JPH09249869A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive composition suitable for forming an adhesive layer at a fine part e.g. a tip end part of a lead frame finger in mask printing method. SOLUTION: This adhesive composition contains an adhesive resin and an inorganic filler, and is a paste state adhesive composition capable of being applied to a prescribed place of a lead frame with a mask printing. In this adhesive composition, a ratio of a solid fraction (a) based on a solvent 1, is 1.2<=a<=2.9 and viscosity ranges (b) are in the ranges of 1000<=b<=1500Pa.S at 0.1rpm shearing speed, 400<=b<=550Pa.S at 0.5rpm and 300<=b<=400Pa.S at 1.0rpm measured at 25 deg.C.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a mask printing system,
For example, the present invention relates to a composition of an adhesive suitable for forming an adhesive layer on a fine portion such as a tip portion of a lead frame finger.

[0002]

2. Description of the Related Art Conventionally, an adhesive film used for fixing a semiconductor element to a lead frame has been used by punching out with a mold, and thus has a problem that burrs are generated and reliability is reduced. Also, since the adhesive film is stretched between the inner leads other than the part that actually participates in the adhesion, not only is the adhesive film wasted, but also the volume of the adhesive film is increased, so that the amount of moisture absorption increases and package cracks occur. It will be easier. In addition, polyimide resin,
It has excellent properties such as high heat resistance and is known as a thin film molding material. Since the polyimide itself has low viscosity, it lacks printability, and because of its high fluidity, sagging occurs and printing on fine parts is not suitable. An adhesive resin and a filler are kneaded and uniformly dispersed to increase the viscosity and produce an ink. It has excellent printability, improves moisture resistance and heat resistance, and reduces the stress by bringing the coefficient of linear expansion closer to the lead frame.

[0003]

However, the above-mentioned adhesive paste has a small adhesive layer thickness, and in order to obtain a certain thickness, it is necessary to repeatedly print on many layers, which is difficult in terms of accuracy. is there. Further, they do not fully satisfy the releasability, shape, adhesive layer thickness and adhesive strength.

[0004]

DISCLOSURE OF THE INVENTION The present invention is a paste-like adhesive composition containing an adhesive resin and an inorganic filler, which can be applied to a predetermined place of a lead frame by metal mask printing. Further, the ratio a of the solid content to the solvent 1 is 1.2 ≦ a ≦ 2.9, and the viscosity range b is 25 ° C. at a shear rate of 0.1 rpm of 10
00 ≦ b ≦ 1500Pa ・ S, 0.5rpm 400 ≦ b
≦ 550Pa · S, 300rpm at 1.0rpm, b ≦ 400Pa
-The above-mentioned adhesive composition characterized by being in the range of S, and the adhesive resin has a glass transition temperature of 100 ° C.
To 250 ° C, viscosity of 20 to 5 at shear rate of 5.0 rpm
The adhesive composition is the adhesive resin composed of a solvent-soluble polyimide resin in the range of 0 Pa · S, and the polyimide resin contains silicon diamine represented by the formula (1) based on all diamines. 2 mol% or more, 50 mol%
The adhesive composition is a polyimide resin containing the following,

Embedded image (In the formula, R ₁ and R ₂ : a divalent aliphatic group or aromatic group having 1 to 4 carbon atoms R ₃ , R ₄ , R ₅ and R ₆ : a monovalent aliphatic group or aromatic group k : Integer of 1 to 20) Further, the inorganic filler has an average particle size of 0.005 to 0.05.
μm (component A) and average particle size 5 to 10 μm (component B)
, 12-18 μm (component C) or 26-35 μm
The above-mentioned adhesive composition is an inorganic filler obtained by blending at least two kinds of spherical silica having a particle size different from that of (Component D), and the paste-like adhesive composition is a polyimide resin 100. 2X + 10 ≦ y ≦ 5X + 30 (x:
The adhesive composition is in the range of average particle diameter, y: compounding weight part) and is in a state capable of metal printing.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As the adhesive resin used in the present invention, either a thermosetting resin or a thermoplastic resin can be used. A polyimide resin, which is a thermoplastic resin, is preferably used because it does not need to be cured. The adhesive resin used in the present invention has a glass transition temperature of 100 to 250 ° C. and a viscosity of 20 to 50 at a shear rate of 5.0 rpm.
A solvent-soluble polyimide resin having a range of Pa · S is preferable. If the glass transition temperature is 100 ° C. or lower, the adhesive layer becomes loose due to the heat applied during wire bonding, and the stability of the chip deteriorates. Also,
When the glass transition temperature is 250 ° C. or higher, since the chip and the lead frame are bonded by thermocompression bonding, the fluidity is deteriorated and the adhesive force may be reduced. Viscosity is 1000 ≤ b ≤ 1500 Pa at shear rate of 0.1 rpm
S, 0.5 rpm 400 ≤ b ≤ 550 Pa · S, 1.0r
If it falls below the lower limit of 300 ≤ b ≤ 400 Pa · S in pm, sagging will occur and the printability will deteriorate, and if it exceeds the upper limit, stringing,
The problem of surface smoothness comes out.

The polyimide resin used in the present invention contains 2,2-bis [4-] as a main amine component and an acid component.
(4-Aminophenoxy) phenyl] propane (BAP
P), 2,5-dimethyl-P-phenylenediamine (2
5DPX), 1,3-bis (aminopropyl) tetramethylenediamine (APDS), 1,3-bis (3-aminophenone) benzene (APB), 3,3 ', 4,4'.
-Biphenyltetracarboxylic dianhydride (BPDA),
Examples thereof include 3,3 ′, 4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA), 4,4′-oxydiphthalic acid dianhydride (ODPA), and phthalic acid dianhydride (PA). The polyimide resin used in the present invention is preferably a polyimide resin containing silicon diamine represented by the formula (1) in an amount of 2 mol% or more and 50 mol% or less with respect to all diamines. When the amount of silicon diamine is less than 2 mol%, Tg becomes low, which causes a problem in W / B property. When it is 50% or more, thermocompression bonding of the chip and the lead frame must be performed at high temperature. However, there is a problem in that the storability tends to occur and the storage stability is not good. The inorganic filler used in the present invention is preferably silica, and it is desirable that its shape is spherical and closer to a true sphere.

The inorganic filler used in the present invention has an average particle size of 0.005 to 0.05 μm (component A), an average particle size of 5 to 10 μm (component B), and 12 to 18 μm (component C).
Alternatively, it is preferably an inorganic filler obtained by blending at least two kinds of spherical silica having a particle size different from 26 to 35 μm (component D). If only a filler having a large particle size is used, the thickness of the adhesive layer can be obtained, but the adhesive force between the chip and the lead frame will be reduced. Therefore,
By reducing the compounding amount of the filler having a large particle diameter and using the filler having a higher viscosity and a small particle diameter, the high adhesive strength is maintained. In addition, in the paste-like adhesive composition of the present invention, the components B, C and D are 2X + 10 ≦ y ≦ 5X + 30 (x: 100 parts by weight of the polyimide resin and 10 parts by weight of the component A).
It is preferable that metal printing can be performed within the range of average particle diameter, y: compounding weight part). If the content of Component A is more than this blend, stringing of the paste will occur, and if it is less than this, the dimensional stability of printing will deteriorate. If the components B, C and D are added in excess of this amount, the adhesive strength will decrease, and if the amount is less than this, the thickness of the adhesive layer will not be sufficient. If necessary, a surface treatment agent such as a silane coupling agent may be used for the filler which is a component of the paste in order to enhance the adhesiveness with the resin.

[0008]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

[Example 1] NMP1281.992g dehydrated and purified was placed in a four-necked flask equipped with a dry nitrogen gas inlet tube, a condenser, a thermometer, and a stirrer, and the mixture was vigorously stirred for 10 minutes while flowing nitrogen gas. Next, 209.362 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and 2,5-dimethyl-P
23.153 g of phenylenediamine (25 DPX),
1,3-bis (aminopropyl) tetramethylenediamine (APDS) 42.248 g was added, and the system was heated to 60 ° C.
Heat to stir and stir until uniform. Then, the system was cooled to 5 ° C. in an ice water bath, and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) 171.560.
80,525 g of 3,3 ', 4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) was added as a powder over 15 minutes, and stirring was continued for 3 hours. During this time, the flask was kept at 5 ° C. Then, the nitrogen gas introduction tube and the cooling tube were removed, a Dean-Stark tube filled with xylene was attached to the flask, and 142.444 g of toluene was added to the system. The system was heated to 175 ° C. instead of the oil bath, and the generated water was removed from the system. After heating for 2.5 hours, generation of water from the system was no longer observed. After cooling, this reaction solution was dissolved in a large amount of methanol to obtain a polyimide resin A.

Silica is a component A (Aerosil NAX50.
Nippon Aerosil Co., Ltd., ingredient B (FB-302X.
Denki Kagaku Kogyo Co., Ltd.), C (FB-48X / Denki Kagaku Kogyo Co., Ltd.) and D (FB-74X / Denki Kagaku Kogyo Co., Ltd.), in which silica is mixed with an adhesive resin before kneading.
It is dried to remove the water adsorbed on silica. Then, it is mixed with a polyimide resin and stirred at a place controlled to have a humidity of 20% or more and less than 40% and a temperature of 25 ° C. To 100 parts by weight of polyimide resin and 10 parts by weight of component A,
Component B, C and D are 2X + 10 ≦ y ≦ 5X + 30 (x: average particle size,
(y: blending weight part) was blended and kneaded by a roll to make the filler uniformly dispersed to prepare a paste.

This paste is printed by metal mask printing
The adhesive layer was obtained by applying it on a 42 alloy plate and heating it in steps from 80 ° C to 250 ° C. After the semiconductor element was pressed thereon at 400 ° C. for 1 second, the shear adhesive strength was measured at room temperature using a push-pull gauge. The adhesive thickness was measured with a micro gauge, and the shape, the detachability and the flow were measured with a surface measuring microscope. The evaluation standard is that the adhesive force is 90% or more excellent and less than 90 as compared with the adhesive force of the film made by not adding the filler to the polyimide resin.
% Or more is ◯, less than 75% is Δ, and less than 50% is x. Removability, shape, and flow were visually divided into four stages. The adhesive thickness was 120 μm or more as excellent, 80 μm or more and less than 120 μm as ◯, 50 μm or more and less than 75 μm as Δ, and 50 μm or less as x. Table 2 shows the evaluation results.

"Examples 2 to 3 and Comparative Examples 1 to 15" In the same manner as in Example 1, polyimide resins B and C were obtained using an acid and an amine in the ratios shown in Table 1. An adhesive composition having the composition shown in Table 2 was obtained from these polyimide resins and inorganic fillers. In the same manner as in Example 1, the adhesive strength, release property, shape,
The adhesive thickness and flow were measured. The results are shown in Table 2.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

EFFECTS OF THE INVENTION Although the adhesive strength of the component A alone is sufficient,
Stringing and adhesive layer thickness are problems. When only the components B, C and D are used, the releasability, the shape and the thickness of the adhesive layer are good, but the adhesive force is not obtained. In the present invention, by mixing the component A and the components B, C and D into the adhesive resin, the releasing property, the shape and the thickness of the adhesive layer are maintained and the adhesive force is improved. By using the fillers having different particle diameters, it is possible to suppress the stringing and the mountain shape of the adhesive layer when used alone, and to maintain the adhesive force.

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Claims (6)

[Claims] 1. An adhesive resin and an inorganic filler are contained,
A paste-like adhesive composition, which can be applied to a predetermined place on a lead frame by metal mask printing. 2. In the adhesive composition, the ratio a of the solid content to the solvent 1 is 1.2 ≦ a ≦ 2.9, the viscosity range b is measured at a temperature of 25 ° C., and the shear rate is 0.1r.
1000 ≦ b ≦ 1500 Pa · S at pm, 400 ≦ b ≦ 550 Pa · S at 0.5 rpm, 300 ≦ b at 1.0 rpm
2. The range of ≦ 400 Pa · S is set.
The adhesive composition as described in the above. 3. The adhesive resin has a glass transition temperature of 100.
The adhesive composition according to claim 1, which is an adhesive resin composed of a solvent-soluble polyimide resin having a viscosity of 20 to 50 Pa · S at a shear rate of 0.5 rpm at a temperature of ℃ to 250 ℃. 4. A polyimide resin comprising the silicon diamine represented by the formula (1) in an amount of 2 mol% or more based on all diamines,
The adhesive composition according to claim 3, which is a polyimide resin containing 50 mol% or less. Embedded image (In the formula, R ₁ and R ₂ : a divalent aliphatic group or aromatic group having 1 to 4 carbon atoms R ₃ , R ₄ , R ₅ and R ₆ : a monovalent aliphatic group or aromatic group k : Integer of 1 to 20) 5. The inorganic filler has an average particle size of 0.005 to 0.005.
0.05 μm (component A) and average particle size 5 to 10 μm (component B), 12 to 18 μm (component C) or 26 to 3
The adhesive composition according to claim 1, which is an inorganic filler obtained by blending at least two kinds of spherical silica having a particle diameter different from 5 μm (component D). 6. The paste-like adhesive composition has 2X + 10 ≦ y ≦ 5X + 30 (x: average particle size) in which 100 parts by weight of the polyimide resin and 10 parts by weight of the component A are added to the components B, C and D. , Y:
The adhesive composition according to claim 1, 2, 3, 4, or 5, which is in a state of being capable of metal printing within the range of (part by weight).