KR20100046463A - An high-adhesive sheet for semi-conductor package singulation - Google Patents

Abstract

PURPOSE: A high adhesive sheet for semiconductor package singulation is provided to prevent a package from being lost or damaged by firmly gripping the package in a cutting process even though the package is small and thick. CONSTITUTION: One side of a base film(1) is processed with a corona. An adhesive layer(2) is coated on the base film processed with the corona. An adhesive compound includes an acryl based polymer, acrylate oligomer, a photo-initiator, a hardener, an adhesive resin, and a leveling agent. The thickness of the adhesive layer is 15 to 35 um.

Description

Strong adhesive sheet for semiconductor package singulation {AN HIGH-ADHESIVE SHEET FOR SEMI-CONDUCTOR PACKAGE SINGULATION}

The present invention relates to a strong adhesive sheet for semiconductor package singulation, and more particularly, during a cutting process for singulation of a package, the cutting process has a strong adhesive property such that package holding or cracking does not occur by holding the package tightly. The present invention relates to a strong adhesive sheet for semiconductor package singulation that can be easily separated from a package and can have an easy peeling force such that a transition (residue and contamination) of the adhesive layer does not occur on the separated package back surface and the cut surface.

In general, the semiconductor manufacturing process is largely divided into a fabrication process and an assembly process. In recent years, the packaging process of some semiconductor (BGA (Ball Grid Array), CSP (Chip Size Package) In the development of thin and thin, EMC (Electromagnetic Compatibility) molding may go through a process of molding several packages at once, and in this case, an additional process of making the individual finished products through a package cutting process is needed. singulation) process.

The adhesive sheet for singulation must prevent package flying or cracking of the package cutting surface during the cutting process made by a high speed blade. Its characteristics are that it should be easy. In particular, the adhesive sheet for singulation must adhere to materials such as epoxy resin or ceramic, which are difficult to attach, and have a small package size and a thick feature, so that the probability of occurrence of package flying is high, and thus a very strong adhesive force is required in the cutting process. According to this trend, the adhesive force is excellent during the cutting process compared to the conventional adhesive tape (backgrinding adhesive sheet or dicing adhesive sheet), and after the process, rapid curing by ultraviolet (UV) or thermal curing is achieved. The development of highly functional adhesive tapes that can be easily removed without residues is becoming important. In addition, the high-performance adhesive tape can be used not only for package cutting but also for various products such as IR cut filter, chip LED, and optical materials such as glass saw. Is evaluated.

Meanwhile, adhesive sheets (for backgrinding or dicing) currently used in the processing of semiconductor wafers are non-UV type with low adhesion (adhesive strength of 500g _f / 25mm or less) and low adhesion (adhesive strength of 500 ~ 1000g _f / 25mm). UV type adhesive sheets are commonly used. However, since the package is relatively thick compared to the wafer, there is a possibility that sufficient adhesion may not be made to the package during the cutting of the package, or problems such as flying of the package and cracking of the cut surface of the package may occur during the cutting process. Using the adhesive sheet has a problem that it is difficult to satisfy the required physical properties. In order to satisfy these required properties, the adhesive force must be increased, but if an additive such as a tackifier resin is added to the adhesive layer to increase the adhesive strength or to increase the thickness of the adhesive layer, serious residues due to the low molecular weight material may be feared and the cohesiveness is insufficient during the cutting process. As a result, a disadvantage arises that the cutting line is pushed or it becomes difficult to support the substrate.

Therefore, by using the existing UV-type technology, it exhibits the opposite adhesive properties before and after the process, but compared to the conventional adhesive sheet for wafer processing, it has sufficient adhesive strength to hold the package when cutting the package and easily peels off the package. In order to satisfy the possible peeling property, a strong adhesive sheet having adhesive strength of 2000 ~ 3000g _f / 25mm before UV irradiation and 5 ~ 20g _f / 25mm after UV irradiation is required, but conventional products have high adhesive strength Since the level is less than about 2000g _f / 25mm, it does not have sufficient adhesive force and has the problem of causing residue and contamination.

The present invention has been made in order to solve the above problems and to have the required physical properties, the object of the present invention is to hold the package tightly during the cutting process for singulation of the package to ensure that the package flying or cracking does not occur The adhesive force before UV irradiation is 2000 so that the package can be easily separated after the cutting process and the peeling force of the adhesive layer does not occur on the back and the cut surface of the separated package. It is to provide a strong adhesive sheet for semiconductor package singulation having a value of ~ 3000g _f / 25mm, the UV adhesive after irradiation is 5 ~ 20g _f / 25mm.

These and other objects and advantages of the present invention will become more apparent from the following description of a preferred embodiment thereof.

The above object is a pressure-sensitive adhesive composition comprising an acrylic polymer, an acrylate oligomer, a photoinitiator, a curing agent, a tackifying resin, and a leveling agent as a pressure-sensitive adhesive layer coated on a corona-treated surface of the base film and a base film having a corona treatment on one side thereof. And a pressure-sensitive adhesive layer having a thickness of 15 to 35 µm, and is achieved by a strongly adhesive sheet for semiconductor package singulation.

Here, the acrylate oligomer is characterized in that the ultraviolet curable type.

In addition, the pressure-sensitive adhesive composition comprises 100 parts by weight of the acrylic polymer and 30 to 100 parts by weight of the acrylate oligomer, 2 to 5 parts by weight of the photoinitiator, 0.5 to 5 parts by weight of the curing agent and 0.001 to 0.003 parts by weight of the tackifier resin and the leveling agent. It is done.

In addition, the acrylate oligomer is characterized by having a functional group of 8 to 10 functional or more.

In addition, the strongly adhesive sheet is characterized in that the adhesive strength before the UV irradiation is 2000 ~ 3000g _f / 25mm, the adhesive strength after the UV irradiation is 5 ~ 20g _f / 25mm.

According to the present invention, it is easy to adhere to a material that is difficult to adhere due to the strong adhesive strength before UV curing, and even when the package size is small and thick, package flying or cracking can be prevented, and also, after UV curing, it is easily peeled off after the process. It is possible to increase the efficiency of the cutting process to improve the quality of the product and economical effect.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. These examples are only presented by way of example only to more specifically describe the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples. .

1 is a cross-sectional view of a strong adhesive sheet for semiconductor package singulation according to the present invention, Figures 2a to 2c is a view for explaining the transition state of the pressure-sensitive adhesive to the back of the individual package separated after the cutting process.

The strong adhesive sheet for semiconductor package singulation according to the present invention is an adhesive layer coated on one surface of the base film and the base film, the pressure-sensitive adhesive composition comprising an acrylic polymer and an acrylate oligomer, a photoinitiator, a curing agent, a tackifying resin and a leveling agent. It is coated and is characterized by including an adhesive layer having a thickness of 15 ~ 35㎛.

Here, in general, when the same pressure-sensitive adhesive layer is different in the adhesive properties according to the thickness, the thickness of the pressure-sensitive adhesive layer of the present invention is too thin (less than 15㎛) low adhesive force can not hold the substrate tightly chip crack or flying a lot It is not suitable as a pressure sensitive adhesive sheet for semiconductor package singulation. On the contrary, when the thickness is over 35 μm, if the thickness is too thick, the adhesive strength is high, which is somewhat advantageous to prevent chip cracking or flying, but the adhesive layer is thick. The adhesive layer of the strong adhesive sheet for semiconductor package singulation according to the present invention is because the adhesive transition (residue and contamination) occurs due to lack of internal cohesion and imbalance, which contaminates the substrate and thus becomes unsuitable as an adhesive sheet for semiconductor package singulation. It is most preferable that the thickness of is 15-35 micrometers.

The base film is a polyolefin film such as polyethylene film, polypropylene film, polybutene film and polymethylpentene film, and polyvinyl chloride film, polyvinylidene chloride film and polyethylene terephthalate film, polyethylene naphthalate film, polybutylene tere Polyester films, such as a phthalate film, etc. can be used. In addition, the base film is preferably visible or ultraviolet light transmission, and particularly preferably ultraviolet light transmission.

In addition, the thickness of the base film is usually 10 ~ 300㎛, preferably 100 ~ 200㎛. The base film may be a single-layered product or a laminated product of various films, and one side of the base material may be coated with conventional physics such as mat treatment, corona discharge treatment, primer treatment, and crosslinking treatment in order to increase adhesiveness and retention with the pressure-sensitive adhesive layer. Or chemical surface treatment can be carried out.

As the pressure-sensitive adhesive composition according to the present invention, a pressure-sensitive adhesive such as rubber, acrylic, silicone, or urethane can be used, and acrylic pressure-sensitive adhesive is particularly preferable.

The acrylic pressure-sensitive adhesive may be a (meth) acrylate polymer, for example methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, butyl methacrylate, 2-ethylhexyl methacrylate or octyl methacrylate. These acrylic adhesives can be used individually or in mixture of 2 or more types. In particular, the glass transition temperature of the acrylic pressure-sensitive adhesive is generally preferably below room temperature, more preferably in the range of -70 ℃ to 0 ℃. Moreover, molecular weight becomes like this. Preferably it is 100,000-1,500,000, More preferably, it is the range of 500,000-1,000,000, and it is advantageous to raise the cohesion force of an adhesive, and to improve compatibility with other additives.

The pressure-sensitive adhesive used in the present invention can be adjusted by setting the adhesive force and the cohesion force to an arbitrary value using a crosslinking agent. As such a crosslinking agent, a polyvalent epoxy compound, a polyvalent aziridine compound, a polyvalent isocyanate compound, a melamine resin, a polyamine, a carboxyl group-containing polymer, etc. are mentioned. When using a crosslinking agent, when the addition amount is too small, cohesion force is low, and when too much, it is preferable to contain 0.5-5 weight part with respect to 100 weight part of acrylic adhesive in consideration of decreasing peel adhesive force.

The pressure-sensitive adhesive is preferably designed as an ultraviolet ray-curable pressure-sensitive adhesive to reduce the adhesive force after the step, in order to facilitate removal from the workpiece. UV-curable oligomers (or monomers) are low-molecular weight compounds having at least one carbon-carbon double bond in their molecules, and those which can form three-dimensional cubic structures by light irradiation are widely used. As examples, low-molecular-weight compounds disclosed in Japanese Patent Application Laid-Open Nos. 60 (1985) -196956 and No. 60 (1985) -223139 are widely used, and trimethylolpropanetriacrylate, tetramethylolmethane tetraacrylate, penta Acrylate compounds such as erythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, urethane acrylate, polyether and polyester acrylate, epoxy acrylate, and acrylic acrylate . Among them, it is preferable to use an acrylate oligomer having a functional group having a functional group of 8 to 10 functional or more. In general, ultraviolet rays and energy ray curing are usually two or more functional oligomers, and the curing efficiency or speed depending on the irradiation of ultraviolet rays and energy rays vary depending on the number of functional groups. In order to achieve the purpose of achieving the purpose of facilitating peeling from the adherend to be significantly lowered, it is preferable to use ultraviolet and energy ray-curable oligomers having functional groups of 8 to 10 or more functionalities. Curing proceeds at a speed, and thus a decrease in adhesive force may be appropriately adjusted.

The content of the ultraviolet curable oligomer in the pressure-sensitive adhesive is usually 10 to 200 parts by weight, preferably 30 to 100 parts by weight based on 100 parts by weight of the acrylic pressure-sensitive adhesive.

In addition, the photoinitiator used to promote the curing of the ultraviolet curable oligomer in the present invention benzyl dimethyl ketal, hydroxycyclohexyl phenyl ketone, 4-benzyl-4'-methyl diphenyl sulfide, isopropyl thioxanthone, 2- Chlorothioxanthone, ethyl-4-dimethylaminobenzoate, 2-ethylhexyl-4-dimethylaminobenzoate, 4-methylbenzophenone, methyl-ortho-benzo-benzoate, methylbenzoylformate, 4 -Phenylbenzophenone, 2,4,6-trimethylbenzoyl-diphenyl phosphine, 2-hydroxy-1,2-diphenyl ethanonebenzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl Ether, benzoin benzoic acid, benzoin dimethyl ketal and the like. Such photoinitiators are generally used in an amount of 0.01 to 15 parts by weight, preferably 1.0 to 10 parts by weight, and more preferably 2 to 5 parts by weight, based on 100 parts by weight of the ultraviolet curable oligomer.

In addition, in the present invention, in order to implement a strong adhesive property of 2000 ~ 3000g _f / 25mm before UV irradiation, using a tackifying resin. Tackifier resins are usually hundreds to thousands of amorphous oligomers (dimers or more, polymers up to about 10,000 molecular weight), which are liquid or solid thermoplastics at room temperature. Natural resins include rosin-based resins such as abietic acid, levofimanic acid and neo-abietic acid, and terpene-based resins such as α-pinene, β-pinene and limonene, and synthetic resins are based on petroleum resin. Aliphatic, aromatic, and the like. In addition, in the pressure-sensitive adhesive composition according to the present invention, additives such as solvents and photosensitizers, anti-aging agents, fillers and leveling agents may be additionally used. It is preferable that such an adhesive resin, a leveling agent, a filler and the like are contained in an appropriate amount based on 100 parts by weight of the acrylic pressure-sensitive adhesive, and in the pressure-sensitive adhesive composition according to the present invention, it is preferable to include a pressure-sensitive adhesive resin and a leveling agent 0.001 to 0.003 parts by weight.

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is not limited to these Examples.

EXAMPLE

Example 1

As the base film, 100 parts by weight of a normal acrylic polymer (concentration of 30% by weight), 50 parts by weight of a 10-functional acrylate oligomer, and a photoinitiator (Ciba Specialty Chemical) were used, using PE (150 μm) corona-treated on one side. 2 parts by weight of Irgaqure-184, Daroqur-TPO, 3 parts by weight of a curing agent (Soken Chemical Co., Ltd., L-45), a tackifying resin (Kolon Oil, POLAREZ PX-95) and a leveling agent (3M, product of FC- 4430) The UV curable pressure-sensitive adhesive composition prepared by adding 0.002 parts by weight was applied to the corona treated surface of the base film to have a thickness of 25 μm to form an pressure-sensitive adhesive layer.

[Example 2]

An adhesive layer was formed in the same manner as in Example 1 except that the adhesive layer had a thickness of 15 μm.

Example 3

A pressure-sensitive adhesive layer was formed in the same manner as in Example 1 except that the pressure-sensitive adhesive layer had a thickness of 35 μm.

Example 4

A pressure-sensitive adhesive layer was formed in the same manner as in Example 1 except that a PE film having a thickness of 100 μm was used as the base film, and the thickness of the pressure-sensitive adhesive layer was 25 μm.

Example 5

An adhesive layer was formed in the same manner as in Example 1, except that a PE film having a thickness of 188 μm was used as the base film, and the thickness of the adhesive layer was 25 μm.

[Comparative Example]

Comparative Example 1

A pressure-sensitive adhesive layer was formed in the same manner as in Example 1 except that the pressure-sensitive adhesive layer had a thickness of 50 μm.

Comparative Example 2

A pressure-sensitive adhesive layer was formed in the same manner as in Example 1 except that the pressure-sensitive adhesive layer had a thickness of 3 μm.

Hereinafter, the experimental example and the results of the physical property test for the pressure-sensitive adhesive sheet prepared in the above Examples and Comparative Examples will be described.

Experimental Example

Experimental Example 1

In this experiment, the peel strength test of the pressure-sensitive adhesive sheet (peel strength) -180 ° peel test. To this end, a 25 mm wide specimen is reciprocated twice with a 2 kg roller on a test plate (SUS304, washed with solvent). After a certain period of time after attachment, the adhesive force is measured using a tensile force meter at a measurement speed of 300 mm / min. The results are shown in Table 1.

TABLE 1

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Peel strength (g _f / 25mm) Pre-UV irrad. 2500 2220 2650 2520 2450 3140 760 After-UV irrad. 11 9 11 15 12 13 15

Experimental Example 2

In this test, the cutting test of the adhesive sheet and the test (flying, crack) to check the state of the package. To this end, the package after the epoxy mold process was attached to the pressure-sensitive adhesive sheet at room temperature, left for a predetermined time, and the cutting test was performed under the following conditions.

-Equipment: NB200

-Blade: DISCO CO. Ltd (Japan)

Blade rpm: 40,000rpm

-Sawing speed: 120mm / sec

Sawing depth: 50㎛

-PKG (after epoxy moldprocess) Chip size: 1mm x 1mm, 5mm x 5mm

After the cutting process, the state of the package was observed as the number of packages in which flying or cracks were observed based on the total number of packages 100, and the results are shown in Table 2 (flying: line was twisted or product was dropped from the adhesive layer). If part occurs, crack: If the line is broken at the cutting surface of the package, the cross section is not smooth).

TABLE 2

Chip size Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 1mm x 1mm Flying 0 4 0 4 2 0 39 Crack 0 7 2 6 0 0 47 5mm x 5mm Flying 0 2 0 2 0 0 22 Crack 0 3 0 4 0 0 21

[Experimental Example 3]

In this experiment, the adhesive transition (residue and contamination) of the adhesive sheet is checked. To this end, the package after the cutting process is irradiated with 100 mW / cm ² for 10 seconds to separate from the adhesive sheet. The transition state of the adhesive on the back of the separated individual package was confirmed using the microscope. The results of confirmation of metastasis are shown in Table 3. (◎: many transitions (more than 20/100), O: few transitions (1 ~ 19/100), X: no transition)

[Table 3]

Chip size Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Residue 1mm x 1mm X O X O X ◎ X 5mm x 5mm X X O X X ◎ X

As a result of confirming through the above-described embodiments, comparative examples and experimental examples, in the case of the strong adhesive sheet for semiconductor package singulation according to the present invention, during the cutting process for singulation of the package, the package is held tightly and cracks are generated. It has a strong adhesive property that does not have a strong adhesive property, it is easy to separate the package after the cutting process, and can have an easy peeling force such that no transition (residue and contamination) of the adhesive layer occurs on the back surface and the cut surface of the separated package. You can check it.

1 is a cross-sectional view of a strong adhesive sheet for semiconductor package singulation according to the present invention.

2A to 2C are diagrams for sequentially explaining the transition state of the pressure-sensitive adhesive to the back of each package separated after the cutting process.

<Brief description of symbols for the main parts of the drawings>

1: base film 2: adhesive layer

3: release film 4: transfer of adhesive (residue and contamination)

Claims (5)

In the strong adhesive sheet for semiconductor package singulation, Base film with corona treatment on one side, A pressure-sensitive adhesive layer coated on the corona-treated surface of the base film, which is coated with a pressure-sensitive adhesive composition containing an acrylic polymer and an acrylate oligomer, a photoinitiator, a curing agent, a tackifying resin, and a leveling agent, and has a thickness of 15 to 35 μm. A strong adhesive sheet for semiconductor package singulation comprising a. The method of claim 1, Said acrylate oligomer is ultraviolet curable, characterized in that the strong adhesive sheet for semiconductor package singulation. The method of claim 2, The pressure-sensitive adhesive composition comprises 100 parts by weight of the acrylic polymer and 30 to 100 parts by weight of the acrylate oligomer, 2 to 5 parts by weight of the photoinitiator, 0.5 to 5 parts by weight of the curing agent, and 0.001 to 0.003 parts by weight of the tackifier resin and the leveling agent. , Strong adhesive sheet for semiconductor package singulation. The method of claim 1, The acrylate oligomer is a strong adhesive sheet for semiconductor package singulation, characterized in that it has a functional group of 8 to 10 or more functional. The method according to any one of claims 1 to 4. The strongly adhesive sheet is 2000 ~ 3000g _f / 25mm adhesive strength before the UV irradiation, 5 ~ 20g _f / 25mm adhesive strength after the UV irradiation, strong adhesive sheet for semiconductor package singulation.

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