JP2001127029A - Manufacturing method surface of protective sheet at polishing of rear of wafer, and semiconductor chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface protective sheet which can manufacture a semiconductor chip efficiently by enabling the worker to recognize the semiconductor chip without fail. SOLUTION: This surface protective sheet for the time of polishing of the rear of a semiconductor wafer is one which is used for polishing of the rear of the wafer and by which the thickness of the wafer is thinned by forming a groove with a depth shallower than the thickness of the wafer from the surface of the wafer where a semiconductor circuit is made, and grinding the rear of the semiconductor wafer after that, and also finally it is divided into individual chips, and this protective sheet comprises base material and an adhesive layer made thereon, and in the tension test of that surface protective sheet, the stress relaxation percentage at tension of 10% is 40% or over after one minute.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface protection sheet used for protecting a circuit surface when grinding the back surface of a wafer.
In particular, the present invention relates to a surface protection sheet used in a wafer processing method for reducing the thickness of a wafer by grinding the back surface and finally dividing the wafer into individual chips. Also,
The present invention relates to a method for manufacturing a semiconductor chip using the surface protection sheet.

[0002]

2. Description of the Related Art In recent years, IC cards have become widespread, and further reduction in thickness is desired. For this reason, conventionally, the thickness is 35
A semiconductor chip having a thickness of about 0 μm is
It is necessary to reduce the thickness to μm or less.
As a method for achieving such a thinner chip, Japanese Patent Application Laid-Open No. Hei 5-335411 discloses a method of manufacturing a semiconductor chip in which a groove having a predetermined depth is formed from the front surface side of a wafer and then ground from the rear surface side. It has been disclosed. At the time of grinding the back surface of the wafer, a surface protection sheet is attached to the surface of the grooved wafer in order to protect the circuit on the wafer surface and to fix the wafer (chip).

A semiconductor chip manufactured by such a method is transferred to the next step after recognizing the position and direction of a wafer (chip) in a state of being fixed to a surface protection sheet in a wafer shape. At this time, the directionality of the wafer is recognized by the groove between the chips. Originally, the width of the groove between the chips depends on the blade width of dicing for forming the groove.If there is internal strain in the surface protection sheet used, the internal strain is released when the wafer is divided into chips. In addition, the chip interval is reduced, and the direction of the wafer cannot be recognized. The internal strain of the surface protection sheet is generated by residual stress due to tension at the time of film formation of the base material or at the time of attaching the wafer, and it is practically impossible to reduce this to zero.

[0004] If the internal strain is too large, there is almost no gap between the chips, and when picking up chips, adjacent chips may come into contact with each other and the chips may be damaged.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and it is possible to reliably recognize a semiconductor chip and to efficiently produce a semiconductor chip. The purpose is to provide a protective sheet. Another object of the present invention is to provide a semiconductor chip manufacturing method capable of improving the manufacturing efficiency by surely recognizing the semiconductor chip.

[0006]

According to the present invention, there is provided a surface protection sheet for grinding a back surface of a wafer, wherein a groove having a depth of cut smaller than the thickness of the wafer is formed from the surface of the wafer on which the semiconductor circuit is formed, and then the semiconductor substrate is formed. A surface protection sheet for a semiconductor wafer used in grinding the back surface of a wafer to reduce the thickness of the wafer by grinding the back surface of the wafer and eventually dividing the wafer into individual chips. The surface protective sheet is characterized in that, in a tensile test of the surface protective sheet, the stress relaxation rate at 10% elongation is 40% or more after 1 minute.

The Young's modulus of the surface protective sheet of the present invention is preferably from 3.0 × 10 ^{7 to} 5.0 × 10 ⁹ Pa.
Further, the Young's modulus of the base material constituting the surface protection sheet ×
The thickness is preferably from 1.0 × 10 ^{3 to} 1.0 × 10 ⁷ N / m.
According to such a surface protection sheet according to the present invention, semiconductor chips can be manufactured efficiently.

In the method of grinding the back surface of a wafer according to the present invention, a groove having a cutting depth smaller than the thickness of the wafer is formed from the front surface of the wafer on which the semiconductor circuit is formed, and the surface protection sheet is attached to the circuit forming surface. Then, while grinding the back surface of the semiconductor wafer to reduce the thickness of the wafer,
Ultimately, it is characterized in that it is divided into individual chips.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to the drawings. As shown in FIG. 1, a surface protection sheet 10 according to the present invention includes a base material 1 and a pressure-sensitive adhesive layer 2 formed thereon. The surface protective sheet 10 of the present invention has excellent stress relaxation properties. Specifically, the stress relaxation rate at the time of 10% elongation in a tensile test is 40% or more, preferably 50% or more after 1 minute, and furthermore. It is preferably at least 60%. The higher the stress relaxation rate, the better, and the upper limit is theoretically 100%, and may be 99.9%, 99% or 95% in some cases.

Since the surface protective sheet 10 of the present invention is excellent in stress relaxation, the residual stress is attenuated immediately after the surface protective sheet 10 is attached to the adherend, and the internal strain is quickly eliminated. Therefore, even after cutting and separating the chips, the chip interval does not become narrow. The stress relaxation rate is measured as follows. That is, a surface protection sheet sample of a predetermined length is pulled at a speed of 200 mm / min, and the stress A at the time of 10% elongation.
From (A−B) / A ×
It is calculated by 100 (%). The Young's modulus (based on JIS K-7127) of the surface protective sheet 10 of the present invention is as follows.
Preferably 3.0 × 10 ^{7 to} 5.0 × 10 ⁹ Pa, more preferably 5.
0 × 10 ^{7 to} 1.0 × 10 ⁹ Pa, particularly preferably 6.0 × 10 ⁷ to 8.
It is in the range of 0 × 10 ⁸ Pa.

When the Young's modulus of the surface protective sheet is in this range, the step of cutting the wafer into a wafer shape after attaching the wafer to the wafer can be performed smoothly. As described later, in the present invention, the pressure-sensitive adhesive layer may be formed of an energy ray-curable pressure-sensitive adhesive. In this case, the stress relaxation rate and the Young's modulus are determined by performing energy beam curing of the pressure-sensitive adhesive layer. Means the previous value.

Further, in the substrate 1 of the surface protective sheet 10 of the present invention, the product of the Young's modulus and the thickness is preferably 1.0 × 10 ^{3 to} 1.0 × 10 ⁷ N / m, more preferably 3.0 × 10 7
^{3 ~5.0 × 10 6 N / m} , particularly preferably ^{5.0 × 10 3 ~3.5 × 10 6} N /
m. If the product of the Young's modulus and the thickness of the base material is in this range, the machine suitability when attaching to the wafer is improved,
It becomes easier to control the attachment tension at a lower level.

The thickness of the substrate 1 is preferably 30 to
It is 1000 μm, more preferably 50 to 800 μm, particularly preferably 80 to 500 μm. The substrate 1 is made of a resin film, and is not particularly limited as long as the above properties are satisfied. Even if the resin itself shows the above properties, the above properties are obtained by adding other additives. It may be something. Further, the substrate 1 may be a film formed and cured of a curable resin, or may be a film formed of a thermoplastic resin.

As the curable resin, a photocurable resin, a thermosetting resin, or the like is used, and preferably, a photocurable resin is used. As the photocurable resin, for example, a resin composition mainly containing a photopolymerizable urethane acrylate oligomer is preferably used. The urethane acrylate oligomer includes a polyol compound such as a polyester type or a polyether type, and a polyvalent isocyanate compound such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and 1,3-xylylene diisocyanate. , 1,4-xylylene diisocyanate, terminal isocyanate urethane prepolymer obtained by reacting diphenylmethane 4,4-diisocyanate and the like,
It is obtained by reacting an acrylate or methacrylate having a hydroxyl group, for example, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate, or the like. Such a urethane acrylate oligomer has a photopolymerizable double bond in the molecule, and is polymerized and cured by irradiation with light to form a film.

The urethane acrylate oligomer preferably used in the present invention has a molecular weight of 1,000 to 5,000.
0, more preferably in the range of 2,000 to 30,000. The above urethane acrylate oligomers can be used alone or in combination of two or more. In many cases, it is difficult to form a film only with the urethane acrylate-based oligomer as described above. Therefore, usually, a film is obtained by diluting a film with a photopolymerizable monomer and then curing the film. The photopolymerizable monomer has a photopolymerizable double bond in the molecule, and in particular, in the present invention, an acrylic ester compound having a relatively bulky group is preferably used.

Specific examples of the photopolymerizable monomer used for diluting such a urethane acrylate oligomer include isobornyl (meth) acrylate,
Alicyclic compounds such as dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, and adamantane (meth) acrylate, phenylhydroxypropyl acrylate, and benzyl Aromatic compounds such as acrylates, or tetrahydrofurfuryl (meth) acrylate, morpholine acrylate, N-vinylpyrrolidone or N-
And heterocyclic compounds such as vinylcaprolactam. Moreover, you may use a polyfunctional (meth) acrylate as needed.

The photopolymerizable monomer is used in an amount of preferably 5 to 900 parts by weight, more preferably 10 to 500 parts by weight, particularly preferably 30 to 200 parts by weight, based on 100 parts by weight of the urethane acrylate oligomer. Can be When the base material 1 is formed from the above-mentioned photocurable resin, by mixing a photopolymerization initiator into the resin, the polymerization curing time by light irradiation and the amount of light irradiation can be reduced.

Examples of such a photopolymerization initiator include photoinitiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds and peroxide compounds, and photosensitizers such as amines and quinones. And specifically, 1
-Hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone and the like can be exemplified. .

The amount of the photopolymerization initiator used is 10
0-15 parts by weight, preferably 0.05-15 parts by weight,
It is more preferably 0.1 to 10 parts by weight, particularly preferably 0.5 to 5 parts by weight. The curable resin as described above,
The oligomer or monomer can be selected from various combinations of compounds so as to have the above-mentioned physical properties.

In addition, calcium carbonate,
Additives such as inorganic fillers such as silica and mica, metal fillers such as iron and lead, and coloring agents such as pigments and dyes may be contained. As a method for forming the substrate 1, a method in which a liquid resin (a resin before curing, a resin solution, or the like) is cast into a thin film on a process sheet, for example, and then formed into a film by a predetermined means, is mentioned. Can be According to such a manufacturing method, stress applied to the resin during film formation is small, and formation of fish eyes is small. In addition, the uniformity of the film thickness is high, and the thickness accuracy is usually within 2%.

As another film forming method, it is preferable to manufacture the film by extrusion molding by a T-die or an inflation method or by a calender method. On the upper surface of the base material 1, that is, on the surface on which the pressure-sensitive adhesive layer 2 is provided, another layer such as a corona treatment or a primer may be provided in order to improve the adhesion to the pressure-sensitive adhesive. The surface protection sheet 10 according to the present invention is manufactured by providing the pressure-sensitive adhesive layer 2 on the substrate 1 as described above. When the pressure-sensitive adhesive layer 2 is made of an ultraviolet-curable pressure-sensitive adhesive, a transparent substrate is used as the substrate 1.

In the present invention, the elasticity of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 2 at 23 ° C. is preferably 5.0 × 1.
0 ^{4 to} 1.0 × 10 ⁸ Pa, more preferably 6.0 × 10 ^{4 to} 8.0 × 10 ⁷
Pa, particularly preferably in the range of 7.0 × 10 ^{4 to} 5.0 × 10 ⁷ Pa. If the elastic modulus of the pressure-sensitive adhesive is in this range, the wafer can be securely fixed to the surface protection sheet, and the suitability for grinding the wafer is improved. In the case where the pressure-sensitive adhesive layer 2 is formed of an energy-ray-curable pressure-sensitive adhesive described later, the above-mentioned elastic modulus means the elastic modulus before performing energy-ray curing.

The thickness of the pressure-sensitive adhesive layer 2 is usually about 3 to 100 μm, preferably about 10 to 100 μm, although it depends on the material.
About 50 μm. The pressure-sensitive adhesive layer 2 can be formed of various conventionally known pressure-sensitive pressure-sensitive adhesives. Such an adhesive is not particularly limited, and for example, an adhesive such as a rubber-based, acrylic, silicone-based, or polyvinyl ether is used. In addition, an energy ray curable type, a heat foaming type, and a hydrophilic pressure-sensitive adhesive can also be used. Particularly, in the present invention, an energy ray-curable pressure-sensitive adhesive is preferably used.

The energy ray-curable pressure-sensitive adhesive generally comprises an acrylic pressure-sensitive adhesive and an energy ray-polymerizable compound as main components. Examples of the energy ray-polymerizable compound used in the energy ray-curable pressure-sensitive adhesive include, for example, JP-A-60-196965 and JP-A-60-22.
Low molecular weight compounds having at least two or more photopolymerizable carbon-carbon double bonds in a molecule capable of forming a three-dimensional network by light irradiation as disclosed in Japanese Patent No. 3139 are widely used. Methylol propane triacrylate, tetramethylol methane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate or 1,4-butylene glycol diacrylate, 1,6-hexanediol Diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate and the like are used.

Further, as an energy ray polymerizable compound,
In addition to the acrylate compounds described above, urethane acrylate oligomers can also be used. As the urethane acrylate oligomer, the same urethane acrylate oligomer that can be used for the base material 1 can be used. The mixing ratio of the acrylic pressure-sensitive adhesive and the energy ray-polymerizable compound in the energy ray-curable pressure-sensitive adhesive is 50 to 200 parts by weight, preferably 50 to 200 parts by weight, based on 100 parts by weight of the acrylic pressure-sensitive adhesive. Fifteen
It is preferably used in an amount of 0 parts by weight, particularly preferably in the range of 70 to 120 parts by weight. In this case, the obtained surface protective sheet has a large initial adhesive strength, and the adhesive strength is significantly reduced after irradiation with energy rays. Therefore, peeling at the interface between the wafer and the energy-ray-curable pressure-sensitive adhesive layer after the back surface grinding is completed is facilitated.

The energy ray-curable pressure-sensitive adhesive may be formed from an energy ray-curable copolymer having an energy ray-polymerizable group in a side chain. Such an energy ray-curable copolymer has the property of having both adhesiveness and energy ray-curability. An energy ray-curable copolymer having an energy ray polymerizable group in a side chain is, for example,
Details thereof are described in JP-A-5-32946, JP-A-8-27239, and the like.

The acrylic energy ray-curable pressure-sensitive adhesive as described above has a sufficient adhesive strength to the wafer before the energy ray irradiation, and the adhesive strength is significantly reduced after the energy ray irradiation. That is, before the energy beam irradiation, the surface protection sheet 10 and the wafer are brought into close contact with a sufficient adhesive force to enable surface protection, and after the energy beam irradiation, the wafer can be easily peeled off from the ground wafer (chip). it can.

As the hydrophilic pressure-sensitive adhesive, for example, the pressure-sensitive adhesive described in JP-A-10-226776 can be used. Such a pressure-sensitive adhesive composition comprises a carboxyl group-containing monomer, a copolymer of another monomer copolymerizable with the monomer, a neutralizing agent and a crosslinking agent. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid. Other monomers copolymerizable with the monomer include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, and 2-butoxyethyl (meth) acrylate. Containing alkoxy group (meta)
An acrylate or a (meth) acrylate having an alkyl group having 1 to 18 carbon atoms is used.

The neutralizing agent is used to neutralize a part or all of the carboxyl groups in the copolymer to impart hydrophilicity to the pressure-sensitive adhesive composition. As such a neutralizing agent, organic amino compounds such as monoethylamine, monoethanolamine, diethylamine, diethanolamine, triethylamine, triethanolamine, and N, N, N'-trimethylethylenediamine are used.

The crosslinking agent is used to partially crosslink the copolymer. Examples of the crosslinking agent include an epoxy-based crosslinking agent, an isocyanate-based crosslinking agent, a methylol-based crosslinking agent,
Chelate-based crosslinking agents, aziridine-based crosslinking agents, and the like are used. The hydrophilic pressure-sensitive adhesive as described above has very little glue residue when the surface protective sheet is peeled off, and because the pressure-sensitive adhesive polymer itself has hydrophilicity, it is excellent in water washability, and the pressure-sensitive adhesive adheres to the wafer. Even if it does, it becomes possible to wash only pure water.

The surface protective sheet 10 of the present invention is prepared by applying the above-mentioned pressure-sensitive adhesive on the substrate 1 at an appropriate thickness according to a generally known method such as a knife coater, a roll coater, a gravure coater, a die coater, and a reverse coater. And dried to form the pressure-sensitive adhesive layer 2 and then, if necessary, laminating a release sheet on the pressure-sensitive adhesive layer.

As described above, the surface protection sheet 10 according to the present invention forms a groove with a depth of cut smaller than the thickness of the wafer from the surface of the wafer on which the semiconductor circuit is formed, and then grinds the back surface of the semiconductor wafer. Thus, in the wafer back surface grinding method for reducing the thickness of the wafer and finally dividing the wafer into individual chips, it is used as a means for protecting the wafer surface and temporarily fixing the wafer.

More specifically, it is used in a wafer back surface grinding method comprising the following steps. First step: A groove 4 having a predetermined depth is formed from the surface of the wafer 3 along a cutting position of the wafer which partitions a plurality of circuits (see FIG. 2). Second step: The surface protection sheet 10 of the present invention is bonded so as to cover the entire surface of the wafer 3 (see FIG. 3).

Third step: The bottom of the groove 4 is removed, and the back surface of the wafer is ground to a predetermined thickness and divided into individual chips 5 (see FIG. 4). Thereafter, when the pressure-sensitive adhesive layer 2 is formed from an energy-ray-curable pressure-sensitive adhesive, the adhesive force is reduced by irradiating with energy rays, the position and the direction of the chip are recognized, and another pressure-sensitive adhesive tape ( A mounting tape in Japanese Patent Application Laid-Open No. Hei 5-335411 is attached, the position and direction are adjusted so that pickup is possible, and the surface protection sheet 10 is peeled off (see FIG. 5). . Thereafter, the chip is picked up from another adhesive tape and mounted on a predetermined base.

According to such a process, the recognizability of the semiconductor chip can be improved, and the semiconductor chip can be manufactured efficiently.

[0036]

As described above, according to the surface protection sheet of the present invention, the recognition of the semiconductor chip can be reliably performed, and the efficiency of the semiconductor chip manufacturing process can be improved. Also, an extremely thin semiconductor chip can be manufactured with high yield.

[0037]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the following, “Young's modulus”, “elastic modulus”, “stress relaxation rate”, “minimization rate of chip spacing”, “alignment”, and “recognition of chip spacing” were evaluated by the following methods. "Young's modulus" JIS K-71 at 200mm / min test speed
27 was measured. "Elastic modulus" G '(torsion shear method) Specimen: 8 mmφ x 3 mm cylinder Measuring instrument: DYNAMIC ANALYZER RDA II (manufactured by REOMETRIC) Frequency: 1 Hz "Stress relaxation rate" Surface protection sheet prepared in Examples and Comparative Examples To a width of 15 mm and a length of 100 mm to obtain a test piece. This test piece was Orientec TENSILON RTA-1
From the stress A at 10% elongation and the stress B one minute after the elongation is stopped (A-B)
/ A × 100 (%). "Narrowing ratio of chip interval" A dicing tape (D-628) manufactured by Lintec Co., Ltd. is attached to an 8-inch wafer (720 μm thick), and cut with a dicing device (DISCO DAD 2H / 6T) using a 35 μm thick blade. Grooves were formed under the conditions of a depth of 400 μm and chip sizes of 8 mm square and 12 mm square. The surface protection sheet prepared in each of the examples and the comparative examples was bonded to the grooved surface using a tape mounter (Adwill RAD-3500m / 12, manufactured by Lintec) under the conditions of the bonding tension shown in Table 1. After the dicing tape was peeled off, it was polished using a grinding device (manufactured by Disco, DFD-840) until the thickness became 80 μm, and the chip interval was measured by placing the polished surface upward on an adsorption stage of an optical microscope. .
In the measurement, the chip spacing perpendicular to the sheet sticking direction was measured at 25 points from the top, bottom, right, left, and center of the wafer. The chip spacing narrowing ratio is Δ (35 μm−average of measured values) / 35
It was calculated as μm｝ × 100. "Alignment" The chipped wafer created by the above method is visually observed, and if the chip spacing is extremely different at each location on the wafer, or if chip misalignment occurs, it is regarded as "defective", and the chip spacing is visually observed. Those that were complete were considered "good". "Recognition of chip spacing" A wafer transfer device (Lintec, LTD-25
At 00f / 8), the groove between the chips was recognized, the wafer was aligned, and the chipped wafer was transferred from the surface protection sheet to a mounting tape. At this time, those which could be processed without any problem were regarded as "good", and those which had an error were regarded as "bad".

[0038]

Example 1 50 parts by weight of a urethane acrylate oligomer having a weight average molecular weight of 5000 (manufactured by Arakawa Chemical Co., Ltd.), 25 parts by weight of isobornyl acrylate and 25 parts by weight of phenylhydroxypropyl acrylate as photopolymerizable monomers
Parts by weight, 2.0 parts by weight of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by Ciba Geigy) as a photopolymerization initiator, and 0.1 parts by weight of a phthalocyanine pigment.
And 2 parts by weight to obtain a photocurable resin composition.

The obtained resin composition was applied on a polyethylene terephthalate film (manufactured by Toray Industries, Inc .: 38 μm in thickness, hereinafter referred to as “PET film”) having a thickness of 110 μm by a fountain die method.
To form a resin composition layer. Immediately after coating, the same PET film was further laminated on the resin composition layer, and thereafter, a high-pressure mercury lamp (160 W / c
m, height 10 cm), and the resin composition layer is cross-linked by ultraviolet irradiation under the condition of a light quantity of 250 mJ / cm ^2.
After curing, the PET films on both sides were peeled off to obtain a base film having a thickness of 110 μm. The Young's modulus of the substrate film was measured by the above method. Table 1 shows the results.

On one side of the substrate film, 100 parts by weight of an acrylic pressure-sensitive adhesive (copolymer of n-butyl acrylate and acrylic acid), 120 parts by weight of a urethane acrylate oligomer having a molecular weight of 8000, and a curing agent (diisocyanate) An adhesive composition obtained by mixing 10 parts by weight of a (system) and 5 parts by weight of a photopolymerization initiator (benzophenone) was applied and dried to form an adhesive layer having a thickness of 20 μm to obtain a surface protective sheet. The elastic modulus of the pressure-sensitive adhesive layer was 1.5 × 10 ⁵ Pa.

The stress relaxation rate and Young's modulus of the obtained surface protective sheet were measured as described above. Table 1 shows the results. Using the obtained surface protection sheet, the back surface of the wafer was ground, and the narrowing ratio of chip spacing, alignment, and recognition of chip spacing were evaluated. Table 1 shows the results.

[0042]

Example 2 The same operation as in Example 1 was performed except that N-vinylcaprolactam was used instead of phenylhydroxypropyl acrylate. Table 1 shows the results.

[0043]

Example 3 The same operation as in Example 1 was carried out except that 50 parts by weight of isobornyl acrylate was used without using phenylhydroxypropyl acrylate. Table 1 shows the results
Shown in

[0044]

Comparative Example 1 Toluene 60 of a styrene-vinyl isoprene block copolymer (Hybler VS-1 manufactured by Kuraray Co., Ltd.)
% Solution was cast on the same support film as in Example 1, and without lamination or UV irradiation,
After drying at 0 ° C. for 2 minutes, a base film having a Young's modulus shown in Table 1 and a thickness of 300 μm was obtained.

Using this base film, a surface protection sheet was produced in the same manner as in Example 1. Table 1 shows the results.

[0046]

Comparative Example 2 A low-density polyethylene film having a thickness of 110 μm (trade name: Sumikasen L70) was used as a base film.
Except using 5), the same operation as in Example 1 was performed.
Table 1 shows the results.

[0047]

Comparative Example 3 As a base film, a low-density polyethylene film having a thickness of 200 μm (trade name: Sumikasen L70)
Except using 5), the same operation as in Example 1 was performed.
Table 1 shows the results.

[0048]

[Table 1]

[Brief description of the drawings]

FIG. 1 shows a sectional view of a surface protection sheet according to the present invention.

FIG. 2 shows a manufacturing process of a thin semiconductor chip using the pressure-sensitive adhesive sheet according to the present invention.

FIG. 3 shows a manufacturing process of a thin semiconductor chip using the pressure-sensitive adhesive sheet according to the present invention.

FIG. 4 shows a manufacturing process of a thin semiconductor chip using the pressure-sensitive adhesive sheet according to the present invention.

FIG. 5 shows a manufacturing process of a thin semiconductor chip using the pressure-sensitive adhesive sheet according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Adhesive layer 3 ... Wafer 4 ... Groove 5 ... Chip

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuyoshi Ebe 1375-19 Shimonoda, Shiraoka-cho, Minamisaitama-gun, Saitama

Claims (4)

[Claims] A groove having a depth of cut shallower than the thickness of the semiconductor circuit is formed from the surface of the wafer on which the semiconductor circuit is formed, and then the back surface of the semiconductor wafer is ground so that the thickness of the wafer is reduced. Is a surface protection sheet for a semiconductor wafer used in wafer back grinding for dividing into individual chips, comprising a base material and an adhesive layer formed thereon, and a tensile test of the surface protection sheet. 3. The surface protection sheet according to claim 1, wherein a stress relaxation rate after 10% elongation is 40% or more after 1 minute. 2. The surface protective sheet according to claim 1, wherein the Young's modulus is 3.0 × 10 ^{7 to} 5.0 × 10 ⁹ Pa. 3. The substrate has a Young's modulus × thickness of 1.0 × 10 ^{3 to} 1.0.
The surface protective sheet according to claim 1, wherein the surface protective sheet has a density of × 10 ⁷ N / m. 4. A groove having a depth of cut smaller than the thickness of the wafer is formed from the surface of the wafer on which the semiconductor circuit is formed, and a substrate and an adhesive layer formed thereon are formed on the circuit formation surface. After 1 minute, a surface protection sheet having a stress relaxation rate of 40% or more at the time of 10% elongation in a tensile test is applied, and then the semiconductor wafer is ground back to reduce the thickness of the wafer. And finally dividing the semiconductor chip into individual chips.