JPS6356921A - Treating method of substrate - Google Patents

Abstract

PURPOSE:To prevent the formation of a spot on an etching surface while improving quality by forming a desired photo-resist pattern onto a substrate, conducting etching treatment and performing washing treatment by a specific solution. CONSTITUTION:A washing containing a surface-active agent or a washing, in which a polyhydric alcohol or water-soluble polyoxyalkylene glycol is added to said washing, as required is used for washing treatment after etching treatment. Pure water is employed normally as a solvent for the washing. A stable surface-active agent effectively displaying a surface-active effect even in an acid solution is particularly advantageous as the surface-active agent. An anionic fluorine group surface active agent, a nonionic fluorine group surface-active agent, an acetylene alcohol group surface-active agent, etc. are cited as such a surface-active agent. These surface-active agents are added, thus improving the holding power of the washing to a substrate in washing treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to an improved method of processing substrates. More specifically, the present invention relates to a processing method for manufacturing a high quality substrate without causing spots on the etched surface after etching treatment in the manufacturing process of semiconductor devices and the like.

Conventional technology In manufacturing semiconductor devices such as ICs and LSIs, a thin film such as a silicon oxide film is usually formed on a substrate such as a silicon wafer, and then a photoresist is uniformly applied to the surface to form a photosensitive layer. After that, a resist pattern is formed by exposure and development, and then using this resist pattern as a mask, the underlying silicon oxide film is
After selectively etching using a mixed aqueous solution of hydrofluoric acid and ammonium fluoride or an aqueous hydrofluoric acid solution, the resist pattern on the substrate is completely removed. Between this etching process and the resist pattern removal process, a cleaning process using pure water is usually performed to wash away the etching solution.

However, in this method, water droplets remain on the etched surface due to water washing after the etching process, and since these water droplets contain a small amount of etching solution, the portions where the water droplets have adhered are left on the etched surface. for,
This method has the disadvantage that the etching solution is concentrated during drying of the substrate, resulting in spots on the substrate. Since these spots cause a decrease in the yield of manufactured semiconductor devices, there has been a strong desire to improve them.

Problems to be Solved by the Invention The present invention responds to such demands by producing high-quality substrates with a high yield without causing spots on the etched surface after etching treatment in the manufacturing process of semiconductor devices, etc. The purpose of this invention is to provide a method for processing waste substrates.

Means for Solving the Problems In order to prevent the formation of such spots, the present invention, S, and Z, have conducted extensive research and have developed a method of cleaning using a specific cleaning solution after the etching process. By doing so, they discovered that the object could be achieved, and based on this knowledge, they completed the present invention.

That is, in the present invention, after forming a desired photoresist pattern on a substrate and performing an etching process, a cleaning process is performed using a surfactant or a solution containing a surfactant and a polyhydric alcohol or a water-soluble polyoxyalkylene glycol. The present invention provides a method for processing a substrate, characterized in that:

The present invention will be explained in detail below.

In the method of the present invention, a cleaning solution containing a surfactant or a cleaning solution to which polyhydric alcohol or water-soluble polyoxyalkylene glycol is added, if necessary, is used for the cleaning treatment after the etching treatment. Pure water is usually used as the solvent for this cleaning solution.

Any surfactant can be used as long as it has a surfactant (wettability) effect, but a stable surfactant that effectively exhibits a surfactant effect even in an acid solution is particularly advantageous. Examples of such surfactants include anionic fluorine surfactants, nonionic fluorine surfactants, and acetylene alcohol surfactants.

The anionic fluorine-based surfactant has the general formula % [In the formula, Rf and R'f are part or all of the hydrogen atoms of a saturated or unsaturated hydrocarbon group having 2 to 20 carbon atoms] A fluorinated hydrocarbon group substituted with a fluorine atom, M is HmaHdododo or N(R□R2R3R,), R1 * "2 tR3
and R4 are each a hydrogen atom or a lower alkyl group, which may be the same or different. , for example straight-chain or branched perfluorocarboxylic acid Cn F2 n+1 COO perfluoroalkanesulfone 7 /L/ O0carboxylic acid CnF2n+1 CIl! l
H2mC00H1CnF2n+ ICH=CHC+1H
2rnCOOH, fluoroalkanesulfo, acid cnF2
n+1cmN (2mso3H, fluoroalkenesulfonic acid C nF2 n + I C H2C H CrH
．． h2 mS 03 H (where n=1 to 10, m=
1 to 15] and their ammonium salts and tetraalkylammonium salts, specifically perfluorocaprylic acid C, F, CooH,
Perfluorooctane sulfonic acid Cll F17 S
O3H, ammonium perfluorocapsonate C,F,, COONH4, tetramethylammonium perfluorocaprylate C,F,5GOON(CH
3), t, C5 Fl t (CH2):! GOOR
, CF's (CF2)3 cF(cF3) (c)
to cooNz, CF3(CF2)6CH=CH(C
H2) 200ONH4 and the like, but are not limited thereto.

Examples of this anionic fluorosurfactant include Pc
-93 (manufactured by Jujutsu 3M) is advantageous because it is easily available.

In addition, as a nonionic fluorine-based surfactant, the general formula % formula % () [In the formula, Rf is a perfluoroalkyl group having 3 to 15 carbon atoms, A is a direct bond, 1,000 CH2 - So2NR1-, +C
H2CH 2 axis element -H2 information CONR2-, -SO3-,
-Co□- or -SO3M(R3)CM. , Co□−
, R is a hydrogen atom, an anru group or an alkyl group having 1 to 18 carbon atoms, n is 0 or an integer of 1 to 20, m is O or an integer of 1 to 5, R1, R2 and R3 are each a hydrogen atom and a carbon number 1 to B alkyl group or +CH2CH20-)-yR4
, X is an integer of 1 to 20, and R4 is an alkyl group having 1 to 2 carbon atoms.
(CP2)7' (CH2CH20) to H1
CF3 (CF2), So□N (C2H5) (CH2
CH20)14 H5CF3(CP, )7So2N(
C2H6)CH2COO(CH2CH20)1゜H1C
F3 (CF'2)?・(CF2)3・C0N(OH
5) (CI(20H20)1°H), but is not limited to these.

Examples of this nonionic fluorosurfactant include F'
c-j7Qc (manufactured by Jujutsu 3M Co., Ltd.) is advantageous because it is easily available as a commercial product.

Furthermore, as an acetylene alcohol surfactant,
General formula (in the formula, R1 is a hydrogen atom or -G-0(-CH, CH2
O+-H1m R2t R3v R4 and R3 are each a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and they may be the same or different, and n and m
are each O or an integer from 1 to 20, and they may be the same or different) and the compound represented by the general formula % formula % (wherein R6 is a hydrogen atom or -C-OH% R?t
R8+1G R9 and R10 are each a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and they may be the same or different. One type is used, and examples thereof include OH3CH30HOH (Surfynol 82) (Surfynol 400 series) (acetyleneol) OH, but the present invention is not limited thereto. These can be used as they are supplied by Air Products and Chemicals (trade name: Surf-inol), Yoken Fine Chemicals (trade name: acetylenol), Dow Chemical Company, General Aniline Company, etc.

These surfactants may be used alone or
Two or more types may be used in combination.

In the cleaning solution used in the method of the present invention, the surfactant is added to pure water in an amount of 0.001 to 10% by weight,
Particularly preferred is one added in an amount of 0.01 to 1% by weight. If it is added in an amount exceeding this range, the surfactant will remain on the substrate, which is undesirable, and if it is added in a smaller amount, the wettability to the substrate will deteriorate, which is undesirable.

A polyhydric alcohol or a water-soluble polyoxyalkylene glycol/I/ can also be added to the solution if necessary. Although high-quality substrates can be manufactured without adding polyhydric alcohols or water-soluble polyoxyalkylene glycols, their addition can increase the retention of the cleaning solution to the substrate during the cleaning process. In particular, it is extremely effective in cases where the transition from cleaning treatment to subsequent treatment, such as cleaning treatment with isopropyl alcohol or drying treatment, takes time.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, and propylene glycol polymers, among which ethylene glycol and propylene glycol are particularly preferred. Examples of the water-soluble polyokine alkylene glycol include propylene oxide, or polyoxyalkylene glycol-type polymers obtained by polymerizing propylene oxide and ethylene oxide, such as monools, diols, or triols thereof. is Adeka Car Ball MH50 (
Asahi Denka Kogyo Co., Ltd.), also Carpole GH50, PH5
Those commercially available as 0 can be preferably used. These polyhydric alcohols or water-soluble polyoxyalkylene glycols may be used alone or in combination of two or more.

The polyhydric alcohol or water-soluble polyoxyalkylene glycol is desirably added in an amount of 0 to 60% by weight, preferably 0.1 to 10% by weight, based on pure water, and the amount added is within the above range. If the amount is too large, the viscosity increases and drying becomes difficult, which is undesirable. On the other hand, if the amount is too small, the holding power of the solution to the substrate decreases, which is not preferable.

The solution used for cleaning in the method of the present invention is
Regardless of whether the resist pattern formed on the substrate to be cleaned is formed from a negative type photoresist or a positive type photoresist, the resist pattern will not be adversely affected.

Next, an example of the substrate processing method of the present invention will be explained. First, a photoresist is uniformly applied onto a silicon wafer on which a thin silicon oxide film has been formed, and then dried to form a photosensitive layer. After exposing the layer to a desired pattern, it is developed and then post-baked to form a resist pattern. Next, using this resist pattern as a mask, the silicon oxide film is selectively niched using an etching solution such as an aqueous solution of hydrofluoric acid, and then the substrate is cleaned with the cleaning solution to remove the etchant on the substrate. Thoroughly wash off any etching solution.

In addition, as the cleaning treatment method in the uninvented method, there are a method of immersing the etched substrate in a tank containing a cleaning solution, a method of spraying the cleaning solution, etc. In the case of the immersion method, This method has the disadvantage that long-term continuous processing is not possible because the etching solution gets mixed into the cleaning solution tank.

However, such a case can be solved by applying a method in which the two substrates are immersed in a pure water bath (the two substrates are immersed) and then immersed in a bath containing the cleaning solution after the etching process.

Effects of the Invention The substrate processing method of the present invention has an excellent effect of cleaning the etching solution adhering to the substrate after the etching process, and moreover, by using a cleaning solution that does not leave water droplets on the etched surface, It is possible to produce high-quality processed substrates without causing spots. Therefore, by using the uninvented method, the yield in manufacturing semiconductor devices can be significantly increased.

Example Next, the present invention will be explained in more detail with reference to Examples.

Example 1 By thermally oxidizing the surface of a silicon substrate, 1.0 μm of S
A positive photoresist, 0FPR-800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), was applied to the substrate on which the film was formed to a thickness of 1.5 μm using a spinner, and prebaked on a hot plate at 110 °C for 90 seconds. Then, a photosensitive layer was provided. Next, this photosensitive layer was exposed using a reduction projection exposure device, and then developed for 60 seconds with a 2.38 deuterium tetramethylammonium hydroxide aqueous solution to obtain a resist pattern on the substrate.

Next, this substrate was post-baked at 130°C for 5 minutes, and then 50% by weight of hydrofluoric acid and 60tff1%
Using a resist pattern as a mask, the SiO□ film on the substrate was etched with a solution containing ammonium fluoride mixed at a weight ratio of 1=6. Next, the fluorine-based surfactant Fc-170c was added to pure water for 100 minutes. Manufactured by 3M Corporation)
A cleaning solution prepared by adding O,j g (1000 ppm) and stirring well [Surface tension 61.2 dyn/c]
yt (25°C)], washed with steam using Inglobil alcohol, and dried.

When this substrate was observed under a microscope, no spots were observed.

Example 2 Pure water 100% was used as a cleaning solution for the substrate after etching treatment.
Surf Inol 465 (Air Products and
Cleaning solution prepared by adding 1.19 (manufactured by Chemicals Co., Ltd.) [Surface tension: 40.8 dyn/cyt (25°C)]
As a result of observing the occurrence of spots on the substrate by the same operation as in Example 1 except for using , no spots were observed.

Example 6 A substrate was prepared in the same manner as in Example 1, except that after the etching process, a cleaning process with pure water was performed, and then the substrate was cleaned using the same cleaning solution as in Example 2. As a result of observing the spots above, no spots were observed at all.

Example 4 Pure water 100% was used as a cleaning solution for the substrate after etching treatment.
Surf Inol 465 (
A cleaning solution prepared by adding LIN (manufactured by Air Products and Chemicals) [surface tension 40.8 dyn/
cM (25°C)] was performed in the same manner as in Example 1, and the occurrence of spots on the substrate was observed. As a result, no spots were observed at all.

Comparative Example When a substrate was subjected to etching treatment and only cleaning treatment with pure water was observed for spots, a large number of spots were observed on the substrate.

Claims (1)

[Claims] 1. After forming a desired photoresist pattern on a substrate and performing an etching process, a cleaning process is performed using a surfactant or a solution containing a surfactant and a polyhydric alcohol or a water-soluble polyoxyalkylene glycol. How to process the substrate.