JP2003226849A - Hot-melt adhesive sheet for electronic member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive hot-melt adhesive sheet for an electronic member, suitably usable for the temporary fixing of an outer lead part of a lead frame, or the like, and the adhesion of the electronic member for splicing, or the like, of CCL, or the like, which hardly require heat resistance, not requiring a long time at high temperature when carrying out the sticking, and allowing a stuck product to be easily separated. <P>SOLUTION: This double layered adhesive sheet has an adhesive layer formed on a filmy supporter. The adhesive layer consists essentially of (a) a crystalline polyurethane resin having 50-90°C flow-starting temperature, (b) a saturated polyester resin having 0-110°C glass transition temperature, and (c) a filler, wherein the mixed proportions of the components (a), (b) and (c) in the adhesive layer are regulated so as to be (a) 100 pts.wt., (b) 5-120 pts.wt. and (c) 20-200 pts.wt. respectively. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive sheet used for adhering electronic members, and more specifically, to temporary fixing of outer lead portions such as lead frames and CCL (Cop).
The present invention relates to a hot melt adhesive sheet for electronic members, which is preferably used as an electronic member for splicing such as per Cladlaminate).

[0002]

2. Description of the Related Art Heretofore, as an adhesive sheet for electronic members, there has been mentioned an adhesive sheet mainly composed of a polyimide film support coated with and laminated with a polyimide resin alone or modified with another resin.

Here, in the conventional adhesive sheet,
The reason for using a material such as a polyimide resin is that the adhesive sheet is required to have sufficient "heat resistance" to withstand heating in the semiconductor device assembly process and the like. A polyimide resin having high heat resistance is used for the adhesive sheet used for the member.

At present, an adhesive sheet using a polyimide resin is most commonly used in the field of adhesion of electronic members of this kind, and is particularly suitable for adhesion of electronic members requiring "heat resistance". Is used for.

[0005]

However, the adhesive sheet using the above-mentioned polyimide resin has defects such as poor handleability because it requires a high temperature and a long time for adhesion.

Further, since materials such as polyimide resin are relatively expensive, they are too expensive to be used as an adhesive for splicing when processing CCL or the like into a flexible printed circuit board (FPC), and thus the final product is too expensive. There was a big problem in reducing the cost.

Similarly, to use it for temporary fixing of the outer lead portion or the like for the purpose of steady rest when evaluating the insulation property,
In addition to the problem that it is too expensive, it has the drawback that it cannot be easily peeled off once it is bonded.

That is, the conventional adhesive sheet using a polyimide resin is preferably used for bonding electronic members requiring heat resistance, but temporary fixing such as outer lead portions requiring almost no heat resistance or In applications such as member splicing, handling property is poor and there is a problem in terms of cost. Therefore, the adhesive sheet is cheaper, high temperature at the time of adhesion, does not require a long time, and is removable. Is strongly demanded.

Therefore, as a result of intensive studies to solve the above-mentioned problems, the present inventor has found that an adhesive layer containing a specific polyurethane resin, polyester resin and filler as essential components on a film-like support. The present inventors have found that a two-layered adhesive sheet obtained by laminating the above objects achieves the above-mentioned object, and completed the present invention.

That is, the present invention was developed from the viewpoint completely different from the conventional adhesive sheet which requires heat resistance, and it is used for temporary fixing of outer lead parts such as lead frames which require almost no heat resistance and for CCL and the like. It is suitable for splicing and other electronic components, and it is inexpensive, and does not require a long time at high temperature during bonding, and it can be easily peeled off even after it has been bonded once. It is intended to provide a melt adhesive sheet.

[0011]

In order to achieve the above object, a hot melt adhesive sheet for electronic members according to the present invention has a two-layered adhesive sheet having an adhesive layer provided on a film-shaped support. The adhesive layer has the following components (a) to (c) as essential constituent components, and the mixing ratio of the adhesive layer is (a) 100 parts by weight:
(B) 5 to 120 parts by weight and (c) 20 to 200 parts by weight. (A) Crystalline polyurethane resin having a flow initiation temperature of 50 to 90 ° C. (b) Saturated polyester resin having a glass transition temperature of 0 to 110 ° C. (filler) Hot melt adhesive for electronic components of the present invention The sheet will be described in more detail.

In the hot melt adhesive sheet for electronic members according to the present invention, the main polymer among the components constituting the adhesive layer is not particularly limited as long as it is a crystalline saturated polyurethane resin (a) having high non-tack property. Although it is not a special one, it has particularly high crystallinity, has high cohesive strength even without cross-linking, and since it has many polar groups in its molecular structure, it has excellent adhesive properties for a wide range of materials. The crystalline linear polyurethane resin having is preferable.

Further, in the present invention, as the characteristic required for the crystalline saturated polyurethane resin (a), the flow initiation temperature is preferably in the range of 50 to 90 ° C., and particularly,
It is preferably in the range of 55 to 80 ° C.

When the flow starting temperature exceeds 90 ° C., it becomes necessary to lengthen the bonding time or increase the bonding temperature for temporarily fixing the outer lead portion of the lead frame or the like. In the case of not only the productivity will be hindered, but also the adverse effects such as the deterioration of the lead position accuracy due to the thermal strain will be caused, which is not preferable. As in the case of (1), adverse effects such as CCL deformation at the bonding step and peeling may occur, which is not preferable.

On the other hand, when the flow starting temperature is lower than 50 ° C., tack is generated in a summer environment, resulting in poor workability, which is not preferable.

Next, as the saturated polyester resin (b) to be blended with the crystalline polyurethane resin (a) which is the main polymer, a saturated polyester resin (b) which plays an auxiliary role of improving the adhesive force to a film-like support described later. The crystalline polyester resin (b) used in the present invention has a glass transition temperature (hereinafter referred to as Tg) of 0 to 1.
It is preferably in the range of 10 ° C, particularly 5 to 100 ° C.
Is more preferably in the range.

If the Tg is less than 0 ° C., tack problems occur in the summer environment, resulting in poor workability, which is also undesirable in this case. On the other hand, if the Tg exceeds 110 ° C., the softening point of the resin is 150. The temperature tends to be higher than 0 ° C., and it becomes necessary to increase the bonding temperature condition when bonding the electronic member or to lengthen the bonding time, which is not preferable.

Further, in the present invention, the mixing ratio of the crystalline polyurethane resin (a) and the saturated polyester resin is such that (b) is 5 to 5 parts by weight with respect to 100 parts by weight of (a).
It is necessary to set it in the range of 120 parts by weight, particularly preferably in the range of 10 to 100 parts by weight.
If the amount of (b) is less than 5 parts by weight, the amount of (b) is too small to improve the adhesiveness to the film-like support, which is not preferable. It is not preferable since it cannot be expected to relax the internal stress that contributes to the adhesive force by deteriorating the rubber elasticity of).

Further, in the present invention, in the hot-melt adhesive sheet for electronic members, in order to reduce the cohesive failure of the adhesive layer at the time of peeling, it is necessary to add the filler (c), whereby the paste is used. It can be easily peeled off without leaving any residue.

Examples of the filler (c) include an inorganic filler and / or an organic filler, and the filler is not particularly limited as long as it is used in this field. Absent.

More specifically, the inorganic filler may be at least one selected from metal oxides, carbides, nitrides or carbonates, and the metal may be Al, Be, V, Fe, Y, C
o, Cu, Ni, Si, Sn, Ti, Cr, Ce, Z
At least one selected from r, Ca, Ta, Nb and the like can be mentioned.

On the other hand, as the organic filler, powdery or granular materials of polymer resin material can be preferably used, and as the polymer resin material, phenol resin, epoxy resin, melamine resin can be used. It may be thermosetting resin such as urea resin, allyl resin, furan resin, unsaturated polyester, silicone resin, polyimide and polyurethane, or olefin resin, acrylic resin, styrene resin, polyvinyl chloride resin. , Polyamide, polyamide-imide, saturated polyester resin, polycarbonate, polyacetal, ionomer resin, polyether sulfone, polyphenylene oxide, polyphenylene sulfide or polysulfone may be a thermoplastic resin such as, in the present invention, these Polymer resin material Or at least one member selected from the can be appropriately selected.

In the present invention, the mixing ratio of the crystalline polyurethane resin (a) and the filler (c) is 20 to 200 with respect to 100 parts by weight of the (a).
It is preferably in the range of parts by weight, particularly 50 to 150.
More preferably, it is in the range of parts by weight.

If the amount of (c) is less than 20 parts by weight relative to 100 parts by weight of (a), the compounding effect, that is, the effect of reducing cohesive failure of the adhesive layer at the time of peeling is difficult to be exhibited. However, it is not preferable because there is no point in blending, and on the other hand, when it exceeds 200 parts by weight, the adhesive force is lowered, and it becomes difficult to obtain the required adhesive force, which is not preferable.

From the above, in the hot-melt adhesive sheet for electronic members according to the present invention, the crystalline polyurethane resin (a), the saturated polyester resin (b) and the filler (c) are essential components, and The preferable mixing ratio of the components is (B) based on 100 parts by weight of (a).
5 to 120 parts by weight and (c) 20 to 20
It is obtained by blending in the range of 0 parts by weight.

In the present invention, the crystalline polyurethane resin (a) and saturated polyester resin (b) are used.
And the filler (c) as an essential component, but if necessary, modifiers such as fatty acid esters, phthalic acid esters, amide compounds and phosphoric acid ester compounds, pigments, vinyl acetate Even if the adhesiveness, melt viscosity, hue, etc. are adjusted by adding an appropriate amount of an elastomer having good compatibility with polyesters such as ethylene vinyl esters and styrene-butadiene rubber, as well as an antioxidant and an antioxidant. It's good.

By the way, in the hot melt adhesive sheet for electronic members of the present invention, the constituent components (a) to (c) contain almost no ionic impurities. Is almost not included,
It also has an advantage that it does not have a bad influence such as corrosion of a metal part such as copper of the electronic member.

In the hot-melt adhesive sheet for electronic members of the present invention, appropriate amounts of the predetermined components (a) to (c) described above are mixed and dispersed in an organic solvent, and the compounded liquid has a predetermined thickness. It is obtained by coating on a film-like support, heating and drying.

As the film-shaped support, a film made of a polymeric material can be preferably used. Specific examples of the polymeric material include polyurethane, polyethylene and ethylene-vinyl acetate. Polymer, polyvinyl chloride, polyamide, polyester, polyacetal, polysulfone, polyphenylene oxide, polybutadiene, polypropylene, cellophane,
Examples thereof include polychloroprene, polyamino acid, nitrile rubber, butyl rubber, silicone rubber, and the like, and examples thereof include a single-layer film formed from this polymer material in a film shape or a laminated film composed of two or more kinds of films. Above all, from the viewpoint of strength and cost, it is preferable to use a support obtained by molding a polyester such as polyethylene terephthalate (hereinafter referred to as PET film) into a film shape.

The thickness of the film-like support is not particularly limited according to its use, but it is generally preferably in the range of 12 to 75 μm, and when the thickness is less than 12 μm, it is thin. If it exceeds 75 μm, it is not preferable because it is too thick and the mechanical strength is inferior. On the other hand, if it exceeds 75 μm, it is too thick and the flexibility and handleability are impaired.

In the present invention, in order to improve the handleability as an adhesive sheet, one surface of each of these film-like supports is subjected to a surface-adhesive treatment such as corona treatment, and the back surface thereof is separated. It is preferable to use a mold-treated product.

The hot-melt adhesive sheet for electronic members of the present invention is particularly preferably used for temporarily fixing outer lead portions such as lead frames and for adhering electronic members for splicing such as CCL.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Examples and specific examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

Example 1 100 parts by weight of a crystalline polyurethane resin having a flow starting temperature of 65 ° C. and 50 parts of a saturated polyester resin having a Tg of 60 ° C.
1 part by weight and 100 parts by weight of silica as a filler are mixed, dissolved and dispersed in an appropriate amount of an organic solvent, and then uniformly stirred and kneaded with a kneader to obtain a P having a thickness of 50 μm.
The hot-melt adhesive sheet for an electronic member of the present invention is obtained by applying it on one surface of an ET film so that the total thickness after drying is 70 μm, and drying in a hot-air circulation dryer at 100 ° C. for 3 minutes. It was That is, the thickness of the adhesive layer is 20 μm
Was prepared so that (the same applies hereinafter).

Example 2 100 parts by weight of a crystalline polyurethane resin having a flow starting temperature of 65 ° C. and 30 parts of a saturated polyester resin having a Tg of 60 ° C.
2 parts by weight of saturated polyester resin consisting of 70 parts by weight of saturated polyester resin having a Tg of 7 ° C. and 100 parts by weight of silica as a filler are mixed, dissolved and dispersed in an appropriate amount of an organic solvent, and then a kneader is used. By uniformly stirring and kneading, a PET film having a thickness of 50 μm is coated on one surface so that the total thickness after drying is 70 μm, and dried at 100 ° C. for 3 minutes in a hot air circulation dryer, The hot melt adhesive sheet for electronic members of the present invention was obtained.

Example 3 Two kinds of saturated polyester resins comprising 70 parts by weight of a saturated polyester resin having a Tg of 60 ° C. and 30 parts by weight of a saturated polyester resin having a Tg of 7 ° C. per 100 parts by weight of a crystalline polyurethane resin having a flow starting temperature of 65 ° C. And 100 parts by weight of silica as a filler are mixed, dissolved and dispersed in an appropriate amount of an organic solvent, and then uniformly stirred and kneaded with a kneader to obtain a PET film having a thickness of 50 μm and a total thickness after drying. The hot melt adhesive sheet for an electronic member of the present invention was obtained by applying it on one surface so as to have a thickness of 70 μm and drying it at 100 ° C. for 3 minutes in a hot air circulation type dryer.

Example 4 100 parts by weight of a crystalline polyurethane resin having a flow starting temperature of 79 ° C. and 50 parts of a saturated polyester resin having a Tg of 60 ° C.
1 part by weight and 100 parts by weight of silica as a filler are mixed, dissolved and dispersed in an appropriate amount of an organic solvent, and then uniformly stirred and kneaded with a kneader to obtain a P having a thickness of 50 μm.
The hot-melt adhesive sheet for an electronic member of the present invention is obtained by applying it on one surface of an ET film so that the total thickness after drying is 70 μm, and drying in a hot-air circulation dryer at 100 ° C. for 3 minutes. It was

Comparative Example 1 100 parts by weight of a crystalline polyurethane resin having a flow starting temperature of 95 ° C. and 30 parts of a saturated polyester resin having a Tg of 60 ° C.
2 parts by weight of saturated polyester resin consisting of 70 parts by weight of saturated polyester resin having a Tg of 7 ° C. and 100 parts by weight of silica as a filler are mixed, dissolved and dispersed in an appropriate amount of an organic solvent, and then a kneader is used. By uniformly stirring and kneading, a PET film having a thickness of 50 μm is coated on one surface so that the total thickness after drying is 70 μm, and dried at 100 ° C. for 3 minutes in a hot air circulation dryer, An adhesive sheet was obtained.

Comparative Example 2 Two kinds of saturated polyester resin consisting of 2 parts by weight of a saturated polyester resin having a Tg of 60 ° C. and 2 parts by weight of a saturated polyester resin having a Tg of 7 ° C. per 100 parts by weight of a crystalline polyurethane resin having a flow starting temperature of 65 ° C. , And 100 parts by weight of silica as a filler are mixed, dissolved and dispersed in an appropriate amount of an organic solvent, uniformly stirred and kneaded with a kneader, and dried on a PET film having a thickness of 50 μm. The adhesive sheet was obtained by applying the adhesive sheet on one side so as to have a thickness of 70 μm and drying in a hot-air circulating dryer at 100 ° C. for 3 minutes.

Comparative Example 3 100 parts by weight of a crystalline polyurethane resin having a flow starting temperature of 65 ° C. and 30 parts of a saturated polyester resin having a Tg of 60 ° C.
2 parts by weight of saturated polyester resin consisting of 70 parts by weight of saturated polyester resin having a Tg of 7 ° C. and 15 parts by weight of silica as a filler are mixed, dissolved and dispersed in an appropriate amount of an organic solvent, and then a kneader is used. By uniformly stirring and kneading, a PET film having a thickness of 50 μm is coated on one surface so that the total thickness after drying is 70 μm, and dried at 100 ° C. for 3 minutes in a hot air circulation dryer, An adhesive sheet was obtained.

Comparative Example 4 A commercially available adhesive film was used in which a polyimide film having a thickness of 50 μm was coated with a polyimide adhesive to a total thickness of 70 μm.

The following comparative tests were carried out on the hot-melt adhesive sheets for electronic members according to the present invention of Examples 1 to 4 and the adhesive sheets of Comparative Examples 1 to 4, respectively.

In this comparative test, (1) adhesive force (temporary fixing force) and (2) releasability of each adhesive sheet were examined, and each test condition is as follows.

(1) Adhesive Force (Temporary Fixing Force) Measurement Test I A copper foil (1/2 ounce,
The thickness of the copper foil is about 18 μm), and the surface area of the copper foil is 60 mm in width and 10 mm in length.
The copper foil was pressure-bonded under the bonding conditions of ° C, a pressure of 0.5 MPa, and a bonding time of 15 seconds, and left for 1 hour. Then, the force required for peeling the adhesive sheet and the copper foil from the adhesive sheet and the copper foil in the test mode T at a pulling rate of 100 mm / min and a chuck distance of 100 mm was measured with a tensile tester for each sample to which the copper foil was pressure-bonded. The adhesive strength of the sample was measured. The results are shown in Table 1. Test II A copper foil was pressure-bonded to each sample in the same manner as in Test I except that the bonding conditions were a temperature of 150 ° C., a pressure of 0.5 MPa, and a bonding time of 1 second, and the bonding of each sample was performed by the same operation as in Test I. The force was measured. The results are shown in Table 1.

(2) Evaluation of Peelability Each sample was heated to 80 ° C. and 150 ° C., and the state of adhesive residue on the copper foil when the copper foil was peeled off from the adhesive sheet at each temperature was visually observed. evaluated. The results are shown in Table 1.

[0046]

[Table 1]

The results shown in Table 1 show that the hot-melt adhesive sheets for electronic members of the present invention according to the examples show good adhesive force even under the relatively low temperature pressure bonding condition of 80 ° C.
It was also confirmed that the removability was good.

On the other hand, in the adhesive sheet according to the comparative example, except for the adhesive sheets other than the comparative example 3, it was recognized that the adhesive strength was remarkably low particularly under the relatively low pressure bonding condition of 80 ° C.

In addition, in the adhesive sheet of Comparative Example 3, the adhesive strength was relatively high, but the releasability was poor, and it was recognized that there is a possibility that the adherend may be broken or re-peeled during re-peeling. .

From the above results, it was confirmed that only the hot-melt adhesive sheet for electronic members of the present invention had good adhesiveness and releasability, and thus the hot-melt adhesive sheet for electronic members of the present invention was confirmed. It has been recognized that the sheet is economically advantageous and well-balanced as an electronic member such as a lead frame or a process material for splicing applications.

[0051]

INDUSTRIAL APPLICABILITY The hot melt adhesive sheet for electronic members of the present invention has the above-mentioned constitution, that is, as a hot melt adhesive sheet for electronic members, a specific polyurethane resin or polyester resin is formed on a film-like support. And an adhesive sheet having a two-layer structure in which an adhesive layer having a filler as an essential component is laminated, the cost is extremely low,
In addition, the effects of not requiring high temperature and long time at the time of adhesion and easily peeling by reheating even after once adhering are exhibited.

In particular, the hot melt adhesive sheet for electronic members of the present invention exhibits excellent functionality as a process material for electronic members such as temporary fixing of lead frame outer leads and splicing of CCL, and at room temperature. It has no tackiness and does not contain a cross-linking agent, so that it has excellent long-term stability and remarkably excellent storage stability.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J004 AA02 AA14 AA15 AA17 AA18                       AB03 CC02 FA05 FA08                 4J040 ED001 ED002 EF001 EF002                       HA076 HA136 HA196 HA206                       JA09 JB01 KA42 LA02 LA06                       LA08 NA19 NA20

Claims (3)

[Claims] 1. A two-layer structure adhesive sheet comprising an adhesive layer provided on a film-shaped support, wherein the adhesive layer contains the following components (a) to (c) as essential constituent components. Moreover, the mixing ratio of the adhesive layer is (b) 5 to 120 parts by weight and (c) 20 to 200 with respect to 100 parts by weight of (a).
A hot melt adhesive sheet for electronic members, characterized in that it is parts by weight. (A) Crystalline polyurethane resin having a flow initiation temperature of 50 to 90 ° C (b) Saturated polyester resin having a glass transition temperature of 0 to 110 ° C (c) Filler 2. The hot melt adhesive sheet for an electronic member according to claim 1, wherein the filler is an inorganic filler and / or an organic filler. 3. The hot melt adhesive sheet for an electronic member according to claim 1, wherein the support is formed by molding polyester into a film.