TWI812930B - Carrier head and polishing device with the carrier head - Google Patents

Abstract

The present invention relates to a carrying head and a polishing device having the carrying head. The carrying head includes: a body made of non-flexible material. A plurality of concave cavities are opened in the end of the body close to the wafer to be polished, and each cavity is provided with a The vent hole is connected to the gas source; the flexible membrane is fixedly connected at the end and is suitable for contact with the wafer to be polished. By setting the body to be made of non-flexible material, it is more convenient to open multiple cavities on the body. Ventilation holes connected to the air source are provided on the cavity, making it more convenient to control the air pressure of each cavity. The end of the polished wafer is fixedly connected to the flexible film, and the flexible film is used to contact the wafer to be polished, ensuring the fit between the flexible film and the wafer to be polished. Since there is no need to set up a separate sealing mechanism between each chamber, instead The body of non-flexible material is used to directly open a concave cavity and a flexible membrane to ensure independent control of each cavity, making the structure and manufacturing process of the carrying head simpler.

Description

Carrying head and polishing device having the same

The present invention relates to the technical field of polishing in semiconductor manufacturing processes, and in particular to a carrier head and a polishing device having the carrier head.

The integrated circuit process usually refers to depositing conductors, semiconductors, and insulating layers on a specific substrate (such as a silicon-based wafer) in a certain process sequence. In the manufacturing process, CMP (Chemical Mechanical Polishing) equipment is mainly used to fully planarize the microscopically rough surface of the wafer after the film deposition process, so as to facilitate the subsequent semiconductor manufacturing process.

The chemical mechanical polishing device fixes one surface of the wafer on the carrier head through negative pressure adsorption, and rotates the station to make the other surface (the process surface) come into contact with the polishing pad on the polishing disk during the process. That is, the carrying head on it is mainly used to adsorb and apply pressure to the wafer. Carrier heads in the prior art usually use multi-layer membrane isolation chamber technology. Each chamber is divided into regions through features such as bulges and wrinkles of the membrane, and different pressure values are introduced into different chamber areas according to process requirements. Taking the load-bearing head shown in Figure 1 using a five-region chamber as an example to illustrate, the diaphragm completes the division of the five regions by forming protrusions and wrinkles on the basis of the base body, that is, the first ring-shaped sealing rib is formed through the edge. Sealed chamber 1; the second sealed chamber 2 is formed by the adjacent annular sealing ribs; the third sealed chamber 3 is formed by the adjacent annular sealing ribs inward; the third sealed chamber 3 is formed by the adjacent annular sealing ribs inward. The fourth sealing chamber 4 is formed; the fifth sealing chamber 5 is formed by the central annular sealing rib.

However, since the load-bearing head of this structure uses a flexible membrane to complete the division of the chamber, each Seals need to be installed between the chambers to prevent leakage in each chamber, making the structure more complex. And since the pressures of different chambers may be different, it is necessary to ensure that the chambers do not interfere with each other, which will bring great challenges to processing and manufacturing. difficulty.

Therefore, the technical problem to be solved by the present invention is to overcome the complex structure and difficult manufacturing process of the load-bearing head in the prior art, thereby providing a load-bearing head with a relatively simple structure and simple manufacturing process and a polishing device having the load-bearing head.

One embodiment of the present invention provides a carrying head, including: a body, the body is made of non-flexible material, and the body is provided with a plurality of cavities near the end of the product to be polished, and each cavity is provided with a ventilation hole. The vent hole is suitable for connecting to the air source; the flexible membrane is fixedly connected to the end of the body and is suitable for contacting the product to be polished. In another embodiment of the invention, the body is made of metal. In another embodiment of the present invention, the body is a disc structure, and the cavity is an annular structure. In another embodiment of the present invention, along the radial direction, from the edge of the body to the center of the body, the volume of the cavity gradually increases. In another embodiment of the present invention, the plurality of cavities have the same depth, and the bottom area of the cavities gradually increases along the edge of the body toward the center of the body. In another embodiment of the present invention, at least one of the recessed cavities is provided with a plurality of convex ribs, the convex ribs extend from the bottom of the recessed cavity in a direction close to the flexible film, and the extension length of the convex ribs is smaller than the The extended length of the cavity. In another embodiment of the invention, the flexible film is bonded to the body. In another embodiment of the invention, the flexible membrane is a rubber membrane. In another embodiment of the present invention, the carrying head further includes: an air tube located at an end of the body away from the flexible membrane. One end of the air tube is connected to the vent hole, and the other end extends out of the body and is suitable for connecting with the body. The air source is connected. In another embodiment of the invention, a sealing device is provided between the air tube and the side of the body. In another embodiment of the present invention, the carrying head further includes: a first pressure sense The sensor is arranged at the vent hole, and the first pressure sensor is arranged in one-to-one correspondence with the cavity; the controller is connected to the first pressure sensor and is suitable for controlling the pressure in the cavity. Another embodiment of the present invention relates to a polishing device, including a carrying head as in any of the above embodiments.

The technical solution provided by the present invention has the following advantages:

1. The carrying head provided by the present invention makes it more convenient to open multiple cavities on the body by configuring the main body to be made of non-flexible material. By arranging ventilation holes connected to the air source on the cavities, it is possible to make each cavity more flexible. The air pressure control is more convenient, and each cavity does not interfere with each other. The flexible film is fixedly connected to the end of the body close to the product to be polished, and the flexible film is in direct contact with the product to be polished, ensuring the fit between the flexible film and the product to be polished. Since there is no need to set up a seal between the chambers, the body of the non-flexible material is used to directly open the cavity and the flexible membrane is used to ensure the independent control of each chamber, and the cavity opened by the non-flexible body does not need to be ventilated during ventilation. They will interfere with each other, making the structure of the load-bearing head relatively simple and the manufacturing process relatively simple.

2. The carrying head provided by the present invention makes the main body simple and easy to obtain by configuring the main body to be made of metal. The processing performance is also better.

3. In the carrying head provided by the present invention, the main body is configured as a disc structure and the cavity is configured as an annular structure, making the processing of the cavity more convenient.

4. The carrying head provided by the present invention is arranged along the radial direction, from the edge of the body to the center direction, the depth of the plurality of cavities is the same, and the bottom area gradually increases, so that the volume of the cavities at the edge can be made smaller. The more precise the pressure control at the edge is, the better the fit between the flexible film at the edge and the edge of the product to be polished will be, thereby improving the polishing effect.

5. The load-bearing head provided by the present invention, by arranging convex ribs on the concave cavity, and the extension length of the convex ribs is smaller than the extension length of the concave cavity, can support the flexible film when the cavity is vacuum, avoiding The deformation of the film is large and causes damage to the product to be polished.

6. The carrying head provided by the present invention adheres the flexible film to the body, so that the flexible film and the body are fixed in a simple and reliable manner, and the volume is small.

7. In the load-bearing head provided by the present invention, the flexible membrane is configured as a rubber membrane, so that the processing is more convenient and the cost is lower.

8. The carrying head provided by the present invention can enhance the sealing effect and prevent the leakage of gas in the cavity by arranging a sealing device between the trachea and the side of the body.

9. The load-bearing head provided by the present invention sets a controller and a first pressure sensor at the ventilation hole of each cavity, so that the pressure in each cavity can be automatically and individually detected. The cavities are independent of each other and do not interfere with each other. At the same time, by arranging the first pressure sensor, the pressure inside each cavity can be controlled, and the contact pressure between the flexible film corresponding to the cavity and the product to be polished can be controlled, and the impact of different cavities on the product to be polished can be controlled. The degree of polishing of the product to be polished can be more flexibly controlled in various parts of the final product to be polished.

1: First sealed chamber

2: Second sealed chamber

3: The third sealed chamber

4: The fourth sealed chamber

5: The fifth sealed chamber

6: Ontology

7: First cavity

8:Second cavity

9: The third cavity

10:The fourth cavity

11:The fifth cavity

12:Vent hole

13:Flexible membrane

14: convex ribs

15: Trachea

16:Sealing device

17: Polishing pad

18:Gland

19:Probe

20:Spring

21:First sealing ring

22:Second sealing ring

23: Sensing area

24:wafer

In order to more clearly explain the specific embodiments of the present invention or the technical solutions in the prior art, the drawings that need to be used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are: Some embodiments of the present invention are not intended to limit the content of the present invention.

Figure 1 is a structural cross-sectional view of a carrying head in the prior art.

Figure 2 is a structural cross-sectional view of the carrying head of the present invention.

3 is a partial structural cross-sectional view of the present invention when polishing the wafer.

4 is a partial structural cross-sectional view of the present invention when adsorbing the wafer.

Figure 5 shows the monitoring method of the present invention when the wafer is not adsorbed when the wafer is adsorbed. Partial structural cutaway view of the state.

FIG. 6 is a partial structural cross-sectional view of the present invention for monitoring the adsorption state of the wafer when adsorbing the wafer.

In order to have a clearer understanding of the characteristics, content and advantages of this invention and the effects it can achieve, this invention is described in detail below in conjunction with the accompanying drawings and in the form of embodiments. The purpose of the diagrams used is only They are for illustration and auxiliary description purposes, so the proportions and configuration relationships of the attached drawings should not be interpreted to limit the patentable scope of this creation.

The term "a" or "an" used herein is used to describe the elements and components of the invention. This terminology is only for convenience of description and to give the basic concept of this creation. This recitation should be understood to include one or at least one, and the singular also includes the plural unless it is expressly stated otherwise. When used with the word "comprising" in a patent application, the term "a" can mean one or more than one. In addition, the word "or" used in this article has the same meaning as "and/or".

Unless otherwise specified, terms such as "above", "below", "up", "left", "right", "down", "body", "base", "vertical", "horizontal", "side" Spatial descriptions such as "higher", "lower", "upper", "above", and "below" indicate the direction shown in the figure. It should be understood that the spatial descriptions used herein are for illustrative purposes only, and that actual implementations of the structures described herein may be spatially configured in any relative orientation, and this limitation does not alter the advantages of embodiments of the invention. For example, in the description of some embodiments, providing that one element is "on" another element may cover situations where the former element is directly on (e.g., in physical contact with) the latter element, as well as when an element is "on" the latter element. Or a situation where multiple intervening components are located between the previous component and the following component.

As used herein, the terms "substantially", "substantially", "substantially" "of" and "appropriate" are used to describe and consider small changes. When used in connection with an event or circumstance, these terms may mean both a definite occurrence of the event or circumstance and a close approximation of the occurrence of the event or circumstance.

As shown in FIGS. 2 to 6 , this embodiment provides a carrying head, including: a body 6 and a flexible film 13 .

The body 6 is made of non-flexible material, and the end of the body 6 close to the product to be polished is provided with multiple cavities. Each cavity is provided with a ventilation hole 12, and the ventilation hole 12 is suitable for connecting to the air source; the flexible membrane 13 is fixedly connected The end of the body 6 is suitable for contact with the product to be polished.

The carrying head in this embodiment is used to adsorb and polish the wafer 24. By setting the body 6 to a non-flexible material, it is more convenient to open multiple cavities on the body 6. By setting the cavity on the cavity to connect to the gas source The ventilation hole 12 makes it easier to control the air pressure of each cavity, and the cavity does not interfere with each other. The flexible membrane 13 is fixedly connected to the end of the body 6 close to the wafer 24, and the flexible membrane 13 is used to directly contact the wafer 24. , ensuring the fit between the flexible film 13 and the wafer 24. Since there is no need to set a seal between the chambers, the body 6 of non-flexible material is used to directly open a concave cavity to ensure the independent control of each chamber, and during ventilation The cavities provided by the non-flexible body 6 will not interfere with each other, so that the structure of the carrying head is relatively simple and the manufacturing process is relatively simple.

The body 6 in this embodiment is made of metal. By configuring the body 6 to be made of metal, the body 6 is easy to obtain. The processing performance is also better. As an alternative embodiment, the body 6 can also be made of non-metallic material, or other non-flexible materials.

As shown in Figure 2, the body 6 in this embodiment has a disc structure, and the cavity has an annular structure. By configuring the body 6 as a disc structure and the cavity as an annular structure, the processing of the cavity is made more convenient. As an alternative embodiment, the cross section of the body 6 can also be square. Shape structure, the cavity is a strip structure, and a plurality of cavity are opened sequentially along the length direction of the body 6.

Along the radial direction, from the edge of the body 6 to the center of the body 6 , the volume of the cavity gradually increases. Specifically, as shown in FIG. 2 , the plurality of cavities have the same depth, and the bottom area of the cavities gradually increases along the edge of the body 6 toward the center of the body 6 . By arranging in the radial direction, from the edge of the body 6 to the center, the depths of the plurality of cavities are the same, and the bottom area gradually increases. This can make the volume of the cavities at the edges smaller, and thereby control the pressure at the edges more accurately. , thereby making the edge of the flexible film 13 and the edge of the wafer 24 more closely adhered, thereby improving the polishing effect. As a changeable implementation, the volume of each cavity may be set according to actual needs. For example, the volume of the cavity near the center may be set to be as small as the cavity at the edge.

In this embodiment, the concave cavity near the center of the body 6 is provided with convex ribs 14. The central concave cavity is provided with two convex ribs 14, and the adjacent concave cavity is provided with one convex rib 14. From the bottom of the concave cavity, Extending in a direction close to the flexible membrane 13 , the extension length of the ribs 14 is smaller than the extension length of the cavity. By arranging the convex ribs 14 on the concave cavity, and the extension length of the convex ribs 14 is smaller than the extension length of the concave cavity, the flexible membrane 13 can be supported when there is a vacuum in the cavity, and the flexible membrane 13 can be prevented from being deformed due to a large amount of deformation. Large enough to cause damage to the wafer 24 . As an alternative implementation, if space allows, the convex ribs 14 can be provided on multiple cavities; or, the convex ribs 14 on each cavity can be specifically set according to actual needs.

The flexible membrane 13 in this embodiment is a rubber membrane, such as silicone, which makes the processing more convenient and the cost lower. Moreover, the flexible film 13 is fixed on the body 6 by adhesion, which makes the fixing method of the flexible film 13 and the body 6 simple and reliable, and the volume is small. Specifically, the flexible membrane 13 is bonded to the body 6 through vulcanized rubber. In order to improve the adaptability of the flexible membrane 13 and improve the functional range of the load-bearing head, the flexible membrane 13 can also be optimized. For example, the shape of the flexible membrane 13 can be changed, such as L-shaped or Z-shaped corners, and different cavity corresponding to The thickness of the flexible membrane 13 varies. do As an alternative embodiment, the flexible membrane 13 may also be made of other rubber membranes with similar properties.

As shown in Figures 5 and 6, in order to facilitate connection with the air source, the carrying head in this embodiment further includes a trachea 15, which is located at one end of the body 6 away from the flexible membrane 13. One end of the trachea 15 is connected to the ventilation hole 12, and the other end of the trachea 15 is connected to the ventilation hole 12. One end extends out of the body 6 and is suitable for connection with the air source. The air pipe 15 protrudes from the side of the body 6, and a sealing device 16 is provided between the air pipe 15 and the body 6, which can enhance the sealing effect and prevent the leakage of gas in the cavity. Specifically, the sealing device 16 in this embodiment is a sealing stud, used to block the edge processing hole. As an alternative embodiment, the sealing device 16 may be a sealing ring, or the sealing device 16 may not be provided.

The carrying head in this embodiment further includes: a first pressure sensor, located at the ventilation hole 12, and the first pressure sensor is arranged in one-to-one correspondence with the cavity; a controller, connected to the first pressure sensor, Suitable for controlling the pressure in the cavity, wherein the carrying head may further include a second pressure sensor provided on the body 6, which includes a pressure cover 18, a probe 19, and a spring 20 provided between the pressure cover 18 and the probe 19 , sealing rings, etc. By arranging the controller and arranging the first pressure sensor at the ventilation hole 12 of each cavity, the pressure in each cavity can be automatically and individually detected, and each cavity is independent of each other. Interference, at the same time, by setting the first pressure sensor, the pressure inside each cavity can be controlled, and then the contact pressure between the flexible film 13 corresponding to the cavity and the wafer 24 can be controlled, thereby controlling different The degree of polishing of the recessed cavity for the product to be polished allows for more flexible control of the degree of polishing at various locations of the finally obtained wafer 24 . As shown in FIG. 5 , the second pressure sensor can be disposed in the body 6 . According to the exemplary embodiment of Figure 5, one end of the probe 19 of the second pressure sensor extends into the fourth cavity 10; the sensing area 23 of the second pressure sensor is fluidly connected to the trachea 15; The probe 19 of the second pressure sensor may have a flange, which abuts against the second sealing ring 22 , and the spring 20 pushes against the probe. 19. When the probe 19 is not subjected to external force, its end remains extended into the fourth cavity 10 and is approximately flush with the end of the body 6. This state is called a free state; in the free state At this time, the flange of the probe 19 and the second sealing ring 22 isolate the fluid connection between the sensing area 23 and the fourth cavity 10, that is, it is in a non-conducting state.

The load-carrying head in this embodiment is provided with five cavities as an example. From the edge to the center, they are the first cavity 7, the second cavity 8, the third cavity 9, the fourth cavity 10 and the fifth cavity. Cavity 11, as shown in Figure 3, when polishing the wafer 24, generally speaking, the cavity from the edge to the center will each apply an inflation pressure ranging from 2 to 10 psi, and the corresponding flexible film 13 of each cavity It will expand and deform under the action of pressure. The expanded flexible film 13 will act on the back of the wafer 24 and make the front of the wafer 24 closely fit with the polishing pad 17. Since the pressure values of different concave cavities are usually different, each concave cavity will have different pressure values. The deformation amount of the flexible film 13 corresponding to the cavity usually exerts different forces on the wafer 24 , which is beneficial to accurately controlling the grinding amount of each area on the front side of the wafer 24 .

As shown in FIG. 4 , during the transportation of the wafer 24 , the wafer 24 is first separated from the polishing pad 17 and closely attached to the flexible film 13 , and then negative pressure is applied to each cavity through the vent hole 12 , and each cavity corresponds to The flexible film 13 will shrink and deform under the action of negative pressure, so the shrunk flexible film 13 will form a partial vacuum with the wafer 24, and the partial vacuum will adsorb the back side of the wafer 24.

During the transportation process of the wafer 24, the adsorption state of the wafer 24 needs to be monitored in real time. In this embodiment, the monitoring is performed by comparing the pressure values of different areas, taking the second cavity 8 and the fourth cavity 10 as an example. To illustrate, as shown in Figure 5, a smaller vacuum degree (such as -2 psi) is applied to the second cavity 8 with a smaller area, and then the pressure value is disconnected from the vacuum source and maintained at pressure, and the pressure is passed through the second cavity 8. The first pressure sensor (not shown) of the cavity 8 monitors the pressure value of the second cavity 8 in real time, and at the same time applies a pressure value with a larger vacuum degree (such as - 8 psi), while keeping the area connected to the vacuum source, and monitoring whether the vacuum degree of the area is negative through the second pressure sensor (shown in the figure) at the fourth cavity 10 . When the wafer 24 is not adsorbed, the flexible film 13 is in a normal flat state, and the probe 19 of the second pressure sensor is in a free state under the action of the gland 18 and the spring 20. At the same time, the first sealing ring 21 and Under the action of the second sealing ring 22, the fourth cavity 10 and the sensing area 23 are in a non-conducting state. At this time, the pressure value difference between the second cavity 8 and the fourth cavity 10 is large. Through difference comparison, it is considered that the wafer 24 is in an unadsorbed state at this time.

As shown in Figure 6, when the wafer 24 is adsorbed, the wafer 24 and the flexible film 13 are in close contact with each other. The flexible film 13 will produce pressure deformation under the action of vacuum adsorption. The shrinkage of the flexible film 13 will cause the second The probe 19 of the second pressure sensor is in a contracted state. At this time, there will be a certain gap between the probe 19 of the second pressure sensor and the second sealing ring 22. Then the second sealing ring 22 is in a failed state and cannot function. The sealing effect is that the sensing area 23 and the fourth cavity 10 are connected to each other and are in a conductive state. Since the fourth cavity 10 is in a state of relatively large vacuum and the second cavity 8 is disconnected from the vacuum source, the fourth cavity 8 is disconnected from the vacuum source. Since the second cavity 8 is connected to the fourth cavity 10 through the air pipe 15, the vacuum value of the second cavity 8 will change greatly (from -2psi to -4psi), and the first pressure of the second cavity 8 will The sensor can detect that the wafer 24 is in an adsorbed state at this time. That is, the second sealing ring 22 keeps the sensing area 23 in a conductive state when the probe 19 is in a contracted state.

This embodiment also provides a polishing device, which includes the above-mentioned carrying head. The flexible film 13 on the carrying head contacts the wafer 24 provided on the polishing pad 17 below to frictionally polish the wafer 24 .

The above-mentioned embodiments are only for illustrating the technical ideas and characteristics of this invention. Their purpose is to enable those familiar with this art to understand the content of this invention and implement it accordingly. They should not be used to limit the patent scope of this invention. Equal changes made in accordance with the spirit revealed in this creation or Modifications should still be covered by the patent scope of this creation.

6: Ontology

7: First cavity

8:Second cavity

9: The third cavity

10:The fourth cavity

11:The fifth cavity

12:Vent hole

13:Flexible membrane

14: convex ribs

Claims (9)

A carrying head, including: a body (6), the body (6) is made of non-flexible material, and the body (6) is provided with a plurality of recessed cavities near the end of the product to be polished, and each recessed cavity is provided with a A plurality of vent holes (12), the plurality of vent holes (12) are suitable for connection with the air source; a ductile flexible membrane (13) is fixedly connected to the end of the body (6), and is suitable for connection with the air source. The product to be polished is in contact with; an air tube (15) is located at one end of the body (6) away from the flexible film (13). One end of the air tube (15) is connected to the plurality of ventilation holes (12), and the other end extends Out of the body (6), it is suitable to be connected to the air source; a plurality of first pressure sensors are provided at the plurality of vent holes (12), and the first pressure sensors are connected to the cavity One-to-one correspondence is provided; a controller is connected to the first pressure sensors and is suitable for controlling the pressure in the cavity; and at least one second pressure sensor is arranged in the body (6), The second pressure sensor includes: a probe (19), one end of which extends into one of the cavities, is substantially flush with the end of the body (6), and has a flange on it. ; A spring (20), which is sleeved on the outer edge of the probe (19), and the bottom end of the spring (20) is against the flange of the probe (19); a gland (18), It is fixed on the body (6), and the top end of the spring (20) is against the gland (18); A first sealing ring (21) is set on the outer edge of the probe (19) and is located above the flange of the probe (19). A sensing area (23) is defined on the probe (19). ) between the flange and the first sealing ring (21) and fluidly connected to the trachea; and at least one second sealing ring (22), which is sleeved on the outer edge of the probe (19) and located on the Below the flange; when the end of the probe (19) is not acted upon by external force, the end of the probe (19) remains extended into the cavities, and the sensing area (23) is in contact with the cavities. In a non-conductive state, when the end of the probe (19) is acted upon by an external force, the end of the probe (19) is in a contracted state, and the sensing area (23) and the cavity are in a conductive state. state; wherein along the radial direction, from the edge of the body (6) to the center of the body (6), the volume of the cavity gradually increases. For example, the carrying head of claim 1, wherein the body (6) is made of metal. The carrying head of claim 1, wherein the body (6) has a disc structure and the cavity has an annular structure. In the carrying head of claim 1, the depths of the plurality of cavities are the same, and the bottom area of the cavities gradually increases along the edge of the body (6) toward the center of the body (6). The load-bearing head according to any one of claims 1 to 4, wherein at least one of the concavities is provided with a plurality of convex ribs (14), and the convex ribs (14) extend from the bottom of the cavity to the side close to the flexible membrane (13). direction extension Stretch, and the extension length of the convex rib (14) is less than the extension length of the cavity. The carrying head of claim 5, wherein the flexible film (13) is bonded to the body (6). The carrying head of any one of claims 1 to 4, wherein the flexible membrane (13) is a rubber membrane. The carrying head of claim 1-4, wherein a sealing device (16) is provided between the air pipe (15) and the side of the body (6). A polishing device, which includes a carrying head according to any one of claims 1-8.