TWI540674B - Electrostatic chuck, chamber and electrostatic chuck production method - Google Patents

Description

Electrostatic chuck, chamber and electrostatic chuck manufacturing method

The present invention relates to the field of semiconductor device manufacturing, and in particular, to a method for fabricating an electrostatic chuck, a chamber, and an electrostatic chuck.

Chucks are often used to carry and hold wafers during semiconductor manufacturing to avoid movement or misalignment of the wafer during processing. Since electrostatic chucks have the advantage of reducing mechanical contact to the wafer, increasing the area at which the wafer can be efficiently processed, electrostatic chucks are often employed in the process chamber to carry and secure the wafer. The existing chuck structure is as shown in FIG. 1 , and the chuck seat 5 is provided with a heat insulating adhesive layer 4 , a heater 3 , a metal layer 2 and an insulating layer 1 in order from the bottom to the top, wherein two of the insulating layers 1 are disposed. The electrodes 6 are connectable to the positive and negative electrodes of the external DC power source, so that electrostatic attraction can be generated to fix the wafer placed on the insulating layer 1. The heater 3 is provided with a resistance wire capable of generating heat to heat the wafer after energization, and in order to improve the heating efficiency, an insulating adhesive layer 4 is disposed between the heater 3 and the chuck holder 5 to prevent heat from being applied to the card. The tray 5 is delivered. Generally, the heat insulating adhesive layer 4 is a silicone resin adhesive having good heat insulating properties. The heat insulating adhesive layer 4 is formed by coating a silicone resin adhesive on the heater 3 and/or the chuck holder 5, thereby forming an insulating bond between the heater 3 and the chuck holder 5. Layer 4 is used to bond the heater 3 and the chuck base 5 together and to insulate therebetween. In order to have a good heat insulating effect, the coated silicone resin binder needs to have a large thickness. However, when the resin adhesive is artificially coated, it is difficult to ensure the flatness of the coating, so that in the subsequent wafer processing, the wafer fixed by the electrostatic chuck may be inclined at an angle, which affects the temperature during heating. Uniformity also results in process quality for wafer processing. In addition, it is difficult to ensure the sealing property of the heat insulating adhesive layer 4 by manual coating, which is liable to cause vacuum leakage, resulting in failure of the entire electrostatic chuck manufacturing.

In view of the above, it is an object of the present invention to provide an electrostatic chuck and a chamber such that the insulating layer sheet in the electrostatic chuck has a good flatness. To achieve the above object, the present invention provides an electrostatic chuck including a chuck holder having a heater and an insulating layer disposed thereon, the insulating layer being disposed above the heater and within the insulating layer An electrode for generating electrostatic attraction is provided, and the electrostatic chuck further includes a heat insulating layer sheet which is stacked between the chuck seat and the heater to constitute a heat insulating layer. Wherein, the insulation layer sheet comprises a plurality of layers of heat insulation film. Wherein, the material of the heat insulation film is polyimine, and the multilayer heat insulation film is formed by vacuum heat pressing to form the heat insulation layer sheet. The thickness of the heat insulating film is 0.04 mm to 0.06 mm, and the thickness of the heat insulating layer sheet is 0.3 mm to 0.6 mm. Wherein, the upper surface of the heat insulation layer sheet is bonded to the heater, and the lower surface of the heat insulation layer sheet is bonded to the chuck seat. The insulating layer is made of alumina ceramic or aluminum nitride ceramic. The air guiding channel is further disposed in the insulating layer, and the air guiding channel is used to introduce a temperature regulating gas to make the temperature of the insulating layer uniform. Wherein, the electrostatic chuck further comprises a metal layer disposed between the insulating layer and the heater. Wherein, the chuck seat is provided with a cooling channel for introducing a cooling liquid to cool the electrostatic chuck. As another aspect of the present invention, the present invention provides a chamber including a susceptor, and the chamber further includes an electrostatic chuck provided by any of the above aspects of the present invention, the electrostatic chuck being disposed on the pedestal . As still another aspect of the present invention, the present invention also provides a method of fabricating an electrostatic chuck for fabricating the electrostatic chuck provided by the present invention. The method includes at least a heat insulating layer sheet forming step and a heat insulating layer sheet mounting step, wherein in the heat insulating layer sheet forming step, a heat insulating layer sheet is prepared; and the heat insulating layer sheet mounting step is performed The heat insulating layer sheet is stacked between the chuck seat and the heater to form a heat insulating layer. In the heat insulating layer sheet forming step, a multilayer heat insulating film is first obtained, and then the multilayer heat insulating film is entirely processed to form a heat insulating layer sheet. In the step of fabricating the heat-insulating layer sheet, a heat-insulating film having a multilayer material of polyimine is first prepared, and then the multilayer heat-insulating film is entirely formed into a heat-insulating layer sheet by a vacuum heat-pressing process. Wherein, in the heat insulating layer sheet forming step, a plurality of heat insulating films having a thickness of 0.04 mm to 0.06 mm are prepared, and then the multilayer heat insulating film is integrally formed into a thickness of 0.3 mm to 0.6 by a vacuum hot pressing process. Mm insulation sheet. Wherein, in the heat insulating layer sheet mounting step, the upper surface of the heat insulating layer sheet is bonded to the heater, and the lower surface of the heat insulating layer sheet is bonded to the chuck seat to form heat insulation. Floor. The beneficial effects of the present invention are as follows: In the electrostatic chuck provided by the present invention, the heat insulating layer is formed by providing a prefabricated heat insulating layer sheet between the chuck holder and the heater, thereby effectively overcoming the heat insulation in the prior art. The flatness of the adhesive layer is difficult to ensure and the problem of vacuum leakage is prone to occur, which not only improves the yield of the electrostatic chuck, but also improves the process quality when the electrostatic chuck is used for semiconductor processing. In addition, the electrostatic chuck provided by the invention can avoid the repeated coating and repeated equalization in the process of manually coating the thermal insulation layer in the prior art, and reduces the processing complexity of the electrostatic chuck. The electrostatic chuck provided by the invention is included in the chamber provided by the invention, so that the chamber effectively overcomes the low flatness and easy occurrence of the thermal insulation layer of the existing chamber due to the electrostatic chuck disposed therein. Problems such as low process quality during semiconductor processing due to problems such as vacuum leakage. The electrostatic chuck manufacturing method provided by the present invention forms a heat insulating layer by first preparing a heat insulating layer sheet and then stacking the prepared heat insulating layer sheet between the chuck seat and the heater. In this way, since the heat insulating layer sheet is separately prepared in advance, it can effectively overcome the problems of low flatness of the heat insulating adhesive layer in the prior art and easy occurrence of vacuum leakage, which not only improves the yield of the electrostatic chuck, Moreover, the process quality when the electrostatic chuck is applied for semiconductor processing is also improved. In addition, the method for manufacturing the electrostatic chuck provided by the invention can avoid the problem of repeated coating and repeated equalization in the process of forming the heat insulating layer by manual glue in the prior art, thereby reducing the complexity of the electrostatic chuck manufacturing and improving the complexity. Production efficiency.

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative and not restrictive. As an aspect of the present invention, an electrostatic chuck is provided. As shown in FIGS. 2 to 4, the electrostatic chuck may be provided with a chuck holder 10, a heat insulating layer 40, a heater 20, and an insulating layer from bottom to top. 30. An electrode 31 for generating electrostatic attraction is further disposed in the insulating layer 30. The two electrodes 31 can externally connect the positive and negative electrodes of the direct current power source to generate electrostatic attraction on the insulating layer 30 to fix the wafer. Typically, the leads of the electrode 31 pass through the electrostatic chuck from the inside of the insulating layer 30 and pass out from the bottom surface of the chuck holder 10 to connect an external DC power source. The insulating layer 40 is machined from a prefabricated insulating layer sheet. The material of the heat insulation layer sheet may be a high temperature heat insulating material such as polyimide. When the electrostatic chuck is fabricated, the heat insulating layer sheet is formed into a shape that matches the shape of the chuck holder 10 and the heater 20, and is placed between the chuck holder 10 and the heater 20 to form a heat insulating layer. The heat insulating layer 40 can prevent heat generated by the heater 20 from being transferred to the chuck holder 10 when the electrostatic chuck is applied in a semiconductor processing process. Moreover, in order to allow the lead of the electrode 31 led out by the insulating layer 30 to pass through the heat insulating layer 40 to reach the bottom surface of the chuck holder 10, a corresponding through hole may be provided in the heat insulating layer 40 for the lead of the electrode 31 to be taken away. line. The electrostatic chuck provided by the present invention adopts a prefabricated heat insulation layer sheet to insulate the chuck seat 10 from the heater 20, since the heat insulation layer sheet can be pre-processed, that is, the heat insulation layer The sheet can be made in advance and independently so that its flatness can be better controlled. Therefore, compared with the prior art, the electrostatic chuck provided by the present invention overcomes the difficulty in ensuring the flatness caused by the conventional application of the thermal insulation adhesive layer on the heater 3 and/or the chuck base 5 It is easy to cause vacuum leakage and reduce the difficulty of processing the electrostatic chuck. Further, as shown in FIG. 3, the heat insulating layer sheet may include a plurality of heat insulating films 41. Specifically, the multilayer heat insulating film 41 can be laminated to form a heat insulating layer sheet, so that the heat insulating layer 40 formed of the heat insulating layer sheet can have a better heat insulating effect. In practical applications, when the heat insulating layer sheet adopts the above structure, the number of layers of the heat insulating film 41 can be flexibly adjusted according to actual needs to obtain a desired thickness of the heat insulating layer sheet and heat insulating properties. Further, since the polyimide has good heat insulating properties and superior comprehensive properties, the material of the heat insulating film 41 may be polyimine, and the multilayer polyimide film may be laminated and connected. After forming the whole, a heat insulating layer sheet is formed. Specifically, the multi-layered polyimide film may be layer-by-layer bonded to form a heat insulating layer sheet; or, the multilayer polyimide film may be formed by vacuum hot pressing to form a heat insulating layer sheet, for example, The multi-layered polyimide film is pressed into a whole by a vacuum hot press to form a heat insulating layer sheet. The vacuum thermocompression can firmly bond the multilayer polyimide film and process it conveniently, so this mode is a preferred embodiment of the present invention. Further, the thickness of the heat insulating film 41 made of polyimide may be 0.04 mm to 0.06 mm, and the thickness of the heat insulating layer sheet may be 0.3 mm to 0.6 mm. Preferably, a polyimide film having a thickness of 0.05 mm can be selected, and the thickness of the heat insulating layer formed by the multilayer polyimide film can be between 0.3 mm and 0.6 mm for processing and obtaining better separation. Thermal effect. It can be understood that the above is only the preferred embodiment provided by the present invention. In practical applications, the thickness of the insulating layer sheet can be adjusted as needed, for example, if the heater 20 is heated at a higher temperature or a higher power. , the number of the heat insulation film 41 can be appropriately increased to increase the thickness of the heat insulation layer sheet, thereby improving the heat insulation effect; if the heater 20 is heated at a slightly lower temperature or a lower power, a smaller amount of heat insulation can be selected. The film 41 is used to reduce processing complexity. Further, the upper surface of the heat insulating layer 40 may be bonded to the heater 20, and the lower surface of the heat insulating layer 40 may be bonded to the chuck holder 10. That is, as a preferred embodiment of the present invention, the prefabricated heat insulating layer 40 may be bonded and fixed to the heater 20 and the chuck base 10, respectively. Further, since both the alumina ceramic and the aluminum nitride ceramic have good insulation, high temperature resistance, and high mechanical strength and thermal conductivity, the material of the insulating layer 30 may be alumina ceramic or aluminum nitride. ceramics. Further, as shown in Fig. 4, the upper surface of the insulating layer 30 is provided with a projection 32, and a recess is formed between the adjacent projections 32. Further, an air guiding passage 33 is provided in the insulating layer 30, and the air guiding passage 33 communicates with a recess of the upper surface of the insulating layer 30 for introducing a gas into the recess. Specifically, the upper surface of the insulating layer 30 may be provided with a plurality of protrusions 32. When the wafer is placed on the insulating layer 30, the lower surface of the wafer will be in contact with the protrusion 32, and the inside of the insulating layer 30 may be provided with a gas guiding channel. 33. The air guiding passage 33 can open a tempering gas such as a heating gas from the outside to the recess of the upper surface of the insulating layer 30, so that the heating gas fills the recess between the protrusions 32, and the above structure can be utilized from the insulating layer 30. The heat and the heat from the heated gas provide a more uniform heating of the wafer. The number of the air guiding passages 33 may be set according to actual needs. Preferably, the air guiding passages 33 may be disposed in a portion outside the insulating layer 30 and communicate with the recesses near the edges on the upper surface of the insulating layer 30. . The heating gas introduced into the pilot gas passage 33 may be an inert gas having a certain heat such as helium gas, argon gas or the like. Still further, as shown in FIG. 4, the electrostatic chuck may further include a metal layer 50 stacked between the insulating layer 30 and the heater 20. Specifically, the metal layer 50 may be disposed on the heater 20, and the insulating layer 30 may be disposed on the metal layer 50. In the above manner, the heater 20 may be heated to the metal layer 50, and then transferred by the metal layer 50. To the insulating layer 30, the metal layer 50 may be a flat metal such that heat can be transferred to the insulating layer 30 more uniformly. The metal layer 50 may be made of aluminum, and the metal layer 50 may be bonded and fixed to the insulating layer 30 and the heater 20, respectively, using an adhesive having better thermal conductivity. Further, a chucking channel 11 may be disposed in the chuck base 10, and the cooling channel 11 may be used to pass a cooling liquid to cool the electrostatic chuck. Specifically, in the process of controlling the temperature of the wafer by using the electrostatic chuck, the cooling liquid can be introduced into the cooling channel 11 to bring the electrostatic chuck into a thermal equilibrium state, and further, the cooling channel 11 is disposed to make the static electricity The chuck can quickly achieve a temperature drop when it needs to cool down. The foregoing is a description of the electrostatic chuck provided by the present invention. It can be seen that the present invention effectively overcomes the prior art by providing a pre-made insulating layer sheet between the chuck holder and the heater to form a heat insulating layer. The flatness of the heat-insulating adhesive layer is difficult to ensure and the problem of vacuum leakage is prone to occur, which not only improves the yield of the electrostatic chuck, but also improves the process quality when the electrostatic chuck is used for semiconductor processing. In addition, the electrostatic chuck provided by the invention can avoid the repeated coating and repeated equalization in the process of manually coating the thermal insulation layer in the prior art, and reduces the processing complexity of the electrostatic chuck. As another aspect of the present invention, there is provided a chamber including a susceptor, and the chamber further includes the electrostatic chuck provided by the present invention described above, and the electrostatic chuck is disposed on the susceptor. Since the chamber provided by the present invention comprises the electrostatic chuck provided by the invention, the existing chamber is effectively overcome the problem that the flatness of the thermal insulating adhesive layer of the existing chamber is low and the vacuum leakage is easy to occur. This leads to problems such as low process quality during semiconductor processing. As still another aspect of the present invention, the present invention also provides a method of fabricating an electrostatic chuck for fabricating the electrostatic chuck provided by the foregoing various embodiments. As shown in FIG. 5, the method includes at least a heat insulation layer sheet forming step 110 and a heat insulation layer sheet mounting step 120: in the heat insulation layer sheet forming step 110, preparing a heat insulating layer sheet; In the hot layer sheet mounting step 120, the insulating layer sheet is stacked between the chuck holder and the heater. Specifically, in the heat insulation layer sheet forming step 110, a heat insulation film is first prepared, and then the one heat insulation film is folded into a plurality of layers to form a multilayer heat insulation film; or a plurality of heat insulation films are prepared first, and then The plurality of heat insulating films are laminated to form a multilayer heat insulating film; finally, the multilayer heat insulating film is formed to form a heat insulating layer sheet. For example, a multilayer heat insulating film can be formed into a heat insulating layer sheet by a vacuum hot pressing process. In practical applications, because the polyimide has good thermal insulation properties and superior comprehensive properties, the material of the thermal insulation film can be selected from polyimine. Further, the thickness of the single-layer heat insulating film may be 0.04 mm to 0.06 mm, and then the multilayer heat insulating film may be formed into a heat insulating layer sheet having a thickness of 0.3 mm to 0.6 mm by a vacuum heat pressing process. In the heat insulation layer sheet forming step 120, the upper surface of the heat insulation layer sheet is bonded to the heater, and the lower surface of the heat insulation layer sheet is bonded to the chuck seat, thereby stacking the heat insulation layer sheets. Between the chuck holder and the heater to form an electrostatic chuck. In addition, the method for fabricating an electrostatic chuck provided by the present invention further includes a gas guiding passage setting step of disposing a gas guiding passage in the insulating layer for introducing a temperature regulating gas such as a heating gas to make the temperature of the insulating layer uniform. Further, the method for fabricating an electrostatic chuck provided by the present invention further includes a metal layer setting step of placing a metal layer between the insulating layer and the heater to more uniformly transfer heat to the insulating layer. Further, the method for fabricating the electrostatic chuck provided by the present invention further includes a cooling channel setting step of providing a cooling channel in the chuck holder for introducing a cooling liquid to cool the electrostatic chuck. For further explanation of the air guiding passage, the metal layer, and the cooling channel, reference may be made to the foregoing description in conjunction with FIG. 4, and details are not described herein again. The electrostatic chuck manufacturing method provided by the present invention forms a heat insulating layer by first preparing a heat insulating layer sheet and then stacking the prepared heat insulating layer sheet between the chuck seat and the heater. In this way, since the heat insulating layer sheet is separately prepared in advance, it can effectively overcome the problems of low flatness of the heat insulating adhesive layer in the prior art and easy occurrence of vacuum leakage, which not only improves the yield of the electrostatic chuck, Moreover, the process quality when the electrostatic chuck is applied for semiconductor processing is also improved. In addition, the method for manufacturing the electrostatic chuck provided by the invention can avoid the problem of repeated coating and repeated equalization in the process of forming the heat insulating layer by manual glue in the prior art, thereby reducing the complexity of the electrostatic chuck manufacturing and improving the complexity. Production efficiency. It is to be understood that the above embodiments are merely exemplary embodiments employed to explain the principles of the invention, but the invention is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and scope of the invention. These modifications and improvements are also considered to be within the scope of the invention.

1, 30‧‧‧ insulation
2, 50‧‧‧ metal layer
3, 20‧‧‧ heater
4‧‧‧Insulation bonding layer
5, 10‧‧‧ chuck seat
6, 31‧‧‧ electrodes
11‧‧‧Cooling channel
32‧‧‧ bumps
33‧‧‧ air guiding channel
40‧‧‧Insulation
41‧‧‧Insulation film

The drawings are intended to provide a further understanding of the invention, and are intended to be a In the drawings: FIG. 1 is a view showing an example of a structure of an electrostatic chuck; FIG. 2 is a view showing an example of an electrostatic chuck according to an embodiment of the present invention; and FIG. 3 is a heat insulating layer according to an embodiment of the present invention. FIG. 4 is a schematic view showing another example of an electrostatic chuck structure according to an embodiment of the present invention; and FIG. 5 is a flow chart showing a method for fabricating an electrostatic chuck according to an embodiment of the present invention.

10‧‧‧ chuck seat

20‧‧‧heater

30‧‧‧Insulation

31‧‧‧ electrodes

40‧‧‧Insulation

Claims (13)

An electrostatic chuck includes a chuck seat, a heater and an insulating layer are disposed above the chuck seat, the insulating layer is disposed above the heater, and an electrode for generating electrostatic attraction is disposed in the insulating layer The electrostatic chuck further includes a heat insulation layer sheet stacked between the chuck seat and the heater to form a heat insulation layer, the heat insulation layer sheet comprising a plurality of layers Thermal insulation film. The electrostatic chuck according to claim 1, wherein the material of the heat insulating film is polyimide, and the heat insulating film is formed by vacuum heat pressing. The electrostatic chuck according to claim 2, wherein the heat insulating film has a thickness of 0.04 mm to 0.06 mm, and the heat insulating layer sheet has a thickness of 0.3 mm to 0.6 mm. The electrostatic chuck according to any one of claims 1 to 3, wherein the upper surface of the heat insulating layer sheet is bonded to the heater, and the lower surface of the heat insulating layer sheet is The chuck seat is bonded. The electrostatic chuck according to any one of claims 1 to 3, wherein the insulating layer is made of an alumina ceramic or an aluminum nitride ceramic. The electrostatic chuck according to any one of claims 1 to 3, wherein the insulating layer is further provided with a gas guiding passage for introducing a temperature regulating gas, so that The insulating layer has a uniform temperature. The electrostatic chuck according to any one of claims 1 to 3, wherein the electrostatic chuck further comprises a metal layer laminated between the insulating layer and the heater. The electrostatic chuck according to any one of claims 1 to 3, wherein the chuck seat is provided with a cooling channel for introducing a cooling liquid to cool the Electrostatic chuck. A chamber comprising a susceptor, the chamber further comprising an electrostatic chuck according to any one of the preceding claims, wherein the electrostatic chuck is disposed on the pedestal on. A method for producing an electrostatic chuck according to claim 1, characterized in that it comprises at least a heat insulating layer sheet forming step and a heat insulating layer sheet mounting step, in the heat insulating layer sheet forming step, First obtaining a multi-layered heat insulating film, and then integrally processing the multi-layered heat insulating film to form a heat insulating layer sheet; in the heat insulating layer sheet mounting step, stacking the heat insulating layer sheet on the chuck seat and the heater A heat insulating layer is formed between them. The manufacturing method according to claim 10, wherein in the step of fabricating the heat insulating layer, a heat insulating film of a polylayer of polyimide is prepared, and then a vacuum heat pressing process is used. The multilayer insulation film is integrally formed into a heat insulation layer sheet. The manufacturing method according to claim 11, wherein in the step of fabricating the heat insulating layer, a plurality of heat insulating films having a thickness of 0.04 mm to 0.06 mm are prepared, and then a vacuum heat pressing process is used. The multilayer heat-insulating film is integrally formed into a heat-insulating layer sheet having a thickness of 0.3 mm to 0.6 mm. The manufacturing method according to any one of the items 1 to 12, characterized in that in the heat insulating layer sheet mounting step, the upper surface of the heat insulating layer sheet and the heater Bonding, bonding the lower surface of the heat insulating layer sheet to the chuck seat to form a heat insulating layer.