CN115401587A

CN115401587A - Polishing head and semiconductor wafer planarization equipment

Info

Publication number: CN115401587A
Application number: CN202211190659.9A
Authority: CN
Inventors: 杨兆明; 王东洁; 曾文昌; 中原司; 张峰; 江涛; 康斌斌
Original assignee: Zhejiang Xinhui Equipment Technology Co ltd
Current assignee: Zhejiang Xinhui Equipment Technology Co ltd
Priority date: 2022-09-28
Filing date: 2022-09-28
Publication date: 2022-11-29
Anticipated expiration: 2042-09-28
Also published as: CN115401587B

Abstract

The invention discloses a polishing head and semiconductor wafer flattening equipment, which are applied to the technical field of semiconductor processing.A wafer pressurizing area and an outer ring pressurizing area which are positioned in a central area are divided on the lower surface of a driving disc; the wafer pressurizing area is provided with a first pressurizing device, the outer ring pressurizing area is provided with a second pressurizing device, and the first pressurizing device and the second pressurizing device are arranged independently; the second pressurizing device is connected with the retaining ring, and the pressure applied to the retaining ring is controlled, so that the wafer is kept from flying during wafer processing, and meanwhile, the deformation of the polishing pad is controlled, and the edge removal amount of the wafer to be polished is controlled. Through setting up first pressure device and second pressure device independent each other, the first pressure device of independent control exerts pressure to wafer fixing device to and the second pressure device of independent control exerts pressure to the retaining ring, can exert controllable pressure through wafer fixing device to the wafer alone according to the removal volume of needs to realize the control to wafer edge removal volume.

Description

Polishing head and semiconductor wafer planarization equipment

Technical Field

The invention relates to the technical field of semiconductor processing, in particular to a polishing head and semiconductor wafer flattening equipment.

Background

The chemical mechanical polishing device is mainly used for global planarization treatment of the micro rough surface of the wafer after the film deposition process so as to carry out the subsequent semiconductor process. Among them, the polishing head plays a very critical role. For a wafer, the edge removal amount control capability directly affects the edge quality of the wafer; the uniformity of the wafer pressure directly affects the flatness of the wafer. Therefore, it is an urgent problem for those skilled in the art to provide a polishing head capable of independently controlling the amount of wafer edge removal in the polishing process.

Disclosure of Invention

The invention aims to provide a polishing head which can control the edge removal amount of a wafer; another object of the present invention is to provide a semiconductor wafer planarization apparatus, which can control the edge removal amount of a wafer.

In order to solve the above technical problem, the present invention provides a polishing head, comprising a driving disk, a retaining ring and a wafer fixing device;

the lower surface of the driving disc is divided into a wafer pressurizing area positioned in a central area and an outer ring pressurizing area surrounding the wafer pressurizing area; the wafer pressurizing area is provided with a first pressurizing device, the outer ring pressurizing area is provided with a second pressurizing device, and the first pressurizing device and the second pressurizing device are arranged independently;

the second pressurizing device is connected with a retaining ring, so that when the wafer to be polished is not flapped during processing, the deformation of the polishing pad is controlled by controlling the pressure applied to the retaining ring, and the edge removal amount of the wafer to be polished is controlled; the first pressurizing device is connected with the wafer fixing device.

Optionally, the first pressurizing device includes a first flexible film located in the wafer pressurizing zone, and a wafer pressurizing channel for delivering air to the first flexible film; the second pressurizing device comprises a second flexible film positioned in the outer ring pressurizing area and an outer ring pressurizing channel used for conveying air to the second flexible film.

Optionally, the torque transmission device further comprises an external drive gear fixedly connected with the drive disc, and an internal drive gear meshed with the external drive gear; the retaining ring inner gear is positioned below the driving inner gear and fixedly connected with the driving inner gear, and the retaining ring outer gear is meshed with the retaining ring inner gear; the retaining ring inner gear is fixedly connected with the wafer fixing device, and the retaining ring outer gear is fixedly connected with the retaining ring.

Optionally, an upper limiting protrusion extending to above the external drive gear is disposed on the upper surface of the internal drive gear, and a sliding stroke gap is disposed between the upper limiting protrusion and the external drive gear.

Optionally, the wafer fixing device is provided with a lower limit protrusion extending to a position below the retaining ring outer gear, and a sliding stroke gap is formed between the lower limit protrusion and the retaining ring outer gear.

Optionally, a pressed ring is fixedly connected to the lower surface of the second pressing device, the outer retainer ring is fixedly connected to the lower surface of the pressed ring, the fixed retainer ring is fixedly connected to the lower surface of the outer retainer ring, and the fixed retainer ring is fixedly connected to the lower surface of the fixed retainer ring.

Optionally, the lower surface of the wafer fixing device is provided with a back film, and the wafer fixing device is further provided with a device for conveying air between the back film and the wafer to be polished and forming an air layer between the wafer and the back film to compensate for thickness variation of the back film.

Optionally, the back pressure channel includes a plurality of output ports, and the output ports are uniformly distributed in the area where the back membrane is located.

Optionally, the back pressure channel is further used for vacuum-pumping and adsorbing the wafer to be polished.

The invention also provides semiconductor wafer planarization equipment which comprises the polishing head.

The invention provides a polishing head, which comprises a driving disc, a retaining ring and a wafer fixing device, wherein the driving disc is fixed on the wafer fixing device; the lower surface of the driving disc is divided into a wafer pressurizing area positioned in the central area and an outer ring pressurizing area surrounding the wafer pressurizing area; the wafer pressurizing area is provided with a first pressurizing device, the outer ring pressurizing area is provided with a second pressurizing device, and the first pressurizing device and the second pressurizing device are arranged independently; the second pressurizing device is connected with the retaining ring, and the edge removal amount of the wafer to be polished is controlled by controlling the pressure applied to the retaining ring; the first pressure device is connected with a wafer fixing device.

Through setting up first pressure device and second pressure device independent of each other, the first pressure device of independent control exerts pressure to wafer fixing device to and the second pressure device of independent control exerts pressure to the retaining ring, can exert controllable pressure to the wafer through wafer fixing device alone according to the marginal removal volume that needs, and exert controllable pressure to the polishing pad through the retaining ring alone to realize the control to wafer marginal removal volume.

The invention also provides semiconductor wafer planarization equipment, which has the beneficial effects and is not repeated herein.

Drawings

In order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is a schematic diagram illustrating a polishing head according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a particular polishing head through which embodiments of the present invention may be passed;

FIG. 3 is a schematic diagram of a prior art polishing head;

fig. 4 is a schematic structural diagram of another specific polishing head according to an embodiment of the present invention.

In the figure: 1. the polishing device comprises a driving disk, 2, a driving flange, 3, a retaining ring, 4, a first pressurizing device, 5, a second pressurizing device, 6, a wafer pressurizing channel, 7, an outer ring pressurizing channel, 8, a driving outer gear, 9, a driving inner gear, 10, a retaining ring inner gear, 11, a retaining ring outer gear, 12, an upper limiting bulge, 13, a lower limiting bulge, 14, a sliding stroke gap, 15, a pressed ring, 16, a retaining ring fixing ring, 17, a pressed plate, 18, a pressurized plate, 19, a back membrane, 20, a wafer to be polished, 21, a back pressure channel, 22, an outer shield, 23, an inner shield and 24 air layers.

Detailed Description

The core of the invention is to provide a polishing head. In the prior art, the edge removal amount of the wafer is often difficult to control, and the focus in the prior art is on how to make the wafer uniformly stressed, and the stress is usually applied integrally. However, the polishing head not only generates pressure on the wafer, but also generates pressure on the polishing pad around the wafer during polishing. The integrated pressure application causes the edge removal amount of the wafer to be difficult to adjust, and the edge removal amount cannot be adjusted according to different task requirements.

The polishing head provided by the invention comprises a driving disc, a retaining ring and a wafer fixing device; the lower surface of the driving disc is divided into a wafer pressurizing area positioned in a central area and an outer ring pressurizing area surrounding the wafer pressurizing area; the wafer pressurizing area is provided with a first pressurizing device, the outer ring pressurizing area is provided with a second pressurizing device, and the first pressurizing device and the second pressurizing device are arranged independently; the second pressurizing device is connected with the retaining ring, and the edge removal amount of the wafer to be polished is controlled by controlling the pressure applied to the retaining ring; the first pressure device is connected with a wafer fixing device.

In order that those skilled in the art will better understand the disclosure, reference will now be made in detail to the embodiments of the disclosure as illustrated in the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a polishing head according to an embodiment of the present disclosure.

Referring to fig. 1, in the embodiment of the present invention, the polishing head includes a driving disk 1, a retaining ring 3, and a wafer fixing device; the lower surface of the driving disc 1 is divided into a wafer pressurizing area positioned in a central area and an outer ring pressurizing area surrounding the wafer pressurizing area; the wafer pressurizing area is provided with a first pressurizing device 4, the outer ring pressurizing area is provided with a second pressurizing device 5, and the first pressurizing device 4 and the second pressurizing device 5 are arranged independently; the second pressurizing device 5 is connected with the retaining ring 3, and when the wafer to be polished is kept not to fly during processing, the deformation of the polishing pad is controlled by controlling the pressure applied to the retaining ring 3, so that the edge removal amount of the wafer 20 to be polished is controlled; the first pressurizing device 4 is connected with a wafer fixing device.

The driving disk 1 is a disk-shaped structure for applying rotation to the wafer 20 to be polished to provide driving force, and in the embodiment of the present invention, the remaining structures of the polishing head are generally disposed on one side of the lower surface of the driving disk 1, and the upper surface of the driving disk 1 is generally disposed with the driving flange 2. The lower surface of the drive plate 1 is divided into a wafer pressing region located in the central region and an outer ring pressing region surrounding the wafer pressing region, the outer ring pressing region is generally annular, and the wafer pressing region is located in the inner side of the outer ring pressing region. The above-mentioned wafer pressing region corresponds to the wafer 20 to be polished, and the outer ring pressing region corresponds to the retainer ring 3.

The wafer pressurizing area is provided with a first pressurizing device 4, and the outer ring pressurizing area is provided with a second pressurizing device 5, wherein the first pressurizing device 4 and the second pressurizing device 5 need to be separated from each other and controlled independently, i.e. the first pressurizing device 4 and the second pressurizing device 5 are arranged independently. The first pressure device 4 is used for providing downward pressure, the first pressure device 4 is connected with a wafer fixing device, the wafer 20 to be polished is fixed by the wafer fixing device in the using process, and the corresponding first pressure device 4 can apply downward pressure to the wafer 20 to be polished.

The above-mentioned second pressure means 5 can also be used for providing a downward pressure, which second pressure means 5 are fixedly connected to the retaining ring 3. The retaining ring 3 presses against the polishing pad at the edge of the wafer 20 to be polished during use, so that the second pressing device 5 can apply downward pressure to the polishing pad at the edge of the wafer 20 to be polished. Besides the retaining ring 3 is used for keeping the wafer to be polished from flying during processing, different deformation quantities can be generated on the polishing pad by applying different pressures to the polishing pad through the retaining ring 3, and the different deformation quantities can cause different edge removal quantities of the wafer to be polished. That is, by controlling the pressure applied to the retainer ring 3, the deformation of the polishing pad can be controlled to control the edge removal amount of the wafer 20 to be polished. Therefore, by controlling the pressure applied to the polishing pad by the retainer ring 3 by the second pressing device 5, the amount of deformation generated by the polishing pad can be controlled, thereby achieving control of the edge removal amount of the wafer 20 to be polished. The amount of edge removal of the wafer 20 to be polished is thus controlled in the embodiment of the present invention by controlling the pressure applied to the retainer ring 3.

In the embodiment of the present invention, the first pressurizing device 4 includes a first flexible film located in the wafer pressurizing area, and a wafer pressurizing passage 6 for supplying air to the first flexible film; the second pressurizing means 5 comprises a second flexible membrane located in the outer ring pressurizing zone, and an outer ring pressurizing channel 7 for feeding air to the second flexible membrane.

In particular, in embodiments of the invention, the flexible membrane may be inflated by supplying compressed air, i.e. air pressure, to the flexible membrane, thereby generating a downward force. Specifically, the first pressing device 4 located in the wafer pressing area is a first flexible film, and the second pressing device 5 located in the outer ring pressing area is a second flexible film. The wafer pressure channel 6 extends from the drive flange 2 to the first flexible film through the inside of the drive plate 1, and the corresponding outer ring pressure channel 7 extends from the drive flange 2 to the second flexible film through the inside of the drive plate 1. Of course, the wafer pressing passage 6 and the outer ring pressing passage 7 may be provided in other manners, and are not limited thereto. Because the driving disc 1 is divided into the wafer pressurizing area and the outer ring pressurizing area, and the wafer pressurizing passage 6 and the outer ring pressurizing passage 7 are arranged in the driving disc 1, the driving disc 1 can be of a split structure or an integrated structure, wherein the integrated structure can enable the driving disc 1 to have higher structural strength, and the split structure can facilitate maintenance of the driving disc 1. The structure of the above-described drive disc 1 is determined on a case-by-case basis, and is not particularly limited herein.

According to the polishing head provided by the embodiment of the invention, the first pressurizing device 4 and the second pressurizing device 5 which are independent from each other are arranged, the first pressurizing device 4 is controlled to apply pressure to the wafer fixing device independently, the second pressurizing device 5 is controlled to apply pressure to the retaining ring 3 independently, controllable pressure can be applied to the wafer through the wafer fixing device independently according to the required edge removal amount, and controllable pressure is applied to the polishing pad through the retaining ring 3 independently, so that the wafer edge removal amount can be controlled.

The detailed structure of a polishing head according to the present invention will be described in detail in the following embodiments of the present invention.

Referring to fig. 2, fig. 2 is a schematic structural diagram of a polishing head according to an embodiment of the present disclosure.

The embodiment of the present invention is further limited in structure on the basis of the above embodiment of the present invention, which is different from the above embodiment of the present invention. The rest of the contents are already described in detail in the above embodiments of the present invention, and are not described herein again.

Referring to fig. 2, in the embodiment of the present invention, the polishing head further includes a torque transmission device, the torque transmission device includes an external drive gear 8 fixedly connected to the drive disk 1, and an internal drive gear 9 engaged with the external drive gear 8; a retaining ring internal gear 10 fixedly connected with the driving internal gear 9 and a retaining ring external gear 11 engaged with the retaining ring internal gear 10, which are positioned below the driving internal gear 9; the retaining ring inner gear 10 is fixedly connected with the wafer fixing device, and the retaining ring outer gear 11 is fixedly connected with the retaining ring 3. The fixed connection is typically a fastening connection.

The torque transmission device is used for transmitting torque to the retaining ring 3 and the wafer fixing device, so as to drive the wafer 20 to be polished to rotate. Specifically, the side on which the driving disk 1 is located may be extended downward to form an annular end portion fixedly connected to the external driving gear 8, and the external driving gear 8 may be fixedly connected to the annular end portion. The driving internal gear 9 meshes with the driving external gear 8, so that torque can be transmitted to the driving internal gear 9. The retaining ring internal gear 10 is normally positioned below the driving internal gear 9, and the retaining ring internal gear 10 is fixedly connected with the lower surface of the driving internal gear 9, so that nine torques can be transmitted to the retaining ring internal gear 10; while retaining the ring gear 10 in fixed connection with the wafer fixture to transmit torque to the wafer fixture. The retaining ring internal gear 10 also intermeshes with the retaining ring external gear 11, while the retaining ring external gear 11 is fixedly connected to the retaining ring 3, thereby transmitting torque to the retaining ring 3. Normally, the retainer ring external gear 11 is located below the drive external gear 8. In the embodiment of the invention, the torque has the same transmission path before being transmitted to the retaining ring internal gear 10, namely, the driving flange 2, the driving disc 1, the driving external gear 8, the driving internal gear 9, the retaining ring internal gear 10; then the torque is divided into two paths, wherein one path is the retaining ring internal gear 10, the fixing device and the wafer 20 to be polished; the other path is retaining ring internal gear 10-retaining ring external gear 11-retaining ring 3.

Specifically, in the embodiment of the present invention, the upper surface of the internal drive gear 9 is provided with the upper limit projection 12 extending above the external drive gear 8, and the sliding stroke gap 14 is provided between the upper limit projection 12 and the external drive gear 8. The upper limit protrusion 12 may have a ring shape, thereby forming an upper limit flange structure. The upper limit projection 12 extends above the external drive gear 8, so that the internal drive gear 9 can be hung inside the external drive gear 8 to mesh with the external drive gear 8.

The sliding stroke gap 14 formed between the upper limit protrusion 12 and the external driving gear 8 is specifically used for realizing floating self-adaptation of the wafer fixing device when applying pressure to the wafer and pressing the wafer on the polishing pad. When polishing the wafer 20 to be polished, the wafer is pressed against the surface of a polishing pad, which is specifically disposed on the surface of a polishing pad. When the polishing head presses the wafer 20 to be polished on the polishing disc, the wafer fixing device can float up and down in the sliding stroke gap 14, so that the verticality error between the polishing head and the polishing disc can be eliminated through the sliding stroke gap 14.

Accordingly, in the embodiment of the present invention, the wafer fixing device is provided with the lower limit protrusion 13 extending below the outer retainer ring gear 11, and a sliding stroke gap 14 is provided between the lower limit protrusion 13 and the outer retainer ring gear 11. The lower limit projection 13 may have an annular shape, and the lower limit projection 13 extends below the retainer ring outer gear 11.

Similar to the above-described sliding stroke gap 14 formed between the upper limit projection 12 and the external drive gear 8, the sliding stroke gap 14 formed between the lower limit projection 13 and the external retainer ring gear 11 is also used to achieve vertical floating between the component corresponding to the wafer pressing region and the component corresponding to the outer ring pressing region, so that the perpendicularity error between the polishing head and the polishing platen can be eliminated by the above-described sliding stroke gap 14. The first pressurizing device 4, the wafer fixing device, the driving inner gear 9 and the retaining ring inner gear 10 are generally wafer pressurizing zone corresponding components, and the rest of the components, including the second pressurizing device 5, the subsequent pressure receiving ring 15, the driving outer gear 8, the retaining ring outer gear 11, the retaining ring fixing ring 16 and the retaining ring 3 are outer ring pressurizing zone corresponding components.

In the embodiment of the present invention, the pressure receiving ring 15 is fixedly connected to the lower surface of the second pressing device 5, the external retainer ring 11 is fixedly connected to the lower surface of the pressure receiving ring 15, the retainer ring fixing ring 16 is fixedly connected to the lower surface of the external retainer ring 11, and the retainer ring 3 is fixedly connected to the lower surface of the retainer ring fixing ring 16. Therefore, the path for the second pressurizing device 5 to apply pressure to the retaining ring 3 is specifically as follows: the second pressing device 5, the pressure receiving ring 15, the retainer outer gear 11, the retainer fixed ring 16, and the retainer ring 3.

In the embodiment of the present invention, the wafer fixing device includes a pressure receiving plate 17, a pressure applying plate 18 and a back film 19, wherein the pressure receiving plate 17 is fixedly connected to the lower surface of the first pressure device 4, the pressure applying plate 18 is fixedly connected to the lower surface of the pressure receiving plate 17, and the back film 19 is fixedly connected to the lower surface of the pressure applying plate 18. And the wafer 20 to be polished is adsorbed on the surface of the back film 19 during polishing. Typically, the outside of the above-mentioned drive disc 1 may be provided with an outer shroud 22 extending downward, and the retaining ring fixing ring 16 may be provided with an inner shroud 23 extending upward, and typically the inner shroud 23 will be located inside the outer shroud 22.

According to the polishing head provided by the embodiment of the invention, the sliding stroke gap 14 formed can eliminate the verticality error between the polishing head and the polishing disk.

Referring to fig. 3 and 4, fig. 3 is a schematic structural diagram of a polishing head in the prior art; FIG. 4 is a schematic diagram of another embodiment of a polishing head according to the present disclosure.

Referring to fig. 3 and 4, in the embodiment of the present invention, the lower surface of the wafer fixing device is provided with a back film 19, and the wafer fixing device is further provided with a device for delivering air between the back film 19 and the wafer 20 to be polished, and forming an air layer 24 between the wafer and the back film to compensate for the thickness variation of the back film.

The air layer 24 is typically transmitted through the back pressure channel 21, and the back pressure channel 21 typically extends from the inside of the drive flange 2, through the wafer fixture to the back membrane 19. Since the back film 19 may have unevenness, the uneven thickness of the back film 19 may cause uneven pressure applied to the wafer 20 to be polished during polishing. The output port of the back pressure channel 21 at least extends to the back film 19, and can deliver compressed air, i.e. air pressure, to the time between the back film 19 and the wafer 20 to be polished, so as to form an air layer 24 between the back film 19 and the wafer 20 to be polished, and the air layer 24 can compensate for the gap formed between the back film 19 and the wafer 20 to be polished due to the uneven thickness of the back film 19, thereby enabling the wafer 20 to be polished to be uniformly pressurized when the wafer 20 to be polished is pressurized.

In general, the back pressure channel 21 usually has a plurality of output ports, and the output ports are uniformly distributed in the area of the back film 19, so that the air layer 24 can be uniformly formed. Different from the wafer pressurizing passage 6 and the outer ring pressurizing passage 7, the back pressure passage 21 can also pump air to form a vacuum environment for adsorption and supply liquid including pure water for cleaning and cooling. Specifically, the back pressure channel 21 is also used for vacuum suction of the wafer 20 to be polished. That is, in the embodiment of the present invention, when the polishing head needs to adsorb the wafer 20 to be polished, the back pressure channel 21 may be used to vacuumize the space between the wafer 20 to be polished and the back film 19 for vacuum adsorption, so as to fix the wafer 20 to be polished while moving the wafer 20 to be polished. Accordingly, the above-mentioned air pressure transmitted through the back pressure channel 21 can also be used for breaking the vacuum. The pure water supplied through the back pressure channel 21 can push away the wafer 20 to be polished attached to the back film 19 after breaking the vacuum, and clean the through holes of the pressure plate 18 and the back film 19.

The working time sequence of the polishing head provided by the embodiment of the invention is as follows: the polishing head moves to a loading position, the polishing head descends, and the back pressure channel 21 is opened in vacuum in a pipeline to adsorb the wafer 20 to be polished; after the wafer is adsorbed on the polishing head, the polishing head rises, moves to a processing position and then descends, and is attached to a polishing pad on the polishing disk through self-adaptive floating of the outer driving gear 8, the inner driving gear 9, the inner retaining ring gear 10 and the outer retaining ring gear 11 on the basis of the sliding stroke gap 14; then closing vacuum in the backpressure channel 21 and simultaneously opening air pressure to break vacuum, then starting to rotate the wafer 20 to be polished, pressurizing the wafer 20 to be polished through the first pressurizing device 4 while rotating, simultaneously pressurizing the retaining ring 3 through the second pressurizing device 5, and simultaneously opening the air pressure in the backpressure channel 21 to polish the wafer 20 to be polished until polishing is finished; after polishing, stopping rotation, closing the wafer to pressurize, pressurizing the outer ring, closing the air pressure in the backpressure channel 21, and simultaneously opening the wafer to be adsorbed in vacuum; and the rear polishing head rises to move to an unloading position, the polishing head descends, the pure water is opened while the vacuum in the backpressure channel 21 is closed, the wafer is pushed away and is closed after the unloading is finished, the pure water in the pipeline is blown off by opening the air pressure, and the whole process of polishing the wafer 20 to be polished once is finished.

According to the polishing head provided by the embodiment of the invention, the air layer 24 can be formed through the backpressure channel 21, the problem of uneven stress caused by uneven thickness of the back film 19 is solved, the thickness change of the back film 19 is solved, and meanwhile, the transportation of the wafer 20 to be polished can be facilitated through vacuum adsorption.

The polishing head in the embodiment of the invention has several important characteristics:

first, the wafer is pressurized by the first pressurizing device 4 using a pressurizing platen, and the material of the platen is SUS (stainless steel) or Ceramics.

Second, a backing film 19 (made of commercially available nonwoven fabric) is interposed between the pressure plate 18 and the wafer 20 to be polished, and serves to prevent the pressure plate from damaging the silicon wafer. Then, holes having a diameter of 1mm or less are uniformly drilled in the back film 19, and air or vacuum is exhausted from the holes to assist the holding and releasing of the wafer 20 to be polished during the handling.

Thirdly, by blowing a small amount of air from the holes provided in the back film 19, the thickness variation of the backing material can be eliminated, and the silicon wafer can be uniformized when being pressurized, thereby improving the processing accuracy.

Fourthly, in order to prevent the polished wafer 20 from flying during processing, the outer ring is provided with a retaining ring 3 in a pressing way; further, the amount of deformation of the polishing pad can be controlled by pressing alone, so that a single edge (roll-off) of the edge of the wafer can be prevented.

Fifthly, the gear is used for transmitting torque, can slide up and down when meshed, has self-adaptability, and can prevent the influence of the perpendicularity error between the shaft and the polishing disc on the processing precision.

The invention also provides semiconductor wafer planarization equipment, which comprises the polishing head provided by any one of the embodiments of the invention. For the rest of the structure of the semiconductor wafer planarization apparatus, reference may be made to the prior art, and further description thereof is omitted here.

Because the polishing head provided by the embodiment of the invention is provided with the first pressure device 4 and the second pressure device 5 which are independent of each other, the first pressure device 4 is controlled to apply pressure to the wafer fixing device independently, and the second pressure device 5 is controlled to apply pressure to the retaining ring 3 independently, so that controllable pressure can be applied to the wafer by the wafer fixing device independently according to the required edge removal amount, and controllable pressure can be applied to the polishing pad by the retaining ring 3 independently, and the control of the wafer edge removal amount is realized. Therefore, the semiconductor wafer flattening equipment provided by the embodiment of the invention can also realize the control of the edge removal amount of the wafer.

The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising one of 8230; \8230;" 8230; "does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.

The above description provides a polishing head and a semiconductor wafer planarization apparatus according to the present invention. The principles and embodiments of the present invention have been described herein using specific examples, which are presented only to assist in understanding the method and its core concepts of the present invention. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. A polishing head is characterized by comprising a driving disc, a retaining ring and a wafer fixing device;

the second pressurizing device is connected with a retaining ring, so that when the wafer to be polished is not subjected to flying during processing, the deformation of the polishing pad is controlled by controlling the pressure applied to the retaining ring, and the edge removal amount of the wafer to be polished is controlled; the first pressurizing device is connected with the wafer fixing device.

2. The polishing head as set forth in claim 1 wherein the first pressurizing means comprises a first flexible membrane located in the wafer pressurizing zone, and a wafer pressurizing passage for delivering air to the first flexible membrane; the second pressurizing device comprises a second flexible film positioned in the outer ring pressurizing area and an outer ring pressurizing channel used for conveying air to the second flexible film.

3. The polishing head according to claim 1, further comprising a torque transmission device, wherein the torque transmission device comprises an external drive gear fixedly connected with the drive disk, and an internal drive gear intermeshed with the external drive gear; the retaining ring inner gear is positioned below the driving inner gear and fixedly connected with the driving inner gear, and the retaining ring outer gear is meshed with the retaining ring inner gear; the retaining ring inner gear is fixedly connected with the wafer fixing device, and the retaining ring outer gear is fixedly connected with the retaining ring.

4. The polishing head according to claim 3, wherein an upper surface of the inner drive gear is provided with an upper limit projection extending above the outer drive gear, and a sliding stroke gap is provided between the upper limit projection and the outer drive gear.

5. The polishing head as claimed in claim 4, wherein the wafer fixing device is provided with a lower limit bulge extending below the outer retaining ring gear, and a sliding stroke clearance is provided between the lower limit bulge and the outer retaining ring gear.

6. The polishing head according to claim 5, wherein a pressure receiving ring is fixedly connected to a lower surface of the second pressurizing device, the outer retaining ring is fixedly connected to a lower surface of the pressure receiving ring, a retaining ring fixing ring is fixedly connected to a lower surface of the outer retaining ring, and the retaining ring is fixedly connected to a lower surface of the retaining ring fixing ring.

7. The polishing head according to claim 1, wherein the lower surface of the wafer holder is provided with a back film, and the wafer holder is further provided with a mechanism for feeding air between the back film and the wafer to be polished to form an air layer with the wafer to compensate for the thickness variation of the back film.

8. The polishing head as set forth in claim 7 wherein the back pressure channel comprises a plurality of output ports, the output ports being evenly distributed over the area of the backing film.

9. The polishing head as set forth in claim 7 wherein the back pressure channel is further adapted to vacuum chuck the wafer to be polished.

10. A semiconductor wafer planarization apparatus, comprising the polishing head as recited in any one of claims 1 to 9.