EP-4741929-A1 - METHOD FOR REMOVING PHOTORESIST ON WAFER, AND SEMICONDUCTOR PROCESS DEVICE

EP4741929A1EP 4741929 A1EP4741929 A1EP 4741929A1EP-4741929-A1

Abstract

The present disclosure provides a method of removing photoresist on a wafer and a semiconductor process device. During the process of removing the photoresist after ion implantation, a spectral intensity of an emitted light generated by a particular element in a chamber corresponding to different sampling moments is obtained; based on spectral intensities corresponding to two adjacent sampling moments, variation characteristic of spectral intensity at each sampling moment is determined; when the variation characteristic corresponding to a current sampling moment satisfies a preset condition, it is determined that the hardened layer removal process is near an end point and the wafer is controlled to descend from its current position toward a heating base according to a preset relationship to remove a hardened layer of the photoresist. By obtaining the spectral intensity of the emitted light produced by a particular element, and judging whether the hardened layer removal process is near the end point based on whether the variation characteristic of the spectral intensity satisfies the preset condition, the wafer is controlled to descend and the temperature is increased only when the hardened layer removal process is near its end point to avoid the hardened layer from popping at high temperature.

Inventors

LI, MENG
KONG, Yuwei
LIN, Yuanwei

Assignees

Beijing NAURA Microelectronics Equipment Co., Ltd.

Dates

Publication Date: 20260513
Application Date: 20240820

Claims (10)

A method of removing photoresist from a wafer, characterized in that : during a process of removing photoresist after ion implantation, obtaining a spectral intensity of emitted light generated by a particular element in a chamber at different sampling moments; determining a variation characteristic of the spectral intensity at each sampling moment based on spectral intensities at two adjacent sampling moments; when the variation characteristic at a current sampling moment satisfies a preset condition, determining that a hardened layer removal process is near an end point and controlling the wafer to descend from its current position toward a heating base according to a preset relationship to remove the hardened layer of the photoresist.
The removal method according to claim 1, characterized in that the variation characteristic is a rate of decrease of the spectral intensity between two adjacent sampling moments, and the variation characteristic satisfies the following formula: Q n = S t n -1 - S t n ÷ S t n -1 ; where Qn is the variation characteristic corresponding to the nth sampling moment, S(tn) is the spectral intensity corresponding to the nth sampling moment, and n is a positive integer.
The removal method according to claim 2, characterized in that the preset condition includes that the variation characteristic corresponding to the current sampling moment is greater than a preset value, and the preset value is a non-negative number.
The removal method according to claim 3, characterized in that the preset value is greater than or equal to 5% and less than or equal to 20%.
The removal method according to claim 3, characterized in that the preset condition further includes a delay duration between the time when the spectral intensity reaches the maximum value and the current sampling moment.
The removal method according to claim 5, characterized in that the delay duration is calculated according to the following formula: T = k / Q max ; wherein, T is the delay duration; k>0, and k is a constant; Qmax is the maximum value of the absolute value of the variation characteristic before the spectral intensity reaches the maximum value.
The removal method according to any one of claims 1 to 6, characterized in that the preset relationship is that the descent displacement Δh of the wafer is equal to the product of the descent duration Δt and a constant a, and a is greater than 0.
The removal method according to any one of claims 1 to 6, characterized in that , before obtaining the spectral intensity of the emitted light generated by the particular element in the chamber at different sampling moments, the removal method further comprises: placing the wafer on the bearing surface of the heating base, and after the preheating duration has expired, controlling the wafer to ascend to an initial high position.
The removal method according to any one of claims 1 to 6, characterized in that , after controlling the wafer to descend from its current position toward the heating base according to a preset relationship to remove the hardened layer of the photoresist, the method further comprises: controlling the wafer to descend to the bearing surface of the heating base to remove the un-crosslinked layer of the photoresist when the variation characteristic corresponding to the current sampling moment satisfies a hardened layer removal termination condition.
A semiconductor process device, characterized in that , comprising: a chamber; a heating base, arranged within the chamber and having a bearing surface for supporting a wafer; a controller, including at least one processor and at least one memory, the memory storing a computer program, the processor executing the computer program to perform the removal method according to any one of claims 1 to 9.

Description

FIELD OF THE TECHNOLOGY The present disclosure relates to a field of semiconductor manufacturing, and in particular, to a method for removing photoresist on a wafer and semiconductor process device. BACKGROUND During semiconductor processing, extremely fine patterns need to be fabricated on wafers. Typically, photolithography is used to transfer a circuit pattern on a mask onto a photoresist coating the wafer surface. Etching is then used to transfer the photoresist pattern onto the wafer. To prevent the wafer from being affected by the photoresist during subsequent processing, residual photoresist on the wafer must be removed. In conventional dry resist removal processes, wafers are typically placed directly at relatively high temperatures for resist removal. However, ion implantation of photoresist carbonizes the surface of the photoresist, causing it to form a hardened layer 110 (as shown in FIG. 1) and an un-crosslinked layer (photoresist, PR) 120. The hardened layer 110 is coated on the outside of the un-crosslinked layer 120, and the hardened layer 110 is susceptible to popping at high temperatures. SUMMARY The present disclosure aims to solve at least one of the technical problems in certain existing technologies, and proposes a method for removing photoresist on a wafer and a semiconductor process device. To achieve the objectives of the present disclosure, a method for removing photoresist from a wafer is provided, including: during the process of removing photoresist after ion implantation, obtaining the spectral intensity of emitted light generated by a particular element in a chamber at different sampling moments;determining, based on the spectral intensities corresponding to two adjacent sampling moments, a variation characteristic of the spectral intensity at each sampling moment;when the variation characteristic corresponding to the current sampling moment satisfies a preset condition, determining that the hardened layer removal process is near its end point and controlling the wafer to descend from its current position toward a heating base according to a preset relationship to remove the hardened layer of the photoresist. In certain embodiments, the variation characteristic is the rate of decrease of the spectral intensity between two adjacent sampling moments, and the variation characteristic satisfies the following formula: Qn=Stn−1−Stn÷Stn−1; where, Qn is the variation characteristic corresponding to the nth sampling moment, S(tn) is the spectral intensity corresponding to the nth sampling moment, and n is a positive integer. In certain embodiments, the preset condition includes the variation characteristic corresponding to the current sampling moment being greater than a preset value, where the preset value is a non-negative number. In certain embodiments, the preset value is greater than or equal to 5% and less than or equal to 20%. In certain embodiments, the preset condition also includes a delay duration between the time when the spectral intensity reaches its maximum value and the current sampling moment. In certain embodiments, the delay duration is calculated according to the following formula: T=k/Qmax; where, T is the delay duration; k>0, and k is a constant; Qmax is the maximum value of the absolute value of the variation characteristic before the spectral intensity reaches the maximum value. In certain embodiments, the preset relationship is that the descent displacement Δh of the wafer is equal to the product of the descent duration Δt and a constant a, and a is greater than 0. In certain embodiments, before obtaining the spectral intensity of the emitted light generated by the particular element in the chamber at different sampling moments, the removal method further includes: placing the wafer on the bearing surface of the heating base and, after the preheating duration has elapsed, controlling the wafer to ascend to an initial high position. In certain embodiments, after controlling the wafer to descend from its current position toward the heating base in a predetermined relationship to remove the hardened layer of the photoresist, the method further includes: when the variation characteristic corresponding to the current sampling moment satisfies the hardened layer removal termination condition, controlling the wafer to descend to the bearing surface of the heating base to remove the un-crosslinked layer of the photoresist. As another technical solution, the present disclosure also provides a semiconductor process device, including: a chamber, a heating base and a controller, the heating base is arranged in the chamber, and has a bearing surface for supporting a wafer; the controller includes at least one processor and at least one memory, the memory stores a computer program, and the processor executes the computer program to execute the removal method described in the present disclosure. The present disclosure has the following beneficial effects: The method of removin