JP5351458B2 - Wafer processing adhesive sheet and method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive sheet for wafer processing which is suitable for dividing a semiconductor wafer and an adhesive agent layer into pieces without damaging a base material layer in an expanding process. <P>SOLUTION: The adhesive sheet for wafer processing has a base material layer, and an adhesive agent layer formed on a surface of the base material layer. The back surface of the base material layer has a slipping property. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a wafer processing adhesive sheet used when a semiconductor wafer is singulated, and a semiconductor device manufacturing method using the sheet. More specifically, the present invention relates to an adhesive sheet for wafer processing that is preferably used when wafers are separated into pieces in an expanding process, and a method for manufacturing a semiconductor device using the sheet.

  A semiconductor wafer such as silicon or gallium arsenide is manufactured in a large diameter state, and this wafer is divided into element pieces (semiconductor chips) and then subjected to a mounting process which is the next process. Specifically, the semiconductor wafer is subjected to dicing, cleaning, drying, expanding, and pick-up processes in a state where it is affixed to an adhesive sheet in advance, and then subjected to the next mounting process.

  Conventionally, in the dicing process, the semiconductor wafer is cut by a rotating blade called a dicing blade that rotates at high speed. This dicing blade includes a disk-shaped base and an annular cutting edge mounted on the outer peripheral portion of the side surface of the base. This cutting edge is formed, for example, by fixing diamond abrasive grains having a particle diameter of about 3 μm to the base, and has a thickness of about 20 μm.

  However, in recent years, semiconductor wafers have become thinner, and more wafers have a brittle insulating film on the surface. For this reason, when a dicing blade is used, there is a problem that the wafer is damaged and the yield of the semiconductor device is deteriorated.

For this reason, as an alternative to the method of dicing a semiconductor wafer using the dicing blade, a stealth dicing method or a tip dicing method (dicing before) is used.
Grinding; abbreviated as “DBG”. ) Has been attempted.

  In the stealth dicing method, a condensing point is aligned from one side of a semiconductor wafer to the inside, and a pulse laser in an infrared region having transparency to the wafer is irradiated, and the wafer is in line with a division line. In this method, the deteriorated layer is continuously formed, and the wafer is divided by applying an external force along the planned dividing line whose strength is reduced by forming the deteriorated layer (for example, Patent Documents 1 and 2). reference).

  Specifically, a semiconductor wafer and a doughnut-shaped fixing jig called a ring frame that holds the outer periphery of the wafer are attached to a sheet composed of, for example, a base material layer and an adhesive layer, and as described above. Irradiate the wafer with a pulsed laser. Next, the wafer is separated into pieces by expanding (expanding) the sheet.

  The expansion of the sheet is performed by pulling down a ring frame that fixes the outer periphery of the wafer while the semiconductor wafer is fixed, or by pulling up a portion up to the outer periphery of the wafer while fixing the ring frame.

  With the above method, the wafer can be prevented from being damaged because the dicing blade rotating at high speed is not directly pressed against the thinned wafer. In addition, the cut surface of the chip and the cut surface of the adhesive layer can be substantially matched.

In addition, the tip dicing method forms a groove with a predetermined depth from the circuit forming surface side (wafer surface side) of the semiconductor wafer, and performs grinding from the surface side (wafer back surface side) of the semiconductor wafer where no circuit is formed, Next, in the same manner as described above, a wafer is attached to a sheet, and the wafer is divided by expanding the sheet. With this method, since the dicing blade that rotates at high speed is not directly pressed against the thinned wafer, damage to the wafer can be prevented (see, for example, Patent Document 3).

Although the semiconductor wafer is divided into chips as described above, since the chip interval is narrow immediately after dicing, the chips may come into contact with each other and the chips may be damaged. Therefore, after the dicing process, an expanding process for separating the chip intervals as described above is usually provided (see, for example, Patent Document 4).
JP 2003-338467 A JP 2005-223283 A JP 2003-147300 A JP 2007-005530 A

  The stealth dicing method or the tip dicing method is used for a semiconductor device of a type in which the adhesive layer constituting the sheet is fixed and left on the back surface of the chip, and the chip is bonded to an adherend such as a substrate through the adhesive layer. When applied to a manufacturing method, it is necessary to divide the adhesive layer for each chip in the expanding step. For this reason, it is required to expand the sheet more than the conventional expanding process.

  However, in the expanding process, when the expansion speed and expansion amount of the sheet are large, the base material layer may be damaged at the boundary between the portion where the sheet is fixed and the portion where the sheet is pulled down or pulled up. Also, the sheet or the adhesive layer may not be sufficiently separated because the sheet cannot be uniformly expanded due to the frictional force at the boundary or the external force is not applied to the adhesive layer due to the frictional force.

  In particular, when using the first dicing method, since the semiconductor wafer has already been separated into pieces in the expanding process, it is more difficult to separate only the adhesive layer without damaging the base material layer. It has become.

The present inventors have intensively studied to solve the above problems. As a result, it was found that the semiconductor wafer and the adhesive layer can be sufficiently singulated without damaging the base material layer in the expanding step by providing easy slipping on the back surface of the base material layer, and to complete the present invention. It came.
That is, the present invention relates to the following [1] to [9].

[1] A wafer processing adhesive sheet comprising a base material layer and an adhesive layer formed on the surface of the base material layer, wherein the back surface of the base material layer has slipperiness.
[2] The adhesive sheet for wafer processing according to [1], wherein a coefficient of dynamic friction measured according to JIS K7125 on the back surface of the base material layer is 0.01 to 0.4.
[3] The adhesive sheet for wafer processing according to [1] or [2], wherein the base material layer includes a base film and an easy-slip layer formed on the back surface of the base film, The adhesive sheet for wafer processing, wherein the slippery layer constitutes the outermost layer of the sheet.

[4] The adhesive sheet for wafer processing according to [3], wherein the slippery layer is made of a silicone-based slippery agent.
[5] The wafer processing adhesive according to [1] or [2], wherein the base material layer is composed of a base material film, and an easy-slip treatment is applied to the back surface of the base material film. Sheet.
[6] The adhesive sheet for wafer processing according to any one of [1] to [5], wherein the adhesive layer is a layer that can be peeled from the base material layer.

  [7] A step of attaching a semiconductor wafer on an adhesive layer constituting the adhesive sheet for wafer processing according to any one of [1] to [6], and a pulse laser having transparency to the wafer Irradiating the wafer along the planned dividing line, forming a deteriorated layer along the planned dividing line inside the wafer, and expanding the adhesive sheet to divide the wafer into semiconductor chips and A step of dividing the adhesive layer, and the adhesive layer is fixedly left on the back surface of the chip, the adhesive layer is peeled off from the base material layer constituting the adhesive sheet, and the chip is attached to the adherend. The manufacturing method of the semiconductor device characterized by including the process of thermocompression bonding through a layer.

  [8] A step of dividing the wafer into semiconductor chips by forming a groove having a depth smaller than the thickness of the wafer from the surface of the semiconductor wafer and grinding the back surface of the wafer, [1] to [6] A step of affixing a divided wafer consisting of the chip group on an adhesive layer constituting the adhesive sheet for wafer processing according to any one of the above, and expanding the adhesive sheet to divide the adhesive layer Process, and the adhesive layer is fixed and remained on the back surface of the chip, the adhesive layer is peeled off from the base material layer constituting the adhesive sheet, and the chip is thermocompression bonded to the adherend through the adhesive layer. The manufacturing method of the semiconductor device characterized by including the process to do.

  [9] A step of attaching a semiconductor wafer on an adhesive layer constituting the adhesive sheet for wafer processing according to any one of [1] to [6], a step of dividing the wafer into semiconductor chips, The step of expanding the adhesive sheet, and the adhesive layer remains fixed on the back surface of the chip, the adhesive layer is peeled off from the base material layer constituting the adhesive sheet, and the chip is attached to the adherend. The manufacturing method of the semiconductor device characterized by including the process of thermocompression bonding through a layer.

  According to the present invention, when a semiconductor wafer is separated into pieces using a sheet having a base material layer and an adhesive layer, the base material layer is damaged because the slipperiness is imparted to the back surface of the base material layer. The sheet can be expanded without any problem, and the wafer and the adhesive layer can be sufficiently separated.

Hereinafter, the adhesive sheet for wafer processing of the present invention will be described in detail.
[Adhesive sheet for wafer processing]
The adhesive sheet for wafer processing of the present invention is a sheet having a base material layer (A) and an adhesive layer (B) formed on the surface of the base material layer (A), the base material layer (A). The back surface is easy to slip.
The adhesive sheet for wafer processing of the present invention is also simply referred to as “adhesive sheet”, and the surface of the base material layer (A) on the adhesive layer (B) side is defined as “front surface”, and the other surface is defined as “back surface”. To do.

<Base material layer (A)>
The back surface of the base material layer (A) constituting the adhesive sheet of the present invention has slipperiness. In the present invention, “having slidability” specifically means a dynamic friction coefficient measured in accordance with JIS K7125 (plastic-film and sheet-friction coefficient test method) on the back surface of the base material layer (A). , Preferably 0.01 to 0.4, more preferably 0.03 to 0.35, still more preferably 0.05 to 0.3. If the dynamic friction coefficient is within the above range, a sufficient slipping effect can be obtained in the expanding process, so that the semiconductor wafer and the adhesive layer (B) are sufficiently separated without damaging the base material layer (A). be able to.

In order to provide the slipperiness to the back surface of the base material layer (A) as described above, << A1 >> from the base material film as the base material layer (A) and the easy slip layer formed on the back surface of the base material film It is preferable to use a layer constituted, or use a layer constituted of a substrate film as << A2 >> substrate layer (A), and subject the back surface of the substrate film to an easy slip treatment.

  Moreover, a base material layer (A) may have a layer etc. which consist of a release agent formed in the base film surface in the range which does not impair the objective of this invention. The surface on the adhesive layer (B) side of the base film is defined as “front surface”, and the other surface is defined as “back surface”.

≪Base film≫
Examples of the base film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene terephthalate film. , Polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, Transparent films such as fluororesin films; colored transparent films and colored opaque films that are colored . Moreover, you may use these bridge | crosslinking films and laminated | multilayer film.

  However, when the adhesive sheet of the present invention is irradiated with energy rays such as ultraviolet rays from the back side of the base material layer (A), the base material film is transparent to the energy rays to be used. Is preferred.

  In addition, the adhesive sheet of the present invention is used by being attached to a semiconductor wafer. However, after the wafer is subjected to required processing, the adhesive layer (B) is fixedly left on the wafer, and the base material layer (A It is suitably used for the process of peeling off from the above. That is, it is suitably used for a process including a step of peeling the adhesive layer (B) from the base material layer (A) and transferring it to the wafer.

  In such a case, the surface tension of the surface of the base material layer (A) is preferably 5 mN / m or more and 40 mN / m or less, more preferably 7 mN / m or more and 37 mN / m or less, particularly preferably 10 mN / m or more and 35 mN or less. A base film is selected so that it may become / m or less. Such a base film having a low surface tension can be obtained by appropriately selecting the material, and a layer made of a release agent by applying a release agent on the surface of the base film (hereinafter referred to as “release layer”). Can also be obtained.

  Examples of the release agent include alkyd type, silicone type, fluorine type, unsaturated polyester type, polyolefin type, and wax type release agents. Of these, alkyd, silicone, and fluorine release agents are particularly preferable because they have heat resistance.

  In order to form a release layer on the surface of the base film using the above release agent, the release agent is used without any solvent or diluted or emulsified, and (1) gravure coater, Mayer bar coater, air knife coater, roll coater. Applying to the surface of the base film using a method such as room temperature curing, heat curing, or electron beam curing, or (2) performing wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, etc. Thus, a laminate of the base film and the release layer may be formed.

The thickness of the base film is usually in the range of 10 to 500 μm, preferably 15 to 300 μm, particularly preferably 20 to 250 μm. If the thickness is less than the above range, the base film may tear during expansion. Moreover, when thickness exceeds the said range, it may be too hard to expand a base film.

≪A1: Easy sliding layer≫
Hereinafter, a description will be given with reference to FIG. In the present invention, in order to impart easy slipping to the back surface of the base material layer (A) 10, it is preferable to form the easy slip layer 40 on the back surface of the base material film 30. The easy slip layer 40 constitutes the outermost layer of the adhesive sheet of the present invention. That is, the coefficient of dynamic friction measured according to JIS K7125 of the easy-slip layer 40 is preferably 0.01 to 0.4, more preferably 0.03 to 0.35, and still more preferably 0.05 to 0.00. It is in the range of 3.

  As a method of forming the easy-slip layer 40 on the back surface of the base film 30, the easy-to-use lubricant is used without any solvent or diluted or emulsified, and (1) a gravure coater, Mayer bar coater, air knife coater, roll coater. Is applied to the back surface of the base film 30 using room temperature curing, heat curing, or electron beam curing, or (2) wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, etc. By doing so, a laminated body of the base film 30 and the easy-slip layer 40 may be formed. In the present invention, the slippery agent refers to a component capable of forming a slippery layer capable of reducing friction between the adhesive sheet and the expanding device.

  Examples of the lubricant include alkyd, silicone, fluorine, unsaturated polyester, polyolefin, and wax lubricants. Among these, alkyd, silicone, and fluorine-based lubricants are particularly preferable because they have heat resistance, and silicone-based lubricants are particularly preferable. Examples of the silicone-based lubricant include various silicone oils and silicone resins. Specific examples thereof include KS-847 (Shin-Etsu Chemical Co., Ltd.), KS-774 (same as left), and KS-776A (same as left). ) And the like. These may be used alone or in combination of two or more.

Examples of the solvent include toluene and 2-butanone.
Alternatively, the slippery layer 40 may be formed by applying and drying a slippery agent obtained by mixing the silicone-based slippery agent and the platinum catalyst on the back surface of the base film 30. The platinum catalyst is used for crosslinking a silicone-based easy-to-lubricant to increase the film strength. Examples of the platinum catalyst include PL-50T (Shin-Etsu Chemical Co., Ltd.).

  The thickness of the easy-sliding layer 40 is preferably in the range of 1 nm to 50 μm, more preferably 10 nm to 5 μm, and still more preferably 20 nm to 1 μm. If the thickness of the slippery layer 40 is less than the above range, the slippery effect may not be obtained, and if it exceeds the above range, it may be difficult to expand the adhesive sheet.

≪A2: Easy slip processing≫
Hereinafter, a description will be given with reference to FIG. In the present invention, in order to impart slipperiness to the back surface of the base material layer (A) 10 in addition to forming a slippery layer, it is preferable to subject the back surface of the base material film 30 to easy slipping.

  The slippery process is not particularly limited as long as the back surface of the base film 30 can be easily slipped and the friction between the adhesive sheet and the expanding device can be reduced. For example, the back surface of the base film 30 can be embossed. The contact area between the back surface of the base film 30 and the expanding device is reduced by a method of forming irregularities on the surface, a sand blasting method in which particles such as silica are sprayed with high-pressure air on the back surface of the base film, and a chemical method such as etching. And a method of obtaining smoothness by making the back surface of the base film 30 highly smooth.

<Adhesive layer (B)>
There is no restriction | limiting in particular as a material which forms an adhesive bond layer (B), What is necessary is just to use the material suitable for use uses, such as wafer processability. For example, the adhesive composition containing an acrylic polymer, an epoxy-type thermosetting resin, and a thermosetting agent is mentioned.

  The thickness of the adhesive layer (B) is usually in the range of 0.1 to 500 μm, preferably 0.5 to 300 μm, particularly preferably 1 to 150 μm. If the thickness is less than the above range, adhesiveness may not be obtained. On the other hand, if the thickness exceeds the above range, the adhesive layer (B) may protrude unnecessarily when the chip is thermocompression bonded to the adherend.

  Moreover, it is preferable that an adhesive bond layer (B) is a layer which can be peeled from a base material layer (A). Thus, when the chip is picked up in the pick-up process, the separated adhesive layer (B) remains adhered to the back surface of the chip and functions as a die bond layer for an adherend such as a substrate.

-Acrylic polymer-
An acrylic polymer is preferably used in order to impart sufficient adhesiveness and film forming property (sheet processability) to the adhesive composition. A conventionally well-known acrylic polymer can be used as an acrylic polymer.

  The glass transition temperature of the acrylic polymer is preferably in the range of −50 ° C. to 50 ° C., more preferably −45 ° C. to 40 ° C., and particularly preferably −40 ° C. to 30 ° C. If the glass transition temperature is too low, the peeling force between the adhesive layer (B) and the base material layer (A) becomes large, and chip pick-up failure may occur. On the other hand, if the glass transition temperature is too high, the adhesive force for fixing the wafer may be insufficient.

  The weight average molecular weight in terms of polystyrene of the acrylic polymer is preferably in the range of 10,000 to 2,000,000, more preferably in the range of 100,000 to 1,500,000. If the weight average molecular weight of the acrylic polymer is too low, the peeling force between the adhesive layer (B) and the base material layer (A) becomes large, and chip pick-up failure may occur. On the other hand, if the weight average molecular weight is too high, the adhesive layer (B) may not be able to follow the unevenness of the adherend such as a substrate, which may cause generation of voids.

  Examples of the raw material monomer for the acrylic polymer include (meth) acrylic acid esters and derivatives thereof. Specific examples include (meth) acrylic acid having 1 to 18 carbon atoms in an alkyl group such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Alkyl ester; cyclic skeletons such as (meth) acrylic acid cycloalkyl ester, (meth) acrylic acid benzyl ester, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, imide acrylate, etc. (Meth) acrylic acid ester having; hydroxyl group-containing (meth) acrylic acid ester such as 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate; glycidyl acrylate , And the like glycidyl methacrylate. Acrylic acid, methacrylic acid, itaconic acid and the like may also be used. These may be used alone or in combination of two or more.

Among these, it is preferable to use a hydroxyl group-containing (meth) acrylic acid ester because an acrylic polymer having good compatibility with the epoxy thermosetting resin can be obtained.
In addition to the above (meth) acrylic acid ester and derivatives thereof, vinyl acetate, acrylonitrile, styrene, or the like may be used as a raw material monomer as long as the object of the present invention is not impaired.

  The said acrylic polymer can be manufactured in accordance with a conventionally well-known method using the said raw material monomer. The acrylic polymers thus obtained may be used alone or in combination of two or more.

-Epoxy thermosetting resin-
Various conventionally known epoxy resins can be used as the epoxy thermosetting resin. Examples of the epoxy resin include a cresol novolak resin represented by the following formula (1), a dicyclopentadiene type epoxy resin represented by the following formula (2), and a biphenyl type epoxy resin represented by the following formula (3). An epoxy resin containing two or more functional groups in the structural unit; an epoxy containing two or more functional groups such as a biphenyl compound represented by the following formula (4), bisphenol A diglycidyl ether and hydrogenated product thereof Compounds.

（但し、式中ｎは０以上、好ましくは０以上２０以下の整数である。）

(In the formula, n is an integer of 0 or more, preferably 0 or more and 20 or less.)

（但し、式中ｎは０以上、好ましくは０以上２０以下の整数である。）

(In the formula, n is an integer of 0 or more, preferably 0 or more and 20 or less.)

（但し、式中ｎは０以上、好ましくは０以上２０以下の整数である。）

(In the formula, n is an integer of 0 or more, preferably 0 or more and 20 or less.)

（但し、式中Ｒはそれぞれ独立に水素原子またはメチル基である。）
これらのエポキシ樹脂は１種単独で用いてもよく、２種類以上を併用してもよい。

(However, in the formula, each R is independently a hydrogen atom or a methyl group.)
These epoxy resins may be used alone or in combination of two or more.

  The content of the epoxy thermosetting resin in the adhesive composition is preferably 1-1500 parts by weight and more preferably 3-1000 parts by weight with respect to 100 parts by weight of the acrylic polymer. When the content of the epoxy thermosetting resin is below the above range, the adhesive layer (B) having sufficient adhesive strength may not be obtained. On the other hand, when the content of the epoxy thermosetting resin exceeds the above range, the adhesive force between the adhesive layer (B) and the base material layer (A) becomes too high, and chip pick-up failure may occur.

-Thermosetting agent-
The thermosetting agent functions as a thermosetting agent for the epoxy thermosetting resin. Preferable thermosetting agents include compounds having 2 or more functional groups capable of reacting with epoxy groups in the molecule, such as phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups and acid anhydrides. Group and the like. In these, a phenolic hydroxyl group, an amino group, and an acid anhydride group are preferable, and a phenolic hydroxyl group and an amino group are more preferable.

  Specific examples of the thermosetting agent include a novolac phenol resin represented by the following formula (5), a dicyclopentadiene phenol resin represented by the following formula (6), and the following formula (7). Examples thereof include polyfunctional phenol resins, phenolic thermosetting agents such as aralkyl phenol resins represented by the following formula (8); and amine thermosetting agents such as DICY (dicyandiamide). These thermosetting agents may be used individually by 1 type, and may use 2 or more types together.

（但し、式中ｎは０以上、好ましくは０以上２０以下の整数を表す。）

(In the formula, n represents an integer of 0 or more, preferably 0 or more and 20 or less.)

（但し、式中ｎは０以上、好ましくは０以上２０以下の整数を表す。）

(In the formula, n represents an integer of 0 or more, preferably 0 or more and 20 or less.)

（但し、式中ｎは０以上、好ましくは０以上２０以下の整数を表す。）

(In the formula, n represents an integer of 0 or more, preferably 0 or more and 20 or less.)

（但し、式中ｎは０以上、好ましくは０以上２０以下の整数を表す。）

(In the formula, n represents an integer of 0 or more, preferably 0 or more and 20 or less.)

  The content of the thermosetting agent in the adhesive composition is preferably 0.1 to 500 parts by weight, more preferably 1 to 200 parts by weight with respect to 100 parts by weight of the epoxy thermosetting resin. If the content of the thermosetting agent is too small, the adhesive composition (B) having sufficient adhesive force may not be obtained due to insufficient curability of the adhesive composition, and if it is excessive, the adhesive composition. The moisture absorption rate of the object may increase and the reliability of the semiconductor device may decrease.

-Other ingredients-
In addition to the above components, in order to improve various physical properties of the adhesive composition, curing accelerators, energy beam curable resins, energy beam polymerization initiators, inorganic / organic particles, plasticizers, antistatic agents, antioxidants In addition, components such as pigments and dyes may be added as long as the object of the present invention is not impaired.

<Other layers>
Other layers may be laminated on the adhesive sheet of the present invention within a range not impairing the object of the present invention. For example, a release film may be laminated on the surface of the (B) layer in order to protect the adhesive layer (B) before using the adhesive sheet. Moreover, in order to fix other jigs, such as a ring frame, you may laminate | stack the adhesive bond layer and adhesive tape different from this (B) layer separately on the outer peripheral part of the adhesive bond layer (B) surface.

[Specific Configuration of Wafer Processing Adhesive Sheet and Manufacturing Method Thereof]
Specific examples of the wafer processing adhesive sheet of the present invention include, for example, a base film 30, an adhesive layer 20 formed on the surface of the base film 30, and a back surface of the base film 30. An adhesive sheet composed of an easy-slip layer 40 (see FIG. 1A); a base film 30, and an adhesive layer 20 formed on the surface of the base film 30, Examples thereof include an adhesive sheet (see FIG. 1 (b)) on which the above-described easy slip treatment is performed. The shape of the adhesive sheet can take any shape such as a tape shape or a label shape.

  The manufacturing method of the above-mentioned adhesive sheet is not particularly limited. For example, an adhesive sheet composed of a base film, an adhesive layer formed on the surface of the base film, and an easy-slip layer formed on the back surface of the base film is manufactured as follows. The order of (1) and (2) can be arbitrarily selected.

  (1) A material for forming an adhesive layer (for example, the adhesive composition) is applied to the surface of the base film and dried, or an adhesive layer is formed on the release film, and this is applied to the base film surface. The adhesive layer is formed on the surface of the base film by transferring to the substrate film.

  (2) Applying a lubricant to the back surface of the base film and drying, or forming an easy slip layer on the release film and transferring it to the back surface of the base film, thereby forming the easy slip layer on the back surface of the base film. Form.

  Moreover, the adhesive sheet which consists of a base film and the adhesive bond layer formed in the surface of this base film, and the above-mentioned slipperiness process is given to the back surface of this base film is to said (2). Instead, it is manufactured by (3) subjecting the back surface of the base film to the above-described slipperiness and imparting the slipperiness to the back surface of the base film.

[Method of Manufacturing Semiconductor Device Using Wafer Processing Adhesive Sheet]
Since the adhesive sheet for wafer processing of the present invention is provided with easy slipping on the back surface of the base material layer (A), when the semiconductor wafer is separated into individual pieces, the base material layer (A) is not damaged. Expansion can be performed, and the wafer and the adhesive layer (B) can be sufficiently separated. Therefore, it can be suitably used for manufacturing a semiconductor device using a stealth dicing method or a tip dicing method as well as a conventional method of dicing using a dicing blade.

  Hereinafter, examples in which the adhesive sheet for wafer processing according to the present invention is used in a stealth dicing method, a tip dicing method, and a conventional method of dicing using a dicing blade will be described.

<Manufacturing of semiconductor device using stealth dicing method>
A manufacturing method of a semiconductor device using a stealth dicing method includes the following steps.
(1) A step of attaching a semiconductor wafer on the adhesive layer (B) constituting the adhesive sheet of the present invention, (2) A pulse laser having transparency to the wafer is applied to the wafer along a line to be divided Irradiating and forming a deteriorated layer along the planned dividing line inside the wafer,
(3) expanding the adhesive sheet to divide the wafer into semiconductor chips and dividing the adhesive layer (B); and (4) providing the adhesive layer (B) on the back surface of the chip. A step of leaving the adhesive layer (B) peeled off from the base material layer (A) constituting the adhesive sheet, and thermally bonding the chip to the adherend through the adhesive layer (B).

-(1) Semiconductor wafer pasting process-
The ring frame and the wafer ground to a predetermined thickness are placed on a laminating apparatus, and the sheet is attached so that the adhesive layer (B) constituting the adhesive sheet of the present invention is in contact with the ring frame and the back surface of the wafer. And press lightly to fix the wafer.

-(2) Altered layer formation process-
From the surface of the semiconductor wafer, a pulse laser having transparency to the wafer is irradiated to the wafer along the planned division line, and an altered layer is formed along the planned division line inside the wafer. This step is performed, for example, according to the descriptions in Patent Documents 1 and 2 described above.

-(3) Expanding process-
The adhesive sheet with the wafer attached is expanded using an expanding device. In this expanding step, the wafer and the adhesive layer (B) are sufficiently separated into chips, and a chip in which the adhesive layer (B) remains fixed is obtained. Further, since the chip interval increases, the possibility of damaging the chips is greatly reduced.

  The expansion speed of the adhesive sheet in the expanding step is usually 1 to 200 mm / second, preferably 10 to 150 mm / second, and the expansion amount is usually 1 to 30 mm, preferably 2 to 20 mm. If the expansion speed and the expansion amount are below the above ranges, it may be difficult to separate the wafer and the adhesive layer (B). Moreover, when an expansion speed and an expansion amount exceed the said range, a base material layer (A) may be damaged.

-(4) Pick-up mounting process-
The adhesive layer (B) is fixed and left on the back surface of the semiconductor chip, the adhesive layer (B) is peeled off from the base material layer (A), and the chip is attached to the adherend via the adhesive layer (B). Place. Here, the adherend is usually a die pad part on an organic substrate or a lead frame, or another chip fixed in advance on a die pad part on the organic substrate or the lead frame.

  The die pad portion or other chip is preferably heated before mounting the chip or immediately after mounting. The heating temperature is usually 80 to 200 ° C., preferably 100 to 180 ° C., the heating time is usually 0.1 seconds to 5 minutes, preferably 0.5 seconds to 3 minutes, and the chip mount pressure is Usually, it is 1 kPa to 600 MPa.

  In addition, after mounting a chip | tip on a die pad part or another chip | tip, you may heat further as needed. The heating conditions at this time are in the above heating temperature range, and the heating time is usually 1 to 180 minutes, preferably 10 to 120 minutes.

  In addition, the adhesive layer (B) may be cured by leaving the chip in a temporarily bonded state without performing the heat treatment after mounting and using heating in resin sealing that is normally performed in the manufacture of a semiconductor device. .

  By passing through such a process, an adhesive bond layer (B) hardens | cures and a chip | tip and a die pad part or another chip | tip can be adhere | attached firmly. Further, since the adhesive layer (B) is fluidized under die bonding conditions, the adhesive layer (B) is sufficiently embedded in the unevenness of the die pad portion or other chips, and generation of voids can be prevented.

<Method for Manufacturing Semiconductor Device Using First Dicing Method>
A method for manufacturing a semiconductor device using the prior dicing method includes the following steps.
(1) forming a groove having a depth smaller than the wafer thickness from the surface of the semiconductor wafer, and grinding the back surface of the wafer to divide the wafer into semiconductor chips;
(2) A process of attaching a divided wafer comprising the chip group on the adhesive layer (B) constituting the adhesive sheet of the present invention,
(3) expanding the adhesive sheet to divide the adhesive layer (B); and (4) adhering the adhesive layer (B) to the back surface of the chip to form the adhesive sheet. A step of peeling the adhesive layer (B) from the base material layer (A) and thermocompression bonding the chip to the adherend through the adhesive layer (B).

-(1) Dicing process-
Using a cutting means such as a dicing saw, a groove having a predetermined depth smaller than the wafer thickness is formed from the wafer surface along the cutting position of the semiconductor wafer forming a plurality of sections. Next, a conventionally known surface protection sheet is attached to the wafer surface, and the back surface of the wafer is ground to be divided into semiconductor chips.

-(2) Bonding process of divided semiconductor wafers composed of semiconductor chip groups-
The adhesive sheet of the present invention is fixed on a laminating apparatus by a ring frame, and one surface of the divided semiconductor wafer composed of the semiconductor chip group is placed on the adhesive layer (B) constituting the adhesive sheet. And lightly pressing to fix the wafer. Next, the surface protection sheet is peeled from the wafer.

  The subsequent (3) expanding step and (4) pick-up mounting step can be performed under the conditions described in the stealth dicing method. When the semiconductor chip is picked up in this way, the adhesive layer (B) can be peeled off from the base material layer (A) by allowing the divided adhesive layer (B) to remain adhered to the back surface of the chip. The chip can be placed on the adherend via the adhesive layer (B).

<Method of Manufacturing Semiconductor Device Using Dicing Blade>
A manufacturing method of a semiconductor device using a dicing blade includes the following steps.
(1) A step of attaching a semiconductor wafer on the adhesive layer (B) constituting the adhesive sheet of the present invention, (2) a step of dividing the wafer into semiconductor chips,
(3) Step of expanding the adhesive sheet, and (4) The adhesive layer (B) is fixed and left on the back surface of the chip, and the adhesive layer (B And the chip is thermocompression bonded to the adherend via the adhesive layer (B).

-(1) Semiconductor wafer pasting process-
The ring frame and the wafer ground to a predetermined thickness are allowed to stand on a laminating apparatus, and the sheet is attached so that the adhesive layer (B) of the adhesive sheet of the present invention is in contact with the ring frame and the back surface of the wafer, Press lightly to fix the wafer.

-(2) Dicing process-
The semiconductor wafer is divided into semiconductor chips using a cutting means such as a dicing saw. The cutting depth at this time is preferably a depth that takes into account the sum of the thickness of the semiconductor wafer and the adhesive layer (B) and the wear of the dicing saw. In addition, since the wafer and the adhesive layer (B) can be divided by expanding the adhesive sheet in the subsequent (3) expanding step, the wafer and the adhesive layer (B) are not necessarily completely separated by a dicing saw or the like. There is no need to divide it.

  The subsequent (3) expanding step and (4) pick-up mounting step can be performed under the conditions described in the stealth dicing method. When the semiconductor chip is picked up in this way, the adhesive layer (B) that has been divided can be adhered and left on the back surface of the semiconductor chip, and the adhesive layer (B) can be peeled off from the base material layer (A). The chip can be placed on the adherend via the adhesive layer (B).

Next, the adhesive sheet for wafer processing of the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
Base material layer (A)
The base material layer (A) having the configuration described below was used. The dynamic friction coefficient on the back surface of the base material layer (A) is a value measured using an autograph AG-IS manufactured by Shimadzu Corporation in accordance with JIS K7125.

  (A) -1: A polyethylene film (thickness: 100 μm) is used as a base film, and 100 parts by weight of “KS-847” (manufactured by Shin-Etsu Chemical Co., Ltd.) and “PL-50T” (Shin-Etsu Chemical ( Co., Ltd.) 1 part by weight dissolved toluene solution was applied to the back of the film (surface tension 33 mN / m) so that the thickness after drying was 100 nm, and dried in an oven at 80 ° C. for 30 seconds. A base material layer (A) -1 having an easy-sliding layer having a thickness of 100 nm was obtained. The dynamic friction coefficient of the back surface of the base material layer (A) -1 was 0.21.

  (A) -2: The same as (A) -1, except that “KS-774” (manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of “KS-847” as a lubricant. A base material layer (A) -2 having an easy-sliding layer was obtained. The dynamic friction coefficient of the back surface of the base material layer (A) -2 was 0.07.

  (A) -3: The same as (A) -1 except that “KS-774” (manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of “KS-847” as a lubricant. A base material layer (A) -3 having an easy-sliding layer was obtained. The dynamic friction coefficient of the back surface of the base material layer (A) -3 was 0.15.

  (A) -4: The same as (A) -1, except that “KS-774” (manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of “KS-847” as a lubricant. A base material layer (A) -4 having an easy-sliding layer was obtained. The dynamic friction coefficient on the back surface of the base material layer (A) -4 was 0.28.

  (A) -5: It is a polyethylene film (no slipperiness, thickness 100 μm) that does not have a slippery layer and is not subjected to slippery treatment. The dynamic friction coefficient on the back surface of the polyethylene film was 0.51.

Adhesive layer (B)
As a material for forming the adhesive layer (B), an adhesive composition having a composition shown in Table 1 was used. In Table 1, a numerical value shows the weight part of solid content conversion. The adhesive composition was applied to a release film (SP-PET3811 (S) manufactured by Lintec Corporation) having a layer made of a silicone release agent on the surface so that the thickness after drying was 20 μm. The film was dried in an oven at 100 ° C. for 1 minute to obtain a transfer film having adhesive layers (B) -1 to (B) -3.

（ａ）アクリル重合体：アクリル酸ブチル５５重量部、アクリル酸メチル１０重量部、グリシジルメタクリレート２０重量部、および２−ヒドロキシエチルアクリレート１５重量部を共重合して得られた、重量平均分子量８０万、ガラス転移温度−２８℃のアクリル重合体。
（ｂ）エポキシ系熱硬化性樹脂：
（ｂ１）エポキシ樹脂：液状ビスフェノールＡ型エポキシ樹脂(ジャパンエポキシレジン
（株）製、ＪＥＲ８２８、エポキシ当量１８４〜１９４ｇ／ｅｑ)
（ｂ２）エポキシ樹脂：固形ビスフェノールＡ型エポキシ樹脂（エポキシ当量８００〜９００ｇ／ｅｑ）
（ｂ３）エポキシ樹脂：ｏ−クレゾールノボラック型エポキシ樹脂（日本化薬（株）製、ＥＯＣＮ−１０４Ｓ、エポキシ当量２１５〜２２０ｇ/ｅｑ）
（ｃ）硬化剤：アデカハードナー３６３６ＡＳ（旭電化製）
（ｄ）硬化促進剤：キュアゾール２ＰＨＺ（四国化成工業）
（ｅ）エネルギー線硬化性樹脂：カヤラッドＤＰＨＡ（日本化薬（株）製）
（ｆ）エネルギー線重合開始剤：イルガキュア１８４（チバ・スペシャルティ・ケミカルズ（株）製）

(A) Acrylic polymer: weight average molecular weight of 800,000 obtained by copolymerizing 55 parts by weight of butyl acrylate, 10 parts by weight of methyl acrylate, 20 parts by weight of glycidyl methacrylate, and 15 parts by weight of 2-hydroxyethyl acrylate An acrylic polymer having a glass transition temperature of -28 ° C.
(B) Epoxy thermosetting resin:
(B1) Epoxy resin: Liquid bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., JER828, epoxy equivalent of 184 to 194 g / eq)
(B2) Epoxy resin: Solid bisphenol A type epoxy resin (epoxy equivalent 800-900 g / eq)
(B3) Epoxy resin: o-cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EOCN-104S, epoxy equivalent of 215 to 220 g / eq)
(C) Hardener: Adeka Hardener 3636AS (Asahi Denka)
(D) Curing accelerator: Curesol 2PHZ (Shikoku Chemicals)
(E) Energy ray curable resin: Kayalad DPHA (manufactured by Nippon Kayaku Co., Ltd.)
(F) Energy beam polymerization initiator: Irgacure 184 (manufactured by Ciba Specialty Chemicals)

[Example 1]
Bonding base material layer (A) -1 and transfer film having adhesive layer (B) -1 to transfer adhesive layer (B) -1 to the surface of base material layer (A) -1 An adhesive sheet was obtained. The following expandability was evaluated using the obtained adhesive sheet. The evaluation results are shown in Table 2.

[Examples 2 to 9, Comparative Examples 1 to 5]
In Example 1, an adhesive sheet was obtained in the same manner as in Example 1 except that the base material layer (A) described in Table 2 or Table 3 and the transfer film having the adhesive layer (B) were used. It was. The following expandability was evaluated using the obtained adhesive sheet. The evaluation results are shown in Table 2 or Table 3.

[Evaluation of expandability]
A 6-inch, 100 μm-thick dry polish wafer was irradiated with a pulse laser having transparency with respect to the wafer from the wafer back surface (dry polish surface) side under the following conditions.
Light source: LD excitation Q switch Nd: YVO4 pulse laser wavelength: 1064 nm
Pulse output: 10μJ
Condensing spot diameter: φ1μm
Pulse width: 40ns
Peak power density at the focal point: 3.2 × 10 ¹⁰ W / cm ²
Repeat frequency: 100 kHz
Wafer processing feed speed: 100 mm / sec. Scheduled line (X, Y) pitch size: 5 mm for both X and Y

Using a tape mounter (RAD2500, manufactured by Lintec Co., Ltd.), the adhesive sheets obtained in Examples and Comparative Examples were attached to the back surface of the wafer after pulse laser irradiation at room temperature. Thereafter, using a semi-automatic expander (ME-300B, manufactured by JCM Corporation), expansion was performed under the following (Condition 1) to (Condition 3). The ratio by which the wafer and the adhesive layer (B) were separated into pieces was determined by the following formulas 1 and 2.
Formula 1: Number of chips actually obtained / total number of chips obtainable from one wafer × 100 (%)
Formula 2: Number of chips in which the adhesive layer (B) remains fixed / 1 Total number of chips obtainable from the wafer × 100 (%)
Condition 1: Expanding temperature: 23 ° C., expansion speed 10 mm / second, expansion amount 10 mm
Condition 2: Expanding temperature: 23 ° C., expansion speed 20 mm / second, expansion amount 10 mm
Condition 3: Expanding temperature: 23 ° C., expansion speed 20 mm / second, expansion amount 15 mm

  Moreover, after implementing the said expand process, the presence or absence of the damage of a base film was confirmed visually. When tearing occurred in the base film, the damaged portions were counted.

Fig.1 (a) is an adhesive sheet comprised from a base film, the adhesive bond layer formed in this base film surface, and the easy-slip layer formed in this base film back surface. FIG.1 (b) is an adhesive sheet comprised from the base film by which the easy-slip process was given to the back surface, and the adhesive bond layer formed in this base film surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Base material layer 20 ... Adhesive layer 30 ... Base film 40 ... Easy slip layer 50 ... Base film back surface to which easy slip processing was performed

Claims (9)

A sheet having a base material layer and an adhesive layer formed on the surface of the base material layer,
The base layer is composed of a base film and an easy-slip layer formed on the back surface of the base film,
The coefficient of dynamic friction measured according to JIS K7125 of the slippery layer is 0.01 to 0.4,
The adhesive sheet for wafer processing , wherein the slippery layer constitutes the outermost layer of the sheet and is crosslinked with a silicone-based slippery agent . The slippery layer was formed by applying the silicone-based slipper as it is without solvent, or by diluting or emulsifying the solvent, coating the back surface of the base film, and curing at normal temperature, heat curing, or electron beam. The adhesive sheet for wafer processing according to claim 1. 3. The wafer according to claim 1, wherein the slippery layer is formed by applying and drying a slippery agent obtained by mixing the silicone-based slippery agent and a platinum catalyst onto a back surface of a base film. Adhesive sheet for processing. The adhesive sheet for wafer processing according to any one of claims 1 to 3, wherein the silicone-based lubricant is at least one selected from silicone oil and silicone resin. The adhesive sheet for wafer processing according to any one of claims 1 to 4, wherein the thickness of the slippery layer is in the range of 1 nm to 1 µm.   The adhesive sheet for wafer processing according to any one of claims 1 to 5, wherein the adhesive layer is a layer that can be peeled from the base material layer. A step of affixing a semiconductor wafer on the adhesive layer constituting the adhesive sheet for wafer processing according to claim 1;
Irradiating the wafer with a pulse laser having transparency to the wafer along the division line, and forming a deteriorated layer along the division line inside the wafer;
Expanding the adhesive sheet to divide the wafer into semiconductor chips and split the adhesive layer, and to leave the adhesive layer on the back surface of the chip to remain, thereby forming the adhesive sheet. A method for manufacturing a semiconductor device, comprising: a step of peeling the adhesive layer from a material layer, and thermocompression bonding the chip to an adherend through the adhesive layer. Forming a groove having a depth smaller than the wafer thickness from the surface of the semiconductor wafer, and grinding the back surface of the wafer to divide the wafer into semiconductor chips;
A step of affixing a divided wafer comprising the chip group on the adhesive layer constituting the adhesive sheet for wafer processing according to any one of claims 1 to 6,
Expanding the adhesive sheet to divide the adhesive layer; and allowing the adhesive layer to adhere and remain on the back surface of the chip; and peeling the adhesive layer from the base material layer constituting the adhesive sheet; A method of manufacturing a semiconductor device, comprising a step of thermocompression bonding the chip to an adherend through the adhesive layer. A step of affixing a semiconductor wafer on the adhesive layer constituting the adhesive sheet for wafer processing according to claim 1;
Dividing the wafer into semiconductor chips;
A step of expanding the adhesive sheet; and an adhesive layer is fixed and left on the back surface of the chip, the adhesive layer is peeled off from the base material layer constituting the adhesive sheet, and the chip is attached to the adherend. The manufacturing method of the semiconductor device characterized by including the process of thermocompression bonding through a layer.

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