JP3496895B2 - Semiconductor wafer processing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a semiconductor wafer, and more specifically, when applying a resist coating solution, a silica-based coating forming coating solution, or the like, the peripheral portion, the edge portion and the back surface portion of the semiconductor wafer. The present invention relates to a processing method for removing an excessive coating film adhesion amount that occurs in such cases.

[0002]

2. Description of the Related Art In the field of manufacturing electronic components such as semiconductor devices and liquid crystal display devices, a resist film is formed and a lithographic process is performed to process a semiconductor wafer such as a silicon wafer or a substrate such as glass. A resist pattern is formed on a base material, and many coatings such as an insulating film, a flattening film, and a passivation film are formed on the base material during the manufacturing process, and such coatings include a silicon oxide film and a silicon nitride film. Silica-based coatings are used.

As a method of forming a resist coating or a silica coating on a substrate, a resist coating solution or an organic solvent solution of a silicon compound such as halogenated silane or alkoxysilane is usually coated on a substrate such as a silicon wafer. It is formed by spin-coating a coating liquid for forming a silica-based coating film, which is the main component, using a spinner, followed by drying and heat treatment.

In this case, since the resist coating solution and the silica-based coating forming coating solution are applied to the substrate by diffusing by centrifugal force, the coating film thickness is relatively uniform in the central portion of the substrate. However, the peripheral portion of the base material has a non-uniform coating film thickness and tends to be a thick film, and the coating liquid also diffuses to the peripheral edge portion and the back surface portion of the peripheral portion of the base material, resulting in excess coating as shown in FIG. Form a film attachment part. Thus, when the resist coating or silica-based coating is formed by performing drying and heat treatment while leaving the excess coating film adhered to the peripheral portion, the edge portion or the back surface portion of the base material, the resist coating or silica-based coating of these portions is formed. Is an extremely fragile film, which breaks and scatters due to contact with the substrate holder when the substrate moves, and the coating film attached to the back surface is dried on a hot plate or placed on the substrate of a heating device. It adheres to the parts and causes the inside of the device to become dirty. Especially in the field of electronic component manufacturing, where high yield and precision are required, even a small amount of scattered matter can have an adverse effect.Therefore, the coating film that has adhered to the periphery, edge, and back surface of the base material must be washed before drying. It is necessary to remove it.

Up to now, the method of cleaning the resist coating film or the silica-based coating film-forming coating film adhered to the peripheral portion, the edge portion or the back surface portion of the substrate has been as follows. A method of removing an organic solvent having a cleaning action by spraying from above the front surface of the base material to the peripheral portion (for example, JIII Journal of Technical Disclosure No. 93-13156) or by spraying from below the back surface of the base material to the back surface portion. Method (for example, JP-A-63-129624 and JP-A-5-259060).
No. publication) is known.

However, in such a cleaning method,
Normally, the cleaning liquid is sprayed from a nozzle having a hole diameter of about 0.1 to 1.0 mm to perform the cleaning process. However, when the cleaning liquid containing bubbles is sprayed from the nozzle, the cleaning liquid is projected discretely. In addition to being unable to perform highly accurate cleaning,
When cleaning a plurality of base materials continuously, there was a problem of lack of stability. In particular, when the cleaning liquid is sprayed from above the surface of the base material to the peripheral portion, a part of the cleaning liquid is scattered and the cleaning liquid is splashed on the resist coating film or the coating film for forming a silica-based film that should remain on the base material. Adhesion occurs, which is a serious problem in practical use. Further, when the cleaning liquid is sprayed from below the back surface of the base material to the back surface, there is no problem of adhesion of the cleaning liquid to the coating film that should remain due to the scattering of the cleaning liquid, but the bubbles mixed in the cleaning liquid show the nozzle tip as shown in FIG. There is a case that the cleaning liquid does not come out without breaking through the bubbles. At this time, since the cleaning liquid does not act on the base material, a portion where the excess coating film adhered portion cannot be removed occurs.
Further, in recent years, the diameter of base materials such as silicon wafers has been increasing. For example, when a resist coating solution or a silica-based coating forming coating solution is applied onto an 8-inch silicon wafer, a cleaning solution is sprayed from below the back surface. Cleaning process
As compared with the case where a silicon wafer having a small diameter is used, there is a problem that accuracy and efficiency are lowered.

Therefore, in the process of cleaning a base material in the field of manufacturing electronic components such as semiconductor devices and liquid crystal display devices, it is useful for a large-diameter base material and adheres to the peripheral portion, edge portion and back surface portion of the base material. There is a strong demand for the development of a treatment method for removing a coating film with high accuracy, efficiency and stability.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides an efficient method for removing excess coating film deposits generated on the peripheral portion, the edge portion and the back surface portion when coating various liquid compositions necessary for processing semiconductor wafers. The object of the present invention is to provide a method for treating a semiconductor wafer, which is good and can provide a stable product without quality variation even if it is continuously used and operated for a long period of time.

[0009]

Means for Solving the Problems The present inventors have developed a peripheral portion, an edge portion and a back surface which are produced when a coating liquid for forming a silica-based coating film or a resist coating liquid for forming an etching pattern is applied to a semiconductor wafer. When cleaning and removing the excess coating film attached to the part by spraying an organic solvent that becomes a cleaning liquid through a nozzle with a small hole diameter, part of the cleaning liquid scatters from the jet flow discharged from the nozzle, which is the coating film or resist. As a result of various studies on the causes that adversely affect the required coating area of the coating film and hinder the production of high-quality products, the gas dissolved in the cleaning liquid was removed from the cleaning liquid due to a sudden pressure drop at the tip of the nozzle. When air bubbles are emitted or when air bubbles mixed in the cleaning liquid are emitted from the nozzle, the droplets generated when the air bubbles are destroyed may disturb the coating surface. That is in the, it and this is the cause bubbles in the nozzle tip is attached, the semiconductor nozzle causes to pass through the hollow tube with a gaseous permeable tube wall disposed in a vacuum atmosphere washing liquid
Installed above the wafer to prevent air bubbles from entering the cleaning solution.
It found that can be prevented by suppressing, leading to completion of the present invention based on this finding.

That is, according to the present invention, in a semiconductor wafer processing step including a liquid composition coating step, an excess coating film adhesion amount generated at a peripheral portion, an edge portion and a back surface portion of the semiconductor wafer is supplied through a nozzle. When cleaning and removing with a jet of solvent, remove the nozzle from the semiconductor
A methyl alcohol degassed by passing a dissolved gas through a hollow tube having a gas permeable tube wall placed in a reduced pressure atmosphere is used as the organic solvent while being placed at a proper position above the wafer. A method for treating a characteristic semiconductor wafer is provided.

The method of removing the excess portion of the liquid composition applied to the semiconductor wafer by the jet flow of the cleaning liquid from the nozzle includes a method of applying the jet flow from below the back surface of the semiconductor wafer and a method of applying the jet flow from above the front surface of the semiconductor wafer. and a method of applying a jet stream, but the present invention is due to the latter method.

The method of the present invention can be applied to the removal of a coating film surplus portion after coating a liquid composition such as a resist coating liquid for pattern formation or a coating liquid for forming a silica based coating film on a semiconductor wafer. You can The pattern forming resist coating liquid and the silica-based coating forming liquid are not particularly limited and may be any of those usually used.

The resist coating solution for pattern formation may be either a negative type or a positive type. For example, a solution obtained by dissolving a photopolymerization initiator and an acrylic copolymer in an organic solvent, or 1,
The thing which melt | dissolved the 2-quinonediazide group containing compound and the alkali-soluble resin in the organic solvent can be mentioned. In this case, as the organic solvent, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, methyl-n
-Amyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, methyl pyruvate,
Examples thereof include ethyl pyruvate, methoxymethyl propionate, ethoxyethyl propionate and the like. The coating liquid for forming a silica-based film usually contains an organic solvent solution of a silicon compound as a main component, and a halogenated silane or an alkoxysilane is used as the silicon compound. Examples of the halogenated silane include tetrachlorosilane, dibromodichlorosilane, vinyltrichlorosilane, methyltrichlorosilane, ethyltrichlorosilane, phenyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane, diethyldichlorosilane, and β-glycidoxyethyltrisilane. Examples thereof include chlorosilane.

As the alkoxysilane, for example, monomethoxytrichlorosilane, dimethoxydichlorosilane, trimethoxymonochlorosilane, monoethoxytrichlorosilane, diethoxydichlorosilane, triethoxymonochlorosilane, monoacryloxytrichlorosilane, diacryloxydisilane. Chlorosilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, monomethyltrimethoxysilane, monoethyltrimethoxysilane, monomethyltriethoxysilane, monoethyltriethoxysilane, monoethyltributoxysilane, monophenyltrimethoxy Silane, monophenyltriethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane , Diphenyldiethoxysilane, diethyldibutoxysilane, vinylmethyldimethoxysilane, vinylethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxy Propyltriethoxysilane,
β-methacryloxyethyltrimethoxysilane, β-methacryloxyethyltriethoxysilane, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ- Examples thereof include glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane. The above-mentioned halogenated silane and alkoxysilane may be used alone,
Moreover, you may use it in mixture of 2 or more types.

These silicon compounds are dissolved in an organic solvent and prepared as a liquid for coating. Alcohols, esters, ketones or aromatic hydrocarbons are suitable as the organic solvent used. Specifically, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, butyl alcohol, cyclohexanol, benzyl alcohol, dimethylolbenzene, furfuryl alcohol, tetrahydrofurfuryl alcohol, diacetone alcohol, ethylene glycol monoalkyl ether. , Diethylene glycol monoalkyl ether, triethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, acetic acid alkyl ester, diethylene glycol monoalkyl ether Tate, triethylene glycol monoalkyl ether acetates, propylene glycol monoalkyl ether acetate, ethyl acetoacetate, alkyl lactate, alkyl benzoate, benzyl acetate, glycerin acetate,
Acetone, methyl ethyl ketone, cyclohexanone, acetylacetone, isophorone, diethyl ketone, methyl isobutyl ketone, methyl-n-butyl ketone, acetonylacetone, benzene, toluene, xylene, ethylbenzene, diethylbenzene, cumene, tetralin, etc. May be used in
Moreover, you may use it in mixture of 2 or more types.

A solution obtained by dissolving the above-mentioned silicon compound in an organic solvent and concentrating it can be used as a coating liquid for forming a silica-based film, but usually contains a hydrolyzate of the above-mentioned silicon compound. It is preferable to use a solution obtained by preparing an organic solvent solution to be concentrated and concentrating it as a coating liquid for forming a silica-based film.

In the method of the present invention, the resist coating solution or the silica-based coating forming coating solution is spin-coated on a semiconductor wafer by a spinner, and then a jet stream of the cleaning solution is supplied to the end portion while rotating the semiconductor wafer. so,
The coating film attached to the peripheral portion, the edge portion and the back surface portion of the semiconductor wafer is removed.
A method of spraying through a supply nozzle is used. Further, the supply amount of the cleaning liquid is appropriately changed depending on the type, the rotation speed, the film thickness, etc. of the resist coating film or the silica-based film forming coating film to be cleaned. In the method of the present invention, the cleaning liquid is
Chill alcohol is used.

Further, the supply of the jet stream of the cleaning liquid is carried out to the edge portion of the semiconductor wafer .
It is required to be carried out from the surface above. And
In this way, by spraying the cleaning liquid from above the front surface of the semiconductor wafer toward the peripheral portion of the base material, the coating film adhered to the peripheral portion and the peripheral portion can be cleaned more efficiently than when spraying the cleaning liquid from below the back surface. In addition, even when using a large-diameter substrate such as an 8-inch semiconductor wafer, perform highly accurate cleaning.
You can Further, in the method of the present invention, the semiconductor wafer surface is
0.1 and a nozzle for ejecting a cleaning liquid from the surface above
A nozzle with an injection hole with a hole diameter of 1.0 mm was used
It In the method of the present invention, if desired, a semiconductor wafer
It is also possible to use the injection of cleaning liquid from below the back surface of the
However, this nozzle has a hole diameter of 0.1 to 1.0 mm.
Those are preferable.

Next, the method of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an explanatory view of the method of the present invention, in which the cleaning liquid from the cleaning liquid tank 1 is loaded on a spinner 5 through a hollow tube 3 formed of a gas-permeable tube wall in a degassing unit 2. It is supplied to the upper nozzle 6 located in the vicinity of the peripheral surface portion of the placed semiconductor wafer 4 and the back surface nozzle 9 located on the back surface side of the wafer. The cleaning liquid supplied to the upper nozzle 6 and the back surface nozzle 9 can be supplied simultaneously or only to one of them by the air operate valves 10 and 11, and further, to a desired nozzle at the same time or at a desired timing by a control system (not shown). The cleaning liquid can be supplied separately.

Here, the degassing unit 2 has a hermetically sealed container 7 having therein a plurality of hollow tubes 3 which serve as flow paths for the cleaning liquid.
The degassing unit 2 is connected to the vacuum pump 8, and the space formed between the tube wall of the hollow tube 3 and the hermetically sealed container 7 is always maintained at a reduced pressure. As a result, the hollow tube 3 formed from the gas-permeable tube wall
The dissolved gas in the cleaning liquid that moves through the inside of the chamber is sucked out to the outside through the tube wall of the hollow tube 3, and the cleaning liquid containing no dissolved gas can be supplied.

Here, the material of the hollow tube 3 formed of a gas permeable tube wall is Teflon (trade name),
Polymer tubes such as polycarbonate, polypropylene and silicone are used. The supply of the cleaning liquid is performed by pressurizing the cleaning liquid in the cleaning liquid tank 1 with gas. The method of supplying the cleaning liquid is not limited to this method, and a pump or the like may be used.

[0022]

EXAMPLES The present invention will be described in more detail with reference to examples. In this example, a method for cleaning a coating film for forming a silica-based coating film will be described, but the method of the present invention is not limited to this. For example, a resist coating solution is applied onto a silicon wafer using a spin coating method. At this time, it can be similarly applied to the cleaning of the resist coating film attached to the peripheral portion, the edge portion, and the back surface portion.

Reference Example 1 OCD Type-6 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), which is a coating liquid for forming a silica-based coating film containing a hydrolyzate of alkoxysilane, was spin-coated on a 4-inch silicon wafer (Tokyo, Japan). TR-6132 manufactured by Ohka Kogyo Co., Ltd.
After applying at 3000 rpm for 20 seconds, the rotation speed is 1
When the cleaning liquid moves in the Teflon hollow tube, it is made up of a sealed container having a plurality of Teflon hollow tubes inside from the cleaning nozzle (hole diameter 0.5 mm) for wafer back surface injection of the same equipment. On the outside of the Teflon-made hollow tube that was made negative pressure by the vacuum pump,
Methyl alcohol from which the dissolved gas was removed through a degassing device that removes the dissolved gas in the cleaning liquid through the Teflon tube wall was sprayed at 40 ml / min for 5 seconds to remove the peripheral portion, the edge portion and the back surface portion of the silicon wafer. The process of cleaning is continuously performed on 50 silicon wafers, and the cleaning state of the peripheral portion, the edge portion, and the back surface portion of each of the 50 silicon wafers is observed. It was removed, and adhesion of the cleaning liquid to the coating film due to splashing of the cleaning liquid was not confirmed at all.

[0024] In Example 1 Reference Example 1, except for changing the washing nozzle above the surface of the wafer peripheral portion performs a cleaning process in the same manner as in Example 1, was observed with the cleaning state, the periphery of the silicon wafer Coatings on the edges, edges and backside were completely removed on all 50 sheets, especially the coatings on the periphery were compared.
It was removed with higher accuracy than in the example, and no adhesion of the cleaning liquid to the coating film was confirmed.

[0025] In Reference Example 2 Reference Example 1, except for changing the silicon wafer of 8-inch silicon wafer was cleaned process in the same manner as in Reference Example 1, edge portion and the back surface of the silicon wafer was observed with the washing state The coating film of the part was completely removed from all 50 sheets, but some coating film remained in the peripheral part, although there was no problem in practical use. Further, no adhesion of the cleaning liquid on the coating film was confirmed.

[0026] In Example 1, except for changing the silicon wafer of 8-inch silicon wafer was cleaned process in the same manner as in Example 1, was observed with the cleaning state, the peripheral portion of the silicon wafer, The coating films on the edges and the back surface were completely removed, and no adhesion of the cleaning liquid to the coating film was confirmed.

[0027] In Comparative Example 1, except that methyl alcohol was not the removal of the dissolved gas was used as cleaning solution, Example 1
When the cleaning state of the peripheral portion, the edge portion and the back surface portion of the coated film of the silicon wafer was observed by the same operation as in 5
It was confirmed that cleaning failure was found in 3 out of 0 sheets, and a large number of cleaning solutions adhered to the coating film due to splashing of the cleaning solution.

[0028]

According to the processing method of the present invention, the silica-based coating film-forming coating film and the resist coating film adhered to the peripheral portion, the edge portion and the back surface portion of the semiconductor wafer are efficiently and adversely affected on the necessary coating portion. It can be washed away without giving. It is also effective for large-diameter semiconductor wafers,
It can be suitably used in the field of manufacturing electronic components such as semiconductor devices and liquid crystal display devices, which require high precision and yield.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method of the present invention.

FIG. 2 is an explanatory diagram of a state of a peripheral portion of a base material when a coating film is formed on the base material by a spinner.

FIG. 3 is an explanatory view of a state where bubbles adhere to the tip of the nozzle. 1 Cleaning liquid tank 2 degassing unit 3 Hollow tube 4 Semiconductor wafer 5 Spinner 6 Upper nozzle 7 sealed containers 8 vacuum pump 9 Back nozzle 10, 11 Air operated valve

Front Page Continuation (72) Inventor Naofumi Nomura 5-20-1 Kamimizuhonmachi, Kodaira-shi, Tokyo Inside Hitachi Semiconductor Division (56) References JP-A-63-110636 (JP, A) JP-A 6-254304 (JP, A) JP-A-6-23314 (JP, A) JP-A-5-267149 (JP, A) JP-A-5-121307 (JP, A) JP-A-5-13322 (JP, A) A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/027

Claims (3)

(57) [Claims] 1. A jet flow of an organic solvent supplied through a nozzle for a surplus coating film adhesion amount generated in a peripheral portion, an edge portion and a back surface portion of a semiconductor wafer in a semiconductor wafer processing step including a liquid composition coating step. When cleaning and removing with a nozzle, place the nozzle in an appropriate position above the semiconductor wafer.
As the organic solvent, methyl alcohol degassed by passing a dissolved gas through a hollow tube having a gas permeable tube wall placed in a reduced pressure atmosphere.
A method for processing a semiconductor wafer, which uses a call . 2. The processing method according to claim 1, wherein the nozzle has a hole diameter of 0.1 to 1.0 mm. 3. The processing method according to claim 1, wherein the degassed organic solvent is sprayed onto the peripheral portion of the semiconductor wafer while rotating the semiconductor wafer .