CN-121983495-A - Etching equipment and detection method

CN121983495ACN 121983495 ACN121983495 ACN 121983495ACN-121983495-A

Abstract

The application provides etching equipment and a detection method, and relates to the technical field of semiconductor etching. The etching structure is used for etching the wafer and comprises a base, an electrostatic chuck, a focusing ring and a cover ring. The detection structure comprises a light source, a first lens and a processing module, wherein the light source outputs detection light, the first lens transmits the detection light to the focusing ring and transmits the detection light reflected by the focusing ring to the processing module, and the processing module acquires the offset of the focusing ring based on the detection light reflected by the focusing ring, namely acquires the position deviation between the focusing ring and the center position of the electrostatic chuck. The alignment structure moves the focus ring based on the offset, eliminating positional deviation of the focus ring relative to the electrostatic chuck. Based on the above, the etching device has a detection structure capable of detecting the center deviation of the focusing ring and the electrostatic chuck, and a calibration structure for eliminating the center deviation, which is helpful for ensuring the etching uniformity of the wafer.

Inventors

DONG QI
YIN GEHUA
LIU HAIYANG
YE PENG
LI HAO
HU DONGDONG
SHI XIAOLI
XU KAIDONG

Assignees

江苏鲁汶仪器股份有限公司

Dates

Publication Date: 20260505
Application Date: 20241029

Claims (14)

1. An etching apparatus, comprising: the etching structure is used for realizing etching of the wafer and comprises a base, an electrostatic chuck, a focusing ring and a cover ring, wherein the electrostatic chuck is positioned on the base, the cover ring surrounds the base, and the focusing ring is positioned on the cover ring and surrounds the electrostatic chuck; The detection structure comprises a light source, a first lens and a processing module, wherein the light source outputs detection light, the first lens transmits the detection light to the focusing ring and transmits the detection light reflected by the focusing ring to the processing module, and the processing module acquires the offset of the focusing ring based on the reflected detection light, wherein the offset is the deviation between the center position of the focusing ring and the center position of the electrostatic chuck; And a calibration structure that moves the focus ring based on the offset, eliminating the offset.
2. The etching apparatus of claim 1, wherein the cover ring has N first openings circumferentially arranged around the base, N being ≡2, the first openings extending upward from a bottom of the cover ring in a first direction parallel to an arrangement direction of the base and the electrostatic chuck; The first lens comprises N first sub-lenses which are respectively positioned in the first open holes and are opposite to the side face of the focusing ring, and the first sub-lenses are used for transmitting the detection light to the focusing ring and transmitting the detection light reflected by the focusing ring to the processing module.
3. The etching apparatus of claim 2, wherein the plane in which the first sub-lens is located has a first included angle with the first direction, and the value range of the first included angle is 0-90 ° excluding an endpoint value.
4. An etching apparatus according to claim 3, wherein the first included angle has a value of 45 °.
5. An etching apparatus according to claim 3, wherein the center of the first sub-lens corresponds to a preset position of the focus ring; the distance between the preset position and the top of the focusing ring is equal to the distance between the preset position and the bottom of the focusing ring.
6. The etching apparatus of any of claims 1-5, wherein the material of the focus ring is a reflective material to reflect the detection light; The cover ring is made of a light-transmitting material so as to transmit the detection light to the focusing ring and the processing module.
7. The etching apparatus of claim 2, wherein the processing module comprises a second lens, a processing module, and a computing module; The second lens comprises N second sub-lenses, the N second sub-lenses are in one-to-one correspondence with the N first sub-lenses, the detection light reflected by the focusing ring is received, and the detection light is transmitted to the processing module; The processing module comprises N linear CCD cameras which are in one-to-one correspondence with the N second sub-lenses and are used for identifying the light positions of the detection light rays so as to obtain light ray distances, the light ray positions reflect the positions of the detection light rays falling on the linear CCD cameras, and the light ray distances are the distances between the light ray positions and the central positions of the linear CCD cameras; the calculation module obtains the offset of the focusing ring based on the light ray distance.
8. The etching apparatus of claim 7, wherein the plane of the second sub-lens is parallel to the plane of the first sub-lens; the plane of the linear CCD camera is parallel to the plane of the second sub-lens, and the center of the linear CCD camera is opposite to the center of the second sub-lens.
9. The etching apparatus of claim 1, wherein the alignment structure comprises a lift structure and a robot; The cover ring is provided with M second openings circumferentially distributed around the base, M is more than or equal to 2, the second openings extend upwards from the bottom of the cover ring to the bottom of the focusing ring along a first direction, and the first direction is parallel to the distribution directions of the base and the electrostatic chuck; The lifting structure comprises M lifting pins which are respectively positioned in the M second holes and used for lifting the focusing ring; the manipulator moves the focus ring based on the offset, eliminating the offset.
10. The etching apparatus according to claim 1, further comprising: the first chamber is a vacuum chamber, and the etching structure is positioned in the first chamber; The second chamber is a non-vacuum chamber and is connected with the first chamber, and the light source and the processing module are positioned in the second chamber.
11. The etching apparatus according to claim 10, further comprising: the light-transmitting window is positioned at the junction of the first cavity and the second cavity, and the detection light is transmitted to the first lens through the light-transmitting window.
12. A detection method is used for detecting and eliminating offset between a focusing ring and an electrostatic chuck in etching equipment, wherein the offset is the deviation between the center position of the focusing ring and the center position of the electrostatic chuck, and is characterized by comprising an etching structure, a detection structure and a calibration structure, wherein the etching structure is used for realizing etching of a wafer and comprises a base, the electrostatic chuck, the focusing ring and a cover ring, the electrostatic chuck is positioned on the base, the cover ring surrounds the base, the focusing ring is positioned on the cover ring and surrounds the electrostatic chuck, the detection structure comprises a light source, a first lens and a processing module, and the detection method comprises the following steps: Controlling the light source to output detection light; Transmitting the detection light to the focusing ring by using the first lens, and transmitting the detection light reflected by the focusing ring to the processing module; acquiring the offset of the focusing ring based on the reflected detection light by using the processing module, wherein the offset is the deviation between the central position of the focusing ring and the central position of the electrostatic chuck; The focus ring is moved based on the offset using the calibration structure to eliminate the offset.
13. The method of claim 12, wherein the processing module includes a second lens, a processing module, and a computing module, and wherein obtaining, with the processing module, the offset of the focus ring based on the reflected detection light comprises: receiving the detection light reflected by the focusing ring by using the second lens, and transmitting the detection light to the processing module; Identifying the light position of the detection light by using the processing module, and obtaining a light distance, wherein the light position reflects the position of the detection light falling on the processing module, and the light distance is the distance between the light position and the central position of the processing module; and acquiring the offset of the focusing ring based on the light ray distance by using the calculation module.
14. The method of claim 13, wherein obtaining, with the computing module, the offset of the focus ring based on the light ray distance comprises: The computing module obtains a gap between the focusing ring and the electrostatic chuck based on the light distance; Then, the calculation module obtains a first offset and a second offset based on the gap, wherein the first offset is the deviation between the center position of the focusing ring and the center position of the electrostatic chuck in the second direction, and the second offset is the deviation between the center position of the focusing ring and the center position of the electrostatic chuck in the third direction; the second direction is perpendicular to the third direction and is parallel to the plane where the electrostatic chuck is located.

Description

Etching equipment and detection method Technical Field The application relates to the technical field of semiconductors, in particular to etching equipment and a detection method. Background With the development of semiconductor devices in smaller size and higher precision, the requirements of wafer processing on dry etching technology, equipment and the like are increasing. The inductively coupled plasma etching technology (Inductively Coupled Plasma, abbreviated as ICP) has the advantages of high etching rate, good directivity, high selection ratio, high contour control precision and the like, and is widely applied to various large wafer processing factories. However, for ICP etching equipment, the centering of the focus ring, i.e., the positional deviation of the focus ring center position relative to the electrostatic chuck center position, will directly affect the wafer etch uniformity and etch rate. If the neutral difference affects the electric field and sheath distribution over the electrostatic chuck, this can lead to uneven plasma distribution over the wafer, particularly near the focus ring, affecting etch rate and uniformity at the wafer edge. Disclosure of Invention In view of the above, the present application provides an etching apparatus and a detection method, and the scheme is as follows: an etching apparatus, comprising: the etching structure is used for realizing etching of the wafer and comprises a base, an electrostatic chuck, a focusing ring and a cover ring, wherein the electrostatic chuck is positioned on the base, the cover ring surrounds the base, and the focusing ring is positioned on the cover ring and surrounds the electrostatic chuck; The detection structure comprises a light source, a first lens and a processing module, wherein the light source outputs detection light, the first lens transmits the detection light to the focusing ring and transmits the detection light reflected by the focusing ring to the processing module, and the processing module acquires the offset of the focusing ring based on the reflected detection light, wherein the offset is the deviation between the center position of the focusing ring and the center position of the electrostatic chuck; And a calibration structure that moves the focus ring based on the offset, eliminating the offset. Optionally, the cover ring is provided with N first openings circumferentially arranged around the base, N is greater than or equal to 2, the first openings extend upwards from the bottom of the cover ring along a first direction, and the first direction is parallel to the arrangement direction of the base and the electrostatic chuck; The first lens comprises N first sub-lenses which are respectively positioned in the first open holes and are opposite to the side face of the focusing ring, and the first sub-lenses are used for transmitting the detection light to the focusing ring and transmitting the detection light reflected by the focusing ring to the processing module. Optionally, the plane where the first sub-lens is located has a first included angle with the first direction, and the value range of the first included angle is 0-90 degrees, and does not include an endpoint value. Optionally, the value of the first included angle is 45 °. Optionally, the center of the first sub-lens corresponds to a preset position of the focus ring; the distance between the preset position and the top of the focusing ring is equal to the distance between the preset position and the bottom of the focusing ring. Optionally, the focusing ring is made of a reflective material to reflect the detection light; The cover ring is made of a light-transmitting material so as to transmit the detection light to the focusing ring and the processing module. Optionally, the processing module comprises a second lens, a processing module and a calculating module; The second lens comprises N second sub-lenses, the N second sub-lenses are in one-to-one correspondence with the N first sub-lenses, the detection light reflected by the focusing ring is received, and the detection light is transmitted to the processing module; The processing module comprises N linear CCD cameras which are in one-to-one correspondence with the N second sub-lenses and are used for identifying the light positions of the detection light rays so as to obtain light ray distances, the light ray positions reflect the positions of the detection light rays falling on the linear CCD cameras, and the light ray distances are the distances between the light ray positions and the central positions of the linear CCD cameras; the calculation module obtains the offset of the focusing ring based on the light ray distance. Optionally, the plane of the second sub-lens is parallel to the plane of the first sub-lens; the plane of the linear CCD camera is parallel to the plane of the second sub-lens, and the center of the linear CCD camera is opposite to the center of the second sub-lens. Optionall