JP2007012670A - Pressure-sensitive adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive tape for dicing/die bonding without transfer, in which a pressure-sensitive adhesive layer of a wafer sticking part is sufficiently peeled from a substrate film at the time of picking up a chip, pressure-sensitive adhesive does not adhere to a jig such as a dicing frame and arbitrary substrate film can be used. <P>SOLUTION: In the pressure-sensitive adhesive tape 1, the pressure-sensitive adhesive layer 12 is installed on at least one face of the substrate film 11. A release layer 13 is partially arranged between the substrate film 11 and the pressure-sensitive adhesive layer 12 in the pressure-sensitive adhesive tape for dicing die bonding of a semiconductor wafer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an adhesive tape used in a process of manufacturing various semiconductors. More specifically, in manufacturing a semiconductor device such as a silicon wafer, the wafer is fixed and diced. The present invention relates to an adhesive tape for semiconductor wafer dicing-die bonding, which is also used in an adhesion process (die bonding) for overlapping with a semiconductor chip.

Adhesive material layer and base material used in the bonding process (die bonding) for fixing wafers etc. and dicing them in the assembly process of semiconductor devices such as ICs, and then superimposing them with lead frames and semiconductor chips Various thermosetting adhesive tapes for semiconductor wafer dicing-die bonding (hereinafter referred to as dicing-die bonding adhesive tapes) configured so that the film layer is peelable have been proposed (for example, Patent Document 1). And 2).
The dicing-die bonding adhesive tape disclosed in the above patent document can be used in the same manner as a conventional dicing tape when dicing. Furthermore, when the chip is picked up, the adhesive layer of the tape is peeled off from the base film of the tape together with the chip, and during die bonding, when the chip is placed on a lead frame or the like and heated, The adhesive attached to the chip works as a thermosetting adhesive, and so-called direct die bonding is possible in which the step of applying the die bonding adhesive is omitted.

By the way, the base film generally used for the normal pressure-sensitive adhesive tape is subjected to surface treatment in order to improve the adhesiveness of the adhesive layer. Specifically, a surface treatment apparatus using a corona discharge, a low-pressure mercury lamp, or the like is used to oxidize the substrate surface by ozone generated by the irradiated energy to modify the surface of the substrate film, or A material for strengthening the adhesion with the adhesive layer called a primer is applied to the surface of the material film.
On the other hand, in the adhesive tape for dicing-die bonding described in the above-mentioned patent document, in order to easily peel the adhesive layer that becomes the wafer bonding portion from the base film, the above-mentioned The surface treatment of the base film is not performed. For this reason, if the adhesive tape described in the above-mentioned patent document is repeatedly adhered to a jig for fixing a wafer such as a dicing frame during dicing, the adhesive layer of the adhesive layer of the tape is used. There was a problem that the adhesive was transferred to the jig. Here, “transfer” means that part or all of the adhesive is not completely peeled off from the adherend and remains on the adherend.

  As a measure for preventing the transfer of such an adhesive, a method such as processing and sticking another pressure-sensitive adhesive tape for the purpose of preventing transfer to a predetermined shape, raw material costs, Both processing costs were expensive. In addition, there are methods such as performing a surface treatment using a corona discharge, a low-pressure mercury lamp, or applying a primer only to a frame pasting portion of a base film that has not been surface-treated. However, when the chip is peeled from the base film that has not been subjected to such surface treatment, the adhesive layer may be in close contact with the base film over time, which may make peeling difficult.

Furthermore, since the adhesive layer may be in close contact with the base film depending on the type of the base film and the smoothness of the surface, chip peeling may be difficult, so in the adhesive tape described in the above patent document When using a specific adhesive, there was a problem that the base film which can be used was limited. Specifically, in the above patent document, a light transmissive support having a surface tension of 40 dyn / cm or less is preferably used as the base film. Here, since the base film has a great influence on the performance such as chipping at the time of dicing, the fact that the base film is limited is a big obstacle for improving the performance of the adhesive tape for dicing die bonding. It was.
JP-A-2-32181 JP-A-8-53655

  Therefore, the present invention provides a dicing die in which the adhesive layer of the wafer bonding portion is peeled off favorably from the base film at the time of picking up the chip, and there is no transfer of the adhesive to a jig such as a dicing frame. An object of the present invention is to provide an adhesive tape for bonding, which can use any base film.

  As a result of intensive studies to solve the above problems, the present inventors set the adhesive strength so that transfer does not occur for the adhesive in the adhesive layer of the tape, and wafer bonding By applying a release agent between the base film of the tape in the part and the adhesive layer, while preventing the adhesive from transferring to the dicing frame when sticking to the dicing frame, In addition, for the wafer bonding part, when the chip is picked up, the adhesive layer of the tape is peeled off from the base film of the tape together with the chip, and so-called direct die bonding is possible. I have found that I can provide wearing tape. The present invention has been made based on such findings.

That is, the present invention
(1) An adhesive tape in which an adhesive layer is provided on at least one surface of a base film, and a release agent layer is partially provided between the base film and the adhesive layer. Dicing semiconductor wafer, characterized in having adhesive-adhesive tape for die bonding,
(2) The adhesive tape according to (1), wherein the release agent layer is provided corresponding to a wafer bonding portion,
(3) The surface energy of the surface in contact with the adhesive layer in the release agent layer is lower than the surface energy of the surface in contact with the adhesive layer in the base film (1) Or the adhesive tape according to item (2),
(4) When adhesively bonded to an adherend, the peel adhesive strength of the adhesive in the adhesive layer to the substrate film is stronger than the peel adhesive strength to the adherend. (1) to (4) characterized in that the adhesive tape according to any one of (1) to (3) and (5) the release agent layer are colored. The adhesive tape according to any one of the above items is provided.
In this specification, a semiconductor device refers to an IC or the like in which a semiconductor chip is bonded to a support member such as a lead frame and sealed with a resin.

The dicing-die bonding adhesive tape of the present invention can be used as a dicing tape during dicing, and can also be used as an adhesive during mounting, and is attached to a jig. Prevents adhesive transfer without providing an anti-transfer layer or surface treatment on the part, and the adhesive layer at the wafer bonding part is good from the base film when picking up the chip Can be peeled off. Any base film can be used for the adhesive tape for dicing-die bonding of the present invention.
In addition, the dicing-die bonding adhesive tape of the present invention has an effect that the wafer bonding portion can be easily distinguished by coloring the release agent layer provided corresponding to the wafer bonding portion. Play.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the description of each drawing, the same elements are denoted by the same reference numerals.
FIG. 1 is a perspective view showing a preferred embodiment of the adhesive tape of the present invention, and FIG. 2 is a cross-sectional view showing a preferred use state of the adhesive tape of the present invention. 1 and 2, 1 is an adhesive tape, 11 is a base film, 12 is an adhesive layer, 13 is a release agent layer, 14 is a wafer, and 15 is a surface of the adhesive layer that contacts the wafer. , 16 is a dicing frame, 17 is a surface in contact with the dicing frame 16 in the adhesive layer 12, 18 is a surface in contact with the adhesive layer 12 in the release agent layer 13, and 19 is adhesive in the base film 11. Each surface in contact with the agent layer 12 is represented.

  The adhesive tape 1 of the present invention is an adhesive tape in which an adhesive layer 12 is provided on at least one surface of a base film 11, and the base film 11 and the adhesive layer 12 A release agent layer 13 is partially provided between the two. Although there is no restriction | limiting in particular in the thickness of the adhesive tape of this invention, Preferably it is 50-300 micrometers.

The base film 11 used in the present invention is not particularly limited and any film can be used. For example, polyethylene, polypropylene, polymethylpentene, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer. Examples thereof include resins such as polymers, ethylene-methyl (meth) acrylic acid esters, ethylene-ethyl (meth) acrylic acid copolymers, ethylene-ionomer copolymers, ethylene-vinyl alcohol copolymers, polybutenes, and elastomers.
These resins may be used alone or in a blend of two or more. Furthermore, the base film may be composed of a single resin film layer as described above, or may be a laminate of two or more films. Although the thickness of a base film does not have a restriction | limiting in particular, Preferably it is 30-200 micrometers.

In the present invention, the adhesive used for the adhesive layer 12 is adhesive to the substrate film 11 of the adhesive in the adhesive layer 12 when the adhesive is adhered to an adherend such as a dicing frame. It is preferable that the peel adhesive strength is stronger than the peel adhesive strength for the adherend. This is to prevent the adhesive from peeling off from the base film 11 and remaining on the adherend when the adhesive tape of the present invention is peeled off from the adherend.
Moreover, the peel adhesive strength of the adhesive layer 12 to the adherend is preferably 0.1 to 10 N / mm, more preferably 1 to 3 N / mm. If the peel adhesion strength to the adherend is too low, the wafer cannot be fixed or cannot be attached to a jig such as a dicing frame, and if it is too high, the adhesive may transfer to the jig. This is not preferable. It does not specifically limit as a kind of adhesive used for this invention, For example, an acrylic adhesive, a urethane type adhesive, etc. can be used. Examples of the adhesive used in the present invention include adhesive components such as epoxy resins, phenol resins, and phenoxy resins to various general-purpose pressure-sensitive adhesives such as acrylic, polyester, urethane, silicone, and natural rubber. What was included can be used.
The thickness of the adhesive layer 12 can be appropriately adjusted depending on the adhesive strength, and is not particularly limited, but is preferably 3 to 50 μm.

In the adhesive tape of the present invention, the release agent layer 13 is partially provided between the base film 11 and the adhesive layer 12. It is preferable that the release agent layer 13 is provided corresponding to the part to which the wafer 14 is bonded. Moreover, it is preferable that the surface energy of the surface 18 in contact with the adhesive layer 12 in the release agent layer 13 is lower than the surface energy of the surface 19 in contact with the adhesive layer 12 in the base film 11. Thereby, the adhesive layer 12 at the wafer bonding portion can be favorably peeled off from the release agent layer 13 on the base film 11 at the time of chip pickup.
The surface energy of the surface 18 of the release agent layer 13 is appropriately adjusted so as to be lower than the surface energy of the surface 19 of the base film 11. The surface energy of the surface 19 in contact with the adhesive layer 12 in the base film 11 is preferably 50 to 80 mN / m. Further, the surface energy of the surface 18 in contact with the adhesive layer 12 in the release agent layer 13 is preferably 10 to 25 mN / m. If the surface energy of the surface 18 of the release agent layer 13 is too low, it is not preferable because the adhesive may not stick to the surface 18 of the release agent layer 13 at all.
The surface energy of the surface 18 in contact with the adhesive layer 12 in the release agent layer 13 is 1/4 to 1/2 of the surface energy of the surface 19 in contact with the adhesive layer 12 in the base film 11. Preferably there is.

  The release agent used for the release agent layer in the present invention is not particularly limited. For example, a curable silicone resin, a polymer having a long alkyl side chain, and the like can be used. A mold agent (for example, paraffin wax type or carnauba wax type) can also be used.

As the curable silicone resin, any reaction type such as a condensation reaction type, an addition reaction type, an ultraviolet ray or an electron beam curable type can be used. These curable silicone resins may be used alone or in combination of two or more.
The curable silicone resin has a degree of polymerization of about 500 to 200,000, preferably about 1,000 to 100,000, and specific examples thereof include KS-718 manufactured by Shin-Etsu Chemical Co., Ltd. 774, −775, −778, −779H, −830, −835, −837, −838, −839, −841, −843, −847, −847H, X-62-2418, −2422, −2125, -2492, -2494, -470, -2366, -630, X-92-140, -128, KS-723A / B, -705F, -708A, -883, -709, -719, Toshiba Silicone Co., Ltd. TPR-6701, -6702, -6703, -3704, -6705, -6722, -6721, -6700, XSR-7029, YSR-3022, YR-3 286, DK-Q3-202, -203, -204, -210, -240, -3003, -205, -3057, SFXF-2560, manufactured by Dow Corning Co., Ltd., manufactured by Toray Dow Corning Silicone Co., Ltd. SD-7226, -7320, -7229, BY24-900, -171, -312, -374, SRX-375, SYL-0FF23, SRX-244, SEX-290, IC Japan Co., Ltd. SlLCOLEASE425 manufactured by the company can be mentioned (all are trade names). In addition, silicone resins described in JP-A-47-34447 and JP-B-52-40918 can also be used.

For applications that dislike curable silicone release agents, such as easy-to-repel water-based adhesives and casting support films for forming resin solutions, or applications where silicone component migration is not allowed, the long alkyl side A polymer having a chain can be used as a release agent.
As the polymer having a long alkyl side chain, a copolymer of an alkyl acrylate having 12 or more carbon atoms, particularly an alkyl chain having 16 to 20 carbon atoms, and acrylic acid is preferable. If the alkyl chain of the alkyl acrylate has less than 12 carbon atoms, sufficient peelability may not be obtained. In particular, a copolymer obtained by long-chain alkylation of polyvinyl alcohol or polyethyleneimine with chlorinated alkyloyl or alkyl isocyanate is preferable, specifically, polyvinyl-N-octadecyl carbamate obtained by reaction of polyvinyl alcohol and octadecyl isocyanate, And polyethyleneimine-N-octadecylcarbamate obtained by the reaction of polyethyleneimine and octadecyl isocyanate.

  The release agent layer using a polymer having the above long alkyl side chain is used as a binder for improving the strength of the layer, adhesion to the antistatic upper layer or polyester film, water resistance, solvent resistance, blocking property, etc. It is preferable to contain a thermoplastic compound such as a thermoplastic polyester resin, an acrylic resin, a polyvinyl resin and / or a high molecular compound such as a thermosetting resin such as a thermosetting acrylic resin, a urethane resin, a melamine resin, or an epoxy resin, Furthermore, it is particularly preferable that the crosslinking agent contains at least one selected from methylolated or alkylolized melamine-based, urea-based, glyoxal-based, acrylamide-based compounds, epoxy compounds, and polyisocyanates.

As a method for applying the release agent onto the base film 11, a known coating method can be applied. For example, a roll coating method, a gravure coating method, a micro gravure coating method, a reverse coating method, a roll brush method, a spray coating method, an air coating method. A knife coating method, an impregnation method, a curtain coating method, or the like can be applied alone or in combination.
Moreover, when using a curable silicone resin as a mold release agent, drying and hardening (thermal curing, ultraviolet curing, etc.) of a coating film can be performed individually or simultaneously. When performing simultaneously, it is preferable to carry out at 100 degreeC or more. The drying and curing conditions are preferably 100 ° C. or higher and 30 seconds or longer. When the drying temperature is less than 100 ° C. and the curing time is less than 30 seconds, the coating film is incompletely cured and the coating film tends to fall off, which is not preferable.

  The thickness of the release agent layer 13 in the present invention is not particularly limited, and may be any thickness as long as it does not peel from the base film and has a release property from the adhesive layer. Specifically, 0.05 to 3 μm is preferable, and 0.1 to 0.5 μm is more preferable. If it is too thin, sufficient release performance may be deteriorated and the effect may not be obtained. On the other hand, if it is too thick, it is uneconomical. This causes inconvenience in production.

  The method for producing an adhesive tape of the present invention is as follows. First, a release agent layer is applied on a base film, and then an adhesive layer is applied to a release treatment surface of a separator and the like, and the base film is attached. You just need to match. As for the coating method, a release agent and an adhesive are applied and dried by a coating machine such as a roll coater, knife coater, roll knife coater, air knife coater, die coater, bar coater, gravure coater, curtain coater, etc. Just do it. Further, with respect to the application of the release agent layer, ultraviolet irradiation or the like can be used in order to improve the adhesion to the base film.

  Before using the adhesive tape, it is preferable to temporarily stick a separator (not shown) to the upper surface of the adhesive layer 2 in order to protect the adhesive layer 2. As the separator, a conventionally known adhesive tape separator can be appropriately used.

  It is preferable that the wafer bonding part in the adhesive tape of this invention is colored. Any coloring method may be used, but it is preferable to add a colorant to the release agent layer 13 for coloring. Thereby, the adhesive layer is configured to be peelable from the release agent and easily transferred to the adherend, and the adhesive layer is difficult to peel off from the base film layer and does not transfer to the adherend. It becomes easy to distinguish the part.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these.

(Preparation of adhesive)
30 parts by mass of a cresol novolac type epoxy resin (epoxy equivalent 197, molecular weight 1200, softening point 70 ° C.) as an epoxy resin, 1.5 parts by mass of γ-mercaptopropyltrimethoxysilane as a silane coupling agent, γ-ureidopropyltriethoxysilane Cyclohexanone was added to a composition comprising 3 parts by mass and 20 parts by mass of silica filler having an average particle size of 16 nm, and the mixture was stirred and mixed, and further kneaded for 90 minutes using a bead mill.
To this, 100 parts by mass of acrylic resin (weight average molecular weight 200,000, glass transition temperature -17 ° C.), 5 parts by mass of dipentaerythritol hexaacrylate as a hexafunctional acrylate monomer, and 2,2-dimethoxy-2-phenyl as a photopolymerization initiator 1 part by mass of acetophenone and 1 part by mass of 2-phenylimidazole as an epoxy curing accelerator were added and mixed by stirring to obtain an acrylic adhesive.

Example 1
A release agent layer portion having a diameter of 170 mm (corresponding to the size of a 6-inch wafer) is provided on a 100 μm-thick high-density polyethylene base film (surface energy 30 mN / m, 250 mm × 300 mm) subjected to corona treatment. A mold release agent composed of a mixture of silicone oil and acrylic resin was partially applied. Furthermore, the prepared adhesive was coated so that the thickness after drying was 20 μm, and an adhesive tape was prepared.

Example 2
An adhesive tape was prepared in the same manner as in Example 1 except that the release agent layer portion was colored blue by adding a paste mainly composed of phthalocyanine blue to the release agent layer.

Example 3
A mold release agent composed of a mixture of silicone oil and acrylic resin was applied to a 100 μm thick high-density polyethylene base film (surface energy 30 mN / m, 250 mm × 300 mm) subjected to corona treatment.
On the other hand, the prepared adhesive was applied to a 100 μm-thick high-density polyethylene substrate film subjected to corona treatment so that the thickness after drying was 20 μm, and an adhesive tape A was prepared. .
The base film coated with the release agent was precut to a diameter of 170 mm and laminated on the adhesive tape A. Under the present circumstances, the base film part of the base film which apply | coated the said mold release agent to the adhesive layer of the adhesive tape A was stuck. Furthermore, the prepared adhesive was coated so that the thickness after drying was 20 μm, and an adhesive tape was prepared.

Example 4
An adhesive tape was prepared in the same manner as in Example 3 except that the release agent layer portion was colored blue by adding a paste mainly composed of phthalocyanine blue to the release agent layer.

Comparative Example 1
The release agent is applied to the entire surface of a 100 μm-thick high-density polyethylene base film that has been subjected to corona treatment, and the prepared adhesive is applied so that the thickness after drying becomes 20 μm. Thus, an adhesive tape was produced.

Comparative Example 2
Corona treatment so as to provide a non-corona-treated portion having a diameter of 170 mm (corresponding to the size of a 6-inch wafer) on a high-density polyethylene base film (surface energy 30 mN / m, 250 mm × 300 mm) having a thickness of 100 μm It produced by doing. Furthermore, the prepared adhesive was coated so that the thickness after drying was 20 μm, and an adhesive tape was prepared.

(Evaluation)
The produced adhesives of Examples 1 to 4 and Comparative Examples 1 and 2 were tested and their characteristics were evaluated. The results are shown in Table 1 below.

<Surface energy>
The surface energy of the wafer bonding part and the dicing frame bonding part on the substrate surface was measured. The evaluation was performed according to JIS K 6768: 1999 (plastic-film and sheet-wetting tension test method).

<Frame glue residue>
The presence or absence of adhesive residue on the dicing frame was confirmed as follows. The adhesive tapes of Examples and Comparative Examples are bonded to a dicing frame (manufactured by DISCO, trade name, DTF2-6-1), left standing for 7 days, the dicing frame is peeled off, and the adhesive is attached to the dicing frame. The presence or absence of adhesive residue in the agent was visually confirmed.
At that time, the case where there was no adhesive residue on the dicing frame was determined as “◯”, and the case where there was adhesive residue was determined as “x”.

<Chip fly during dicing>
A wafer having a thickness of 0.10 mm was obtained by polishing a back surface of a 6-inch diameter bare wafer. The separator was peeled off from the dicing die-bonding film, and the mirror wafer was roll-bonded to the exposed adhesive layer at 40 ° C., followed by full dicing to a 1 mm square chip size. Thereafter, the presence or absence of chip fly during dicing was evaluated. The case where there was no chip jump was judged as “◯”, and the case where there was a chip was judged as “X”.

<Pickup property>
Full dicing was performed in the same manner as above except that the chip size was changed to 5 mm square, 10 mm square, and 15 mm square. Thereafter, ultraviolet rays were irradiated from the support substrate side (200 mJ / cm ² ), and a silicon chip was picked up by a push-up method using a needle from the substrate side. The case where the pick-up was possible was determined as “◯”, and the case where the pick-up was not possible was determined as “X”.

<Pickup push-up height>
In the 10 mm square chip that was subjected to full dicing as described above, the pin push-up height at the time of pickup was changed, and the minimum push-up height at which the pickup success rate was 90% or more was investigated. A lower push-up height is more advantageous for pickup.

As is clear from the results in Table 1, in the adhesive tape of Comparative Example 1, since the release agent is applied to the entire surface of the base film, the surface energy of the wafer bonding portion and the dicing frame bonding portion is high. Equally, when the adhesive tape was peeled from the dicing frame, it was peeled off at the release agent layer portion, resulting in adhesive residue remaining on the dicing frame. Moreover, in the adhesive tape of the comparative example 2, since the corona treatment was carried out to the dicing frame bonding part, the adhesive residue of an adhesive agent did not arise in a dicing frame, but the adhesive layer of a wafer bonding part Since it was in close contact with the base film, it was difficult to pick up unless the pickup was pushed up, and even a 15 mm square chip could not be picked up.
On the other hand, in the adhesive tapes of Examples 1 to 4, since the adhesive layer of the wafer bonding part peels well from the base film at the time of chip pickup, it can be picked up without problems, There was no transfer of the adhesive to the dicing frame. Moreover, the wafer bonding part of the adhesive tapes of Examples 2 and 4 was colored blue, and the wafer bonding part was excellent in visibility.

It is a perspective view which shows one preferable embodiment of the adhesive tape of this invention. It is sectional drawing which shows the use condition of the adhesive tape of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adhesive tape 11 Base film 12 Adhesive layer 13 Release agent layer 14 Wafer 15 The surface in contact with a wafer in an adhesive layer 16 Dicing frame 17 The surface in contact with a dicing frame in an adhesive layer 18 Separation Surface in contact with adhesive layer in mold layer 19 Surface in contact with adhesive layer in base film

Claims (5)

  An adhesive tape having an adhesive layer provided on at least one side of a base film, and having a release agent layer partially between the base film and the adhesive layer Characteristic semiconductor wafer dicing-adhesive tape for die bonding.   The adhesive tape according to claim 1, wherein the release agent layer is provided corresponding to a wafer bonding portion.   The surface energy of the surface in contact with the adhesive layer in the release agent layer is lower than the surface energy of the surface in contact with the adhesive layer in the base film. The adhesive tape as described.   When the adhesive is adhered to an adherend, the adhesive strength of the adhesive in the adhesive layer to the substrate film is stronger than the adhesive strength of peeling to the adherend. The adhesive tape of any one of Claims 1-3. The pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein the release agent layer is colored.

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