Method and apparatus for wafer bonding

1 . A wafer bonding method, comprising:

determining a first position parameter of a first alignment mark on a first wafer using a first type of optical beam, the first type of optical beam being absorbed by a region of the first wafer other than the first alignment mark;

determining a second position parameter of a second alignment mark on a second wafer using the first type of optical beam, the first type of optical beam being absorbed by a region of the second wafer other than the second alignment mark;

performing a first alignment, comprising: moving the first wafer and the second wafer to be opposite to each other by changing a relative position between the first wafer and the second wafer according to the first position parameter and the second position parameter, to align the first alignment mark with the second alignment mark;

before bonding the first wafer to the second wafer, performing a second alignment at a predetermined bonding distance, in a vertical direction, between the first wafer and the second wafer, comprising:

while maintaining the first wafer and the second wafer at the predetermined bonding distance in the vertical direction, adjusting, using a second type of optical beam, the relative position between the first wafer and the second wafer, in a plane normal to the vertical direction, to align the first alignment mark with the second alignment mark, wherein a wavelength of the second type of optical beam is larger than a wavelength of the first type of optical beam, and the second type of optical beam has better penetration capability than the first type of optical beam to pass through at least one of the first wafer or the second wafer for performing the second alignment, the first type of optical beam being non-transmissive through the first wafer and the second wafer; and

based on the second alignment using the second type of optical beam, bonding the first wafer to the second wafer.

2 . The wafer bonding method of claim 1 , wherein before performing the second alignment, the wafer bonding method further comprises:

adjusting a relative distance, in the vertical direction, between the first wafer and the second wafer until the relative distance satisfies the predetermined bonding distance.

3 . The wafer bonding method of claim 2 , wherein adjusting the relative distance between the first wafer and the second wafer until the relative distance satisfies the predetermined bonding distance comprises:

adjusting at least a position of the first wafer or a position of the second wafer in a direction perpendicular to at least one of the first wafer or the second wafer, until the relative distance between the first wafer and the second wafer satisfies the predetermined bonding distance.

4 . The wafer bonding method of claim 1 , wherein performing the second alignment comprises:

determining a relative position parameter between the first alignment mark and the second alignment mark using the second type of optical beam; and

adjusting, according to the relative position parameter, the relative position between the first wafer and the second wafer to align the first alignment mark with the second alignment mark.

5 . The wafer bonding method of claim 4 , wherein:

the relative position parameter comprises a relative position parameter between the first alignment mark and the second alignment mark in a direction parallel to at least one of the first wafer or the second wafer; and

performing the second alignment comprises:

adjusting, according to the relative position parameter, at least a position of the first wafer or a position of the second wafer in the direction parallel to the at least one of the first wafer or the second wafer to align the first alignment mark with the second alignment mark.

6 . The wafer bonding method of claim 1 , wherein performing the second alignment comprises:

adjusting at least a position of the first wafer or a position of the second wafer in a direction perpendicular to at least one of the first wafer or the second wafer; and

synchronously adjusting, using the second type of optical beam, at least the position of the first wafer or the position of the second wafer in a direction parallel to at least one of the first wafer or the second wafer, to align the first alignment mark with the second alignment mark and make a relative distance between the first wafer and the second wafer satisfy the predetermined bonding distance.

7 . The wafer bonding method of claim 1 , wherein performing the second alignment comprises:

irradiating the relative position between the first alignment mark and the second alignment mark with the second type of optical beam;

acquiring a first transmission image of the first alignment mark and the second alignment mark on a side on which the second type of optical beam emerges from the first wafer and the second wafer; and

adjusting, according to the first transmission image, the relative position between the first wafer and the second wafer to align the first alignment mark with the second alignment mark.

8 . The wafer bonding method of claim 7 , wherein the first transmission image comprises:

a first projection image of the first alignment mark and a second projection image of the second alignment mark.

9 . The wafer bonding method of claim 1 , wherein performing the second alignment comprises:

irradiating the relative position between the first alignment mark and the second alignment mark using the second type of optical beam;

acquiring a first reflection image formed by reflection of the first alignment mark and the second alignment mark on a side on which the second type of optical beam irradiates the first wafer; and

adjusting, according to the first reflection image, the relative position between the first wafer and the second wafer to align the first alignment mark with the second alignment mark.

10 . The wafer bonding method of claim 9 , wherein the first reflection image comprises:

a third projection image of the first alignment mark and a fourth projection image of the second alignment mark.

11 . The wafer bonding method of claim 1 , wherein the first alignment mark comprises a first alignment reference point, and the second alignment mark comprises a second alignment reference point;

wherein performing the first alignment comprises at least one of the following:

making a first distance between the first alignment reference point and the second alignment reference point in a first direction less than or equal to a first distance threshold; or

making a second distance between the first alignment reference point and the second alignment reference point in a second direction less than or equal to a second distance threshold;

wherein performing the second alignment comprises at least one of the following:

making a third distance between the first alignment reference point and the second alignment reference point in the first direction less than or equal to a third distance threshold; or

making a fourth distance between the first alignment reference point and the second alignment reference point in the second direction less than or equal to a fourth distance threshold;

wherein the first direction and the second direction are perpendicular to each other in a direction parallel to at least one of the first wafer or the second wafer; and

the first distance threshold is greater than the third distance threshold, and the second distance threshold is greater than the fourth distance threshold.

12 . The wafer bonding method of claim 1 , wherein determining the first position parameter of the first alignment mark on the first wafer using the first type of optical beam comprises:

irradiating the first wafer using the first type of optical beam;

acquiring a second reflection image formed by reflection of the first type of optical beam at the first alignment mark; and

determining the first position parameter according to the second reflection image.

13 . The wafer bonding method of claim 1 , wherein determining the second position parameter of the second alignment mark on the second wafer using the first type of optical beam comprises:

irradiating the second wafer using the first type of optical beam;

acquiring a third reflection image formed by reflection of the first type of optical beam at the second alignment mark; and

determining the second position parameter according to the third reflection image.

14 . The wafer bonding method of claim 1 , wherein the first position parameter is a coordinate parameter of the first wafer relative to a predetermined first coordinate system; and

the second position parameter is a coordinate parameter of the second wafer relative to a predetermined second coordinate system.

15 . The wafer bonding method of claim 1 , wherein the first type of optical beam is red light, and the second type of optical beam is infrared light.

16 . A wafer bonding apparatus, comprising:

a first bearing table, configured to hold a first wafer, wherein the first wafer is provided with at least one first alignment mark;

a second bearing table, opposite to the first bearing table, and configured to hold a second wafer, wherein the second wafer is provided with at least one second alignment mark;

a first alignment component, located on a side on which the first bearing table bears the first wafer, and configured to determine a first position parameter of the first alignment mark on the first wafer using a first type of optical beam, the first type of optical beam being absorbed by a region of the first wafer other than the first alignment mark;

a second alignment component, located on a side where the second bearing table bears the second wafer, and configured to determine a second position parameter of the second alignment mark on the second wafer using the first type of optical beam, the first type of optical beam being absorbed by a region of the second wafer other than the second alignment mark;

a mobile component, connected to the first bearing table and the second bearing table, and configured to perform a first alignment, comprising: moving the first wafer and the second wafer to be opposite to each other by changing a relative position between the first wafer and the second wafer according to the first position parameter and the second position parameter, to align the first alignment mark with the second alignment mark;

a third alignment component, located on at least a side of the first bearing table or a side of the second bearing table, and configured to, before bonding the first wafer to the second wafer, control the mobile component to perform a second alignment at a predetermined bonding distance, in a vertical direction, between the first wafer and the second wafer, comprising:

while maintaining the first wafer and the second wafer at the predetermined bonding distance in the vertical direction, adjusting, using a second type of optical beam, the relative position between the first wafer and the second wafer, in a plane normal to the vertical direction, to align the first alignment mark with the second alignment mark, wherein a wavelength of the second type of optical beam is larger than a wavelength of the first type of optical beam, and the second type of optical beam has better penetration capability than the first type of optical beam to pass through at least one of the first wafer or the second wafer for performing the second alignment, the first type of optical beam being non-transmissive through the first wafer and the second wafer; and

a bonding component, connected to the first bearing table and the second bearing table, and configured to, based on the second alignment using the second type of optical beam, bond the first wafer to the second wafer.

17 . The wafer bonding apparatus of claim 16 , wherein the first bearing table comprises at least one first opening at a position corresponding to the first alignment mark; and

the second bearing table comprises at least one second opening at a position corresponding to the second alignment mark.

18 . The wafer bonding apparatus of claim 16 , wherein the third alignment component comprises:

a first light-emitting unit, located on a side of the first bearing table or a side of the second bearing table, and configured to emit the second type of optical beam, wherein the second type of optical beam passes through the first wafer and the second wafer; and

a first receiving unit, located on another side of the first bearing table or another side of the second bearing table, which is opposite to the side on which the first light-emitting unit is located, and configured to receive the second type of optical beam passing through the first wafer and the second wafer.

19 . The wafer bonding apparatus of claim 18 , wherein the first light-emitting unit is located on a same side of the first bearing table as the first alignment component, and the first receiving unit is located on a same side of the second bearing table as the second alignment component; or

the first light-emitting unit is located on the same side of the second bearing table as the second alignment component, and the first receiving unit is located on the same side of the first bearing table as the first alignment component.

20 . The wafer bonding apparatus of claim 16 , wherein the third alignment component comprises:

a second light-emitting unit, located on a side of the first bearing table or a side of the second bearing table, and configured to emit the second type of optical beam, wherein the second type of optical beam is reflected on the first wafer and the second wafer; and

a second receiving unit, located on a same side of the first bearing table or a same side of the second bearing table as the second light-emitting unit, and configured to receive the second type of optical beam reflected on the first wafer and the second wafer.