Method for removing resistive mask

FIELD: manufacturing semiconductor devices including removal of resistive mask from silicon wafer surfaces upon photolithographic operations.

SUBSTANCE: proposed method for removing resistive mask includes silicon wafer treatment upon photolithographic operations to remove photoresist from surface; treatment is conducted in two stages; first stage includes treatment in sulfuric acid (H2SO4) and hydrogen peroxide (H2O2) solution of 3 : 1 proportion at temperature T = 125 °C for 5 minutes; second stage includes washing first in warm deionized water (H2O) at T = 65-70 °C for 5 minutes followed by washing in two baths, each having spillover points in four sides, at water flowrate of 400 l/h and wash time of 5 minutes in each bath; wafers are checked for adequate cleaning by focused incident light beam at maximum six luminous points.

EFFECT: reduced number of operations required to remove resistive mask, ability of attaining clean surfaces free from photolithographic contaminants.

1 cl

 

The invention relates to the technology of manufacturing semiconductor devices and IP, in particular to the removal of the resistive mask from the surface of silicon wafers after photolithographic operations.

Known methods of removing resistive mask from the surface of silicon wafers, the essence of which consists in removing the layer of photoresist in an organic solvent (dimethylformamide, acetone, methyl ethyl ketone) [1].

The main disadvantages of these methods are multi-stage, complexity, uncontrolled pollution, aggressive reagents. the high temperature of the solution, which leads to an increase in the rate of etching, further etching of oxide.

The aim of the invention is to remove the resistive mask and getting a good cleaning dirt from the surface, after photolithography.

This objective is achieved in that the treatment is carried out in two stages: in the first stage, the treatment is carried out in sulfuric acid (H2SO4) and hydrogen peroxide (H2About2) in the ratio 3:1 at a temperature of processing 125°C for 5 minutes, and the second stage are washed first in warm deionized water (H2O) at a temperature T=65-70°C for 5 minutes, then washing are two baths with four-sided overflow, the water flow rate 400 l/h, the time / the key 5 minutes in each bath.

The essence of the method lies in the fact that on the surface of silicon wafers is complete removal of the photoresist solution containing the following components: sulfuric acid (H2SO4) and hydrogen peroxide (H2O2).

The proposed method differs from the known fact that the removal of the acid (H2SO4allows you to clean the surface from dirt, made the whole process of photolithography, since the surface condition affects the quality of subsequent operations.

The solution includes the following ratio of components:

H2SO4:H2About2=3:1 at a temperature of T=125°C.

Control cleaning is performed under a focused beam of light, the number of luminous points reaches no more than 6 pieces.

Summary of the invention the following examples.

Example 1. The process is carried out in two stages, with the first stage processing of lead in sulfuric acid (H2SO4) and hydrogen peroxide (H2About2) in the ratio 3:1 at a temperature of T=125°C for 5 minutes, and the second stage are washed first in warm deionized water (H2O) at a temperature T=65-70°C for 5 minutes, then washing are two baths with four-sided overflow, the water flow rate 400 l/h, the time of washing 5 minutes in each is Anna. H2SO4:H2O2=1:1 at a temperature of T=125±5°C.

Control cleaning is performed under collimated light, the number of points of light reaches not more than 10 pieces.

Example 2. The method is carried out analogously to example 1. The process is carried out at a ratio of components:

H2SO4:H2O2=2:1,2 at a temperature of T=125±5°C.

Control cleaning is performed under a focused beam of light, the number of luminous points reaches no more than 8 pieces.

Example 3. The method is carried out analogously to example 1. The process is carried out at a ratio of components:

H2SO4:H2O2=3:1 at a temperature of T=125±5°C.

Control cleaning is performed under a focused beam of light, the number of luminous points reaches no more than 6 pieces.

Example 4. The method is carried out analogously to example 1. The process is carried out at a ratio of components:

H2SO4:H2O2=4:1,5 at a temperature of T=125±5°C.

Control cleaning is performed under a focused beam of light, the number of luminous points reaches no more than 6 pieces.

As follows from the results of the experiments, one of the most effective solutions for the removal of resistive mask is the solution consisting of the following components: sulfuric acid (H2SO4), hydrogen peroxide (H2O2)in the following proportions:

H2SO4:H2O2=4:1,5 at a temperature of T=125±5°C.

Thus, removal of resistive mask from the surface of the silicon substrate provides an opportunity to prepare a semiconductor substrate with a specific surface and specific relief for further technological operations.

The source of information

1. Technology and design of integrated circuits, microprocessors and microassemblies. / Edited Loukaitou. - M.: Radio and communication, 1989 - 400.

Method of removing resistive mask, including the surface treatment of silicon wafers after photolithographic operations for the removal of photoresist from the surface, wherein the treatment is carried out in two stages, with the first stage of processing carried out in a solution of sulfuric acid (H2SO4and perakis hydrogen (H2About2) in the ratio 3:1 at a temperature of T=125°C for 5 min, and the second stage are washed first in warm deionized water (H2O) at a temperature T=65-70°C for 5 min, followed by washing are two baths with four-sided overflow, the water flow rate 400 l/h, the time of washing 5 min in each bath, the control of the cleaning is performed under a focused beam of light, the number of luminous points reaches no more than 6 pieces.



 

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