Relative position measurement based alignment system, double workpiece stage system and measurement system

• US 10,359,712 B2
• Filed: 08/26/2016
• Issued: 07/23/2019
• Est. Priority Date: 08/31/2015
• Status: Active Grant

• Current Assignee: Shanghai Micro Electronics Equipment Company Limited
• Original Assignee: Shanghai Micro Electronics Equipment Company Limited
• Inventors: Li, Yunfeng
• Primary Examiner(s): Smith, Zandra V
• Assistant Examiner(s): Stevenson, Andre C
• Application Number:
  US15/756,272
• Publication Number:
  US 20180253020A1
• Time in Patent Office: 1,061 Days
• CPC Class Codes: G03F 7/70716 Stages
• CPC Class Codes: G03F 7/709 Vibration, e.g. vibration detection, compensation, suppression or isolation
• CPC Class Codes: G03F 9/00 Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically G03F7/22 takes precedence; preparation of photographic masks G03F1/00; within photographic printing apparatus for making copies G03B27/00
• CPC Class Codes: G03F 9/7007 Alignment other than original with workpiece
• CPC Class Codes: G03F 9/7026 Focusing
• CPC Class Codes: G03F 9/7034 Leveling
• CPC Class Codes: G03F 9/7084 Position of mark on substrate, i.e. position in (x, y, z) of mark, e.g. buried or resist covered mark, mark on rearside, at the substrate edge, in the circuit area, latent image mark, marks in plural levels
• CPC Class Codes: G03F 9/7088 Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection
• CPC Class Codes: H01L 21/682 Mask-wafer alignment in general G03F7/70, G03F9/70

Abstract

An alignment system, a dual-wafer-stage system and a measurement system are disclosed, the alignment system including a main frame (201, 301), a first wafer stage (205, 305), an alignment sensor (202, 302), a position acquisition module (208, 308) and a signal processing device (203, 303). The position acquisition module (208, 308) collects positional data from the first wafer stage (205, 305) and the reflector (204, 304) simultaneously. The reflector (204, 304) is arranged on the alignment sensor (202, 302). In other words, positional data of the alignment sensor (202, 302) and positional data of the first wafer stage (205, 305) are collected simultaneously. In addition, the data can be processed to indicate the relative position of the first wafer stage (205, 305) relative to the alignment sensor (202, 302) whose vibration has been zeroed. That is, a position where an alignment mark is aligned can be obtained with the relative vibration amplitude of the alignment sensor (202, 302) being zeroed. This can circumvent the impact of vibration of the alignment sensor (202, 302) and allow increased repeatability accuracy of alignment.

Claims

1. An alignment system, comprising:

a main frame;

a first wafer stage configured to carry a wafer, the wafer comprising an alignment mark;

an alignment sensor attached to the main frame and arranged above the alignment mark, the alignment sensor being configured to output an optical signal;

a position acquisition module, configured to collect a relative positional data of the first wafer stage with respect to the alignment sensor and output the relative positional data of the first wafer stage; and

a signal processing device, configured to receive and process the optical signal from the alignment sensor and the relative positional data and to calculate a position for alignment of the alignment mark of the wafer,

wherein the position acquisition module comprises a light source module configured to provide visible light beams, wherein the light source module is configured to emanate a first visible light beam to the alignment sensor, the first visible light beam being reflected by the alignment sensor and forming a reference beam; and

simultaneously, the light source module is configured to emanate a second visible light beam to the first wafer stage, the second visible light beam being reflected by the first wafer stage and forming a measuring beam.

2. The alignment system of claim 1, wherein the alignment sensor comprises an illumination module configured to provide an ultraviolet light or an extreme ultraviolet light for illuminating the alignment mark for alignment.

3. The alignment system of claim 2, wherein the alignment sensor further comprises an optoelectronic detector configured to detect and receive reflected and diffracted light beams from the alignment mark and output the optical signal.

4. The alignment system of claim 1, wherein the position acquisition module further comprises an optoelectronic system configured to receive the reference beam and produce a reference optoelectronic signal, and the optoelectronic system is further configured to receive the measuring beam and produce a measuring optoelectronic signal.

5. The alignment system of claim 4, wherein the relative positional data of the first wafer stage with respect to the alignment sensor is obtained by subtracting the reference optoelectronic signal from the measuring optoelectronic signal.

6. The alignment system of claim 1, further comprising a reflector arranged on the alignment sensor, and wherein the first visible light beam is reflected by the reflector and forms the reference beam.

7. The alignment system of claim 1, wherein the signal processing device comprises:

a light intensity signal acquisition and processing module configured to acquire the optical signal from the alignment sensor, convert the optical signal to a digital electrical signal and output the digital electrical signal; and

an alignment and management module, configured to receive and process the optical signal from the alignment sensor and the relative positional data and calculate the position for alignment of the alignment mark on the wafer.

8. The alignment system of claim 1, wherein the alignment sensor is arranged above a center of the first wafer stage.

9. A dual-wafer-stage system, comprising:

the alignment system as defined in claim 1;

a projection objective secured on the main frame; and

a second wafer stage under the projection objective.

10. The dual-wafer-stage system of claim 9, wherein the projection objective is arranged above a center of the second wafer stage.

11. The dual-wafer-stage system of claim 9, wherein the second wafer stage is configured for exposure of a wafer.

12. The dual-wafer-stage system of claim 11, wherein an alignment process by the alignment system proceeds in parallel with an exposure process on the wafer.

13. A measurement system, comprising:

a first measurement device comprising a detection source configured to deliver a measuring signal to a target object and acquire a detection signal;

a second measurement device configured to monitor the detection source and acquire a disturbance signal affecting an accuracy of the detection signal; and

a signal processing device, configured to receive the detection signal and the disturbance signal and correct the detection signal based on the disturbance signal,

wherein the position acquisition module comprises a light source module configured to provide visible light beams, wherein the light source module is configured to emanate a first visible light beam to the reflector, the first visible light beam being reflected by the reflector and forming a reference beam; and

simultaneously, the light source module is configured to emanate a second visible light beam to the target object, the second visible light beam being reflected by the target object and forming a measuring beam.

14. The measurement system of claim 13, wherein:

the first measurement device is implemented as an alignment device, the detection source is implemented as an alignment sensor, the target object is implemented as an alignment mark and the measuring signal is implemented as an optical signal.

15. The measurement system of claim 14, wherein the second measurement device is implemented as a position acquisition module, and wherein the disturbance signal is implemented as a relative positional data of the alignment sensor with respect to the target object.

16. The measurement system of claim 15, wherein the position acquisition module comprises a reflector arranged on the alignment sensor, and wherein the relative positional data is acquired by the reflector.

17. The measurement system of claim 13, wherein the position acquisition module further comprises an optoelectronic system configured to receive the reference beam and produce a reference optoelectronic signal, and the optoelectronic system is further configured to receive the measuring beam and produce a measuring optoelectronic signal, and wherein the relative positional data of the alignment sensor with respect to the target object are obtained based on the reference optoelectronic signal and the measuring optoelectronic signal.