JP2978313B2 - Semiconductor device and epoxy resin composition for semiconductor encapsulation used therein - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a semiconductor device that has excellent thermal shock resistance, small thermal stress during mounting on a substrate, and excellent package crack resistance and humidity resistance.

[0002] In recent years, semiconductor elements such as ICs and LSIs have been increasing in size as their integration degree has increased. in addition,
The plastic package for protecting the semiconductor device from the external environment has been made thinner by adopting a surface mounting form typified by a quad flat package (QFP), a small outline package (SOP), etc. due to its higher packing density. Is progressing. As the size of the semiconductor element increases, problems such as damage to the element and package cracks due to internal stress generated between the element and the encapsulating resin composition occur, and a surface mounting mode is adopted. As a result, the moisture contained in the sealing resin composition causes a vaporization explosion due to heat at the time of mounting, causing a package crack or deteriorating the moisture resistance thereafter. Is required.

[0003]

As a method for reducing the internal stress, a content ratio of an inorganic filler contained in a sealing resin composition is conventionally increased to reduce a thermal expansion coefficient of the sealing resin. A method of lowering the elastic modulus by mixing or preliminarily reacting silicone or rubber with the sealing resin composition has been adopted. However, in the above method of increasing the content of the inorganic filler, the viscosity of the entire composition increases with an increase in the content, and an excessive increase significantly impairs the moldability. (Hereinafter abbreviated as “%”). With this, sufficient low stress property cannot be obtained. In addition, in the above-described method of lowering the elastic modulus of the sealing resin by mixing silicone, rubber, or the like, the diffusion of moisture contained in the sealing resin composition is accelerated, and as a result, the package resistance during mounting is reduced. There is a problem that the cracking property is deteriorated.

Further, as a method of improving the package crack resistance during mounting, a method of using a low moisture-absorbing material and including it in a sealing resin composition has been used. However, the low moisture-absorbing material has a problem that when used in a high-temperature atmosphere because of its low glass transition temperature, the amount of deformation of the obtained sealing resin increases.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a semiconductor device having low internal stress and excellent thermal stress during mounting.

[0006]

In order to achieve the above object, a semiconductor device according to the present invention is obtained by encapsulating a semiconductor element with an epoxy resin composition containing the following components (A) to (C). In the semiconductor device, the content of the inorganic filler as the component (C) is from 80 to 9 in the epoxy resin composition.
The inorganic filler which is set to 5% by weight and which is the component (C) contains 80% by weight or more of a spherical inorganic filler having a Wardell's sphericity of 0.7 to 1.0. Is set in the following (a) to (f). (A) An epoxy resin represented by the following general formula (1).

Embedded image (B) A phenol aralkyl resin represented by the following general formula (2).

Embedded image (C) an inorganic filler. (A) Less than 3% by weight having a particle size of less than 1 μm. (B) those having a particle size of less than 1μm than 7 [mu] m is 10 to 22 wt%. (C) the particle size 7μm or 3 1 of less than μm is 10 to 24
weight%. (D) particle size 31μm or 61 but less than μm is 20-4
0% by weight. (E) particle size 61μm or 9 1 of less than μm is 20-4
0% by weight. (F) Less than 10% by weight having a particle size of 91 μm or more.

[0007]

In other words, the present inventors have conducted a series of studies in order to obtain a sealing resin having low stress and excellent thermal stress during mounting. As a result, when the above-mentioned special epoxy resin and phenol aralkyl resin are combined, and furthermore, an inorganic filler having a specific particle size distribution is blended in a specific ratio in addition to this combination, the internal stress is reduced, and the excellent mounting The inventors have found that thermal stress properties can be obtained, and have reached the present invention.

Next, the present invention will be described in detail.

The epoxy resin composition used in the present invention comprises a special epoxy resin (component A), a phenol aralkyl resin (component B), and an inorganic filler containing a specific ratio of an inorganic filler having a specific particle size distribution. (C component) and is usually in the form of a powder or a tablet obtained by compressing it.

The special epoxy resin (component A) is a biphenyl type epoxy resin and has the following general formula (1)
It is represented by

[0011]

Embedded image

By adding a lower alkyl group to a phenyl ring having a glycidyl group, the phenyl ring has water repellency. The epoxy resin component may be composed of the special epoxy resin alone, or may be used in combination with other commonly used epoxy resins.
In the former case, all of the A component is composed of only the special epoxy resin represented by the general formula (1), and in the latter case, a part of the A component is represented by the general formula (1). It is made of special epoxy resin. Examples of the commonly used epoxy resin include cresol novolak type,
Various epoxy resins such as phenol novolak type, novolak bis A type and bisphenol A type are exemplified. As the novolak type epoxy resin, those having an epoxy equivalent of 150 to 250 and a softening point of 50 to 130 ° C. are usually used. As the cresol novolak type epoxy resin,
Those having an epoxy equivalent of 180 to 210 and a softening point of 60 to 110 ° C are generally used. When both are used in this way, it is preferable that the epoxy resin represented by the general formula (1) is set to 20% or more of the entire epoxy resin component, and particularly preferable to be 50% or more.

The above phenol aralkyl resin (component B)
Is a compound represented by the following general formula (2), which acts as a curing agent for the epoxy resin component.

[0014]

Embedded image

The phenol aralkyl resin (component B)
Can be obtained, for example, by reacting aralkyl phenol and phenol with a Friedel-Crafts catalyst. Generally, a condensation heavy compound of α, α′-dimethoxy-p-xylene and a phenol monomer is known. And as said phenol aralkyl resin (component B), softening point 70-110 degreeC, hydroxyl equivalent 150-220.
It is preferable to use one having In addition, the phenol aralkyl resin may constitute the curing agent component by itself, or may be used in combination with other commonly used phenol resins. In the former case, the entire curing agent component is composed of the phenol aralkyl resin, and in the latter case, a part of the curing agent component is composed of the phenol aralkyl resin. Examples of the commonly used phenol resin include phenol novolak, cresol novolak and the like. These novolak resins have a softening point of 50 to 110 ° C and a hydroxyl equivalent of 70 to 110.
It is desirable to use 150. When the phenol aralkyl resin is used in combination with such a normal phenol resin, the phenol aralkyl resin is preferably set to 50% or more of the entire curing agent component, and particularly preferably 70% or more. is there. The mixing ratio of the phenol aralkyl resin (including a normal phenol resin) is determined by the special epoxy resin (A component).
It is preferable that the hydroxyl groups in the phenol aralkyl resin be 0.7 to 1.3 equivalents per equivalent of epoxy group therein. More preferred is 0.9-1.1
Is equivalent.

Examples of the inorganic filler (component C) include crystalline and fusible fillers, as well as aluminum oxide, beryllium oxide, silicon carbide, silicon nitride and the like. Then, 80% or more of the whole inorganic filler has a Wardel sphericity of 0.7 to 1.0, and the whole inorganic filler needs to be set to the following particle size configuration. . 0.7 in the above Wardel sphericity
Having a sphericity of ~ 1.0 means that an index for measuring the sphericity of a particle by (diameter of a circle equal to the projected area of the particle) / (diameter of the smallest circle circumscribing the projected image of the particle) is 0.7 to It has a value of 1.0. That is, in the inorganic filler, the epoxy resin composition has excellent fluidity when the Wardel sphericity and the particle size configuration are within the predetermined ranges. This is because fluidity is impaired outside the range of the particle size configuration shown below.

(A) Less than 3% by weight of particles having a particle size of less than 1 μm. (B) those having a particle size of less than 1μm than 7 [mu] m is 10 to 22 wt%. (C) the particle size 7μm or 3 1 of less than μm is 10 to 24
weight%. (D) particle size 31μm or 61 but less than μm is 20-4
0% by weight. (E) particle size 61μm or 9 1 of less than μm is 20-4
0% by weight. (F) Less than 10% by weight having a particle size of 91 μm or more.

It is necessary that the content of the inorganic filler having the above properties is set in the range of 80 to 95% of the entire epoxy resin composition. That is, if the content is less than 80%, the thermal shock resistance and the thermal stress resistance are impaired, and if it exceeds 95%, the fluidity is reduced.

In the epoxy resin composition used in the present invention, a curing accelerator, a flame retardant, a coupling agent, a wax and the like may be used, if necessary, in addition to the components A to C.

Examples of the curing accelerator include amine-based, phosphorus-based, boron-based, and phosphorus-boron-based curing accelerators, which may be used alone or in combination.

As the flame retardant, a compound such as a novolak-type brominated epoxy or a bis-A-type epoxy, antimony trioxide and antimony pentoxide may be used alone or in combination.

As the above-mentioned coupling agent, methoxy or ethoxysilane such as glycidyl ether type, amine type, thiocyan type and urea type may be used alone or in combination as appropriate. A method of using the inorganic filler can be appropriately selected from a method of performing a dry blending method or a method of performing a preliminary heating reaction with the inorganic filler, and a method of performing a preliminary mixing with the organic component material.

Examples of the wax include compounds such as higher fatty acids, higher fatty acid esters, and higher fatty acid calcium, which are used alone or in combination.

The epoxy resin composition used in the present invention may contain a silicone oil and a rubber component such as a silicone rubber or a synthetic rubber in addition to the above-mentioned additives to reduce stress or to perform a humidity resistance test. An ion trapping agent represented by hydrotalcite or the like may be blended for the purpose of improving the reliability in the above.

The epoxy resin composition used in the present invention can be produced, for example, as follows. That is, first, the above-mentioned special epoxy resin, phenol aralkyl resin, inorganic filler and other additives are appropriately mixed and premixed, and then kneaded in a kneading machine such as a mixing roll machine in a heated state to melt and mix. I do. After cooling to room temperature, it can be manufactured by a series of steps of pulverizing by a known means and tableting as required.

[0026]

The semiconductor device thus obtained is
An epoxy resin composition using a special epoxy resin (component A) and a phenol aralkyl resin (component B), and further containing an inorganic filler (component C) having a specific particle size distribution and a specific ratio in addition to this combination. Accordingly, the semiconductor element is obtained by resin sealing, the occurrence of package cracks in solder mounting is suppressed, and excellent moisture resistance reliability is provided.

Next, examples will be described together with comparative examples.

First, prior to the examples, three types of silica powders X to Z having a particle size distribution as shown in Table 1 below were prepared.

[0029]

[Table 1]

[0030]

Examples 1 to 8 and Comparative Examples 1 to 3 Tables 2 and 3 below
And the above-mentioned silica powder were blended in the proportions shown in the same table.
The mixture was kneaded for a minute to obtain a powdery epoxy resin composition.

[0031]

[Table 2]

[0032]

[Table 3]

The melt viscosities at 175 ° C. of the thus obtained epoxy resin compositions of Examples and Comparative Examples were measured. A semiconductor device (80 pink wedge flat package: QFP-) is formed by resin-sealing a semiconductor element by transfer molding using the epoxy resin composition.
80) was produced. 85 ° C. /
After absorbing moisture at 85% RH for 48 hours, the number of package cracks after solder immersion at 260 ° C for 10 seconds was measured. Further, the number of package cracks generated was measured while changing the moisture absorption time to 72 hours. Furthermore, at -65 ° C / 5 min.
A temperature cycle test (TCT test) was performed at 2000 times and 4000 times at 150 ° C./5 minutes, and the number of package cracks was measured.

[0034]

[Table 4]

[0035]

[Table 5]

From the results of Tables 4 and 5, Comparative Example 1 was obtained.
The product has poor moisture absorption resistance. Further, Comparative Examples 2 and 3 are inferior in moisture absorption resistance and thermal shock resistance, and have high melt viscosity. On the other hand, in the example product, the number of package cracks generated in the heating test under moisture absorption and the TCT test was smaller than that of the comparative example product, and the melt viscosity was lower. For this reason, the products of Examples are excellent in moisture absorption resistance and thermal shock resistance, and also excellent in moldability.

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification symbol FI H01L 23/31 (72) Inventor Kazuhiro Ikemura 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Hisashi Nakajima 1-2-1, Shimohozumi, Ibaraki-shi, Osaka, Japan Nippon Denko Corporation (72) Inventor Takashi Takashi 1-2-1, Shimohozumi, Ibaraki-shi, Osaka, Japan Nippon Denko Corporation (56) References JP-A-3-232258 (JP, A) JP-A-3-66151 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 23/29, 23/31

Claims (2)

(57) [Claims] In a semiconductor device having a semiconductor element encapsulated with an epoxy resin composition containing the following components (A) to (C), the content of the inorganic filler as the component (C) is reduced. The inorganic filler which is set to 80 to 95% by weight of the epoxy resin composition and which is the component (C) has a spherical inorganic filler having a Wardel sphericity of 0.7 to 1.0. A semiconductor device containing at least 80% by weight and having an overall particle size set in the following (a) to (f). (A) An epoxy resin represented by the following general formula (1). Embedded image (B) A phenol aralkyl resin represented by the following general formula (2). Embedded image (C) an inorganic filler. (A) Less than 3% by weight having a particle size of less than 1 μm. (B) those having a particle size of less than 1μm than 7 [mu] m is 10 to 22 wt%. (C) the particle size 7μm or 3 1 of less than μm is 10 to 24
weight%. (D) particle size 31μm or 61 but less than μm is 20-4
0% by weight. (E) particle size 61μm or 9 1 of less than μm is 20-4
0% by weight. (F) Less than 10% by weight having a particle size of 91 μm or more. 2. An epoxy resin composition for semiconductor encapsulation comprising the following components (A) to (C), wherein the content of the inorganic filler as the component (C) is 8 in the epoxy resin composition.
The inorganic filler which is set to 0 to 95% by weight and which is a component (C) contains 80% by weight or more of a spherical inorganic filler having a Wardel sphericity of 0.7 to 1.0. An epoxy resin composition for semiconductor encapsulation, wherein the whole particle size is set to the following (a) to (f). (A) An epoxy resin represented by the following general formula (1). Embedded image (B) A phenol aralkyl resin represented by the following general formula (2). Embedded image (C) an inorganic filler. (A) Less than 3% by weight having a particle size of less than 1 μm. (B) those having a particle size of less than 1μm than 7 [mu] m is 10 to 22 wt%. (C) the particle size 7μm or 3 1 of less than μm is 10 to 24
weight%. (D) particle size 31μm or 61 but less than μm is 20-4
0% by weight. (E) particle size 61μm or 9 1 of less than μm is 20-4
0% by weight. (F) Less than 10% by weight having a particle size of 91 μm or more.