A method, apparatus, and manufacturing system for compensating critical dimensions of a wafer.

Abstract

This invention provides a method, apparatus, and manufacturing system for compensating critical dimensions of wafers. The method includes: acquiring the previous batch exposure energy value, previous batch exposure focal length, and previous batch critical dimension value of a previous batch of wafer products; monitoring the photoresist film thickness of the previous batch of wafers; when the previous batch critical dimension value does not meet a set threshold, correcting the exposure focal length and exposure energy value using the correspondence between the photoresist film thickness and the wafer's critical dimension to obtain a reference exposure focal length and reference exposure energy value for the next batch of wafer products; and exposing the next batch of wafer products using the reference exposure focal length and reference exposure energy value. This method is used to better compensate for critical dimensions and improve product yield.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a method, apparatus and manufacturing system for compensating critical dimensions of a wafer. Background Technology

[0002] Every step of chip manufacturing is an extremely precise process. For photolithography, the two main metrics that need to be controlled are overlay (OVL) and critical dimension (CD). Only when both OVL and CD are within the required range can the electrical performance and yield of the chip be guaranteed.

[0003] Control of exposure density (CD) is typically achieved by fine-tuning the exposure energy (DOSE) of the exposure unit. Currently, Advanced Process Control (APC) usually only uses the measurement results from a scanning electron microscope (CDSEM) that measures critical dimensions as the input source for exposure energy feedback control. However, in practical applications, many other factors affect CD.

[0004] Therefore, there is an urgent need for a method that can accurately compensate for the critical dimensions of the wafer, so that the CD of the exposed chip can reach the target CD. Summary of the Invention

[0005] The purpose of this invention is to provide a method, apparatus and manufacturing system for compensating critical dimensions of wafers, so as to better compensate for critical dimensions and improve product yield.

[0006] To achieve the above objectives, the present invention provides a method for compensating for critical dimensions of a wafer, comprising: acquiring the previous batch exposure energy value, the previous batch exposure focal length, and the previous batch critical dimension value of a previous batch of wafer products; monitoring the photoresist film thickness of the previous batch of wafers; when the previous batch critical dimension value does not meet a set threshold, correcting the exposure focal length and the exposure energy value using the correspondence between the photoresist film thickness and the critical dimension of the wafer, thereby obtaining a reference exposure focal length and a reference exposure energy value for the next batch of wafer products; and exposing the next batch of wafer products using the reference exposure focal length and the reference exposure energy value.

[0007] The beneficial effects of the wafer critical dimension compensation method provided by the present invention are as follows: by monitoring the photoresist film thickness, the phenomenon of poor focal length caused by different film layer thicknesses and deviations in critical dimensions of different patterns can be eliminated, thereby better compensating for critical dimensions and improving product yield.

[0008] In one possible implementation, before obtaining the previous batch exposure energy value, previous batch exposure focal length, and previous batch critical dimension value of the previous batch of wafer products, the method further includes:

[0009] Using the same exposure energy value, multiple preset wafers with different photoresist film thicknesses are exposed to obtain multiple target wafers; the critical dimensions of each target wafer are measured; a scatter plot of photoresist film thickness and wafer critical dimensions is established using the photoresist film thickness and critical dimensions corresponding to the multiple target wafers; the scatter plot is fitted to obtain the correspondence between photoresist film thickness and wafer critical dimensions.

[0010] In one possible implementation, the monitoring of the photoresist film thickness of the previous batch of wafers includes: monitoring the photoresist film thickness of the previous batch of wafers using an offline monitor.

[0011] Secondly, the present invention provides a wafer critical dimension compensation device, which includes modules / units for performing any of the possible design methods described in the first aspect. These modules / units can be implemented in hardware or by hardware executing corresponding software.

[0012] Thirdly, embodiments of this application provide an electronic device including a processor and a memory. The memory stores one or more computer programs; when the one or more computer programs stored in the memory are executed by the processor, the electronic device is able to implement any of the possible design methods described in the first aspect above.

[0013] Fourthly, this application also provides a computer-readable storage medium comprising a computer program that, when run on an electronic device, causes the electronic device to perform any of the possible designs described in the first aspect above.

[0014] Fifthly, embodiments of this application also provide a method comprising a computer program product, which, when run on an electronic device, causes the electronic device to perform any of the possible designs described in the first aspect above.

[0015] For the beneficial effects of the second to fifth aspects mentioned above, please refer to the description in the first aspect mentioned above. Attached Figure Description

[0016] Figure 1 A schematic flowchart of a wafer critical dimension compensation method provided by the present invention;

[0017] Figure 2 A schematic diagram of a manufacturing system architecture provided by the present invention;

[0018] Figure 3 This is a schematic diagram of a wafer critical dimension compensation device provided by the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all of them. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] To address the problems mentioned in the background art, one embodiment of this application provides a method for compensating for critical dimensions of a wafer. Figure 1 This is a flowchart of a wafer critical dimension compensation method provided in an embodiment of this application. This method can be applied to APC (Advanced Process Control) systems, such as... Figure 1 As shown, the method includes the following steps:

[0022] S101, obtain the previous batch exposure energy value, previous batch exposure focal length and previous batch critical dimension value of the previous batch of wafer products.

[0023] For example, the previous batch exposure energy value, previous batch exposure focal length, and previous batch critical dimension value of the previous batch of wafer products can be obtained from the Manufacturing Execution System (MES).

[0024] S102, the thickness of the photoresist film of the previous batch of wafers was monitored.

[0025] Specifically, in this embodiment, an offline monitor can be added to the original APC system, which can monitor the thickness of the photoresist film layer.

[0026] S103, when the critical dimension value of the previous batch does not meet the set threshold, the exposure focal length and the exposure energy value are corrected by using the correspondence between the photoresist film thickness and the critical dimension of the wafer, so as to obtain the reference exposure focal length and reference exposure energy value of the next batch of wafer products.

[0027] This step mainly utilizes the known correspondence between photoresist film thickness data and key dimensions to correct the exposure focal length and exposure energy value, thereby obtaining the reference exposure focal length and reference exposure energy value for the next batch of wafer products.

[0028] S104 uses a reference exposure focal length and a reference exposure energy value to expose the next batch of wafer products.

[0029] In this embodiment, the two key factors affecting critical dimensions, exposure energy and exposure focal length, are taken into account. Data on the thickness of the photoresist film is used as feedback information to reduce the impact of photoresist film thickness fluctuations on critical dimensions and improve product yield.

[0030] It should be understood that before obtaining the previous batch exposure energy value, previous batch exposure focal length, and previous batch critical dimension value of the previous batch of wafer products, the process further includes: exposing multiple preset wafers with different photoresist film thicknesses using the same exposure energy value to obtain multiple target wafers; measuring the critical dimension of each target wafer; establishing a scatter plot of photoresist film thickness and wafer critical dimension using the photoresist film thickness and critical dimension corresponding to the multiple target wafers; and fitting the scatter plot to obtain the correspondence between photoresist film thickness and wafer critical dimension. Specifically, the above-mentioned correspondence between photoresist film thickness and wafer critical dimension can be obtained by constructing a scatter plot using the exposure energy and critical dimension of multiple batches of over-shipped chips, and fitting the scatter plot to obtain a curve of exposure energy and critical dimension, thereby obtaining the correspondence between photoresist film thickness and wafer critical dimension. This application does not limit the method for obtaining the above-mentioned correspondence between photoresist film thickness and wafer critical dimension.

[0031] Other embodiments of this application also provide a manufacturing system. For example... Figure 2 As shown, the manufacturing system includes an advanced process control system (APC system), a manufacturing execution system (MES system), a coating and developing machine, an exposure machine, a CD measurement and testing machine, and an offline monitor, etc. The advanced process control system (APC system) includes a wafer critical dimension compensation device, which is used to perform any of the wafer critical dimension compensation methods described above.

[0032] From the above description, it can be seen that the embodiments of this application achieve the following technical effects: In the wafer critical dimension compensation device of this application, the APC system receives the previous batch exposure energy value, previous batch critical dimension value, and previous batch exposure focal length of the previous batch of products sent by the MES system. The APC system obtains the photoresist film thickness of the previous batch of wafers monitored by the offline monitor. When the previous batch critical dimension value does not meet the set threshold, the exposure focal length and the exposure energy value are corrected by using the correspondence between the photoresist film thickness and the critical dimension of the wafer, so as to obtain the reference exposure focal length and reference exposure energy value of the next batch of wafer products. The next batch of wafer products is exposed using the reference exposure focal length and reference exposure energy value to correct the target critical dimension value. The target exposure energy value and exposure focal length determined in this way are more accurate, ensuring that the target critical dimension value of the chip product is more stable, reducing the rework rate of the chip product, and ensuring that the electrical performance of the chip product is better and the yield of the chip product is higher.

[0033] In some embodiments of this application, such as Figure 3 As shown, the wafer critical dimension compensation device in the aforementioned advanced process control system achieves the above... Figure 3 The method described in the illustrated embodiment includes: an acquisition unit 301, a monitoring unit 302, a correction unit 303, and a compensation unit 304. The acquisition unit 301 is used to acquire the previous batch exposure energy value, the previous batch exposure focal length, and the previous batch critical dimension value of the previous batch of wafer products; the monitoring unit 302 is used to monitor and obtain the photoresist film thickness of the previous batch of wafers; the correction unit 303 is used to, when the previous batch critical dimension value does not meet a set threshold, use the correspondence between the photoresist film thickness and the critical dimension of the wafer to correct the exposure focal length and the exposure energy value, thereby obtaining a reference exposure for the next batch of wafer products.

[0034] Focal length and reference exposure energy value; compensation unit 304, used to expose the next batch of wafer products using the reference exposure focal length and reference exposure energy value.

[0035] Optionally, it also includes a determining unit 305, configured to: before acquiring the previous batch exposure energy value, previous batch exposure focal length, and previous batch critical dimension value of the previous batch of wafer products, further include: exposing multiple preset wafers with different photoresist film thicknesses using the same exposure energy value to obtain multiple target wafers; measuring each of the target wafers...

[0036] Key dimensions of the wafer; by using the photoresist film thickness and key dimensions corresponding to multiple target wafers, a scatter plot of photoresist film thickness and key dimensions of the wafer is established, and the scatter plot is fitted to obtain the correspondence between photoresist film thickness and key dimensions of the wafer.

[0037] Optionally, the monitoring unit 302 monitors the photoresist film thickness of the previous batch of wafers, specifically for: monitoring the photoresist film thickness of the previous batch of wafers through an offline monitor.

[0038] The above Figure 3 All relevant content of each step involved in the method embodiment shown can be referenced from the functional description of the corresponding 5-unit module, and will not be repeated here.

[0039] The present invention also provides a computer-readable medium having a computer program stored thereon, which, when executed by a computer, implements the method described in the above-described method embodiments.

[0040] The present invention also provides a computer program product that, when executed by a computer, implements the method described in the above-described method embodiments.

[0041] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A method for compensating critical dimensions of a wafer, characterized in that, The method comprises the following steps: obtaining a previous batch exposure energy value, a previous batch exposure focal length and a previous batch critical dimension value of a previous batch wafer product; monitoring a photoresist film thickness of the previous batch wafer; when the previous batch critical dimension value does not satisfy a set threshold value, correcting the exposure focal length and the exposure energy value by using a corresponding relationship between the photoresist film thickness and the critical dimension of the wafer to obtain a reference exposure focal length and a reference exposure energy value of a next batch wafer product; exposing the next batch wafer product by using the reference exposure focal length and the reference exposure energy value.

2. The method of claim 1, wherein, Before the step of obtaining the previous batch exposure energy value, the previous batch exposure focal length and the previous batch critical dimension value of the previous batch wafer product, the method further comprises the following steps: exposing a plurality of preset wafers with different photoresist film thicknesses by using a same exposure energy value to obtain a plurality of target wafers; measuring critical dimensions of the target wafers; establishing a scatter plot about the photoresist film thickness and the critical dimension of the wafer by using the photoresist film thickness and the critical dimension of the target wafers; and fitting the scatter plot to obtain the corresponding relationship between the photoresist film thickness and the critical dimension of the wafer.

3. The method of claim 1, wherein, The step of monitoring the photoresist film thickness of the previous batch wafer comprises the following step: monitoring the photoresist film thickness of the previous batch wafer by using an off-line monitor.

4. A wafer key dimension compensation device, characterized by, The method comprises the following steps: an obtaining unit, configured to obtain a previous batch exposure energy value, a previous batch exposure focal length and a previous batch critical dimension value of a previous batch wafer product; a monitoring unit, configured to monitor a photoresist film thickness of the previous batch wafer; a correcting unit, configured to, when the previous batch critical dimension value does not satisfy a set threshold value, correct the exposure focal length and the exposure energy value by using a corresponding relationship between the photoresist film thickness and the critical dimension of the wafer to obtain a reference exposure focal length and a reference exposure energy value of a next batch wafer product; a compensating unit, configured to expose the next batch wafer product by using the reference exposure focal length and the reference exposure energy value.

5. The apparatus of claim 4, wherein, The method further comprises a determining unit, configured to: Before the step of obtaining the previous batch exposure energy value, the previous batch exposure focal length and the previous batch critical dimension value of the previous batch wafer product, the method further comprises the following steps: exposing a plurality of preset wafers with different photoresist film thicknesses by using a same exposure energy value to obtain a plurality of target wafers; measuring critical dimensions of the target wafers; establishing a scatter plot about the photoresist film thickness and the critical dimension of the wafer by using the photoresist film thickness and the critical dimension of the target wafers; and fitting the scatter plot to obtain the corresponding relationship between the photoresist film thickness and the critical dimension of the wafer.

6. The apparatus of claim 4, wherein, The monitoring unit monitors the photoresist film thickness of the previous batch wafer, and is specifically configured to: monitor the photoresist film thickness of the previous batch wafer by using an off-line monitor.

7. A manufacturing system characterized by, The method comprises the following steps: an advanced process control system, a manufacturing execution system, a coating and developing machine, an exposure machine, a CD measurement machine and a dispatching system, wherein the advanced process control system comprises a wafer critical dimension compensation device, and the wafer critical dimension compensation device is configured to execute the method in any one of claims 1 to 3.

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