CN102375343A

CN102375343A - Workbench position measuring system

Info

Publication number: CN102375343A
Application number: CN2010102562151A
Authority: CN
Inventors: 齐芊枫; 郑椰琴; 吴立伟
Original assignee: Shanghai Micro Electronics Equipment Co Ltd; Shanghai Micro and High Precision Mechine Engineering Co Ltd
Current assignee: Shanghai Micro Electronics Equipment Co Ltd; Shanghai Micro and High Precision Mechine Engineering Co Ltd
Priority date: 2010-08-18
Filing date: 2010-08-18
Publication date: 2012-03-14

Abstract

The invention provides a workbench position measuring system. The workbench position measuring system comprises a lens, a main base plate, a wafer supporting stage, a marble, one or more grating ruler groups and one or more read head groups corresponding to the one or more grating ruler groups. The lens is fixed on the main base plate. The one or more read head groups form a read head set. The read head set is installed on the main base plate. The one or more grating ruler groups are fixed around the wafer supporting stage. The wafer supporting stage is installed on the marble and moves on the surface of the marble. The one or more read head groups can read motion information through relative motion between the one or more read head groups and the one or more grating ruler groups. Readings of the read head set is collected through the lens so that motion information of the wafer supporting stage on the surface of the marble is obtained. The workbench position measuring system can stably, effectively and accurately measure workbench motion. The workbench position measuring system has a high integrated level, is relatively independent and complete, and is subjected to a small influence from maintenance of other subsystems.

Description

Workbench position measuring system

Technical Field

The invention relates to a measuring system in a photoetching machine, in particular to a measuring system for the horizontal position of a worktable in the photoetching machine.

Background

At present, the common photoetching machines in the market adopt an interferometer measuring system to measure the horizontal position of a working platform. The interferometer measuring system has the advantages of large measuring range, high precision and the like, and is widely applied to position measurement of the workbench. However, the interferometer measurement system has high environmental requirements, and needs to correctly measure environmental parameters such as air pressure, temperature, humidity, etc., and continuously compensate the interferometer, even if the temperature and air pressure of the interferometer fluctuate little, the change of the air factors can finally cause the laser wavelength change, and the position change of 50 nm is caused on the measurement length of 500 mm. Laser alignment errors vary over time, which can lead to cosine and abbe errors, and therefore continuous calibration is necessary. The interferometer measurement system has high requirements on vibration, and meanwhile, the layout of the measurement system is complex, and the requirements on the design and adjustment of a light path are high. In addition, the interferometer measurement system has low integration level, and is easy to cause deviation of an optical path due to accidental touch of a certain adjusting piece during maintenance of other subsystems.

Disclosure of Invention

The invention aims to provide a workbench position measuring system in a photoetching machine, which is used for solving the defects of complex layout and low integration degree of an interferometer measuring system.

The present invention relates to a system for measuring a position of a table, comprising: the lens is fixed on the main substrate, one end of the lens, which is close to the grating ruler group, is sunk in the main substrate, one end of the lens, which is far away from the grating ruler group, is exposed out of the main substrate, the reading heads are combined into a reading head set, the reading head set is installed on the main substrate, the grating ruler group is fixed on the periphery of the support table, and the support table is installed on the marble and moves on the surface of the marble.

Preferably, in the workbench position measuring system, the readhead sets and the grating scale sets are arranged in a quadrilateral layout.

Preferably, in the workbench position measuring system, the readhead sets and the grating scale sets are arranged in a cross layout.

Preferably, in the workbench position measuring system, the grating ruler set comprises a plurality of horizontal grating lines extending along the X direction and a plurality of vertical grating lines extending along the Y direction; the reading head group consists of three rows of reading heads, and the middle row of reading heads of the three rows of reading heads corresponds to the vertical grating lines of the grating ruler group and is used for measuring the movement of the wafer bearing table in the X direction; the two rows of the three rows of the read heads correspond to the horizontal grating lines of the grating ruler group and are used for measuring the movement of the wafer bearing table in the Y direction, and the rotation angle of the wafer bearing table relative to the marble is obtained by combining the reading results of the two rows of the read heads on the two sides in the Y direction.

Preferably, in the table position measuring system, the set of readheads is a sensor.

Preferably, in the workbench position measuring system, the grating ruler set comprises a plurality of horizontal grating lines extending along the Y direction and a plurality of vertical grating lines extending along the Y direction; the reading head set 106 includes only two rows of reading heads, one row of reading heads corresponds to the vertical grating lines of the grating ruler set and is used for measuring the movement of the wafer stage in the X direction, and the other row of reading heads corresponds to the horizontal grating lines of the grating ruler set and is used for measuring the movement of the wafer stage in the Y direction.

According to the workbench position measuring system, the workbench position measuring system consisting of the grating ruler group and the multiple rows of reading heads is adopted, the motion of the workbench can be stably, effectively and accurately measured, the workbench position measuring system is high in integration level, relatively independent and complete, and is less influenced by maintenance of other subsystems. The method for measuring the motion information of the wafer bearing table of the photoetching machine can monitor the environmental influence in real time, so that the positioning reaches the nanometer precision, and the inherent repetition precision is higher than that of a laser interferometer measuring system.

Drawings

The various aspects of the present invention will become more apparent after reading the detailed description of the invention with reference to the attached drawings. Wherein,

FIG. 1 is a schematic diagram of a stage position measurement system in a lithography machine;

FIG. 2 is a schematic top view of the corresponding read head set and grating ruler set; and

fig. 3 is a schematic diagram of the arrangement layout structure of the read head group and the grating ruler group.

Detailed Description

Embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Like reference numerals refer to like parts throughout the description.

The worktable position measuring system composed of the two-dimensional grating ruler and the multiple rows of reading heads can stably, effectively and highly accurately measure the movement of the worktable, has higher integration level, is relatively independent and complete, is less influenced by the maintenance of other subsystems, and has simpler structure and layout than a laser interferometer measuring system and lower requirements on design and adjustment.

The method for measuring the motion information of the wafer bearing table of the photoetching machine can monitor the environmental influence in real time, so that the positioning reaches the nanometer precision, and the inherent repetition precision is higher than that of a laser interferometer measuring system.

FIG. 1 is a schematic diagram of a stage position measurement system in a lithography machine. Referring to fig. 1, the stage position measurement system 100 includes a lens 101, a main substrate 102, a stage 103, a marble 104, at least one grating scale set 105, and at least one head set 106. The lens 101 is fixed on the main substrate 102, and one end of the lens 101 close to the grating scale group 105 is recessed in the main substrate 102, and one end of the lens 101 far from the grating scale group 105 is exposed out of the main substrate 102. The head group 106 is synthesized into a head set, and the head set is mounted on the main substrate 102, the head group 106 is a sensor, and corresponds to the position of the grating scale group 105. The wafer bearing platform 103 is arranged on the marble 104 and moves on the surface of the marble 104, the grating ruler set 105 is fixed on the periphery of the wafer bearing platform 103 and moves along with the wafer bearing platform, and the movement information of the relative movement of the reading head set 106 and the grating ruler set 105 is the movement information of the wafer bearing platform 103 on the surface of the marble 104.

The stage 103 moves horizontally in a long stroke or a precise motion on the marble 104, and the stage 103 rotates along the marble 104. The grating scale group 105 is fixed on the periphery of the wafer bearing platform 103 and moves along with the wafer bearing platform 103, the reading head group 106 reads movement information according to the relative movement of the reading head group 106 and the grating scale group 105, and the reading of the reading head group is collected through the lens 101 to obtain the movement information of the wafer bearing platform 103 on the surface of the marble 104.

Fig. 2 is a schematic top view structure diagram of the read head group and the grating ruler group. Referring to fig. 2, the grating scale group 105 includes a plurality of horizontal grating lines 202 extending in an X direction and a plurality of vertical grating lines 203 extending in a Y direction, wherein the X direction and the Y direction are as indicated in fig. 2; the horizontal grating lines 202 correspond to the two rows of the read heads 2012 on both sides of the three rows of the read heads 201 and measure the movement of the stage 103 in the Y direction, and the vertical grating lines 203 correspond to the one row of the read heads 2011 in the middle of the three rows of the read heads 201 and measure the movement of the stage 103 in the X direction.

The reading head group 106 consists of three rows of reading heads 201, and a middle row of reading heads 2011 of the three rows of reading heads 201 corresponds to the vertical grating line 203 of the grating scale group 105 and is used for measuring the movement of the wafer bearing table 103 in the X direction; the two rows of reading heads 2012 on two sides of the three rows of reading heads 201 correspond to the horizontal grating ruling lines 202 of the grating ruler set 105, and are used for measuring the movement of the wafer carrying table 103 in the Y direction, and obtaining the rotation angle of the wafer carrying table 103 relative to the marble 104 by combining the reading results measured by the two rows of reading heads 2012 on two sides in the Y direction.

In addition, in another preferred embodiment of the present invention, each grating ruler set comprises a horizontal grating line and a vertical grating line; each of the readhead sets 106 includes only two rows of readheads, one row of readheads corresponding to the vertical grating lines of the grating rulers for measuring the movement of the wafer stage in the X direction, and the other row of readheads corresponding to the horizontal grating lines of the grating rulers for measuring the movement of the wafer stage in the Y direction.

The reading head group 106 corresponds to the grating ruler group 105, and the reading information of the reading head group is collected through the lens 101 to obtain the motion information of the wafer bearing platform 103 on the surface of the marble 104. In this embodiment, the first, second, and third read heads 2150, 2160, 2170 belong to the middle row of read heads 2011 of the three rows of read heads 201 for measuring X-direction motion of the grating scale group 105, i.e., the stage 103, while the fourth and fifth read heads 2271, 2272, sixth and seventh read heads 2281, 2282 are for measuring relative rotational motion of the read heads and the grating scales. When the grating scale group 105, that is, the wafer stage 103, moves in the positive X direction, the first reading head 2150, the fourth reading head 2271 and the fifth reading head 2272 operate, and at this time, the reading heads do not need to be switched, the first reading head 2150 can measure the movement of the wafer stage 103 in the positive X direction, and the fourth reading head 2271 and the fifth reading head 2272 can measure the relative angular rotation of the wafer stage 103. Similarly, when the wafer stage 103 moves in the negative Y-direction, three reading heads are provided in the corresponding Y-direction for measuring the position and rotation of the Y-direction movement of the wafer stage 103, and the Y-direction reading heads do not need to be switched. At this time, the X-directional heads are sequentially switched from the first head 2150 to the second head 2160 and from the fourth head 2271 and the fifth head 2272 to the sixth head 2281 and the seventh head 2282.

Fig. 3 is a schematic diagram of the arrangement layout structure of the read head group and the grating ruler group. Referring to fig. 3, the group of readheads 106 and the group of rasters 105 are arranged in an approximately quadrilateral layout 301 or in a cross layout 302, and the measurement system in the approximately quadrilateral layout 301 can measure the stroke of the stage in a wide range. In the measurement system of the quadrilateral layout 301, two additional vertical grating lines and two pairs of reading heads are always simultaneously used for measuring the angular rotation, the angular rotation obtained by measurement in one direction can be selected as a main measurement value, and the corresponding other measurement value is used as verification.

Claims

1. A table position measurement system, comprising: the lens is fixed on the main substrate, one end of the lens, which is close to the grating ruler group, is sunk in the main substrate, one end of the lens, which is far away from the grating ruler group, is exposed out of the main substrate, the reading heads are combined into a reading head set, the reading head set is installed on the main substrate, the grating ruler group is fixed on the periphery of the support table, and the support table is installed on the marble and moves on the surface of the marble.

2. The system of claim 1, wherein the set of readheads and the set of rasters are arranged in a quadrilateral configuration.

3. The system of claim 1, wherein the set of readheads and the set of rasters are arranged in a cross configuration.

4. The stage position measurement system of claim 1, wherein the set of gratings comprises a plurality of horizontal grating lines extending in an X-direction and a plurality of vertical grating lines extending in a Y-direction; the reading head group consists of three rows of reading heads, and the middle row of reading heads of the three rows of reading heads corresponds to the vertical grating lines of the grating ruler group and is used for measuring the movement of the wafer bearing table in the X direction; the two rows of the three rows of the read heads correspond to the horizontal grating lines of the grating ruler group and are used for measuring the movement of the wafer bearing table in the Y direction, and the rotation angle of the wafer bearing table relative to the marble is obtained by combining the reading results of the two rows of the read heads on the two sides in the Y direction.

5. A table position measurement system according to claim 1, wherein the set of readheads is a sensor.

6. The stage position measurement system of claim 1, wherein the set of gratings comprises a plurality of horizontal grating lines extending in an X-direction and a plurality of vertical grating lines extending in a Y-direction; the reading head set 106 includes only two rows of reading heads, one row of reading heads corresponds to the vertical grating lines of the grating ruler set and is used for measuring the movement of the wafer stage in the X direction, and the other row of reading heads corresponds to the horizontal grating lines of the grating ruler set and is used for measuring the movement of the wafer stage in the Y direction.