JPH11300897A - Release film for adhering sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a release film suitable for adhering surface protection of an adhering sheet for wafer processing by providing a silicone resin coating on at least one side of a plastic film so that a silicon element strength of the silicone resin coating surface by a fluorescent X-ray method is a specified value. SOLUTION: A silicone resin coating is provided on at least one side of a plastic film, and a silicon element strength A (unit: kcps) of the silicone resin coating surface by a fluorescent X-ray method satisfies an expression 3<=A<=6 or 3.5<=A<=5. A solvent resistance friction increasing rate by toluene is 300% or lower of an initial value. The plastic film is at least one type selected from a polyethylene terephthalate, a polyethylene-2,6-naphthalate, a polyethylene-α,β- bis(2-chlorophenoxy)ethane-4,4'-dicarboxylate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a release film used for protecting an adhesive surface of an adhesive sheet. In particular, the present invention relates to a release film for an adhesive sheet such as an adhesive sheet for surface protection or an adhesive sheet for dicing used when processing a silicon wafer or the like used for a semiconductor integrated circuit (IC) or the like.

[0002]

2. Description of the Related Art Conventionally, a release film formed by coating a silicone resin on the surface of a plastic film, for example, a polyester film, a polyethylene film, or a polypropylene film, and providing a film thereon is used for an adhesive sheet such as an adhesive tape. Widely used to protect surfaces.

[0003] Such a release film is disclosed in
No. 2,393, JP-A-60-141553, JP-A-3-231812, JP-B-4-59207, and JP-B-6-2393 are known.

A semiconductor represented by an IC is usually
A wafer manufactured by slicing a high-purity silicon single crystal or the like is manufactured into chips after an etching step, a polishing step, and a dicing step. In each of these steps, the wafer is protected during surface protection and processing. An adhesive sheet is used for fixing. Particularly, in the polishing step, when polishing the wafer surface opposite to the circuit pattern surface formed on the wafer in the etching process, an adhesive sheet is used for the purpose of protecting the circuit pattern surface.

[0005] Such an adhesive sheet is required to have extremely low contamination on the wafer surface.

In recent years, as the pattern width at the time of etching on the wafer is reduced to 0.3 μm or less, it is a release agent from a release film used for protecting the adhesive surface of the adhesive sheet. There is a problem of contamination such that the silicone resin component is transferred to the adhesive surface and then retransferred to the wafer pattern surface.

[0007] Further, the adhesive sheet used in the dicing step of cutting the wafer into a predetermined size and forming chips is used to fix the wafer with a constant adhesive force at the time of dicing, but to obtain the same at the end of dicing. A high degree of adhesive force controllability is required to reduce the adhesive force by applying ultraviolet light, heat, or the like to the adhesive sheet so that the semiconductor chip can be easily detached.

At this time, when the silicone resin component is transferred from the release film used for protecting the adhesive surface of the pressure-sensitive adhesive sheet to the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet, the controllability of the pressure-sensitive adhesive force of the sheet is significantly reduced. is there.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a release film suitable for protecting an adhesive surface of an adhesive sheet, particularly an adhesive sheet for processing a wafer.

[0010]

As a result of intensive studies by the present inventors, the object of the present invention has been industrially advantageously achieved by the present invention having the following constitution.

[1] A plastic film has a silicone resin film on at least one surface, and the silicon element surface (unit: kcps) of the silicone resin film surface by fluorescent X-ray method satisfies the following formula (1). Release film for adhesive sheet.

3 ≦ A ≦ 6 ‥‥ (1) [2] The silicon element strength (unit: kcps) of the surface of the silicone-based resin film by the fluorescent X-ray method satisfies the following formula (2). The release film for an adhesive sheet according to [1].

3.5 ≦ A ≦ 5 ‥‥ (2) [3] The solvent friction increase rate due to toluene is 30 as the initial value.
The release film for an adhesive sheet according to the above [1] or [2], which is within 0%.

[4] The release film for an adhesive sheet according to any one of [1] to [3], wherein the adhesive sheet is an adhesive sheet for processing a wafer.

[5] The plastic film is at least one selected from polyethylene terephthalate, polyethylene-2,6-naphthalate, and polyethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate. [1] above,
The release film for a pressure-sensitive adhesive sheet according to any one of items [4] to [4].

The feature of the present invention resides in that the silicon element strength (unit: kcps) of the silicone resin film on the release surface of the plastic film by the fluorescent X-ray method is set within a certain range, thereby providing an excellent adhesive sheet. Thus, it was possible to satisfy the contradictory property that the transfer of the silicone resin film to the adhesive surface of the sheet can be extremely reduced while maintaining the releasability. By using the release film of the present invention, the contamination of the silicone resin component from the adhesive sheet used in the semiconductor manufacturing process to the wafer surface can be extremely reduced.

Further, by using the release film of the present invention as a release film for protecting the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet used in the dicing step, the transfer of the silicone resin component to the pressure-sensitive adhesive sheet can be extremely reduced. As a result, it was possible to control the decrease in the adhesive strength during irradiation of the adhesive sheet with ultraviolet light or heating.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

As the plastic film of the present invention,
For example, synthetic polymer films (including sheets) such as a polypropylene film, a polyester film, and a nylon film can be exemplified. Among them, heat resistance,
Polyethylene terephthalate film, polyethylene-2,6-naphthalate film, and polyethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate film, which are excellent in surface properties and the like, are preferable, and in particular, Excellent in mechanical strength and dimensional stability 2
An axially stretched polyethylene terephthalate film, a biaxially stretched polyethylene-2,6-naphthalate film, and a biaxially stretched polyethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate film are preferred.

The plastic film constituting the present invention is produced by a conventional method, and particularly, a biaxially oriented polyethylene terephthalate film, a biaxially oriented polyethylene-2,6-naphthalate film, a biaxially oriented polyethylene-α, The film thickness of the β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate film is 15 to 350 μm, preferably 20 to 100 μm.
Those having a range of μm are preferably applied in terms of mechanical properties, dimensional stability, heat resistance, price and the like.

In the present invention, the silicone resin film is a film containing a polyorganosiloxane having a structure represented by the following formula (3) as a main component, and the polyorganosiloxane being crosslinked to form a film. In particular, a silicone-based coating in which the crosslinking reaction is performed in an addition reaction type is preferable in order to further clarify the objects and effects of the present invention.

[0022]

(Wherein, R1 represents a methyl group and / or a phenyl group, and Vi represents a vinyl group.) Specifically, the polyorganosiloxane and the organohydrogenpolypoly represented by the above formula (1) It is generally obtained by forming a crosslinked structure of silicone by addition reaction with siloxane in the presence of a platinum catalyst represented by chloroplatinic acid.

At this time, drying and curing (thermal curing, ultraviolet curing, etc.) of the silicone resin film can be performed individually or simultaneously. When performing at the same time,
Although it depends on the heat resistance (thermal dimensional stability) of the plastic film, it is 80 ° C to 200 ° C, preferably 120 ° C.
It is preferable to heat for 15 seconds or more in a temperature range of -180 ° C.

Further, in the present invention, the silicon element strength (unit: kc
ps) must satisfy the following expression (1). When the silicon element strength (unit: kcps) exceeds 6, preferably 5, it is not preferable because the transfer amount of the silicone resin film to the pressure-sensitive adhesive sheet surface after peeling increases.

The silicon element strength (unit: kcp)
When s) is 3, preferably less than 3.5, it is not preferable because peeling from the pressure-sensitive adhesive sheet becomes insufficient.

In particular, in order to reduce the migration of the silicone resin film to the adhesive surface of the adhesive sheet, which is a feature of the present invention, the molar amount of vinyl groups and the amount of organohydrogenpolysiloxane in the polyorganosiloxane must be adjusted. By adjusting the rubber hardness of the silicone resin film from 15 ° to 50 °
° is preferable. At this time, the rubber hardness of the silicone-based resin film was determined by mixing a predetermined amount of chloroplatinic acid reacted with polyorganosiloxane oil with the predetermined amount of polyorganosiloxane and organohydrogenpolysiloxane, and removing the solvent under vacuum. Thereafter, the sheet is heated at 120 ° C. for 10 minutes to form a sheet-like silicone resin film having a thickness of about 10 mm, which is measured by a JIS rubber hardness meter.

In the present invention, the coating method for forming the silicone resin film is not particularly limited, but is usually an aromatic hydrocarbon such as benzene, toluene and xylene, and an aliphatic hydrocarbon such as cyclohexane, n-hexane and n-heptane. A direct gravure coater or a micro gravure coater using a coating material obtained by dissolving a silicone resin at a concentration of 4 to 18% by weight in an organic solvent such as hydrocarbon, halogenated hydrocarbon such as perchloroethylene, ethyl acetate, methyl vinyl ketone, etc. , A reverse gravure coater, a direct kiss coater, a reverse kiss coater, a comma coater, a die coater, a bar-rod type coating device, or the like. Among them, it is preferable to use a microgravure coater, a direct kiss coater, or a reverse kiss coater, because the uniformity of the thickness of the silicone resin film is good and the occurrence of coating unevenness is small.

In the present invention, the adhesive sheet was bonded to the release film of the present invention if the rate of increase in solvent friction with toluene on the surface of the release film provided with the silicone resin film was within 300% of the initial value. Even when the sheet is stored for a long period of six months or more, the transfer of the silicone resin film to the adhesive surface of the sheet can be maintained in an extremely low state, which is preferable.

[0029]

EXAMPLES The present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

The properties of the release film were evaluated by the following methods. 1) Measurement of silicon element intensity by X-ray fluorescence method: A release film is cut into a predetermined size (50 mmφ), and the silicon element intensity A on the release surface side is counted by an X-ray fluorescence apparatus under the following conditions. Next, after removing the silicone-based resin film on the surface with sandpaper, washing and drying with methyl ethyl ketone, the silicon element strength B is counted under the same condition method as described above. The value obtained by subtracting the silicon element strength B from the silicon element strength A thus obtained was defined as the silicon element strength (unit: KCPS) of the silicone resin film.

-Device name: X-ray SPECTROMETER RIX manufactured by Rigaku
1000 ・ X-ray tube: Horizontal Cr target ・ Element coating: Si06 ・ Spectral crystal: LIF1 ・ Slit: COARSE ・ Primary filter: OUT ・ Diaphram: 30mm ・ Applied voltage, current (XG): 50kv-50mA ・ PHA: 100-350・ PEAK: 2θ / 144.520deg, time / 40 seconds ・ BG.1: 2θ / 143.000deg, time / 10 seconds ・ BG.2: 2θ / 146.100deg, time / 10 seconds 2) Releasability: with release film Polyester adhesive film (Nitto Denko 31B adhesive tape: 50 μm thickness, 50 m
m width) was adhered while being pressed with a 5 kg roller, and left at 20 ° C. for 20 hours, and the 180 ° peel strength was measured at a peeling speed of 300 mm / min using a tensile tester. Here, if the peeling force is 15 g or less, it can be said that the releasability is good. 3) Silicone transferability to the adhesive surface: Nitto Denko 31B adhesive tape is bonded on the release layer of the release film in the same manner as in 2), and then 10 sheets are stacked and 2 kg / cm ^2.
While maintaining the pressure of 50 ° C. for 50 hours. Next, after leaving this sheet at room temperature for 10 minutes, the adhesive sheet was peeled off from the release film. The obtained adhesive sheet is cut into a predetermined size (50 mmφ), and the silicon element strength C on the release surface side of the sheet is counted by a fluorescent X-ray method. Next, after removing the 31B tape adhesive layer with a solvent (using methyl ethyl ketone), the silicon element strength D is counted under the same condition method as described above. The value obtained by subtracting the silicon element strength D from the silicon element strength C obtained in this way is the amount of silicone transferred to the pressure-sensitive adhesive sheet (unit: KCP).
S). If the silicone transfer amount (unit: KCPS) is 0.10 or less, “「 ”, exceeding 0.10 and 0.1
When it was less than 5, it was evaluated as “○”, when it exceeded 0.15, when it was less than 0.20, it was “△”, and when it was 0.20 or more, it was “x”.
If it is “Δ” or more, it can be said that silicone transferability to the pressure-sensitive adhesive sheet is good. 4) Transferability of silicone to the adhesive surface after being left for a long time after bonding: release film and 31B in the same manner as in 3) above
Lay 10 sheets with adhesive tape together, 2kg
After leaving at a temperature of 20 ° C. for 3 months while applying a pressure of / cm ^2, the amount of transferred silicone was measured in the same manner as in 3) above. The silicone transfer amount (unit: KCPS) is 0.
If it is 10 or less, “「 ”, more than 0.10, if less than 0.15,“ ○ ”, more than 0.15, less than 0.20,“ △ ”; “×” was assigned.
If it is “Δ” or more, it can be said that silicone transferability to the pressure-sensitive adhesive sheet after long-term storage is good. 5) Solvent friction increase rate due to toluene: Using a tester Sangyo Gakushin type friction tester, a silicone resin-based coating surface of a release film impregnated with 3 cc of toluene was applied with a cotton cloth (Kanakin No. 3) at a load of 500 g. After double rubbing, Nitto Denko polyester adhesive tape (31B tape:
(Thickness: 25 μm; width: 18 mm) are attached with a 5 kg roll, and left for 10 minutes. After that, 18
The peel resistance is measured at a peel angle of 300 mm / min in the 0 ° direction.

The peel resistance of the silicone resin-based coating surface of the release film which has not been subjected to friction treatment with toluene as a blank is measured in the same manner as described above. From the obtained peeling resistance value, the solvent friction increase rate was determined by the following equation (4).

Solvent friction increase rate (%) = (peeling resistance of release film after friction with toluene impregnated cloth) 布 (peeling resistance of blank release film) × 100 ‥ (4) [Example 1] 50 μm thickness One side of a biaxially stretched polyester film "Lumirror S28" manufactured by Toray Industries, Inc. was coated with the following composition A as a thermosetting silicone resin coating agent using a gravure roll (# 200, oblique line type), and heated at 160 ° C.
After drying in an oven for 15 seconds and heat curing, the humidity was 20
% Or less in an atmosphere at a temperature of 50 ° C. for 3 days to obtain a release film. The silicon element strength of the silicone resin-coated surface of the obtained release film measured by a fluorescent X-ray method was 3.7 kcps.

The results are shown in Table 1. The releasability, transferability to silicone, and transferability to silicone 3 months after laminating the pressure-sensitive adhesive sheet are all very good.

[Thermosetting Silicone Resin Coating Composition / A] 1) KS847H 4.6 parts by weight from Shin-Etsu Chemical 2) 0.05 parts by weight PL-50T from Shin-Etsu Chemical 3) 100 parts by weight toluene [Example 2] A release film was obtained in the same manner as in [Example 1] except that the silicone resin coating composition was changed to the following composition B. The silicon element strength of the silicone-based resin coated surface of the obtained release film by a fluorescent X-ray method was 5.7 kcps.
Met.

The results are shown in Table 1. The results show that the release property, the silicone transfer property, and the silicone transfer property after 3 months from bonding the pressure-sensitive adhesive sheet are all good.

“Thermosetting Silicone Resin Coating Composition / Composition B” 1) 6.5 parts by weight of KS847H manufactured by Shin-Etsu Chemical 2) 0.07 parts by weight of PL-50T manufactured by Shin-Etsu Chemical 3) 100 parts by weight of toluene [Example 3] A release film was obtained in the same manner as in [Example 1] except that the silicone resin coating composition had the following composition C. The silicon element strength of the silicone-based resin coated surface of the obtained release film by a fluorescent X-ray method was 4.9 kcps.
Met.

The results are shown in Table 1. As can be seen from the table, the releasability, transferability to silicone, and transferability to silicone three months after laminating the pressure-sensitive adhesive sheet are all very good.

“Thermosetting Silicone Resin Coating Composition C” 1) 5.5 parts by weight of KS847H manufactured by Shin-Etsu Chemical 2) 0.06 parts by weight of PL-50T manufactured by Shin-Etsu Chemical 3) 100 parts by weight of toluene [Example 4] A release film was obtained in the same manner as in [Example 1] except that the silicone resin coating composition had the following composition D. The silicon element strength of the silicone-based resin coating surface of the obtained release film by a fluorescent X-ray method was 3.2 kcps.
Met.

The results are shown in Table 1. The results show that the releasability, silicone transferability, and silicone transferability three months after lamination of the adhesive sheet are all good.

“Thermosetting Silicone Resin Coating Composition / Composition D” 1) 4.2 parts by weight of KS847H manufactured by Shin-Etsu Chemical 2) 0.04 parts by weight of PL-50T manufactured by Shin-Etsu Chemical 3) 100 parts by weight of toluene [Example 5] A release film was obtained in the same manner as in [Example 1] except that the aging treatment was not performed. The silicon element strength of the silicone resin-coated surface of the obtained release film measured by a fluorescent X-ray method was 3.7 kcps.

The results are shown in Table 1. The results show that the release property, the silicone transfer property, and the silicone transfer property after 3 months from bonding the pressure-sensitive adhesive sheet are all good.

Comparative Example 1 A release film was obtained in the same manner as in [Example 1] except that the silicone resin coating composition was changed to the following composition E. The silicon element strength of the silicone resin coating surface of the obtained release film by the fluorescent X-ray method is
It was 7.0 kcps.

The results are shown in Table 1. As shown in FIG.
Both silicone migration properties after three months after bonding the adhesive sheet are inferior.

“Thermosetting Silicone Resin Coating Composition / Composition E” 1) KS847H 7.3 parts by weight manufactured by Shin-Etsu Chemical 2) PL-50T manufactured by Shin-Etsu Chemical 0.08 parts by weight 3) 100 parts by weight of toluene [Comparative Example 2] A release film was obtained in the same manner as in [Example 5] except that the silicone resin coating composition was changed to the following composition F. The silicon element strength of the silicone resin coated surface of the obtained release film by a fluorescent X-ray method was 2.9 kcps.
Met.

The results are shown in Table 1. As shown, the pressure-sensitive adhesive sheet was inferior in both releasing property and silicone transferability.

“Thermosetting Silicone Resin Coating Composition / Composition F” 1) KS847H 3.8 parts by weight from Shin-Etsu Chemical 2) PL-8OT 0.08 parts by weight from Shin-Etsu Chemical 3) 100 parts by weight toluene

[0048]

[Table 1]

[0049]

As described above, when the release film of the present invention is used, the transfer (transfer) of the silicone resin to the pressure-sensitive adhesive sheet can be extremely reduced. This makes it possible to extremely reduce the contamination of the wafer by the pressure-sensitive adhesive sheet, particularly when the pressure-sensitive adhesive sheet is used as a pressure-sensitive adhesive surface protection film for a wafer processing pressure-sensitive adhesive sheet used in a semiconductor manufacturing process. Furthermore, by using the release film of the present invention, it is possible to maintain the adhesiveness of the adhesive sheet for a long period of time.

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Claims (5)

[Claims] 1. A plastic film having a silicone resin film on at least one surface thereof, and a silicon element strength A (unit: k) of the silicone resin film surface determined by a fluorescent X-ray method.
(cps) is a release film for an adhesive sheet satisfying the following expression (1). 3 ≤ A ≤ 6 ‥‥ (1) 2. The release film for an adhesive sheet according to claim 1, wherein the silicon element strength A (unit: kcps) of the surface of the silicone resin film by a fluorescent X-ray method satisfies the following formula (2). . 3.5 ≦ A ≦ 5 ‥‥ (2) 3. The release film for an adhesive sheet according to claim 1, wherein a solvent friction increase rate by toluene is within 300% of an initial value. 4. The release film for an adhesive sheet according to claim 1, wherein the adhesive sheet is an adhesive sheet for processing a wafer. 5. The plastic film is at least one selected from polyethylene terephthalate, polyethylene-2,6-naphthalate, and polyethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate. The release film for a pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein: