JPH0912991A - Tacky agent of sheet for fixing semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tacky agent, comprising an elastomer, a tackifying resin and a curing agent in a specific proportion, excellent in chip holding and nonfouling properties, capable of performing the full dicing into minimal chips and useful as a sheet for fixing a semiconductor wafer. SOLUTION: This tacky agent of a sheet for fixing a semiconductor wafer comprises (A) 100 pts.wt. elastomer such as a natural rubber, (B) 5-200 pts.wt. tackifying resin such as a rosin-based resin and (C) 0.05-30 pts.wt. curing agent such as tolylene diisocyanate. Furthermore, the tacky agent of the sheet for fixing the semiconductor wafer preferably has 3.0×10<5> to 5.9×10<6> dyn/cm<2> storage elastic modulus and 20-300gf/20mm peel strength from a semiconductor wafer at 180 deg. (at 300mm/min peeling rate).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive agent for a sheet for fixing a semiconductor wafer when the semiconductor wafer is cut and separated into chip pieces, and in particular, it has a very small chip holding property and a non-contaminating property, and is a very small semiconductor chip. The present invention relates to a pressure-sensitive adhesive for a semiconductor wafer fixing sheet, which is suitable for cutting.

[0002]

2. Description of the Related Art Conventionally, a pressure-sensitive adhesive for a semiconductor wafer fixing sheet is used as a sheet for fixing a semiconductor wafer when it is cut into a chip shape to be formed (for example, JP-A-60-19695).
No. 6 publication). The semiconductor wafer cutting / separating means includes a full dicing method of cutting the semiconductor wafer with a rotary round blade, and a half dicing method in which a shallow wedge-shaped groove is formed on the surface of the semiconductor wafer according to the chip pieces to be formed and then external force is applied. There is a dicing method.

In order to make the sheet compatible with the full dicing method, the chip holding property (adhesive strength) must be set so that it can withstand not only the impact at the time of full dicing but also the water pressure received at the time of washing after separation. In particular, in the case of a chip of 0.3 to 1.0 mm square called a very small chip, it is necessary to exhibit the above properties with a small contact area.

[0004]

An emulsion type acrylic pressure-sensitive adhesive is known as a pressure-sensitive adhesive used for such a special purpose, but it is easily soluble in water and has a spherical shape with a diameter of about 0.3 μm. Since water easily enters the interface between the agent surface and the semiconductor wafer, cooling water supplied during dicing reduces the adhesive strength and the semiconductor wafer is splattered unnecessarily when it is diced (the problem of low chip retention). There is. Further, since a surfactant is added to the emulsion type acrylic pressure-sensitive adhesive, the problem that the surfactant adheres to the wafer chip and contaminates the chip and also deteriorates the electrical characteristics of the chip (non- It has a problem of high pollution).

Further, Japanese Patent Application Laid-Open No. 60-196956 discloses a semiconductor wafer having a light-transmissive support and an adhesive layer provided on the support and cured by light irradiation. A thin plate is disclosed. A chip element in which a semiconductor wafer is firmly fixed to an adhesive layer when the semiconductor wafer is cut and separated, and after cutting the semiconductor wafer is irradiated with ultraviolet rays to cure the adhesive layer to reduce the adhesive force and cut and separated. Can be picked up easily. However,
This method has a new problem that an expensive ultraviolet irradiation device is indispensable and an expensive product is obtained.

Therefore, an object of the present invention is to firmly fix a semiconductor wafer on a sheet when cutting and separating the semiconductor wafer, and to use an adhesive when picking up the cut and separated small pieces of semiconductor elements. It is an object of the present invention to provide a pressure-sensitive adhesive for a semiconductor wafer fixing sheet, which can be easily picked up without adhering to the element and can be manufactured at low cost without requiring a special device.

[0007]

Means for Solving the Problems As a result of intensive investigations in view of the above, the present inventor has determined that the main components of the adhesive used in the sheet for fixing a semiconductor wafer are an elastomer, a tackifying resin and a curing agent, and a predetermined amount. It has been found that the above problems can be solved by manufacturing in a ratio, and the present invention has been completed.

That is, the adhesive of the semiconductor wafer fixing sheet according to the present invention comprises 100 parts by weight of the elastomer, 5 to 200 parts by weight of the tackifying resin, and 0.05 to 30 of the curing agent.
It is characterized in that the weight part is the main part.

The elastomer is adopted because the elastomer has a soft molecular skeleton, so that it adheres firmly to the semiconductor wafer and the chips do not scatter unnecessarily during dicing and can be stably diced. Further, the blade is not damaged due to scattering of chips, the durability of the blade is improved, and the productivity is improved.

As the elastomer, natural rubber, synthetic isoprene rubber, SBR (styrene butadiene rubber), styrene / butadiene block copolymer, butyl rubber, polyisobutylene / silicon rubber, polyvinyl isobutyl ether / chloroprene, nitrile rubber, kraft rubber, Styrene / ethylene / butylene block copolymer,
Styrene / propylene / butylene block copolymer, styrene / isoprene block copolymer, acrylonitrile / butadiene copolymer, methyl methacrylate /
There are butadiene copolymers, polyisobutylene / ethylene / propylene copolymers, ethylene vinyl acetate copolymers, polybutadiene, acrylonitrile / acrylic ester copolymers, polyvinyl ethers, etc., and not only these but also mixtures thereof. Good. Further, these recycled rubbers may be used.

The reason why the tackifying resin is adopted is to impart the conventional tackiness while achieving the above object. If the amount of the tackifying resin added is too small, the tackifying effect does not appear and the tackifying resin becomes soft. 5 to 200 parts by weight, preferably 10 to 1 since the non-contaminating property becomes too low.
00 parts by weight is good.

Specific examples of the tackifying resin contained in the pressure-sensitive adhesive of the present invention include rosin-based resins, terpene-based resins,
There are aliphatic petroleum resins, aromatic petroleum resins and hydrogenated petroleum resins, and these may be used alone or as a mixture.
Examples of the rosin-based resin include rosin, polymerized rosin, hydrogenated rosin, rosin ester, hydrogenated rosin ester, and rosin phenol resin, and examples of the terpene-based resin include terpene, terpene phenol resin, and aromatic modified terpene resin. There is. Examples of the hydrogenated petroleum resin include aromatic ones, dicyclopentadiene-based ones, and aliphatic ones.

The reason why the above-mentioned curing agent is adopted as the pressure-sensitive adhesive according to the present invention is to increase the cohesive force as a pressure-sensitive adhesive while enhancing the non-contaminating property, but if too much is mixed, the physical properties of the pressure-sensitive adhesive as a whole are unstable. If it is too small, the non-staining property will be low, so 0.05 to 30 parts by weight, preferably 1.0
It is preferable to mix the mixture in an amount of up to 5.0 parts by weight.

Examples of the curing agent include isocyanate, a mixture of sulfur and a fluxing accelerator, polyalkylphenol, organic peroxide and the like, and these may be used alone or as a mixture. Examples of the isocyanate include phenylene diisocyanate, tolylene diisocyanate, diphenyl metadiisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, and the like.
Examples of the sulfur and the fluxing accelerator include a thiazole fluxing accelerator, a sulfenamide fluxing accelerator, a thiuram fluxing accelerator and a dithioate salt fluxing accelerator. Examples of the polyalkylphenol include butylphenol, octylphenol, and nonylphenol, and examples of the organic peroxide include benzoyl peroxide, dichromyl peroxide, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, and peroxy. Examples include esters and peroxydicarbonates.

Incidentally, conventionally known fillers, antioxidants, softeners, stabilizers or colorants can be appropriately selected and added to the pressure-sensitive adhesive according to the present invention.

Further, another feature of the present invention according to the present application is that the storage elastic modulus of the pressure-sensitive adhesive obtained by adjusting and blending the above-mentioned main components within the above-mentioned predetermined amount range is 3.0 ×.
It is set within the range of 10 ^{5 to} 5.9 × 10 ⁶ dyn / cm ² . If this storage elastic modulus is too small, the surface tension energy will be too large and softened, and the non-contaminating property that the adhesive will adhere to the cut / separated element will decrease.If it is too large, the surface tension energy will be insufficient. It is preferable to set it within the above range, because it is hardened and the cut elements are undesirably scattered during cutting and separation. The storage elastic modulus is a value when the pressure-sensitive adhesive is measured with a viscoelasticity measuring device at 30 ° C.

Another feature of the present invention of the present application is that the adhesive obtained by adjusting and blending the above-mentioned main components within the range of the above-mentioned predetermined amount has a 180-degree peeling adhesive force (peeling speed). 300 mm / min) is 20 to 300
gf / 20mm, preferably 60-100gf / 20m
m. In addition, this value is JIS Z 02.
It is based on 37.

The reason for limiting the value to such a value is that such a value varies depending on the composition and thickness of the pressure-sensitive adhesive, but the chip holding property is further improved by specifying the value. If the 180-degree peeling adhesive force (peeling speed 300 mm / min) is too large, the non-contaminating property is lowered, and if it is too small, the chips that should be fixed during dicing will fly unintentionally.

As the support for supporting the pressure-sensitive adhesive according to each invention of the present application, a conventionally known support can be appropriately selected and used, and examples thereof include plastic films such as polyvinyl chloride, polyethylene terephthalate, polyethylene and polypropylene. and so on. The thickness of the support can be appropriately changed and used, and is generally selected from the range of 10 to 500 μm.

[0020]

EXAMPLES Examples and comparative examples of the adhesive for a semiconductor wafer fixing sheet according to the present invention will be described in detail while disclosing main compounds and their characteristic values in Tables 1 to 4. The unit of the numerical value of the compound in each table is parts by weight.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

[Table 3]

[0024]

[Table 4]

As an elastomer, the plasticity (JIS K 6
300) 30 natural rubber from Malaysia, Arakawa Chemical Co., Ltd. Alcon P-90 (C5C9
Hydrogenated petroleum resin) is mixed in the ratio shown in the table, and ANTAGE W-50 manufactured by Kawaguchi Chemical Co., Ltd. is used as an antiaging agent outside the table.
2 parts by weight of 0 and 570 parts by weight of toluene were added and stirred and dissolved, and CORONATE 2067 manufactured by Nippon Polyurethane Industry Co., Ltd. as an isocyanate-based curing agent was added at a ratio shown in the table to obtain an adhesive. In Comparative Examples 3 and 4 disclosed in Table 3, the terpene resin (YSRESIN 12 manufactured by Yasuhara Chemical Co., Ltd.) was used as the tackifying resin.
50), terpene phenol resin (YS RESI of the same company)
N POLY STAR 100) was used.

The characteristic values were measured by applying the pressure-sensitive adhesive prepared in the above mixing ratio to a polyvinyl chloride film having a thickness of 10 μm and heating and drying at 100 ° C. for 1 minute.

The storage elastic modulus in the characteristic value is measured at a temperature of 30.
The temperature is measured by using a viscoelasticity measuring device Dynamic Analyzer RDA-11 manufactured by Rheomatric Far East Co. at 180 ° C., and the 180-degree peeling adhesive force (peeling speed 300 mm / min) is based on JISZ 0237, and the unit is It is gf / 20mm.

The chip-holding property is such that the chip does not fly at all when it is fully cut into 0.5 mm square chips 20 minutes after a silicon semiconductor wafer having a thickness of 400 μm is stuck on the semiconductor fixing sheet. 5 ”, 10% or less than 20% of the chips are skipped“ 4 ”, 10% or more and less than 20% of the chips are skipped“ 3 ”, 20% or more and less than 50% of the chips are skipped“ 2 ” , "1" means that more than 50% of the chips were blown.

The non-staining property means that no adhesive can be found when observing the surface of the wafer when it is peeled off after the silicon semiconductor wafer is attached to the adhesive and stored at 65 ° C. for 7 days under a microscope of 200 times. "4" for tatami, maximum diameter 2
If there was a glue lump with a diameter of 0 μm or more and less than 100 μm, it was “3”, if there was a glue lump with a maximum diameter of 1 mm or more, it was “2”, and if the glue remained on the entire surface of the wafer, it was “1”. did.

In Examples 1 to 4, the storage elastic modulus was 3.0 ×.
In the range of 10 ^{5 to} 5.9 × 10 ⁶ dyn / cm ² and 18
0 degree peeling adhesive strength (peeling speed 300 mm / min) is 20 to 3
Since it was in the range of 00 gf / 20 mm, the chip holding property was excellent and the non-contaminating property was also excellent.

The pressure-sensitive adhesives of Examples 5 to 8 were the elastomers 10
It was produced at a compounding ratio of 0 parts by weight, 5 to 200 parts by weight of tackifying resin and 0.05 to 30 parts by weight of a curing agent, but the storage elastic modulus is 3.0 × 10 ^{5 to} 5.9 × 10. ⁶ dyn
/ Cm ² and the 180 degree peeling adhesive strength (peeling speed 300 mm / min) is outside the range of 20 to 300 gf / 20 mm. It was a little inferior in the property and / or the non-staining property.

In the pressure-sensitive adhesives of Comparative Examples 1 to 4, the blending ratio of the main components was out of the range of the present invention, the storage elastic modulus and the 180 ° peeling adhesive force were also out of the ranges described above, and the tackifying resin was not included. The chip retention was poor (see Comparative Example 1), and the high number was poor in non-staining property (see Comparative Example 2). Further, when the amount of the curing agent was large, the chip retention was poor (see Comparative Example 3), and when the curing agent was not included, the non-staining property was poor (see Comparative Example 4).

Examples 9 to 12 are pressure sensitive adhesives prepared in the same manner as in Examples 1 to 8 as disclosed in Table 4.
A Malaysian natural rubber having a plasticity of 20 was used, and in Examples 10 to 12, a Malaysian natural rubber having a plasticity of 45 was used. Further, as tackifying resins, Examples 9 and 10 were used.
The above-mentioned ARKON P-90 is used in Examples 11 and 12, and the above-mentioned YS RESIN 1250 and YS are used in Examples 11 and 12.
RESIN POLY STAR 100 was used for each. The characteristic values in Table 4 are obtained by the same method as described above.

As is clear from the examples, the chip holding property, even when the plasticity of the elastomer or the tackifying resin itself is changed,
It was possible to obtain an adhesive having excellent non-staining properties.

[0035]

The adhesive of the semiconductor wafer fixing sheet according to the present invention is characterized by containing 100 parts by weight of elastomer, 5 to 200 parts by weight of tackifying resin, and 0.05 to 30 parts by weight of curing agent. Therefore, the chip holding property and the non-contaminating property are high, and in particular, there is an effect that full dicing into a very small chip can be performed.

The storage elastic modulus of the pressure-sensitive adhesive having the above compounding ratio is 3.0.
By specifying x10 ^{5 to} 5.9x10 ⁶ dyn / cm ² , the chip holding property and the non-contaminating property are further high, and in particular, there is an effect that full dicing into an extremely small chip can be performed.

A pressure-sensitive adhesive for a semiconductor wafer fixing sheet according to another invention is a 180-degree peeling adhesive force (peeling speed 300 mm /
(Minute) is limited to 20 to 300 gf / 20 mm, whereby the chip retention and non-contamination are further enhanced, and there is an effect that full dicing into a very small chip can be performed.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Uchida 2-13-1, Tai, Kamakura City, Kanagawa Toyo Kagaku Co., Ltd.

Claims (3)

[Claims] 1. A pressure sensitive adhesive for a semiconductor wafer fixing sheet, comprising 100 parts by weight of an elastomer, 5 to 200 parts by weight of a tackifying resin and 0.05 to 30 parts by weight of a curing agent. 2. 3.0 × 10 ^{5 to} 5.9 × 10 ⁶ dyn /
A storage elastic modulus of cm ² is provided.
An adhesive for a semiconductor wafer fixing sheet as described above. 3. A 180-degree peeling adhesive force (peeling speed 300 mm / min) to a semiconductor wafer is 20 to 300 gf / 2.
The pressure-sensitive adhesive for a sheet for fixing a semiconductor wafer according to claim 1, which has a thickness of 0 mm.