KR20090002469A - Apparatus and method for exposuring wafer - Google Patents

Apparatus and method for exposuring wafer Download PDF

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Publication number
KR20090002469A
KR20090002469A KR1020070065826A KR20070065826A KR20090002469A KR 20090002469 A KR20090002469 A KR 20090002469A KR 1020070065826 A KR1020070065826 A KR 1020070065826A KR 20070065826 A KR20070065826 A KR 20070065826A KR 20090002469 A KR20090002469 A KR 20090002469A
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KR
South Korea
Prior art keywords
exposure
meef
value
mask
wafer
Prior art date
Application number
KR1020070065826A
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Korean (ko)
Inventor
김중찬
Original Assignee
주식회사 하이닉스반도체
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Priority to KR1020070065826A priority Critical patent/KR20090002469A/en
Publication of KR20090002469A publication Critical patent/KR20090002469A/en

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/68—Preparation processes not covered by groups G03F1/20 - G03F1/50
    • G03F1/70—Adapting basic layout or design of masks to lithographic process requirements, e.g., second iteration correction of mask patterns for imaging
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/70491—Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring processes
    • G03F7/705—Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B17/00—Systems involving the use of models or simulators of said systems

Abstract

Set reference exposure conditions to be applied differently for each exposure field on the wafer, obtain mask layout data of a mask to be used for pattern transfer onto the wafer, and then pattern transfer the mask layout data and the reference exposure conditions. Simulation is performed to measure the mask error enhancing factor (MEEF) value and to compensate for the difference between the measured mask error enhancing factor (MEEF) value and the reference mask error enhancing factor (MEEF) value allowed for exposure of the wafer. After exposing and setting exposure conditions for each exposure field, a wafer exposure method for performing exposure for each exposure field of a wafer with changed exposure conditions and an exposure apparatus for performing such exposure method are presented.

Description

Wafer exposure equipment and exposure method {Apparatus and method for exposuring wafer}

1 is a view for explaining a wafer exposure apparatus according to an embodiment of the present invention.

2 is a view for explaining a wafer exposure method according to an embodiment of the present invention.

3 to 5 are views for explaining a wafer exposure method according to an embodiment of the present invention.

The present invention relates to lithography, and more particularly, to a wafer exposure apparatus and an exposure method for improving pattern critical dimension (CD) uniformity.

As the degree of integration of semiconductor devices increases, the design rules of patterns to be implemented on wafers have also become finer. Accordingly, in order to improve line uniformity (CD) uniformity between exposure fields during wafer exposure, an exposure method of changing the dose of exposure energy for each exposure field is performed. Such an exposure method is effective for improving line uniformity (CD) uniformity between exposure fields, but as the design rule becomes more finer, a method of finely and precisely controlling exposure conditions for each exposure field is required.

Moreover, the method of applying different exposure energy doses for each exposure field is based on the cell region in which the patterns are repeated more regularly, and thus the line width of the resulting photoresist (PR) pattern due to the pattern transfer in this cell region. (CD) Reflects data. Accordingly, line width variations generated in individual minimum line width transistor patterns, for example, gate lines of minimum line width, are not reflected in the process of changing the exposure energy dose. Therefore, there is a demand for development of an exposure method that can further improve pattern uniformity during pattern transfer.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a wafer exposure apparatus and an exposure method capable of implementing pattern uniformity improvement during pattern transfer onto a wafer.

According to an aspect of the present invention for the technical problem, the step of setting the reference exposure conditions to be applied differently for each exposure field (field) on the wafer, obtaining the layout data (mask layout data) of the mask to be used for pattern transfer on the wafer Performing a pattern transfer simulation using the mask layout data to measure a mask error reinforcement element (MEEF) value, and permit the exposure of the measured mask error reinforcement element (MEEF) value and the wafer. And changing and setting exposure conditions for each exposure field to compensate for a difference from a reference mask error enhancing element (MEEF) value, and performing exposure for each exposure field of the wafer with the changed set exposure conditions. An exposure method is presented.

The measuring of the mask error reinforcing element MEEF may include setting a target area to measure a mask error reinforcing element MEEF in the mask layout data, and simulating the pattern transfer with respect to the measurement target area. May be performed by applying the reference exposure conditions, and measuring the mask error reinforcing element (MEEF) value by measuring a line width (CD) of the simulation result.

The changing of the exposure conditions may include changing an exposure energy dose, a focus and an illumination system included in the reference exposure conditions, and applying the changed exposure conditions to the measurement target area. Performing pattern transfer simulation again, re-measuring a mask error reinforcing element (MEEF) value by measuring a line width (CD) of the simulation result, and re-measured mask error reinforcing element (MEEF) value Repeating the step of comparing the reference mask error reinforcement element (MEEF) value with the changed mask condition to compensate for the difference between the measured mask error reinforcement element (MEEF) value and the reference mask error reinforcement element (MEEF) value. May include obtaining them.

The measurement target area may be set to an area including a pattern having a minimum line width CD among the mask layout data.

According to another aspect of the present invention, an exposure unit performing scan exposure for each exposure field of a wafer, an exposure control unit in which reference exposure conditions are set to be applied differently for each exposure field, and used for pattern transfer onto the wafer A storage unit storing mask layout data of the mask, a simulation model for performing a pattern transfer simulation for measuring a mask error reinforcement element (MEEF) value using the mask layout data, And an exposure compensator configured to change and set exposure conditions for each of the exposure fields according to the measured mask error enhancing element (MEEF) value.

According to the present invention, it is possible to provide a wafer exposure apparatus and an exposure method capable of implementing pattern uniformity improvement when transferring a pattern onto a wafer.

According to an embodiment of the present invention, when performing an exposure process for transferring a pattern on a wafer, an exposure method for predicting and applying a mask error enhancing element (MEEF) value for each exposure field is proposed. Then, a configuration of an exposure apparatus for performing this exposure method is presented.

The defect that lowers the uniformity of the pattern line width when transferring the pattern onto the wafer by the exposure process may be corrected by adjusting the exposure energy dose for each exposure field. However, in the case of a defect mainly caused by a mask error enhancement factor (MEEF) reflecting the influence of topology, it is more accurate to feed back the MEEF value for each exposure field. Is required for implementation. Therefore, in the exemplary embodiment of the present invention, the MEEF value is predicted through simulation, and the exposure energy dose value is differently applied to each exposure field in consideration of the predicted MEEF value, and the exposure field of each pattern is formed on the wafer. Improve line width uniformity In this case, different modified illumination systems having different illumination system conditions for each exposure field may be applied.

1 is a view for explaining a wafer exposure apparatus according to an embodiment of the present invention. 2 is a view for explaining a wafer exposure method according to an embodiment of the present invention. 3 to 5 are views for explaining a wafer exposure method according to an embodiment of the present invention.

Referring to FIG. 1, an exposure apparatus according to an exemplary embodiment of the present disclosure may include an exposure unit 110 that performs exposure, a control unit 120 that controls exposure of the exposure unit 110, and an exposure beam that corrects an exposure condition. It may be configured to include the government (130). The exposure unit 110 is configured such that the mask 113 is introduced such that the exposure light provided from the exposure source 111 is incident. The exposure light having an image of the pattern layout formed in the mask 113 is incident on the wafer 117 mounted on the stage by the projection lens 115. In this case, the exposure of the wafer 117 is performed on the entire wafer 117 by scanning the exposure light sequentially for each exposure field.

The reference exposure conditions are input and set in the exposure control unit 120 to be applied differently for each exposure field. These reference exposure conditions may be set to include conditions in which different focus, illumination, and / or exposure energy dose amounts are set for each field so as to improve the pattern line width (CD) uniformity during pattern transfer.

The exposure compensator 130 stores a simulation model simulating a pattern transfer process on the wafer 117 and mask layout data of a mask 113 to be used during exposure. It may be configured to include a storage unit 133. The simulation model 131 is constructed in the exposure apparatus to perform pattern transfer simulation for measuring a mask error reinforcing element (MEEF) value accompanying exposure using mask layout data. The exposure compensation unit 130 changes exposure conditions for each exposure field input to the control unit 120 according to the mask error enhancing element (MEEF) value measured through simulation, and resets the new exposure conditions to the control unit 120. Enter it. Accordingly, the controller 120 controls the operation of the exposure unit 110 to apply the changed exposure conditions to the corresponding exposure field. This exposure process can be performed as in the process flow as shown in FIG. 2.

Referring to FIG. 2, in the exposure method according to the exemplary embodiment of the present disclosure, after the wafer 117 and the mask 113 are mounted on the exposure unit 110, the control unit 120 may be configured for each exposure field on the wafer 117. Reference exposure conditions to be applied differently are set. At this time, a measurement area for measuring the MEEF value involved in the exposure process is set (201 in FIG. 2). This measurement area can be set by inputting the mask laying out data as coordinates. For example, the layout data of the mask 113 to be used for pattern transfer onto the wafer 117 is secured from the storage unit 133 of FIG. 1 with the same data as the layout 300 shown in FIG. 3 ( 203 in FIG. 2).

The layout 300 may be a pattern layout formed as a mask pattern on the actual mask 113. In this layout 300, the measurement area A is set. The measurement area A sets a region in which pattern line width CD is relatively weak in pattern transfer, and a priori experience may be applied to the area setting. For example, it is relatively difficult to secure the line width CD of the pattern having the smallest pattern line width CD among the mask layout data. Therefore, the area including the minimum pattern can be set as the measurement area A as shown in FIG. 4. have. The line width measurement point 403 for one of the patterns 401 of the measurement area A is set. The linewidth measurement is performed on the linewidth measurement point 403.

Since the MEEF value is given as the ratio of the line width CD change value on the wafer to the line width CD change value on the mask, the line width CD change on the mask during the reduced exposure causes a large line width CD change on the wafer. Factors influencing this MEEF value may take into account the size, shape and exposure conditions of the pattern. Although manufacturing is performed in consideration of the MEEF value when manufacturing the mask 113, the MEEF value considering the MEEF value accompanying the actual exposure may be different from the MEEF value that is allowed during exposure, that is, the reference MEEF value on the spec allowed during exposure. have. In the embodiment of the present invention, the MEEF value is predicted to be accompanied by the actual exposure in the exposure apparatus, and the exposure conditions are changed in consideration of the MEEF value.

For example, in order to perform pattern transfer simulation using the mask layout data of the measurement area (A in FIG. 4), a simulation model (131 in FIG. 1) is introduced (205 in FIG. 2). The simulation model is introduced as a model that simulates the process of transferring the pattern onto the wafer according to the exposure conditions. Using this simulation model (131 of FIG. 1), pattern transfer simulation is performed on layout data of the measurement area (A of FIG. 4). This simulation result can be obtained with an image 503 as shown in FIG. 5. The line width CD measurement is performed at the measurement point (503 in FIG. 5) corresponding to the line width measurement point (403 in FIG. 4) set in the obtained simulation result image 500. The measured linewidth (CD) and the linewidth (CD) obtained from the mask layout data are compared with the target linewidth (CD) and the like to obtain the MEEF value involved in the exposure simulation (207 of FIG. 2).

The difference between the measured MEEF value and the reference MEEF value may be interpreted as a defect in pattern transfer when the exposure scan for each exposure field is performed with actual reference exposure conditions. In particular, the line width CD is difficult to be secured with respect to a weak pattern included in the measurement target area A, for example, a pattern having a minimum line width. Therefore, the exposure conditions are changed to compensate for this difference in MEEF value. The measured MEEF value obtained through this simulation is predicted to be a value accompanying the exposure by the reference exposure conditions because the simulation process is performed by the reference exposure conditions currently set in the controller 120 (FIG. 1). This measured MEEF value is compared with the allowed reference MEEF value (209 in FIG. 2). If the two values are analyzed to be different, the exposure conditions are changed (211 in FIG. 2). If there is no difference, since the MEEF value is satisfied, actual exposure is performed (213 in FIG. 2).

Changing and setting the exposure conditions may include changing the exposure energy dose, focus, and illumination system included in the reference exposure conditions. Such changes can be made by changing the dose, focus, or illumination system, within the limited range allowed within the exposure process or on the equipment specification. The pattern transfer simulation is again performed on the measurement target area A by applying the changed exposure conditions, and the mask error reinforcing element (MEEF) value is measured again by measuring the line width (CD) of the simulation result, and then again. Repeat the process of comparing the measured mask error reinforcement factor (MEEF) value with the reference mask error reinforcement factor (MEEF) value, and the difference between the measured mask error reinforcement factor (MEEF) value and the reference mask error reinforcement factor (MEEF) value Get compensated exposure conditions for each exposure field.

The changed exposure conditions thus obtained are input to the controller 120 from the exposure compensator (130 in FIG. 1), and the controller 120 controls the exposure unit 110 to expose the corresponding exposure fields according to the input exposure conditions. Thus, wafer exposure is performed.

According to the present invention, the mask error reinforcing element (MEEF) value, which is an important variable for the uniformity of the pattern line width (CD) during pattern transfer according to the exposure, is compared with the reference value set in the specification and the measured value simulated in the exposure equipment, to determine whether the exposure proceeds. And after obtaining the correction value and the correction value, the exposure for each exposure field is performed by varying the exposure conditions. As a result, it is possible to suppress defects that may occur due to topology issues and the like in the wafer while improving the pattern line width (CD) uniformity.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the technical spirit of the present invention. Do.

Claims (5)

Setting reference exposure conditions to be applied differently for each exposure field on the wafer; Obtaining mask layout data of a mask to be used for pattern transfer onto the wafer; Performing a pattern transfer simulation on the mask layout data and the reference exposure conditions to measure a mask error enhancing element (MEEF) value; Changing and setting exposure conditions for each exposure field to compensate for a difference between the measured mask error enhancing element (MEEF) value and the reference mask error enhancing element (MEEF) value allowed for exposure of the wafer; And And performing exposure for each exposure field of the wafer under the changed set exposure conditions. The method of claim 1, Measuring the mask error reinforcing element (MEEF) value, Setting a target area to measure a mask error reinforcing element (MEEF) in the mask layout data; Performing the pattern transfer simulation on the measurement target area by applying the reference exposure conditions; And And measuring the mask error enhancing element (MEEF) value by measuring a line width (CD) of the simulation result. The method of claim 1, Changing and setting the exposure conditions Changing the exposure energy dose, focus, and illumination system included in the reference exposure conditions; Performing pattern transfer simulation on the measurement target area by applying the changed exposure conditions; Re-measuring a mask error reinforcing element (MEEF) value by measuring a line width (CD) of the simulation result; And Repeating the remeasurement of the mask error enhancing component (MEEF) value with the reference mask error enhancing component (MEEF) value, Obtaining the modified exposure conditions in which a difference between the measured mask error enhancing element (MEEF) value and the reference mask error enhancing element (MEEF) value is compensated for. The method of claim 1, The measurement target area And a region including a pattern having a minimum line width (CD) among the mask layout data. An exposure unit configured to perform scan exposure for each exposure field of the wafer; An exposure controller in which reference exposure conditions are set to be applied differently for each of the exposure fields; A storage unit which stores mask layout data of a mask to be used for pattern transfer onto the wafer; A simulation model for performing a pattern transfer simulation to measure a mask error reinforcement element (MEEF) value using the mask layout data; And And an exposure compensation unit configured to change and set exposure conditions for each exposure field according to the measured mask error enhancing element (MEEF) value.
KR1020070065826A 2007-06-29 2007-06-29 Apparatus and method for exposuring wafer KR20090002469A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101322723B1 (en) * 2011-01-28 2013-10-28 에이에스엠엘 네델란즈 비.브이. Lithographic apparatus and methods for determining an improved configuration of a lithographic apparatus
KR101334422B1 (en) * 2010-08-06 2013-11-29 캐논 가부시끼가이샤 Evaluation method, decision method, and storage medium

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101334422B1 (en) * 2010-08-06 2013-11-29 캐논 가부시끼가이샤 Evaluation method, decision method, and storage medium
KR101322723B1 (en) * 2011-01-28 2013-10-28 에이에스엠엘 네델란즈 비.브이. Lithographic apparatus and methods for determining an improved configuration of a lithographic apparatus

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