KR19980015772A - Semiconductor wiper cleaning method - Google Patents

Abstract

The present invention relates to a method for cleaning semiconductor wafers for removing impurity particles generated as a result of a dry etching process and reaction by-products generated as a result of UV baking treatment of a photoresist to form contact holes having a relatively small line width size . Forming an insulating interlayer on the entire surface of the conductive layer formed on the silicon substrate, forming a first photosensitive layer pattern having a predetermined shape on the interlayer insulating film, UV-baking the first photosensitive layer pattern, Forming a contact hole having a predetermined line size by removing a part of the interlayer insulating film by a dry etching process using the second photosensitive layer pattern as an etching mask; Removing the second photosensitive layer pattern and the reaction by-products remaining on the interlayer insulating film, wherein the reaction by-products are washed with a mixed solution containing sodium hydroxide and hydrogen peroxide, The second cleaning step is performed. Therefore, according to the present invention, it is possible to effectively remove polymer components generated as a result of UV-baking the photoresist and impurity particles generated as a result of the dry etching process to form contact holes having a relatively small line-width size.

Description

Method for cleaning semiconductor wafers

The present invention relates to a method for cleaning a semiconductor wafer, and more particularly, to a method of cleaning a semiconductor wafer, which is capable of effectively removing a polymer component generated by UV-baking a photoresist to form a contact hole having a relatively small line- To a cleaning method.

In general, as the degree of integration of semiconductor devices increases, the width and spacing of wirings become smaller and the size of the contact holes becomes smaller. Small line width size contact holes requiring large aspect ratios are a difficult problem for photolithography and dry etching processes. That is, improvement of the photolithography process is required to form a contact hole having a small line width size, but satisfying this is not a simple problem. Therefore, in general, in order to form a photosensitive layer pattern having a small line-width size, a photosensitive layer made of a photoresist is exposed and developed to pattern the photosensitive layer in a predetermined shape, and then the photosensitive layer pattern is baked by ultra-violet (UV) Flow.

That is, by using the pattern of the photosensitive layer having a relatively small linewidth size as an etching mask, the exposed portion is removed by a dry etching process to form a contact hole having a predetermined line size. Thereafter, the photosensitive layer pattern remaining after the ashing process is removed, and the reaction by-products and the impurity particles generated as a result of the dry etching process are removed by a sulfuric acid cleaning process.

However, although it can be seen that, in the case of not applying the UV baking to the photosensitive layer pattern of a predetermined shape, the by-product by the etching process is removed from the semiconductor wafer by a series of cleaning steps, however, When UV baking is applied to a photosensitive layer pattern of a predetermined shape in order to form a contact hole having a predetermined shape, the reaction by-products of the polymer component and the dry etching process result in the formation of the impurity particles, and the reaction by-products and the impurity particles are removed by a series of cleaning processes But remains on the semiconductor wafer without being removed, thereby causing problems in the performance of the subsequent process.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a method of forming a contact hole having a relatively small line width, And to provide a cleaning method capable of removing impurity particles generated as a result of a dry etching process performed as an etching mask and reaction byproducts generated as a result of the UV baking process from a semiconductor wafer.

FIGS. 1 to 3 are sectional views sequentially showing a cleaning process after forming a contact hole according to an embodiment of the present invention. FIG.

Description of the Related Art [0002]

110. conductive layer 120; The interlayer insulating film

130. First photosensitive layer pattern 130 '. The second photosensitive layer pattern

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming an interlayer insulating film on a surface of a conductive layer formed on a silicon substrate; Forming a first photosensitive layer pattern having a predetermined shape on the interlayer insulating film; UV-baking the first photosensitive layer pattern to form a second photosensitive layer pattern having a relatively small linewidth size; Forming a contact hole having a predetermined line size by removing a part of the interlayer insulating film by a dry etching process using the second photosensitive layer pattern as an etching mask; Removing the photosensitive layer pattern remaining on the interlayer insulating film by an ashing process; And removing the by-products of the dry etching process by a cleaning process, wherein the cleaning process includes a first cleaning step of cleaning with a sulfuric acid solution and a second cleaning step of cleaning with a mixed solution containing sodium hydroxide and hydrogen peroxide And a cleaning step of cleaning the semiconductor wafer.

According to a preferred embodiment of the present invention, the mixing ratio of sodium hydroxide: hydrogen peroxide: deionized water constituting the mixed solution used in the second washing step is 4: 2: 13.

FIGS. 1 to 3 are cross-sectional views illustrating removal of by-products by ashing and cleaning processes after forming contact holes according to an embodiment of the present invention.

That is, the method of cleaning a semiconductor wafer according to the present invention includes the steps of: forming an interlayer insulating film 120 on the entire surface of a conductive layer 110 formed on a silicon substrate; Forming a second photosensitive layer pattern 130 'having a relatively small linewidth size by UV-baking the first photosensitive layer pattern 130, forming a second photosensitive layer pattern 130' Forming a contact hole having a predetermined line width size by removing a part of the interlayer insulating layer 120 by a dry etching process using the layer pattern 130 'as an etch mask; Removing the photosensitive layer pattern 130 'remaining on the photosensitive layer pattern 130'; and removing by-products of the dry etching process by a cleaning process, wherein the cleaning process includes a first cleaning step using a sulfuric acid solution Number It comprises a second washing step using a screen that contains a mixture of sodium and hydrogen peroxide.

1, which is a cross-sectional view of a first photosensitive layer pattern 130 having a predetermined shape, a conductive layer (not shown) is formed on a silicon substrate (not shown) by a sputtering process or a plasma deposition process, A material is deposited to a predetermined thickness to form the conductive layer 110. An insulating material such as BPSG is deposited to a predetermined thickness on the entire surface of the conductive layer 110 by a chemical vapor deposition (CVD) process or the like to form an interlayer insulating film 120. A photoresist PR is applied on the interlayer insulating layer 120 to a predetermined thickness by spin coating to form a photosensitive layer 130 and then patterned into a predetermined shape by exposing and developing the photosensitive layer 130 . As a result, the first photosensitive layer pattern 130 is formed on the interlayer insulating layer 120.

Referring to FIG. 2, which is a cross-sectional view of forming the first photosensitive layer pattern 130 as a second photosensitive layer pattern 130 ', the first photosensitive layer pattern 130 formed by the above- The first photosensitive layer pattern 130 is dried by UV baking to form a second photosensitive layer pattern 130 'so as to form a line width size relatively smaller than the line width size of the photosensitive layer 130. At this time, in the UV baking, since the semiconductor wafer is not contained in the carrier and the surface area with respect to the mass is large, the semiconductor wafer is heated almost instantaneously. Therefore, the time required for UV baking is maintained for about 40 seconds to 4 minutes. Meanwhile, the line width of the second photosensitive layer pattern 130 formed as a result of the UV baking is relatively smaller than the line width of the first photosensitive layer pattern 130.

Referring to FIG. 3 illustrating a cross-sectional view of an ashing process and a cleaning process performed after a contact hole having a predetermined line size is formed by a dry etching process using the second photosensitive layer pattern 130 'as an etching mask, A part of the interlayer insulating layer 120 exposed through the second photosensitive layer pattern 130 'is removed by a dry etching process having a favorable anisotropic etching characteristic such as a reactive ion etching (RIE) process, . As a result, a part of the conductive layer 110 is exposed through the contact hole formed in the interlayer insulating layer 120. Meanwhile, the second photosensitive layer pattern 130 'remaining on the interlayer insulating layer 120 is removed by an ashing process, and a dry etching process for forming a contact hole having a predetermined line width size The reaction by-products and impurity particles generated as a result of the cleaning process are removed by the cleaning process.

At this time, the ashing process is performed with the ashing equipment for about 1 minute and 30 seconds. Also, the cleaning process first performs an initial cleaning process with a sulfuric acid solution for about 10 minutes, and then performs a subsequent cleaning process with a mixed solution of sodium hydroxide and hydrogen peroxide for a predetermined time. Here, the mixing ratio of sodium hydroxide: hydrogen peroxide: deionized water constituting the mixed solution used in the subsequent washing treatment is about 4: 2: 13. Meanwhile, in order to prevent the interlayer insulating layer 120 from being damaged while the subsequent cleaning process is being performed, the cleaning treatment time by the mixed solution takes about 5 to 15 minutes, and the temperature of the mixed solution is about 30 ° C. Lt; RTI ID = 0.0 > 50 C. < / RTI > Preferably, the cleaning treatment time is about 10 minutes and the temperature of the mixed solution is maintained at a temperature of about 40 占 폚.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined by the appended claims. .

Therefore, according to the present invention, a cleaning process is performed with a sulfuric acid solution so as to remove a polymer component generated as a result of UV-baking of a photoresist to form a contact hole having a relatively small linewidth size by a cleaning process After the post-cleaning treatment with a mixed solution of sodium hydroxide and hydrogen peroxide, the impurity particles remaining on the semiconductor wafer can be completely removed.

Claims (3)

Forming an interlayer insulating film on the entire surface of the conductive layer formed on the silicon substrate; Forming a first photosensitive layer pattern having a predetermined shape on the interlayer insulating film; UV-baking the first photosensitive layer pattern to form a second photosensitive layer pattern having a relatively small linewidth size; Forming a contact hole having a predetermined line size by removing a part of the interlayer insulating film by a dry etching process using the second photosensitive layer pattern as an etching mask; Removing the photosensitive layer pattern remaining on the interlayer insulating film by an ashing process; Removing by-products of the dry etching process by a cleaning process, Wherein the cleaning step comprises a first cleaning step of cleaning with a sulfuric acid solution and a second cleaning step of cleaning with a mixed solution containing sodium hydroxide and hydrogen peroxide. The method according to claim 1, Wherein the mixing ratio of sodium hydroxide: hydrogen peroxide: deionized water is about 4: 2: 13. 3. The method according to claim 2, Wherein the cleaning is carried out at a temperature of 30 to 50 占 폚.