KR20220131228A - Base film for dicing tape - Google Patents

Abstract

The base film for dicing tapes contains a polyethylene-based resin and a polypropylene-based resin, and has a storage elastic modulus at 100° C. of 20 MPa or more and 200 MPa or less, and a storage elastic modulus at 110° C. of 10 MPa or more and 170 MPa or less, The storage modulus at 120°C is 5 MPa or more and 140 MPa or less, and the stress in MD (at the time of 100% elongation) is 5 MPa or more and less than 20 MPa.

Description

Base film for dicing tape

The present invention relates to a base film for dicing tapes (hereinafter, simply referred to as a "base film" in some cases).

As a method for manufacturing semiconductor devices such as IC chips, for example, a wafer circuit in which a circuit is formed on a semiconductor wafer having a substantially disk shape is divided by dicing on a dicing tape for wafers to obtain individual semiconductor devices. The method is widely used. And after dicing, for example, a dicing tape is stretched to form a gap between semiconductor devices (ie, expanding), and then each semiconductor device is picked up by a robot or the like.

A dicing tape is generally comprised by the adhesive layer which fixes a wafer, and the base film containing polyolefin etc. As this base film, for example, a layer molded from a particulate thermoplastic acrylic resin composed of a core layer made of a soft acrylic acid ester-based resin and a shell layer made of a semi-rigid to hard methacrylic acid ester-based resin; The base film (refer patent document 1) in which the layer which consists of polyethylene-type resin was laminated|stacked is proposed. Moreover, the base film (refer patent document 2) which laminated|stacked the outer layer which consists of ethylene-methacrylic acid copolymer resin, and the inner layer which consists of ethylene- vinyl acetate copolymer resin etc. is proposed. Further, for example, it is a base film provided with a pressure-sensitive adhesive layer on one surface and formed of polyvinyl chloride, polyolefin, ethylene-vinyl acetate copolymer, polyester, polyimide, polyamide, etc., the pressure-sensitive adhesive layer of the base material and It is proposed that the dynamic frictional force against the SUS430BA plate on the outermost layer on the opposite side is less than 10.0N at a temperature of 23°C and a humidity of 50%. And in the dicing tape provided with this base film, it is described that expanding uniformly in a longitudinal direction and a lateral direction is realizable (refer patent document 3).

Patent Document 1: Japanese Patent No. 4643134 Patent Document 2: Japanese Patent No. 5568428 Patent Document 3: Japanese Patent No. 6211771

However, in the base film described in Patent Documents 1 and 2, a polyethylene-based resin is used, but since a resin having a low melting point is used, there is a problem that thermal deformation occurs at a high temperature and heat resistance is insufficient.

In addition, in the dicing tape provided with the base film described in Patent Document 3, the stress in the machine axis (length) direction (hereinafter referred to as "MD") of the base film significantly increases depending on the orientation of the resin. There was a problem that the flexibility (expandability) of the film was insufficient.

Therefore, this invention was made|formed in view of the said problem, and an object of this invention is to provide the base film for dicing tapes which can make heat resistance and flexibility compatible.

In order to achieve the above object, the base film for a dicing tape of the present invention is a base film for a dicing tape comprising a polyethylene-based resin and a polypropylene-based resin, and has a storage elastic modulus at 100°C of 20 MPa or more and 200 MPa or less. and the storage modulus at 110 ° C. is 10 MPa or more and 170 MPa or less, the storage modulus at 120 ° C. is 5 MPa or more and 140 MPa or less, and the stress in MD (at 100% elongation) is 5 MPa or more and less than 20 MPa. characterized.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the base film for dicing tapes excellent in heat resistance and flexibility.

Hereinafter, the base film for dicing tapes of this invention is demonstrated concretely. Here, this invention is not limited to the following embodiment, It can change suitably and apply it in the range which does not change the summary of this invention.

The base film of this invention is a base film for dicing tapes containing polyethylene-type resin and polypropylene-type resin. More specifically, the base film of the present invention is, for example, a film formed of a polyolefin-based resin, and a block polypropylene copolymerized with linear low-density polyethylene and ethylene (hereinafter simply referred to as “block polypropylene” in some cases). ), or homo polypropylene obtained by polymerization of propylene alone (hereinafter, simply referred to as “homo polypropylene” in some cases).

<Linear Low Density Polyethylene>

The linear low-density polyethylene has a branched branch in the linear structure of the high-density polyethylene. And since this side chain branch is short and there are few short-chain branches, compared with low-density polyethylene, crystallinity is high and it is excellent in heat resistance. In addition, since it has the aforementioned branched side chains, the degree of crystallinity is not excessively increased as compared with high-density polyethylene, and flexibility is also excellent.

In addition, from the viewpoint of strength, a linear low-density polyethylene prepared using a metallocene-based catalyst or a Ziegler catalyst may be used.

Moreover, it is preferable that the density of a linear low-density polyethylene is 0.910-0.919 g/cm<3>. When it is 0.910 g/cm 3 or more, the degree of crystallinity increases, so that the heat resistance of the base film can be improved. can

Further, the melt mass flow rate (MFR) of the linear low-density polyethylene is preferably 1.0 to 6.0 g/10 min, more preferably 1.5 to 4.0 g/10 min, and still more preferably 2.0 to 3.0 g/10 min. In the case of 1.0 g/10 min or more, the molecular weight is not too large, so the flexibility and processability of the base film can be improved, and in the case of 6.0 g/10 min or less, the molecular weight is not too small, so heat resistance of the base film can be improved. .

And the said melt mass flow rate can be obtained by measuring based on the prescription|regulation of JISK7210:1999.

As described above, it is possible to provide a base film excellent in heat resistance, flexibility, and isotropy by using a linear low-density polyethylene as a resin for forming the base film.

<Block polypropylene copolymerized with ethylene, homopolypropylene obtained by polymerization of propylene alone>

As polypropylene, in general, homopolypropylene obtained by polymerization of propylene alone, random polypropylene obtained by copolymerizing ethylene and propylene, and homopolypropylene obtained by copolymerizing ethylene and propylene in the presence of homopolypropylene after polymerization Block polypropylene (block polypropylene copolymerized with ethylene) is mentioned.

Among these, random polypropylene has a low stereoregularity and a small degree of crystallinity, so it is excellent in flexibility, but has a low melting point.

On the other hand, since homopolypropylene has a high stereoregularity and a high degree of crystallinity contributing to the melting point, it is excellent in heat resistance. In addition, although the degree of crystallinity is large, rigidity is large, but by mixing the aforementioned linear low-density polyethylene, flexibility contributing to the expandability of the base film can be obtained.

In addition, the block polypropylene copolymerized with ethylene is a block polypropylene composed of propylene and ethylene, and has a sea-island structure in which polyethylene (island component) is dispersed in homopolypropylene (sea component). structure) and has an EPR phase (rubber phase) around the polyethylene. Therefore, while retaining the heat resistance possessed by the homo polypropylene, the EPR image is formed on the boundary line of the sea-island, and thus the flexibility is excellent.

As described above, as a resin for forming the base film, by using a block polypropylene copolymerized with ethylene, or a homopolypropylene obtained by polymerization of propylene alone, together with the aforementioned linear low-density polyethylene, a substrate excellent in heat resistance, flexibility and isotropy A film may be provided.

<Base film>

In the base film of this invention, the storage elastic modulus (E') in 100 degreeC is 20 MPa or more and 200 MPa or less. When it is 20 MPa or more, it is possible to prevent shrinkage of the base film in the heating process, and when it is 200 MPa or less, excessive increase in the rigidity of the base film is suppressed, and flexibility (expandability) can be improved.

And it is preferable that it is 23-150 Mpa, and, as for the storage elastic modulus (E') in 100 degreeC, 25-100 Mpa is more preferable.

Moreover, similarly, in the base film of this invention, the storage elastic modulus (E') in 110 degreeC is 10 Mpa or more and 170 Mpa or less. When it is 10 MPa or more, it is possible to prevent shrinkage of the base film in the heating process, and when it is 170 MPa or less, excessive increase in the rigidity of the base film is suppressed, and flexibility (expandability) can be improved.

And it is preferable that it is 15-120 Mpa, and, as for the storage elastic modulus (E') in 110 degreeC, 20-80 Mpa is more preferable.

Moreover, in the base film of this invention, the storage elastic modulus (E') in 120 degreeC is 5 Mpa or more and 140 Mpa or less. When it is 5 MPa or more, it is possible to prevent shrinkage of the base film in the heating process, and when it is 140 MPa or less, excessive increase in the rigidity of the base film is suppressed, and flexibility (expandability) can be improved.

And it is preferable that it is 10-90 Mpa, and, as for the storage elastic modulus (E') in 120 degreeC, 15-40 Mpa is more preferable.

In addition, the said "storage elastic modulus" means what is measured using the dynamic viscoelasticity measuring apparatus based on JIS-K7244-4.

Moreover, in the base film of this invention, the stress (at the time of 100% elongation) in MD is 5 MPa or more and less than 20 MPa. In the case of 5 MPa or more, since the blade does not move in the base film during dicing, it is possible to prevent chipping at the cutting end surface of the wafer, and since it is not excessively soft, the chip can be pushed up by the needle even in the pickup process have. Moreover, when it is less than 20 Mpa, an excessive raise of the rigidity of a base film can be suppressed, and a softness|flexibility (expandability) can be improved.

Similarly, in the base film of the present invention, it is preferable that the stress (at the time of 100% elongation) in the direction (hereinafter referred to as "TD") orthogonal to MD of the base film is 5 MPa or more and less than 20 MPa. In the case of 5 MPa or more, since the blade does not move in the base film during dicing, it is possible to prevent chipping at the cutting end surface of the wafer, and since it is not excessively soft, the chip can be pushed up by the needle even in the pickup process have. Moreover, when it is less than 20 Mpa, an excessive raise of the rigidity of a base film can be suppressed, and a softness|flexibility (expandability) can be improved.

And, as for the stress (at the time of 100% elongation) in MD and TD, 7 MPa or more and 15 MPa or less are preferable.

Moreover, in the base film of this invention, it is preferable that the absolute value of the difference of the stress in MD (at the time of 100% elongation) and TD (at the time of 100% elongation) is 2 MPa or less. By such a structure, the isotropy of a base film improves further.

And the said "stress" means the stress measured based on JISK7161-2:2014.

In addition, the blending ratio of the linear low-density polyethylene in the base film and the block polypropylene copolymerized with ethylene (or the homopolypropylene obtained by polymerization of propylene alone) is particularly limited unless the characteristics of the base film of the present invention are deteriorated. Although there is no restriction|limiting, from a viewpoint of further improving the heat resistance and isotropy of a base film, in a mass ratio, the range of linear low-density polyethylene:block polypropylene (or homo polypropylene) =30:70-90:10 is preferable, 40 The range of :60-80:20 is more preferable, and the range of 50:50-80:20 is still more preferable.

In addition, when the entire base film is 100 parts by mass, the blending amount of the resin component composed of linear low-density polyethylene and block polypropylene copolymerized with ethylene (or homopolypropylene obtained by polymerization of propylene alone) is 90 parts by mass or more. desirable.

50-300 micrometers is preferable and, as for the thickness of a base film, 70-200 micrometers is more preferable. When the thickness of the base film is 50 µm or more, the handling property of the base film is improved, and when the thickness is 300 µm or less, the flexibility (expandability) of the base film can be improved. And in the case of the base film for wafers, 50-150 micrometers is preferable and 70-100 micrometers is more preferable. Moreover, in the case of the base film for packages, 100-300 micrometers is preferable and 150-200 micrometers is more preferable.

<Production method>

The base film of this invention is manufactured by using the resin material containing the above-mentioned polyethylene-type resin and polypropylene-type resin, for example by extrusion-molding at predetermined temperature with the extruder provided with a T-die. And you may manufacture the base film of this invention by the well-known calendering method or inflation method.

<Other forms>

Various additives may be contained in the base film of this invention. As the additive, known additives commonly used in dicing tapes can be used, for example, a crosslinking aid, an antistatic agent, a heat stabilizer, an antioxidant, an ultraviolet absorber, a lubricant, an antiblocking agent, a colorant, and the like. . And these additives may be used individually by 1 type, or may use 2 or more types together.

Further, examples of the crosslinking aid include triallyl isocyanurate and the like. When the base film contains a crosslinking aid, the content of the crosslinking aid in the base film is 100 parts by mass of a resin that forms the base film. With respect to this, 0.05-5 mass parts is preferable, and 1-3 mass parts is more preferable.

Example

Hereinafter, the present invention will be described based on examples. In addition, this invention is not limited to these Examples, These Examples can be modified and changed based on the meaning of this invention, and these are not excluded from the scope of the present invention.

The material used for preparation of the base film for dicing tapes is shown below.

(1) LLDPE-1: linear low-density polyethylene, melting point: 120°C, density: 0.913 g/cm 3 , MFR: 2.0 g/10 min (manufactured by Tosoh Corporation, trade names: NIPOLON-Z, ZF220)

(2) LLDPE-2: linear low-density polyethylene, melting point: 124°C, density: 0.919 g/cm 3 , MFR: 2.0 g/10 min (manufactured by Prime Polymer Co., Ltd., trade name: ULT-ZEX, 2022F)

(3) LDPE: low density polyethylene, melting point: 106°C, density: 0.920 g/cm 3 , MFR: 7.0 g/10 min (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIKATHENE, CE4506)

(4) Block PP: Block polypropylene copolymerized with ethylene, melting point: 164° C., density: 0.900 g/cm 3 , MFR: 0.6 g/10 min (manufactured by Sumitomo Chemical Co., Ltd., trade name: Noblen, AD571)

(5) Homo PP: Homo polypropylene obtained by polymerization of propylene alone, melting point: 163° C., density: 0.900 g/cm 3 , MFR: 0.5 g/10 min (manufactured by Sumitomo Chemical Co., Ltd., trade name: Noblen, D101)

(6) Random PP: Random polypropylene copolymerized with ethylene and propylene, melting point: 132°C, density: 0.890 g/cm 3 , MFR: 1.5 g/10 min (manufactured by Sumitomo Chemical Co., Ltd., trade name: Noblen, S131)

(7) Olefin-based thermoplastic elastomer: olefin-based elastomer copolymerized with ethylene and propylene, melting point: no, density: 0.889 g/cm 3 , MFR: 8.0 g/10 min (manufactured by Exxon Mobil, trade name: Vistamaxx, 3588FL)

(Example 1)

<Production of base film>

First, each material shown in Table 1 was mixed, and the resin material of Example 1 which had the composition (mass part) shown in Table 1 was prepared. Next, this resin material was extruded using a Laboplastomer (manufactured by Toyo Seiki Co., Ltd.) with a T dice having a width of 230 mm under conditions of a die temperature of 220 to 240 ° C. A base film with

<Calculation of storage modulus (E')>

100 of the produced base film (MD) using a dynamic viscoelasticity measuring device (manufactured by Hitachi High-Tech Sciences, Ltd., trade name: DMS6100) under the conditions of a starting temperature of 25°C, an ending temperature of 250°C, and a temperature increase rate of 6°C/min. The storage modulus (E') at °C, 110 °C, and 120 °C was calculated. And when the storage elastic modulus (E') at 100 ° C. is 20 MPa or more, the storage elastic modulus (E') at 110 ° C. is 10 MPa or more, and the storage elastic modulus (E') at 120 ° C. is 5 MPa or more, the substrate It was set as the thing excellent in the heat resistance of a film. Table 1 shows the above results.

<Measurement of stress (at 100% elongation) in MD and TD>

Based on JISK7161-2:2014 using the produced base film, the sample for a measurement was obtained. Next, the obtained measurement sample was set in a tensile tester (manufactured by Shimadzu Corporation, trade name: AG-5000A) so that the gap between the grippers was 40 mm, and the temperature was 23 according to JIS K7161-2:2014. A tensile test was performed at a tensile rate of 300 mm/min under an environment of 40°C and a relative humidity of 40%. And the stress (100% stress) at the time of 100% elongation in MD and TD of a base film was measured, and when a stress was less than 20 MPa, it was set as the thing excellent in the softness|flexibility of a base film. In addition, the difference between the stress in MD (at 100% elongation) and the stress in TD (at 100% elongation) was calculated, and the case where the absolute value of the difference in stress was 2 MPa or less was regarded as excellent in isotropy of the base film. Table 1 shows the above results.

(Examples 2-12, Comparative Examples 1-6)

Except having changed the composition of the resin component into the composition (part by mass) shown in Table 1, it carried out similarly to Example 1 mentioned above, and produced the base film which has the thickness shown in Table 1.

And it carried out similarly to Example 1 mentioned above, the storage elastic modulus (E') was computed, and the stress (at the time of 100% elongation) was measured. Table 1 shows the above results.

As shown in Table 1, the base films of Examples 1 to 8 composed of linear low-density polyethylene and block polypropylene copolymerized with ethylene, and homopolypropylene obtained by polymerizing linear low-density polyethylene and propylene alone In the base film of Examples 9-12 comprised, the storage elastic modulus (E') in 100 degreeC is 20 MPa or more, the storage elastic modulus (E') in 110 degreeC is 10 MPa or more, and the storage elastic modulus in 120 degreeC (E) ') is 5 MPa or more, so it can be seen that the heat resistance is excellent. In addition, since the stress in MD and TD of the base film is less than 20 MPa, it is excellent in flexibility and, since the absolute value of the difference in stress is 2 MPa or less, it can be seen that the isotropy is excellent.

On the other hand, in the base film of Comparative Example 1, since it consists only of the block polypropylene copolymerized with ethylene, rigidity increases and flexibility (expandability) falls. Therefore, it can be seen that the base film of Comparative Example 1 lacks flexibility and isotropy.

In addition, in the base film of Comparative Example 2, since it consists only of homopolypropylene obtained by polymerization of propylene alone, the rigidity is high and the flexibility is lowered, and as shown in Table 1, the stress in the MD of the base film is greater than 20 MPa. , and the film was broken at the TD of the base film. Therefore, it can be seen that the base film of Comparative Example 2 lacks flexibility and isotropy.

In addition, in the base film of Comparative Example 3, random polypropylene is included instead of block polypropylene copolymerized with ethylene, and this random polypropylene, as described above, has excellent flexibility but has a low melting point. It can be seen that the base film has a low storage elastic modulus (E') and lacks heat resistance.

In addition, since the base film of Comparative Example 4 is made of only linear low-density polyethylene, the melting point is low and thermal deformation occurs at high temperature. Therefore, it can be seen that the base film of Comparative Example 4 has a low storage elastic modulus (E') and lacks heat resistance. In addition, since the film fractured due to melting, the storage modulus (E') at 120°C could not be measured.

In addition, since the base film of Comparative Example 5 consists only of low-density polyethylene having a high density (0.920 g/cm 3 ), it lacks isotropy, and the MFR of the low-density polyethylene is large (7.0 g/10 min) and has a low melting point. Therefore, it can be seen that the heat resistance is insufficient. In addition, since the film fractured due to melting, the storage modulus (E') at 120°C could not be measured.

In addition, the base film of Comparative Example 6 contains an olefinic thermoplastic elastomer, and this olefinic thermoplastic elastomer has a low softening temperature. lack can be seen. In addition, the storage modulus (E') at 110°C and 120°C could not be measured because the film broke due to melting.

As explained above, this invention is suitable for the base film for dicing tapes.

Claims (7)

As a base film for a dicing tape comprising a polyethylene-based resin and a polypropylene-based resin,
The storage modulus at 100 ° C. is 20 MPa or more and 200 MPa or less, the storage modulus at 110 ° C. is 10 MPa or more and 170 MPa or less, and the storage modulus at 120 ° C. is 5 MPa or more and 140 MPa or less,
When the stress in MD (at 100% elongation) is 5 MPa or more and less than 20 MPa
A base film for a dicing tape, characterized in that. According to claim 1,
Stress in TD (at the time of 100% elongation) is 5 Mpa or more and less than 20 Mpa, The base film for dicing tapes characterized by the above-mentioned. 3. The method of claim 2,
The base film for a dicing tape, characterized in that the absolute value of the difference between the stress in the MD (at the time of 100% elongation) and the stress at the TD (at the time of 100% elongation) is 2 MPa or less. 4. The method according to any one of claims 1 to 3,
linear low-density polyethylene;
Block polypropylene copolymerized with ethylene, or homo polypropylene obtained by polymerization of propylene alone
A base film for a dicing tape, comprising: 5. The method of claim 4,
The mass ratio of the said linear low-density polyethylene and the said block polypropylene is linear low-density polyethylene:block polypropylene =30:70-90:10, The base film for dicing tapes characterized by the above-mentioned. 5. The method of claim 4,
A mass ratio of the linear low-density polyethylene to the homopolypropylene is linear low-density polyethylene:homopolypropylene=30:70 to 90:10, The base film for dicing tapes. 7. The method according to any one of claims 4 to 6,
The base film for a dicing tape, characterized in that the melt mass flow rate of the linear low-density polyethylene is 1.0 to 6.0 g/10 min or more.