CN-122008068-A - Wafer grinding method and device based on acoustic emission signals

CN122008068ACN 122008068 ACN122008068 ACN 122008068ACN-122008068-A

Abstract

The invention belongs to the field of wafer processing, and discloses a wafer grinding method based on acoustic emission signals, which can avoid quality defects of a ground wafer, enables a preset wafer dome to be propped against a basic grinding surface, grinds the preset wafer through relative rotation of the basic grinding surface and the preset wafer, acquires the acoustic emission signals of the preset wafer in real time, adjusts propping force to the preset wafer based on the acoustic emission signals, and enables a grinding entity to prop against the preset wafer, an acoustic emission sensor is embedded in the grinding entity, the grinding entity is formed by matching a plurality of grinding sub-entities respectively corresponding to different radial directions of the preset wafer, and adjacent grinding sub-entities can relatively move along the vertical direction, so that the plurality of grinding sub-entities correspondingly exert different propping forces in the radial directions of the preset wafer. The invention also discloses a wafer grinding device which is used for the wafer grinding method in real time.

Inventors

FENG SHAOJIE
WU SHUJING
WANG DAZHONG
WANG TONGYU
CHEN JIAPENG

Assignees

上海工程技术大学

Dates

Publication Date: 20260512
Application Date: 20260330

Claims (10)

1. The wafer grinding method based on the acoustic emission signal is used for single-sided grinding of a preset wafer and is characterized in that: the preset wafer dome is propped against a basic grinding surface, and the preset wafer is ground through the relative rotation of the basic grinding surface and the preset wafer; acquiring an acoustic emission signal of the preset wafer in real time, adjusting the propping force to the preset wafer based on the acoustic emission signal, The grinding entity is abutted against the preset wafer, an acoustic emission sensor is embedded in the grinding entity, the grinding entity is formed by matching a plurality of grinding sub-entities which respectively correspond to different radial directions of the preset wafer, and adjacent grinding sub-entities can relatively move along the vertical direction, so that the plurality of grinding sub-entities correspondingly apply different abutting forces in the radial directions of the preset wafer.
2. The acoustic emission signal based wafer grinding method of claim 1, wherein: the nesting and matching of the grinding fruiting bodies are realized through sliding grooves and protruding blocks extending in the vertical direction.
3. The acoustic emission signal based wafer grinding method of claim 1, wherein: wherein the grinding entity is enabled to rotate relative to the preset wafer.
4. The acoustic emission signal based wafer grinding method of claim 3, wherein: The top of the grinding entity is provided with a propping loading plate, so that the propping loading plate is rotationally coupled with the grinding entity, the propping loading plate and the grinding entity can move relatively along the vertical direction, a plurality of propping springs are arranged between the propping loading plate and the grinding entity, the propping springs respectively correspond to the grinding sub-entities, and the elasticity coefficients of the propping springs are different.
5. The acoustic emission signal based wafer grinding method of claim 3, wherein: the grinding device comprises a grinding body, a driving rotating shaft, a conductive slip ring, a transmitting sensor and an external control end, wherein the driving rotating shaft is used for driving the grinding body to rotate, the conductive slip ring is sleeved on the driving rotating shaft, and the transmitting sensor is electrically connected with the external control end through the conductive slip ring.
6. A wafer polishing apparatus based on an acoustic emission signal for carrying out the wafer polishing method according to any one of claims 1 to 5, comprising a polishing base and a polishing base rotatably provided on the polishing base, characterized by further comprising: the grinding body is provided with a containing channel which extends along the vertical direction and is open at two ends, A signal generating component which is inserted and arranged in the accommodating channel and comprises the acoustic emission sensor, The fixed bracket is arranged on the grinding base and is positioned near the grinding base plate, The execution assembly comprises a driving air cylinder, a driving motor, the propping loading plate, the propping spring and the conductive slip ring which are all arranged on the fixed bracket, wherein the air cylinder output part of the driving air cylinder props against the propping loading plate along the vertical direction, the driving rotating shaft is the output shaft of the driving motor, The base grinding surface is the upper surface of the grinding base, the number of the accommodating channels and the number of the signal generating components are multiple, and the accommodating channels are correspondingly formed in the grinding fruiting bodies.
7. The acoustic emission signal based wafer grinding apparatus of claim 6, wherein: Wherein the fixed bracket is provided with a motor mounting seat and a cylinder mounting seat, the motor mounting seat, the propping loading plate and the grinding entity are sequentially distributed from top to bottom along the vertical direction, The driving cylinder is arranged on the cylinder mounting seat, the driving motor is arranged on the motor mounting seat, and the cylinder output part passes through the cylinder mounting seat and the motor mounting seat.
8. The acoustic emission signal based wafer grinding apparatus of claim 7, wherein: Wherein the cylinder output part is provided with an output rod part, a transition plate part and a pressing rod part which are integrally and continuously arranged along the vertical direction, The output rod part passes through the cylinder mounting seat, the pressing rod part passes through the motor mounting seat, the pressing rod part is provided with a free end propped against the propping loading plate, and the free end is in point contact with the propping loading plate through an arc surface.
9. The acoustic emission signal based wafer grinding apparatus of claim 6, wherein: Wherein the conductive slip ring comprises a stator ring part and a rotor ring part which are arranged from outside to inside, the rotor ring part is fixedly sleeved on the driving rotating shaft, the stator ring part is fixedly arranged on the motor mounting seat through a shifting fork, The rotor ring part is connected with the acoustic emission sensor through a signal wire, and the stator ring part is electrically connected with the external control end.
10. The acoustic emission signal based wafer grinding apparatus of claim 6, wherein: wherein the signal generating component further comprises a fixed plug, a pre-tightening spring and an acoustic wave guide post, The fixed choke plug, the pre-tightening spring, the acoustic emission sensor and the acoustic wave guide pillar are sequentially abutted towards the preset wafer along the vertical direction, the bottom end of the acoustic wave guide pillar is abutted with the preset wafer, The fixed plug is detachably arranged on the top surface of the grinding entity through an assembling flange at the top end, The fixing plug is provided with a wire passing through hole which opens the accommodating channel to the outside, and the acoustic emission sensor is routed through the wire passing through hole.

Description

Wafer grinding method and device based on acoustic emission signals Technical Field The invention belongs to the field of wafer processing, and particularly relates to a wafer grinding method and device based on acoustic emission signals. Background Wafer grinding is an important process for realizing wafer thickness control and global planarization in the semiconductor manufacturing process, and the processing quality directly influences the yield of subsequent polishing, photoetching and packaging processes. At present, in the actual grinding process, a wafer dome is abutted against a basic grinding surface by applying a preset pressure to the whole wafer, and the wafer and the basic grinding surface are enabled to rotate relatively, so that a grinding interface is formed between the wafer and the basic grinding surface, the applied pressure is a key technological parameter for determining the grinding removal rate, the surface quality and the wafer integrity of the wafer in the grinding process, the existing wafer grinding equipment obtains grinding information based on signals such as motor current, spindle vibration and the like in the aspects of pressure detection and adjustment, and adjusts the preset pressure based on the information so as to adjust the grinding state of the wafer. However, the defects of the implementation are that the signals such as the motor current, the spindle vibration and the like are difficult to accurately identify the situation of local grinding abnormality on the wafer in time, uneven thickness and edge damage of the wafer after grinding are not caused, and the relative rotation linear speeds of the base grinding surface to the wafer are different along the radial direction of the wafer on a grinding interface, so that the wafer has different grinding efficiencies at different positions in the radial direction, namely different parts. In summary, the above two aspects make it difficult to avoid the quality defect of the finished product of the polished wafer. Disclosure of Invention Aiming at the defects of the prior art, the invention provides the wafer grinding method and the device based on the acoustic emission signal, which not only can timely and accurately identify the abnormal local grinding condition on the wafer, but also can adapt to the characteristic that the wafer has different grinding efficiency in the radial direction to apply a plurality of different pressures, thereby avoiding the quality defect of the ground wafer. In order to achieve the above purpose, the present invention provides the following technical solutions: A wafer grinding method based on acoustic emission signals is used for carrying out single-sided grinding on a preset wafer and is characterized in that the preset wafer is propped against a basic grinding surface, the preset wafer is ground through relative rotation of the basic grinding surface and the preset wafer, acoustic emission signals of the preset wafer are obtained in real time, propping force on the preset wafer is adjusted based on the acoustic emission signals, an acoustic emission sensor is embedded in a grinding body through propping the preset wafer by the grinding body, the grinding body is formed by matching a plurality of grinding sub-bodies which respectively correspond to different radial directions of the preset wafer, and adjacent grinding sub-bodies can move relatively along the vertical direction, so that the plurality of grinding sub-bodies correspondingly exert different propping forces in the radial directions of the preset wafer. Preferably, the nesting fit of the grinding bodies is achieved by means of a chute, a projection extending in a vertical direction. Preferably, the abrasive body is caused to rotate relative to the predetermined wafer. Further, a propping loading plate is arranged above the grinding entity, so that the propping loading plate is rotationally coupled with the grinding entity, the propping loading plate and the grinding entity can move relatively along the vertical direction, a plurality of propping springs are arranged between the propping loading plate and the grinding entity, the plurality of propping springs respectively correspond to the plurality of grinding sub-entities, and the elasticity coefficients of the plurality of propping springs are different. Further, a driving rotating shaft for driving the grinding entity to rotate is arranged, a conductive slip ring is sleeved on the driving rotating shaft, and the emission sensor is electrically connected with an external control end through the conductive slip ring. The wafer grinding device based on the acoustic emission signals is used for implementing the wafer grinding method and comprises a grinding base and a rotatable grinding base plate arranged on the grinding base, and further comprises a grinding entity, wherein the grinding entity is provided with a containing channel which extends along the vertical direction and is