the density ratio of the entire tablet was 98%. Other than that, it was the same as in Comparative Example 2 above.

[Density ratio of the whole tablet]
The diameter (about 14 mm), height, and weight (about 6.0 g) of each semiconductor sealing tablet thus obtained were measured, and the density ratio of the whole tablet was calculated by the following formula (1). . This is also shown in Tables 2 and 3 below.

[Density ratio of each divided piece of tablet]
First, using a rotary diamond cutter with a blade thickness of 0.3 mm, each of the semiconductor sealing tablets obtained as described above was cut at a right angle to the pressing direction (height direction) to obtain a height. Divided into 3 equal parts perpendicular to the direction. During this cutting, the tablet was cut at a low speed while cooling with water in order to prevent breakage of the tablet and melting due to frictional heat with the cutter. Next, the divided pieces were washed with water, and the adhering chips and the like were removed, followed by vacuum drying for 12 hours in an atmosphere of 24 ° C. and 4 kPa (absolute pressure) using a vacuum dryer. Subsequently, humidity was adjusted for 24 hours in an atmosphere of 24 ° C. and 55% RH. And the specific gravity of each divided piece (upper part, center part, lower part) was measured according to JIS K6911 (specific gravity measuring method) (the divided pieces are small, and the specific gravity measurement error is large when the specific gravity is measured from the dimensions. Therefore, the density ratio of each divided piece of the tablet was calculated by the following formula (2). This is also shown in Tables 2 and 3 below.

[Pressure force ratio]
In the production of each tablet for semiconductor sealing, the total pressure applied to the upper and lower punches during pressure compression (pressure by a hydraulic cylinder) was measured, and the ratio of the above pressures based on Example 3 was as follows. Tables 2 and 3 show.

[Number of voids]
Moreover, the semiconductor device (20 samples) was produced on the following conditions using each semiconductor sealing tablet obtained as mentioned above. Then, the inside of the obtained semiconductor device was observed using an X-ray apparatus, the number of voids having a size of 100 μm or more was counted, and the average value of the number of voids of 20 semiconductor devices was calculated. The results are shown in Tables 2 and 3 below.

Semiconductor device size: 144 pink quad flat package (144-pin QFP)
20mm x 20mm
Chip size: 7.5mm x 7.5mm
Transfer molding conditions: Thermosetting at 175 ° C. for 90 seconds Molding pressure: 6.9 MPa
Molding machine: Multi-plunger system manufactured by TOWA

  From the results of Tables 2 and 3 above, if the difference in moving distance between the upper and lower punches is reduced to 0 or less and the density ratio of the whole tablet is 93% or more, a tablet with a small density deviation can be obtained, When it was sealed using it, the number of voids could be greatly reduced.

  More specifically, from the comparison between Examples 1 and 3 and Comparative Example 2 and the comparison between Examples 2 and 4 and Comparative Example 4, even though the density ratio of the whole tablet is the same, the tablet of the Example has a density deviation. When it was small and sealed with it, the number of voids was small. Furthermore, even when the density ratio of the whole tablet was the same, when producing the tablet of an Example, the pressurizing force at the time of press-pressing could be made smaller than a comparative example. From this, it can be seen that the manufacturing method of the example can reduce the burden on the tableting machine. Further, when Example 5 and Comparative Example 4 were compared, a tablet with a density ratio of 98% as a whole could be produced in Example 5, but could not be produced in Comparative Example 4. From this, it can be seen that the manufacturing method of the example can produce a tablet with higher density for semiconductor encapsulation.

  Further, from the comparison between Example 1 and Example 3 and the comparison between Example 2 and Example 4, when the density ratio of the whole tablet is the same, the difference in the movement distance of the upper and lower punches at the time of tablet production is smaller. The density deviation can be reduced, and the number of voids can be reduced. And as in Examples 3 to 5, if the movement distances of the upper and lower punches are equal, the number of divided pieces showing a density ratio that is 2% or more and 3% or less lower than the maximum density ratio can be less than two. When such a tablet is used for sealing, the number of voids generated can be further reduced. However, as in Comparative Example 1, even if the movement distances of both the upper and lower punches are made equal and the density deviation is small, if the density ratio of the whole tablet is as low as 92%, the number of voids increases, and the density The effect of reducing the bias was not obtained.

It is explanatory drawing partially broken which shows an example of the tableting machine used in the manufacturing method of the tablet for semiconductor sealing of this invention.

Claims (4)

  A tablet for semiconductor sealing formed by compressing a powdered semiconductor sealing material under pressure, and the ratio of the density of the entire tablet to the true specific gravity [(density of the whole tablet / true specific gravity) × 100] is 93%. The ratio of the density of the three divided pieces obtained by dividing the tablet into three equal parts at right angles to the pressing direction with respect to the true specific gravity [(density of the divided pieces / true specific gravity) × 100] is within 3%.   Of the above three divided pieces, a divided piece having a value 2% or more lower than the value of the divided piece having the maximum density ratio ((density of the divided piece / true specific gravity) × 100) relative to the true specific gravity. The tablet for semiconductor encapsulation according to claim 1, wherein the number of is less than two.   A method for producing a semiconductor sealing tablet for producing a semiconductor sealing tablet by compressing and compressing a powdered semiconductor sealing material from two directions along one axis. The moving distance of one pressing surface is set within a range of 85 to 100% of the moving distance of the other pressing surface, and the ratio of the density of the entire tablet to the true specific gravity [(density of the entire tablet / true (Specific gravity) × 100] is pressed so as to be 93% or more.   3. A semiconductor device in which a semiconductor chip is mounted on a lead frame, and the semiconductor chip and the lead frame are sealed with a semiconductor sealing material, wherein the semiconductor sealing material is for semiconductor sealing according to claim 1 or 2. A semiconductor device using a tablet.

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