JP4071118B2 - Cleaning sheet and cleaning method for substrate processing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet for cleaning various types of substrate processing apparatuses that dislike foreign matters such as semiconductor, flat panel display, and printed circuit board manufacturing apparatuses and inspection apparatuses, and a cleaning method for a substrate processing apparatus using the same, and cleaning using the cleaning method The present invention relates to a substrate processing apparatus.
[0002]
[Prior art]
In various types of substrate processing apparatuses, each transport system and the substrate are transported while being in physical contact. At that time, if foreign matter adheres to the substrate or the transport system, subsequent substrates are successively contaminated. For this reason, it is necessary to periodically stop the apparatus and perform a cleaning process, which requires a reduction in operating rate and a great deal of labor.
[0003]
In order to solve these problems, a method of transporting a substrate to which an adhesive substance is adhered and cleaning and removing foreign substances adhering to the inside of the substrate processing apparatus (see Patent Document 1), transporting a plate-like member to the back surface of the substrate A method (see Patent Document 2) for removing adhering foreign matter has been proposed. According to these methods, since there is no need to stop the substrate processing apparatus and perform the cleaning process, there is no problem that the operating rate is reduced and a great amount of labor is required. In particular, the former method is based on the removal of foreign matters. It is excellent.
[0004]
[Patent Document 1]
JP-A-10-154686 (pages 2 to 4)
[Patent Document 2]
Japanese Patent Laid-Open No. 11-87458 (pages 2 to 3)
[0005]
[Problems to be solved by the invention]
However, according to the studies by the present inventors, in the above-described proposed method, if the cleaning member conveyed into the apparatus contains a metal such as an alkali metal or an alkaline earth metal or a compound thereof as an impurity, an expected result In addition to not being able to obtain a cleaning effect, there is a possibility that the inside of the apparatus may be contaminated by these impurities. In this case, the product wafer is contaminated, and the wiring of the device is corroded or the transistor characteristics are deteriorated. It turns out that a problem occurs.
[0006]
SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to provide a cleaning member that does not cause contamination of an apparatus due to metal impurities when transported into a substrate processing apparatus and cleaning and removing foreign matter in the apparatus.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the inventors of the present invention have intensively studied. As a result, when the foreign substances in the apparatus are cleaned and removed by being transported into the substrate processing apparatus, the specific metal contained in the cleaning layer that comes into contact with the apparatus is used. Using a cleaning element with a controlled amount of element or its compound can reduce equipment contamination due to metal impurities, which can cause serious problems such as contamination of product wafers, corrosion of device wiring, and deterioration of transistor characteristics. Knowing that it can be prevented, the present invention has been completed.
[0008]
That is, the present invention relates to a cleaning sheet for a substrate processing apparatus that is transported into the substrate processing apparatus to clean and remove foreign substances in the apparatus, and one unsaturated double bond is present in the molecule of the pressure-sensitive adhesive polymer. It has a cleaning layer that is substantially free of adhesive force and is composed of a resin layer obtained by polymerization and curing of a curable resin composition containing the compound and the polymerization initiator having an active energy source. , K, Mg, Al, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn The content of each metal element or compound thereof is included in each component of the curable resin composition. by regulating the content of the metallic element or a compound thereof, for the substrate processing apparatus, characterized in that it is set to less than 5ppm (μg / g) respectively in terms of metal element Leaning seat, in particular, those relating to the cleaning sheet of the structure having a cleaning layer on a support. Furthermore, the present invention relates to a cleaning method for a substrate processing apparatus, characterized in that these cleaning sheets are conveyed into the substrate processing apparatus.
[0009]
The present invention also relates to a cleaning sheet having the above-described structure having a cleaning layer on one side of the support and an adhesive layer on the other side, and further the cleaning sheet is interposed between the adhesive member and the conveying member. In this case, the conveying member with a cleaning function is bonded. The present invention also relates to a cleaning method for a substrate processing apparatus, wherein the transport member with a cleaning function having the above-described configuration is transported into the substrate processing apparatus.
Furthermore, the present invention can provide a substrate processing apparatus cleaned by each of the cleaning methods described above.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the cleaning layer contains metal elements such as Na, K, Mg, Al, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, and Zn, or a compound thereof as a metal impurity. In conversion, it is necessary to be 5 ppm (μg / g) or less, preferably 2 ppm or less, more preferably 1 ppm or less. By regulating the content of metal impurities in this way, device contamination due to metal impurities when the substrate processing apparatus is cleaned can be reduced, and problems such as product wafer contamination can be prevented.
[0011]
In addition, said content can be measured as follows.
The cleaning layer is cut to 4 cm ² (2 cm × 2 cm), placed in a platinum dish, weighed, and heated with a gas burner to burn. Thereafter, it is placed in an electric furnace and heated at 550 ° C. for 1 hour and at 600 ° C. for 1 hour until there is no remaining charcoal. After standing to cool, 2 ml of concentrated hydrochloric acid is added and heated at 50 ° C. to dissolve the resulting ash. After allowing this to cool, ultrapure water was added to dilute to 50 ml, and Na and K were analyzed by atomic absorption analysis (“Z-6100” manufactured by Hitachi, Ltd.), Mg, Al, Ca, Ti, Cr, Mn For Fe, Co, Ni, Cu, and Zn, the amount of each element is measured by ICP spectroscopic analysis (“SPS-1700HVR” manufactured by Seiko Instruments Inc.).
[0012]
When such a cleaning layer has a tensile modulus of elasticity (test method: JIS K7127) of 10 MPa or more, preferably 10 to 2,000 MPa, the protrusion of the cleaning layer at the time of label cutting or cutting failure can be suppressed. This is desirable because a label sheet with a cleaning function can be produced without contamination in the pre-cut method. If the tensile elastic modulus is too small, the above problems at the time of cutting or adhesion to the contact part (cleaned part) in the apparatus at the time of transportation may cause a transportation trouble. If the tensile elastic modulus is too large, the transportation system The performance of removing the adhering foreign matter on the top is reduced.
[0013]
Such a cleaning layer is not particularly limited in its material, but is preferably composed of a resin layer polymerized and cured by an active energy source such as ultraviolet rays or heat. This is because the above-described polymerization curing causes the molecular structure to become a three-dimensional network, which is substantially non-adhesive, and does not adhere strongly to the apparatus contact portion at the time of conveyance, thereby obtaining a cleaning member that can be reliably conveyed into the substrate processing apparatus. Because.
Here, “substantially non-adhesive” means that there is no pressure-sensitive tack representing the adhesive function when the essence of the adhesive is friction, which is resistance to slipping. This pressure-sensitive tack is expressed in the range where the elastic modulus of the adhesive substance is up to 1 MPa, for example, according to the Dahlquist standard.
[0014]
The polymerized and cured resin layer includes a pressure-sensitive adhesive polymer having at least one unsaturated double bond in the molecule (hereinafter referred to as a polymerizable unsaturated compound), a polymerization initiator, and, if necessary, a crosslinking agent. And a curable resin composition containing such as those obtained by curing with an active energy source, particularly ultraviolet rays.
[0015]
In this curable resin composition, by regulating the content of the specific metal element or compound thereof contained in each constituent component, that is, the material of each component to be used can be selected, or the metal element or compound thereof. By performing an appropriate treatment for reducing the content, the content of the metal element or the compound thereof in the polymerized and cured resin layer is set to 5 ppm or less in terms of metal element.
In addition, when a protective film, which will be described later, is bonded to a cleaning layer made of a polymerized and cured resin layer, the metal element or a compound thereof may be transferred from the protective film into the cleaning layer. In this case, including regulating the transfer amount, the content of the metal element or the compound thereof in the cleaning layer is set to 5 ppm or less in terms of metal element.
[0016]
As the pressure-sensitive adhesive polymer, an acrylic polymer having (meth) acrylic acid and / or (meth) acrylic acid ester as a main monomer is preferable. In synthesizing this acrylic polymer, a compound having two or more unsaturated double bonds in the molecule is used as a copolymerization monomer, or a compound having an unsaturated double bond in the molecule is functionalized in the synthesized acrylic polymer. An unsaturated double bond may be introduced into the molecule of the acrylic polymer, for example, by a chemical bond between the groups. With this introduction, the acrylic polymer itself can be involved in the polymerization curing reaction.
[0017]
The polymerizable unsaturated compound is preferably a non-volatile and low molecular weight material having a weight average molecular weight of 10,000 or less, particularly 5,000 or less so that three-dimensional networking can be efficiently performed during curing. It is preferable to have a molecular weight of
Examples of such polymerizable unsaturated compounds include phenoxy polyethylene glycol (meth) acrylate, ε-caprolactone (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri ( (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, oligoester (meth) acrylate, and the like. Among these, one or more are used. .
[0018]
As the polymerization initiator, when heat is used as an active energy source, a thermal polymerization initiator such as benzoyl peroxide or azobisisobutyronitrile is used. When using light, benzoyl, benzoin ethyl ether, cibenzyl, isopropyl benzoin ether, benzophenone, Michler's ketone chlorothioxanthone, dodecyl thioxanthone, cymethyl thioxanthone, acetophenone diethyl ketal, benzyl dimethyl ketal, α-hydroxycyclohexyl phenyl ketone, 2- Photopolymerization initiators such as hydroxymethylphenylpropane and 2,2-dimethoxy-2-phenylacetophenone are used.
[0019]
The cleaning layer composed of such a polymerized and cured resin layer has a 180 ° peel-off adhesive strength (measured according to JIS Z0237) with respect to a silicon wafer (mirror surface) of 0.2 N / 10 mm width or less, preferably 0.8. The width should be 01 to 0.1 N / 10 mm. By making such low or non-adhesive, it does not adhere to the apparatus contact portion during transport, and does not cause transport troubles.
[0020]
In the present invention, the cleaning sheet of the present invention can be obtained by forming such a cleaning layer alone into a sheet or tape or by providing it on an appropriate support. The cleaning sheet is transported to various substrate processing apparatuses as it is or attached to the transport member with an adhesive, and the cleaning layer is brought into contact with the site to be cleaned. And it can be removed reliably.
[0021]
In the present invention, as a particularly preferred embodiment, it is preferable to provide a cleaning sheet in which a cleaning layer is provided on one side of the support and an adhesive layer is provided on the other side of the support. In this case, the thickness of the support is usually 10 to 100 μm, the thickness of the cleaning layer is usually 5 to 100 μm, and the thickness of the adhesive layer is usually 5 to 100 μm (preferably 10 to 50 μm). Good.
This sheet is bonded to the conveyance member via the pressure-sensitive adhesive layer on the other surface side to obtain a conveyance member with a cleaning function. Similarly to the above, the transport member is transported to various substrate processing apparatuses, and the cleaning layer is brought into contact with the portion to be cleaned, so that the foreign matter attached to the portion can be easily and reliably removed by cleaning.
[0022]
The material of the support is not particularly limited. For example, polyolefin such as polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate, polybutylene terephthalate, polyurethane , Ethylene / vinyl acetate copolymer, ionomer resin, ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid ester copolymer, polystyrene, polycarbonate, and other plastic films.
These plastic films may be a single layer film made of the above resin or a laminated film. Further, one or both surfaces may be subjected to a surface treatment such as corona treatment.
[0023]
The pressure-sensitive adhesive layer provided on the other surface of the support is not particularly limited with respect to the material constitution, and any of those made of a normal pressure-sensitive adhesive such as acrylic or rubber can be used. Among them, as an acrylic pressure-sensitive adhesive, a component having a weight average molecular weight of 100,000 or less obtained by polymerization reaction of a monomer mixture containing (meth) acrylic acid alkyl ester as a main monomer and, if necessary, other copolymerizable monomers added Those having an acrylic polymer as the main component is preferably 10% by weight or less.
Such a pressure-sensitive adhesive layer has a 180-degree peeling adhesion to a silicon wafer (mirror surface) of 0.01 to 10 N / 10 mm width, preferably 0.05 to 5 N / 10 mm width. If the adhesive strength is too high, the support film may be torn when the cleaning sheet is peeled off from the conveying member.
[0024]
A protective film (separator) may be bonded to the surface of the cleaning layer or the pressure-sensitive adhesive layer until the cleaning sheet is used. There is no limitation on the material, for example, polyolefins such as polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, etc., which have been subjected to release treatment with a silicone-based, long-chain alkyl-based, fluorine-based, fatty acid amide-based, silica-based release agent, etc. Polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate, polybutylene terephthalate, polyurethane, ethylene / vinyl acetate copolymer, ionomer resin, ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid ester A plastic film having a thickness of usually 10 to 100 μm made of a resin such as a polymer, polystyrene or polycarbonate is used.
[0025]
In the transport member with a cleaning function of the present invention, the transport member to which the cleaning sheet is bonded is not particularly limited, and various substrates are used depending on the type of substrate processing apparatus that is a target for removing foreign matter. Specific examples include semiconductor wafers, substrates for flat panel displays such as LCDs and PDPs, and other substrates such as compact disks and MR heads.
[0026]
In the present invention, the substrate processing apparatus to be cleaned is not particularly limited, and examples thereof include an exposure irradiation apparatus for forming a circuit, a resist coating apparatus, a sputtering apparatus, an ion implantation apparatus, a dry etching apparatus, and a wafer prober. Examples include various inspection devices. The present invention can provide each of the above substrate processing apparatuses cleaned by the above method.
[0027]
【Example】
Next, examples of the present invention will be described in more detail. However, the present invention is not limited only to these examples. In the following, “parts” means parts by weight.
[0028]
Example 1
For 100 parts of acrylic polymer A (weight average molecular weight 700,000) obtained from a monomer mixture consisting of 75 parts of 2-ethylhexyl acrylate, 20 parts of methyl acrylate and 5 parts of acrylic acid, 200 parts of polyethylene glycol 200 200 parts of methacrylate (trade name “NK Ester 4G” manufactured by Shin-Nakamura Chemical Co., Ltd.), 3 parts of polyisocyanate compound (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.) and benzyldimethyl ketal (Ciba An ultraviolet curable resin composition A was prepared by uniformly mixing 3 parts of trade name “Irgacure 651” manufactured by Specialty Chemicals.
[0029]
Separately, in a three-necked flask type reactor having an internal volume of 500 ml equipped with a thermometer, a worship machine, a nitrogen inlet tube and a reflux condenser, 73 parts of 2-ethylhexyl acrylate, n-acrylic acid n -10 parts of butyl, 15 parts of N, N-dimethylacrylamide, 5 parts of acrylic acid, 0.15 part of 2,2'-azobisisobutyronitrile as a polymerization initiator, 100 parts of ethyl acetate, totaling 200 g The mixture was added and stirred while introducing nitrogen gas for about 1 hour, and the air inside was replaced with nitrogen.
Thereafter, the internal temperature was set to 58 ° C., and this state was maintained for about 4 hours for polymerization to obtain a polymer solution. To 100 parts of this polymer solution, 3 parts of a polyisocyanate compound (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.) was uniformly mixed to prepare an adhesive solution A.
[0030]
The thickness after drying the pressure-sensitive adhesive solution A is 15 μm on the release-treated surface of the separator A made of a long polyester film (thickness 38 μm, width 250 mm) treated on one side with a silicone-based release agent. After coating, and drying, a long polyester film (thickness 25 μm, width 250 mm) is laminated on the pressure-sensitive adhesive layer as a support, and the above UV curable resin composition A is further thickened on the film. Was applied to a thickness of 40 μm, a resin layer was provided, and a release treatment surface of the same separator A as above was bonded to the surface to obtain a laminated sheet.
[0031]
The laminated sheet was irradiated with ultraviolet rays having a central wavelength of 365 nm and an integrated light quantity of 1,000 mJ / cm ² to prepare a cleaning sheet A having a cleaning layer composed of a polymerized and cured resin layer. The separator A on the cleaning layer side of the cleaning sheet A was peeled off, and the 180 ° peel adhesive strength (measured according to JIS Z0237) on the silicon wafer (mirror surface) was examined. As a result, it was 0.06 N / 10 mm. Further, the tensile strength (tensile modulus: measured according to test method JIS K7127) of this cleaning layer was 440 MPa.
[0032]
The separator A on the pressure-sensitive adhesive layer side of the cleaning sheet A was peeled off and attached to the mirror surface of an 8-inch silicon wafer with a hand roller to produce a conveying member A with a cleaning function. Note that the adhesive strength of the adhesive layer peeled off from the silicon wafer (mirror surface) by 180 ° was 1.5 N / 10 mm width.
[0033]
Further, in order to examine the content of metal impurities in the cleaning layer in the conveying member A with the cleaning function, a sample for measuring metal impurities was separately prepared according to the following procedure, and the content of the metal impurities was measured.
First, an ultraviolet curable resin composition A is applied on the separator A so as to have a thickness of 40 μm, and another separator A is laminated thereon, and then an ultraviolet ray having a central wavelength of 365 nm is applied to an integrated light quantity of 1,000 mJ / The resin composition A was polymerized and cured by irradiation with cm ² to prepare a metal impurity measurement sample.
[0034]
Next, this sample was cut into 4 cm ² (2 cm × 2 cm), the separator A on both sides was peeled off, placed in a platinum dish, weighed, and heated by a gas burner to burn.
Then, it put into the electric furnace and heated at 550 degreeC for 1 hour and 600 degreeC for 1 hour until there was no unburned charcoal. After allowing to cool, 2 ml of concentrated hydrochloric acid was added and heated to 50 ° C. to dissolve the resulting ash. After allowing this lysate to cool, ultrapure water is added to dilute it to 50 ml, and Na and K are analyzed by atomic absorption analysis (“Z-6100”, manufactured by Hitachi, Ltd.), Mg, Al, Ca, Ti, Cr , Mn, Fe, Co, Ni, Cu, and Zn, the amount of each element was measured by ICP spectroscopic analysis (“SPS-1700HVR” manufactured by Seiko Instruments Inc.).
The results were as follows: Na: 0.9 ppm, K: 0.5 ppm, Mg: 0.1 ppm, Al: 0.2 ppm, Ca: 0.2 ppm, Ti: 0.1 ppm, Cr: 0.1 ppm, Mn: 0.00. 1 ppm, Fe: 0.1 ppm, Co: 0.1 ppm, Ni: 0.1 ppm, Cu: 0.1 ppm, Zn: 0.8 ppm.
[0035]
Using a laser surface inspection apparatus, foreign matters of 0.2 μm or more on the mirror surface of two new 8-inch silicon wafers were measured and found to be 5 and 5, respectively. These silicon wafers were transferred to an oxide film dry etching apparatus having a separate electrostatic adsorption mechanism with the mirror surface facing downward, and the mirror surface was measured by a laser surface inspection apparatus. In the area, there were 30,576 and 31,563 foreign matters of 0.2 μm or more, respectively.
[0036]
When the above-mentioned oxide film dry etching apparatus having the wafer stage on which 30,576 foreign substances have adhered is transported with the cleaning member transporting member A after removing the separator A on the cleaning layer side, it is transported without any trouble. did it. This operation was repeated 5 times. After that, a new 8-inch silicon wafer was transported with the mirror surface facing downward, and a foreign matter of 0.2 μm or more was measured with a laser surface inspection device. As a result, 90% of the foreign matter was removed from the initial stage. It was.
After that, the product wafer was processed, and it was found that the product wafer can be produced without any problem without being contaminated with metal impurities.
[0037]
Comparative Example 1
Instead of 100 parts of the acrylic polymer A in the UV curable resin composition A, 100 parts of an acrylic polymer (“Leocoat R-1020” manufactured by Toray Cortex Co., Ltd.) is used, and benzyldimethyl as a photopolymerization initiator. An ultraviolet curable resin composition was used in the same manner as in Example 1 except that 3 parts of thioxanthone photopolymerization initiator (“KAYACURE DETX-S” manufactured by Nippon Kayaku Co., Ltd.) was used instead of 3 parts of ketal. B was prepared.
A cleaning sheet B was prepared in the same manner as in Example 1 except that this resin composition B was used. Further, using this cleaning sheet B, in the same manner as in Example 1, a conveying member B with a cleaning function was prepared. Was made.
[0038]
The separator A on the cleaning layer side of the conveying member B with the cleaning function was peeled off, and the 180 ° peel adhesion (measured according to JIS Z0237) to the silicon wafer (mirror surface) was measured. As a result, it was 0.07 N / 10 mm. there were. The tensile strength of this cleaning layer was 420 MPa.
[0039]
Further, in order to examine the content of the metal impurity in the cleaning layer, a metal impurity measurement sample was prepared in the same manner as in Example 1, and the content of the metal impurity was measured. The results were as follows: Na: 7.1 ppm, K: 6.5 ppm, Mg: 5.2 ppm, Al: 5.8 ppm, Ca: 5.1 ppm, Ti: 5.0 ppm, Cr: 6.1 ppm, Mn: 5. They were 0 ppm, Fe: 5.1 ppm, Co: 5.7 ppm, Ni: 5.3 ppm, Cu: 7.0 ppm, Zn: 7.3 ppm.
[0040]
Next, the transport member B with a cleaning function was transported to the oxide film dry etching apparatus having the wafer stage to which the 31,563 foreign substances had been adhered, and the separator A on the cleaning layer side was peeled off. We were able to carry without trouble. This operation was repeated 5 times. After that, a new 8-inch silicon wafer was transported with the mirror surface facing downward, and a foreign matter of 0.2 μm or more was measured with a laser surface inspection device. As a result, 88% of the foreign matter was removed from the initial stage. It was.
However, after that, when the product wafer was processed, the apparatus was contaminated with metal impurities, so that the product wafer was contaminated, and defects due to deterioration of device characteristics occurred frequently. For this reason, in order to remove the metal contamination of an apparatus, much effort was required, such as stopping an apparatus and opening and cleaning an apparatus.
[0041]
【The invention's effect】
As described above, according to the present invention, Na, K, Mg, Al, Ca, Ti, Cr, Mn, Fe, and Co in the cleaning layer are used for cleaning and removing foreign substances in the substrate by transporting the substrate into the substrate processing apparatus. , Ni, Cu, Zn Each metal element or its compound content is set to be 5 ppm (μg / g) or less in terms of metal element, so that it does not cause device contamination due to metal impurities. A high cleaning member can be provided.

Claims (6)

In a cleaning sheet for a substrate processing apparatus that is transported into the substrate processing apparatus to remove foreign substances in the apparatus, a compound having at least one unsaturated double bond in the molecule in the pressure-sensitive adhesive polymer and polymerization start A cleaning layer having a substantially non-adhesive force comprising a resin layer obtained by polymerizing and curing a curable resin composition containing an agent with an active energy source. The cleaning layer includes Na, K, Mg, Al , Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn The content of each metal element or compound thereof is included in each component of the curable resin composition. A cleaning sheet for a substrate processing apparatus, wherein the content is set to 5 ppm (μg / g) or less in terms of metal elements by regulating the content of each. The cleaning sheet for a substrate processing apparatus according to claim 1, further comprising a cleaning layer on the support. The cleaning sheet for a substrate processing apparatus according to claim 2, further comprising a cleaning layer on one side of the support and an adhesive layer on the other side. A conveying member with a cleaning function, wherein the cleaning sheet for a substrate processing apparatus according to claim 3 is bonded to the conveying member via an adhesive layer. A cleaning method for a substrate processing apparatus according to claim 1 or 2, wherein the cleaning sheet for a substrate processing apparatus or the transport member with a cleaning function according to claim 4 is transported into the substrate processing apparatus.   A substrate processing apparatus cleaned by the cleaning method according to claim 5.