Photoresist removal method and photoresist removal system applying the same

Abstract

The present invention provides a photoresist removal method and a photoresist removal system using the method, comprising the following steps: (S1) immersing a wafer in a container containing photoresist remover; (S2) removing the wafer from the container and placing it on a support stage; (S3) rotating the support stage during the spraying time and spraying the wafer with photoresist remover using a spraying unit at a flow rate of 1 ml / sec to 10 ml / sec; (S4) stopping the spraying of photoresist remover onto the wafer during the reaction time; and (S5) performing a cleaning and drying process on the wafer.

Description

Technical Field

[0001] This invention relates to a photoresist removal method, and more particularly to a photoresist removal method that effectively reduces the amount of photoresist used. Prior Technology

[0002] Photolithography is a crucial technology in semiconductor device manufacturing. It typically involves creating the circuit patterns required for semiconductor devices through exposure and photoresist applications, culminating in the removal of the photoresist from the semiconductor device surface. Since photoresist materials are mostly organic compounds such as carbon, hydrogen, and oxygen, photoresist strippers are commonly used to peel the photoresist from the semiconductor device surface. In practice, the wafer to be processed is first immersed in a recyclable photoresist stripper, then removed and rinsed with fresh photoresist stripper. However, during the rinsing process with fresh photoresist stripper, to achieve the desired photoresist removal rate, the rinsing time can reach 360 seconds or even longer. If the photoresist stripper flow rate is calculated at 1-10 ml per second, the consumption can reach 360-3600 ml or more, significantly increasing the manufacturing and processing costs of semiconductor devices.

[0003] Therefore, how to design a photoresist removal method that can improve the aforementioned problems is a topic worthy of research. Summary of the Invention

[0004] The purpose of this invention is to provide a photoresist removal method that effectively reduces the amount of photoresist used.

[0005] To achieve the above objectives, the present invention provides a photoresist removal method applied to a wafer with photoresist. The method includes the following steps: (S1) immersing the wafer in a container containing photoresist remover; (S2) removing the wafer from the container and placing it on a support stage; (S3) rotating the support stage during the spraying time and spraying the wafer with photoresist remover using a spraying unit at a flow rate of 1 ml / sec to 10 ml / sec; (S4) stopping the spraying of photoresist remover onto the wafer during the reaction time; and (S5) performing a cleaning and drying process on the wafer.

[0006] In one embodiment of the present invention, in step (S3), the rotational speed of the support platform is not less than 500 revolutions per second.

[0007] In one embodiment of the present invention, in step (S3), the rotational speed of the support platform is 500 revolutions per second to 1000 revolutions per second.

[0008] In one embodiment of the present invention, in step (S4), the support platform remains stationary.

[0009] In one embodiment of the present invention, in step (S4), the rotational speed of the support platform is not higher than 20 revolutions per second.

[0010] In one embodiment of the present invention, the spraying time is 5 to 30 seconds.

[0011] In one embodiment of the present invention, the reaction time is 10 seconds to 180 seconds.

[0012] In one embodiment of the present invention, in step (S3), the spraying unit moves back and forth along a straight path passing through the center of the wafer to spray photoresist.

[0013] In one embodiment of the present invention, the following step is included before step (S5): (S6) repeating the cycle of steps (S3) to (S4) 1 to 3 times.

[0014] The present invention further provides a photoresist removal system that applies the aforementioned photoresist removal method. Simple Explanation of the Diagram

[0015] Figure 1 is a flowchart of the photoresist removal method of the present invention. Figure 2 is a flowchart of another embodiment of the photoresist removal method of the present invention. Implementation

[0016] Since the various embodiments and examples are merely illustrative and not limiting, those skilled in the art, upon reading this specification, may devise other embodiments and examples without departing from the scope of the invention. The features and advantages of these embodiments will become more apparent from the following detailed description and the claims.

[0017] In this document, the terms "a" or "an" are used to describe the elements and components described herein. This is used for ease of explanation and to provide a general meaning regarding the scope of the invention. Therefore, unless it is clearly intended otherwise, this description should be understood to include one or at least one, and the singular includes the plural.

[0018] In this document, the terms “comprising,” “having,” or any other similar terms are intended to cover non-exclusive inclusions. For example, an element or structure containing a plurality of elements is not limited to those listed herein, but may include other elements not expressly listed but which are generally inherent to the element or structure.

[0019] The photoresist removal method of this invention is mainly applied to wafers with photoresist, but it can also be applied to other semiconductor devices requiring photoresist removal. Please refer to Figure 1, which is a flowchart of the photoresist removal method of this invention. As shown in Figure 1, the photoresist removal method of this invention includes the following steps:

[0020] Step (S1): Immerse the wafer in a container containing photoresist remover.

[0021] First, this invention provides a receiving tank, into which photoresist is poured to ensure sufficient volume. Next, a wafer is placed into the receiving tank (e.g., using a robotic arm for handling) and immersed in the photoresist to induce initial swelling and dissolution of the photoresist on the wafer surface. In this invention, the receiving tank can simultaneously hold multiple wafers, ensuring each wafer is immersed in the photoresist, and the photoresist in the tank can be repeatedly recycled.

[0022] Step (S2): Remove the wafer from the self-contained slot and place it on the support stage.

[0023] After immersing the wafer in the aforementioned step (S1), the present invention then removes one of the multiple wafers to be processed from the receiving tank and places the removed wafer on a support platform (e.g., using a robotic arm for handling). At this time, the remaining wafers to be processed remain immersed in the photoresist remover in the receiving tank.

[0024] Step (S3): During the spraying time, rotate the support stage and use the spraying unit to spray the wafer with photoresist at a flow rate of 1 ml / sec to 10 ml / sec.

[0025] After placing the wafer on the support stage in the aforementioned step (S2), the present invention can continuously rotate the support stage holding the wafer to be processed within a set spraying time, and continuously spray fresh photoresist (different from the recyclable photoresist in the containment tank) onto the wafer using a spraying unit. The spraying unit mainly includes nozzles and control elements, which can control the movement of the nozzles and start / stop the spraying of photoresist. In one embodiment of the present invention, the spraying unit moves the nozzles back and forth along a straight path passing through the center of the wafer to spray the photoresist. Combined with the rotation of the support stage, the photoresist can be sprayed more evenly onto the surface of the wafer to be processed. In one embodiment of the present invention, the spraying unit sprays the photoresist at a flow rate of 1 ml / sec to 10 ml / sec, but the present invention is not limited thereto. In one embodiment of the present invention, the set spraying time is 5 seconds to 30 seconds to save on the amount of photoresist used, but the present invention is not limited thereto.

[0026] In one embodiment of the present invention, in step (S3), the rotation speed of the carrier stage is not less than 500 revolutions per second. Preferably, in step (S3), the rotation speed of the carrier stage is between 500 and 1000 revolutions per second. Accordingly, by rotating the carrier stage at a high speed to drive the wafer to rotate, the photoresist sprayed by the spraying unit can be more evenly distributed on the wafer surface.

[0027] Step (S4): Stop spraying the photoresist onto the wafer within the reaction time.

[0028] After spraying the photoresist remover onto the wafer in the aforementioned step (S3), the present invention can then continuously stop spraying the photoresist remover onto the wafer within a set reaction time. Through the surface tension of the previously sprayed photoresist remaining on the wafer surface and the wafer itself, a liquid film of the photoresist remover can be formed on the wafer surface, allowing sufficient time for the photoresist remover to react with the photoresist on the wafer surface, promoting further swelling and dissolution of the photoresist. In one embodiment of the present invention, the set reaction time is 10 seconds to 180 seconds to provide sufficient reaction time between the photoresist remover and the photoresist on the wafer surface, but the present invention is not limited to this.

[0029] In one embodiment of the present invention, in step (S4), the support stage remains stationary. That is, during the set reaction time, except for stopping the spraying of photoresist onto the wafer, the wafer is placed on the support stage to allow the photoresist to fully react with the surface of the wafer being contacted.

[0030] In one embodiment of the present invention, in step (S4), the rotation speed of the support stage is no higher than 20 revolutions per second. That is, within the set reaction time, except for stopping the spraying of photoresist on the wafer, the support stage rotates at a low speed to drive the wafer to rotate, so that the photoresist left on the wafer surface can move appropriately and be more evenly distributed on the wafer surface, thereby improving the reaction rate and reaction effect.

[0031] Step (S5): Perform cleaning and drying processes on the wafer.

[0032] After stopping the spraying of photoresist on the wafer in the aforementioned step (S4), the present invention can then perform a cleaning and drying process on the wafer. The wafer surface is rinsed with clean water to remove residual photoresist and photoresist, and the wafer is rotated by a rotating support stage to accelerate the drying of the wafer surface, thereby completing the entire photoresist removal process of the wafer.

[0033] Please refer to Figure 2, which is a flowchart of another embodiment of the photoresist removal method of the present invention. As shown in Figure 2, the photoresist removal method of the present invention further includes the following steps:

[0034] Step (S6): Repeat steps (S3) to (S4) 1 to 3 times.

[0035] In this embodiment, after stopping the spraying of photoresist remover onto the wafer in step (S4), the present invention can return to step (S3), recalculate another spraying time to rotate the support stage and spray photoresist remover onto the wafer, and then recalculate another reaction time to stop spraying photoresist remover onto the wafer, thus completing another cycle of steps (S3) to (S4). Depending on the type of photoresist on the wafer surface, the photoresist removal method of the present invention can selectively repeat the cycle of steps (S3) to (S4) 1 to 3 times after step (S4), but the present invention is not limited thereto. Only after all the cycles of steps (S3) to (S4) have been completed will the subsequent cleaning and drying process (S5) be executed.

[0036] For example, in one embodiment of the present invention, the photoresist removal method of the present invention sets the rotation speed of the stage to 500 revolutions per second in step (S3), the spraying unit sprays the photoresist remover at a flow rate of 1 ml / sec, and the spraying time is 90 seconds. In step (S4), the reaction time is set to 90 seconds, and steps (S3) to (S4) are repeated once. After performing the photoresist removal method of the present invention under the aforementioned settings, the total time consumed is 360 seconds, but the total amount of photoresist removed is only 180 ml. Compared with the conventional method, which continuously uses photoresist remover to rinse the wafer to achieve a similar photoresist removal effect under the same time and flow rate conditions, requiring 360 ml of photoresist remover, the photoresist removal method of the present invention significantly saves the amount of photoresist removed.

[0037] For example, in one embodiment of the present invention, the photoresist removal method of the present invention sets the rotation speed of the stage to 500 revolutions per second in step (S3), the spraying unit sprays the photoresist remover at a flow rate of 1 ml / sec for 30 seconds, and sets the reaction time to 150 seconds in step (S4), and repeats the cycle from step (S3) to step (S4) once. After executing the photoresist removal method of the present invention under the aforementioned conditions, the total time consumed is 360 seconds, but the total amount of photoresist used is only 60 ml. Compared to conventional methods that achieve similar photoresist removal by simply rinsing the wafer with photoresist under the same time and flow rate conditions, which requires 360 ml of photoresist remover, the photoresist removal method of the present invention significantly saves on the amount of photoresist used.

[0038] The present invention further provides a photoresist removal system that applies the aforementioned photoresist removal method. The photoresist removal system of the present invention performs the aforementioned photoresist removal method to remove photoresist from the wafer surface.

[0039] In summary, the photoresist removal method of this invention, through the design of spraying photoresist remover and increasing the reaction time between the photoresist remover and the wafer, utilizes the surface tension of the interaction between the photoresist remover and the wafer to form a liquid film of photoresist remover on the wafer surface, causing the photoresist to swell and dissolve after the reaction. The photoresist removal method of this invention requires only 10-50% of the amount of photoresist remover used in conventional techniques, effectively reducing the amount of photoresist used and related process costs.

[0040] The above embodiments are merely illustrative in nature and are not intended to limit the embodiments of the subject matter of the application or its application or use. Furthermore, although at least one exemplary embodiment has been presented in the foregoing embodiments, it should be understood that numerous variations are possible with respect to the invention. It should also be understood that the embodiments described herein are not intended to limit the scope, use, or configuration of the claimed subject matter in any way. Rather, the foregoing embodiments will provide a simple guide for those skilled in the art to implement one or more of the embodiments. Moreover, various changes can be made to the function and arrangement of the elements without departing from the scope defined by the claims, and the claims include known equivalents and all foreseeable equivalents at the time of filing of this patent application.

[0041] S1~S6: Steps

Claims

1. A photoresist removal method applied to a wafer having photoresist, the method comprising the following steps: (S1) immersing the wafer in a receiving tank containing a photoresist remover; (S2) removing the wafer from the receiving tank and placing it on a support stage; (S3) rotating the support stage for a spraying time and spraying a fresh photoresist remover onto the wafer using a spraying unit at a flow rate of 1 ml / sec to 10 ml / sec; (S4) stopping the spraying of the fresh photoresist remover onto the wafer for a reaction time; and (S5) performing a cleaning and drying process on the wafer.

2. The photoresist removal method as described in claim 1, wherein in step (S3), the rotation speed of the stage is not less than 500 revolutions per second.

3. The photoresist removal method as described in claim 2, wherein in step (S3), the rotational speed of the stage is between 500 and 1000 revolutions per second.

4. The photoresist removal method as described in claim 1, wherein in step (S4), the carrier stage remains stationary.

5. The photoresist removal method as described in claim 1, wherein in step (S4), the rotational speed of the stage does not exceed 20 revolutions per second.

6. The photoresist removal method as described in claim 1, wherein the spraying time is 5 to 30 seconds.

7. The photoresist removal method as described in claim 1, wherein the reaction time is 10 seconds to 180 seconds.

8. The photoresist removal method as claimed in claim 1, wherein in step (S3), the spraying unit moves back and forth along a straight path passing through the center of the wafer to spray the fresh photoresist.

9. The photoresist removal method as described in claim 1, wherein before step (S5) the following step is further included: (S6) repeating the cycle of step (S3) to step (S4) 1 to 3 times.

10. A photoresist removal system applying the photoresist removal method described in any one of claims 1 to 9 above.

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