Exposure dose correction method
By pre-collecting and storing the linewidth feature distribution of the equipment and photomask, the problem of low measurement efficiency when adding new etching equipment is solved, and exposure dose correction data is generated quickly, thereby improving semiconductor production efficiency and capacity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI HUALI INTEGRATED CIRCUIT CORP
- Filing Date
- 2021-06-29
- Publication Date
- 2026-07-14
AI Technical Summary
In existing semiconductor integrated circuit manufacturing, when adding a new etching machine, it is necessary to repeatedly measure the AEI linewidth data, resulting in low machine expansion efficiency and occupying the capacity of the measurement machine.
The linewidth feature distribution of each machine and photomask is collected in advance and stored in the database. Before exposure, the machine and photomask are selected to obtain the linewidth feature distribution from the database, which is then combined to form the bus linewidth feature distribution and generate exposure dose correction data.
It improves the efficiency of generating exposure dose correction data files, reduces the number of measurements required for machine expansion, and increases production efficiency and capacity.
Smart Images
Figure CN113534615B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for manufacturing semiconductor integrated circuits, and more particularly to an exposure dose correction (DOMA) method. Background Technology
[0002] In semiconductor integrated circuit manufacturing, the photolithography layer needs to be patterned using photolithography and etching processes. The photolithography process forms a photoresist pattern through exposure and development, followed by after-develop inspection (ADI) to obtain the ADI linewidth (CD); then etching and after-etch inspection (AEI) are performed to obtain the AEI CD.
[0003] Among them, the post-etch linewidth uniformity (AEI CDU) of the critical lithography layer is a key parameter closely related to chip yield. DOMA (Demonstration Object Modeling) is a widely used method for correcting AEI CDU distribution differences on wafers in technology nodes below 40nm. The basic principle of DOMA is to adjust the exposure energy at different locations on the wafer during lithography to adjust the CDU at different locations, thereby obtaining the optimal AEI CDU. Since DOMA corrects the fingerprint distribution of CDU characteristics resulting from the combination of the lithography tool, mask, and etching tool, the DOMA correction file is associated with each of these tools; each combination corresponds to a unique DOMA correction file. When new tools and masks need to be added to the production line, a large amount of AEI CDU data needs to be collected to obtain the DOMA correction file corresponding to different tool combinations, which seriously affects the efficiency of tool expansion and occupies the capacity of online metrology tools.
[0004] like Figure 1 The diagram shown is a flowchart of an existing exposure dose correction method; it includes the following steps:
[0005] Step S101: Provide a wafer that needs to be photolithographically etched and etched.
[0006] Step S102: Perform exposure without exposure dose correction on the lithography machine.
[0007] Step S103: Etching is performed on the etching machine.
[0008] Step S104: Perform AEI measurement to obtain AEI line width data.
[0009] Step S105: Perform CD analysis based on AEI linewidth data.
[0010] Step S106: Combine the CD analysis results from step S105 with the exposure dose sensitivity 301 to obtain the exposure dose recipe (DR), which corresponds to the DOMA file.
[0011] Next, the exposure dose is corrected according to the exposure dose menu, and then step S102 is performed according to the corrected exposure dose.
[0012] like Figure 2 The diagram shown is a correspondence between the DOMA file and the combinations of various lithography equipment, photomasks, and etching equipment in existing exposure dose correction methods. Figure 2 The image shows three lithography stations 101a, 101b, and 101c, two photomasks 102a and 102b, and three etching stations 103a, 103b, and 103c.
[0013] Assuming the etching equipment 103c is a newly added equipment, in order to obtain the DOMA file related to the etching equipment 103c, there are a total of 6 combinations between the etching equipment 103c, the three lithography equipment 101a, 101b and 101c, and the two photomasks 102a and 102b. Figure 2 The six combinations are connected together with corresponding arrow lines. This requires repeating steps S101 to S106 six times. The AEI linewidth data obtained from step S104 is... Figure 2 The values corresponding to AEI linewidths 104a, 104b, 104c, 104d, 104e, and 104f are respectively. The exposure dose menu obtained from the six steps S106 is... Figure 2 These correspond to the exposure dose menus 105a, 105b, 105c, 105d, 105e, and 105f, respectively.
[0014] As can be seen from the above, with 3 lithography machines and 2 photomasks, each additional etching machine requires at least 6 sets of combined AEI linewidth data to obtain the DOMA file related to the newly added etching machine. If there are more lithography machines and photomasks, it is obvious that more AEI linewidth data needs to be collected, which will seriously affect the efficiency of machine expansion and occupy the capacity of online measurement machines. Summary of the Invention
[0015] The technical problem to be solved by the present invention is to provide an exposure dose correction method that can quickly and easily generate exposure dose correction data files. In particular, it can improve the efficiency of generating exposure dose correction data files and thus increase production capacity when there are new equipment or photomasks that need to be expanded.
[0016] To solve the above-mentioned technical problems, the exposure dose correction method provided by the present invention includes the following steps:
[0017] Step 1: Collect the linewidth feature distribution of each machine and each photomask, and store the collected linewidth feature distributions in the database.
[0018] Step 2: Before exposing the wafer, pre-select the required equipment and photomask, and select the corresponding linewidth feature distribution from the database based on the selected equipment and photomask, and combine them to form a bus width feature distribution.
[0019] Step 3: Obtain the exposure dose correction data for the wafer based on the bus width characteristic distribution.
[0020] Step 4: Expose the wafer. During the exposure process, the exposure of the wafer is corrected according to the exposure dose correction data.
[0021] A further improvement is that the equipment includes a lithography equipment and an etching equipment.
[0022] A further improvement is that the lithography machine includes one or more, the etching machine includes one or more, and the photomask includes one or more.
[0023] A further improvement is that the linewidth feature distribution of each of the lithography machines and the linewidth feature distribution of the photomask are obtained through the following steps:
[0024] Step 11: Select one of the photolithography machines and one of the photomasks, and perform exposure and development to obtain the corresponding ADI CD data.
[0025] Step 12: Decompose the obtained ADI CD data to obtain the linewidth feature distribution of the selected lithography machine and the linewidth feature distribution of the selected photomask.
[0026] Step 13: Change the combination of the selected lithography machine and the selected photomask, and repeat steps 11 and 12 until the linewidth feature distributions of all the lithography machines and all the photomasks are obtained, and store each linewidth feature distribution in the database.
[0027] A further improvement is that, when a new lithography machine is added, the linewidth feature distribution of the newly added lithography machine is obtained separately using the following steps:
[0028] The newly added lithography machine is selected as the lithography machine, and steps 11 and 12 are repeated to obtain the linewidth feature distribution of the newly added lithography machine.
[0029] A further improvement is that, when the newly added photomask is present, the linewidth feature distribution of the newly added photomask is obtained separately using the following steps:
[0030] The newly added photomask is selected as the photomask, and steps 11 and 12 are repeated to obtain the linewidth feature distribution of the newly added photomask.
[0031] A further improvement is that the linewidth feature distribution of each etching station is obtained through the following steps:
[0032] Step 14: Arbitrarily select a lithography machine that has obtained the linewidth feature distribution and arbitrarily select a photomask that has obtained the linewidth feature distribution.
[0033] Step 15: Expose and develop using the selected lithography machine and the photomask, and after development, etch using the selected etching machine to obtain the corresponding AEI CD data.
[0034] Step 16: Remove the linewidth feature distribution of the selected lithography machine and the linewidth feature distribution of the selected photomask from the obtained AEI CD data to obtain the linewidth feature distribution of the selected etching machine.
[0035] Step 17: Replace the selected lithography machine and repeat steps 14 to 16 or steps 15 to 16 until the linewidth feature distributions of all the etching machines are obtained and store all the obtained linewidth feature distributions in the database.
[0036] A further improvement is that, when a new etching station is added, the new etching station is selected as the lithography station and steps 14 to 16 or steps 15 to 16 are repeated until the linewidth feature distribution of the new etching station is obtained.
[0037] A further improvement is that, in step two, the bus width feature distribution is the AEI CD linewidth feature distribution formed after the wafer is exposed and etched.
[0038] A further improvement is that, in step one, a set of linewidth feature distributions of each of the aforementioned equipment and each of the aforementioned photomasks are collected on each photolithography layer.
[0039] This invention collects the linewidth feature distributions of each machine and photomask in advance. This allows for the selection of the corresponding linewidth feature distribution from the database based on the selected machine and photomask before exposure, and the combination of the selected linewidth feature distributions to form a bus linewidth feature distribution. Exposure dose correction data can then be obtained through the bus linewidth feature distribution, thus enabling the quick and easy generation of exposure dose correction data files.
[0040] Especially when new equipment or photomasks need to be added, unlike the existing technology which requires multiple combination tests of the new equipment or photomask with other equipment or photomasks to obtain the exposure dose correction data file, this invention only needs to calculate the linewidth characteristic distribution of the added equipment or photomask to generate the exposure dose correction data file related to the new equipment or photomask. Therefore, it can improve the efficiency of generating exposure dose correction data files and thus increase production capacity. Attached Figure Description
[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:
[0042] Figure 1 This is a flowchart of an existing exposure dose correction method;
[0043] Figure 2 It is a diagram showing the correspondence between the DOMA file and the combinations of various lithography equipment, photomasks and etching equipment in the existing exposure dose correction methods;
[0044] Figure 3 This is a flowchart of the exposure dose correction method according to an embodiment of the present invention;
[0045] Figure 4 This is a diagram illustrating the formation pathway of various DOMA files when an etching machine is added to the exposure dose correction method in this embodiment of the invention. Detailed Implementation
[0046] like Figure 3 The diagram shown is a flowchart of the exposure dose correction method according to an embodiment of the present invention; as shown Figure 4 The diagram illustrates the formation pathways of various DOMA files when an etching machine is added to the exposure dose correction method of this invention. The exposure dose correction method of this invention includes the following steps:
[0047] Step 1: Collect the linewidth feature distribution of each machine and each photomask and store the collected linewidth feature distributions in database 401.
[0048] In this embodiment of the invention, the equipment includes a lithography equipment and an etching equipment.
[0049] The lithography machine includes one or more, the etching machine includes one or more, and the photomask includes one or more. Figure 4 The image shows three lithography stations 201a, 201b and 201c, two photomasks 202a and 202b, and three etching stations 203a, 203b and 203c.
[0050] Typically, the entire production process of the same wafer product includes multiple photolithography layers, and a set of linewidth feature distributions of each of the aforementioned equipment and each of the aforementioned photomasks are collected on each photolithography layer.
[0051] The linewidth feature distribution of each of the lithography machines and the linewidth feature distribution of the photomask are obtained through the following steps:
[0052] Step 11: Select one of the photolithography machines and one of the photomasks, and perform exposure to obtain the corresponding ADICD data. Step 11 corresponds to... Figure 3 In steps S201 to S203, step S201 provides a wafer to be exposed, step S202 exposes and develops the provided wafer with uncorrected exposure dose, and step S203 measures the linewidth of the exposed and developed wafer, i.e., performs ADI CD measurement.
[0053] ADI CD measurement methods can be selected according to the characteristics of different photolithography layers.
[0054] Step 12: Decompose the obtained ADI CD data to obtain the linewidth feature distribution of the selected lithography machine and the linewidth feature distribution of the selected photomask. Figure 3 In step S203, the ADI CD data, i.e. ADI linewidth data, obtained by decomposing the linewidth feature distribution can yield the linewidth feature distribution of the lithography machine and the linewidth feature distribution of the selected photomask. Here, ADI inter402 represents the linewidth feature distribution of the lithography machine, and ADI intra403 represents the linewidth feature distribution of the photomask.
[0055] In step 12, the linewidth feature distribution of the selected lithography machine and the linewidth feature distribution of the selected photomask are obtained by fitting the ADI CD data or by other means.
[0056] Step 13: Change the combination of the selected lithography machine and the selected photomask, and repeat steps 11 and 12 until the linewidth feature distributions of all the lithography machines and all the photomasks are obtained, and store each linewidth feature distribution in the database 401.
[0057] When a new lithography machine is added, the linewidth feature distribution of the newly added lithography machine is obtained separately using the following steps:
[0058] The newly added lithography machine is selected as the lithography machine, and steps 11 and 12 are repeated to obtain the linewidth feature distribution of the newly added lithography machine.
[0059] When the newly added photomask is present, the linewidth feature distribution of the newly added photomask is obtained separately using the following steps:
[0060] The newly added photomask is selected as the photomask, and steps 11 and 12 are repeated to obtain the linewidth feature distribution of the newly added photomask.
[0061] The linewidth feature distribution of each etching machine is obtained through the following steps:
[0062] Step 14: Arbitrarily select a lithography machine that has obtained the linewidth feature distribution and arbitrarily select a photomask that has obtained the linewidth feature distribution.
[0063] Step 15: Exposure and development are performed using the selected lithography machine and the photomask, i.e., the process is carried out. Figure 3 Steps S201 and S202 shown
[0064] After development, etching is performed using the selected etching equipment. This step corresponds to... Figure 3 Step S204, as shown, obtains the corresponding AEI CD data, i.e., AEI linewidth data. This step corresponds to... Figure 3 As shown in step S205, AEI CD measurement is performed to obtain AEI CD data.
[0065] Step 16: Remove the linewidth feature distribution of the selected lithography machine and the linewidth feature distribution of the selected photomask from the obtained AEI CD data to obtain the linewidth feature distribution of the selected etching machine. Figure 3 The arrow in step S205 indicates the removal of the ADI linewidth feature distribution, which corresponds to the linewidth feature distribution of the lithography machine and the linewidth feature distribution of the photomask. This process then yields the linewidth feature distribution of the selected etching machine. Figure 3 In the database 401, AEI inter404 represents the linewidth feature distribution of the etching machine.
[0066] In step 16, the linewidth feature distribution of the selected etching equipment is obtained by fitting the AEI CD data or by other means.
[0067] Step 17: Replace the selected lithography machine and repeat steps 14 to 16 or steps 15 to 16 until the linewidth feature distributions of all etching machines are obtained, and store all the obtained linewidth feature distributions in the database 401. The data storage method of the linewidth feature distributions in the database can be adjusted according to the actual situation.
[0068] When a new etching station is added, the newly added etching station is selected as the lithography station and steps 14 to 16 or steps 15 to 16 are repeated until the linewidth feature distribution of the newly added etching station is obtained.
[0069] Figure 4 In this context, assuming that the etching equipment 203c is a newly added etching equipment, and that the lithography equipment 201a and the photomask 202a are selected during step 14, Figure 4 The arrows in the diagram indicate the combination relationship between the lithography equipment, the photomask, and the etching equipment. Clearly, this embodiment of the invention only requires one combination. The AEI CD data of this combination obtained in step 15 is... Figure 4 The image shows an AEI linewidth of 204a; in step 16, the linewidth characteristic distribution of the etching equipment 203c can be obtained based on the AEI linewidth 204a. The linewidth characteristic distribution of the etching equipment 203c is shown in... Figure 4 The AEI inter linewidth feature distribution 404c is used to represent it; at the same time, the exposure dose menu 205a can also be obtained based on the AEI linewidth 204a. The exposure dose menu 205a is the exposure dose menu corresponding to the combination of the lithography stage 201a, the photomask 202a and the etching stage 203c.
[0070] Step 2: Before exposing the wafer, pre-select the required equipment and photomask, and select the corresponding linewidth feature distribution from the database 401 based on the selected equipment and photomask, and combine them to form a bus width feature distribution.
[0071] In this embodiment of the invention, the bus width feature distribution is the AEI CD linewidth feature distribution formed after the wafer is exposed and etched. Figure 3 In step two, corresponding to step S206, the AEI linewidth data obtained in step S206 is obtained by combining the linewidth feature distributions in the database 401. Now, let's take... Figure 4 The following explanation uses the combination related to the etching machine 203c as an example:
[0072] Figure 4In the diagram, ADI inter linewidth feature distribution 402a represents the linewidth feature distribution of the lithography machine 201a, ADI inter linewidth feature distribution 402b represents the linewidth feature distribution of the lithography machine 201b, and ADI inter linewidth feature distribution 402c represents the linewidth feature distribution of the lithography machine 201c. ADI intra linewidth feature distribution 403a represents the linewidth feature distribution of the photomask 202a, and ADI intra linewidth feature distribution 403b represents the linewidth feature distribution of the photomask 202b.
[0073] In addition to the AEI linewidth 204a, and Figure 4 The corresponding AEI linewidth data for the other 5 combinations are as follows:
[0074] The ADI inter linewidth characteristic distribution 402a, ADI intra linewidth characteristic distribution 403b and AEI inter linewidth characteristic distribution 404c are combined to form AEI linewidth 204b;
[0075] The ADI inter linewidth characteristic distribution 402b, ADI intra linewidth characteristic distribution 403a, and AEI inter linewidth characteristic distribution 404c are combined to form AEI linewidth 204c;
[0076] The ADI inter linewidth characteristic distribution 402b, ADI intra linewidth characteristic distribution 403b and AEI inter linewidth characteristic distribution 404c are combined to form AEI linewidth 204d;
[0077] The ADI inter linewidth feature distribution 402c, ADI intra linewidth feature distribution 403a, and AEI inter linewidth feature distribution 404c are combined to form AEI linewidth 204e;
[0078] The ADI inter linewidth feature distribution 402c, ADI intra linewidth feature distribution 403b, and AEI inter linewidth feature distribution 404c are combined to form the AEI linewidth 204f.
[0079] The superposition calculation method of combining the linewidth feature distributions to form a bus width feature distribution can be adjusted according to the actual situation.
[0080] Step 3: Obtain the exposure dose correction data for the wafer based on the bus width characteristic distribution.
[0081] The method for generating exposure dose correction data for the wafer based on the bus width characteristic distribution can be adjusted according to actual conditions.
[0082] Figure 4 The image shows five dose exposure menus related to the exposure dose correction data obtained through the bus width feature distribution, namely: dose exposure menu 205b obtained through AEI linewidth 204b, dose exposure menu 205c obtained through AEI linewidth 204c, dose exposure menu 205d obtained through AEI linewidth 204d, dose exposure menu 205e obtained through AEI linewidth 204e, and dose exposure menu 205f obtained through AEI linewidth 204f.
[0083] Step four involves exposing the wafer, and during the exposure process, the wafer exposure is corrected according to the exposure dose correction data. The exposure corresponding to step four is the exposure after DOMA correction, which can improve AEICDU.
[0084] In this embodiment of the invention, the linewidth feature distribution of each machine and photomask is collected in advance. This allows the corresponding linewidth feature distribution to be selected from the database 401 before exposure, based on the selected machine and photomask. The selected linewidth feature distribution is then combined to form a bus width feature distribution. Exposure dose correction data can be obtained through the bus width feature distribution, thus enabling the quick and easy generation of exposure dose correction data files.
[0085] Especially when new equipment or photomasks need to be added, unlike the existing technology which requires multiple combination tests of the new equipment or photomask with other equipment or photomasks to obtain the exposure dose correction data file, the embodiments of the present invention only need to calculate the linewidth feature distribution of the added equipment or photomask to generate the exposure dose correction data file related to the new equipment or photomask. Therefore, it can improve the efficiency of generating exposure dose correction data files and thus increase production capacity.
[0086] The present invention has been described in detail above through specific embodiments, but these are not intended to limit the invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the invention, and these should also be considered within the scope of protection of the present invention.
Claims
1. A method for correcting exposure dosage, characterized in that, Includes the following steps: Step 1: Collect the linewidth feature distribution of each machine and each photomask and store the collected linewidth feature distributions in the database; Step 2: Before exposing the wafer, pre-select the required equipment and photomask, and select the corresponding linewidth feature distribution from the database based on the selected equipment and photomask, and combine them to form a bus width feature distribution; Step 3: Obtain the exposure dose correction data for the wafer based on the bus width characteristic distribution; Step 4: Expose the wafer, and during the exposure process, correct the exposure of the wafer according to the exposure dose correction data; The equipment includes a lithography machine and an etching machine; The lithography machine includes one or more, the etching machine includes one or more, and the photomask includes one or more. The linewidth feature distribution of each of the lithography machines and the linewidth feature distribution of each of the photomasks are obtained through the following steps: Step 11: Select one of the photolithography machines and one of the photomasks, and perform exposure and development to obtain the corresponding ADI CD data; Step 12: Decompose the obtained ADI CD data to obtain the linewidth feature distribution of the selected lithography machine and the linewidth feature distribution of the selected photomask; Step 13: Change the combination of the selected lithography machine and the selected photomask, and repeat steps 11 and 12 until the linewidth feature distributions of all the lithography machines and all the photomasks are obtained, and store each linewidth feature distribution in the database.
2. The exposure dose correction method as described in claim 1, characterized in that: When a new lithography machine is added, the linewidth feature distribution of the newly added lithography machine is obtained separately using the following steps: The newly added lithography machine is selected as the lithography machine, and steps 11 and 12 are repeated to obtain the linewidth feature distribution of the newly added lithography machine.
3. The exposure dose correction method as described in claim 1, characterized in that: When the newly added photomask is present, the linewidth feature distribution of the newly added photomask is obtained separately using the following steps: The newly added photomask is selected as the photomask, and steps 11 and 12 are repeated to obtain the linewidth feature distribution of the newly added photomask.
4. The exposure dose correction method as described in claim 1, characterized in that: The linewidth feature distribution of each etching machine is obtained through the following steps: Step 14: Arbitrarily select a lithography machine that has already obtained the linewidth feature distribution and arbitrarily select a photomask that has already obtained the linewidth feature distribution; Step 15: Expose and develop using the selected lithography machine and the photomask, and after development, etch using the selected etching machine to obtain the corresponding AEI CD data; Step 16: Remove the linewidth feature distribution of the selected lithography machine and the linewidth feature distribution of the selected photomask from the obtained AEI CD data to obtain the linewidth feature distribution of the selected etching machine. Step 17: Replace the selected etching equipment and repeat steps 14 to 16 or steps 15 to 16 until the linewidth feature distributions of all etching equipment are obtained and store each obtained linewidth feature distribution in the database.
5. The exposure dose correction method as described in claim 4, characterized in that: When a new etching station is added, the newly added etching station is selected as the etching station and steps 14 to 16 are repeated or steps 15 to 16 are repeated until the linewidth feature distribution of the newly added etching station is obtained.
6. The exposure dose correction method as described in claim 1, characterized in that: In step two, the bus width feature distribution is the AEI CD linewidth feature distribution formed after the wafer is exposed and etched.
7. The exposure dose correction method as described in claim 1, characterized in that: In step one, a set of linewidth feature distributions of each of the aforementioned equipment and each of the aforementioned photomasks are collected on each photolithography layer.