Film support and CMP polishing head

Abstract

The utility model discloses a membrane supporting piece and a CMP (chemical mechanical polishing) head, the membrane supporting piece comprises a disc-shaped main body, the disc-shaped main body is provided with a first surface, a second surface and an annular side wall located between the first surface and the second surface, and the first surface is a working surface matched with an elastic membrane; a plurality of circular vent holes which are distributed at intervals and penetrate through the disc-shaped main body are formed in the central area of the disc-shaped main body; a plurality of air guide holes, a first air guide groove and a plurality of second air guide grooves are formed in the edge area of the disc-shaped main body; the plurality of air guide holes penetrate through the disc-shaped main body and are distributed at intervals in the circumferential direction of the disc-shaped main body; the first air guide grooves are annular and distributed in the edge of the first surface in the circumferential direction of the disc-shaped body. The air guide holes are located in the inner sides of the first air guide grooves, and each second air guide groove is communicated with one air guide hole and the first air guide groove on the first surface. According to the utility model, the wafer grinding uniformity of the CMP process can be improved, the edge morphology of the wafer after CMP is improved, and the surface thickness uniformity of the wafer is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of semiconductor device manufacturing, especially to a film support and CMP polishing head. BACKGROUND

[0002] Chemical mechanical polishing (CMP) is a planarization technique used to planarize the surface of an integrated circuit formed on a semiconductor wafer so that high-density multilayer interconnects can be formed on the planarized surface. Currently, CMP has been applied to the manufacture of interlayer dielectric (ILD), plug, shallow trench isolation (STI), damascene, etc.

[0003] A CMP apparatus includes a rotatable platen and a rotatable polishing head for holding a wafer, the platen having a polishing pad thereon and rotatable with the platen, and a slurry supply for supplying slurry to the polishing pad.

[0004] During CMP, the wafer is placed between the CMP polishing head and the polishing pad, the CMP polishing head exerts pressure on the wafer and drives the wafer to rotate to produce a mechanical polishing effect between the wafer and the polishing pad, and at the same time, the material layer to be planarized of the wafer reacts with the slurry to produce a chemical polishing effect.

[0005] A conventional CMP polishing head includes a disc-shaped film support (also known as "hole plate"), and the cross-sectional structure of the film support for a 6-inch wafer is as shown in Figure 1 The elastic film 3 covers the bottom surface of the film support 1 and is fixed around the elastic film 3 by a fixing ring 4, and the film support 1 is provided with a plurality of large air holes 2.

[0006] As shown in Figure 2 During CMP, gas is injected into the CMP polishing head, the gas reaches the elastic film 3 through the air holes 2 on the film support 1, and the elastic film 3 is pushed by the injected gas and extends outward, thereby exerting pressure on the wafer 5.

[0007] The goal of CMP is to planarize the material layer on the wafer, but the uniformity of the material layer is crucial to the yield of subsequent processes and the reliability of the device to be formed. During CMP, the pressure exerted by the CMP polishing head on the wafer is crucial to the uniformity of the material layer.

[0008] As shown in Figure 2 With the current film support 1, only a larger pressure can be formed in the central region of the elastic film 3, and the extension of the edge region of the elastic film is insufficient, so that the pressure on the wafer 5 in the edge region of the elastic film 3 (the position of the dashed circle in the figure) is smaller, resulting in uneven distribution of polishing rate in different regions of the wafer surface, and further resulting in poor polishing uniformity of the wafer surface, causing a large thickness difference between the edge region and the central region of the wafer.

[0009] For example, for TC-SAW (temperature compensated surface acoustic wave) devices, the thickness has a strong correlation with the frequency, and the film thickness of the IDT (interdigital transducer) and PAD (pad) needs to be tightened from the range of ± 700A to the range of ± 350A during the fine grinding (SLCMP) process, and the side surface of the wafer with the device has the characteristics of thin edge region and thick center region, and according to the current CMP, the wafer edge region cannot be polished to the same thickness as the center region according to this specification; Specifically, the conventional CPM polishing head is used for CMP on the surface to be planarized of the TC-SAW wafer, as shown in the figure, the thickness difference between the edge region and the center region of the wafer surface during the rapid grinding (TC CMP) process is as high as 4000A, and after the CMP process is completed, the thickness of all position points on the front surface of the wafer is measured, as shown in the figure, the thickness difference between the wafer edge and the wafer center region is large, and the defective morphology (thickness does not meet the requirement region) that needs to be removed at the wafer edge reaches 12.8% / Pcs. Figure 3 Figure 4 Practical new type content

[0010] The purpose of the present application is to provide a film support and a CMP polishing head, which can improve the uniformity of the CMP process for wafer grinding, improve the edge morphology of the wafer after CMP, and improve the surface thickness uniformity of the wafer.

[0011] In order to achieve the above purpose, the present application provides a film support for a CMP polishing head, which comprises:

[0012] A disc-shaped body having a first surface, a second surface and an annular side wall between the first surface and the second surface, the first surface being a working surface matched with an elastic film;

[0013] A plurality of circular air vents are arranged in the central region of the disc-shaped body and penetrate the disc-shaped body;

[0014] The edge region of the disc-shaped body is provided with a plurality of air guide holes, a first air guide groove and a plurality of second air guide grooves;

[0015] The plurality of air guide holes penetrate the disc-shaped body and are arranged in the circumferential direction of the disc-shaped body;

[0016] The first air guide groove is annular and arranged in the circumferential direction of the disc-shaped body at the edge of the first surface;

[0017] The air guide holes are located on the inner side of the first air guide groove, and each second air guide groove is in communication with one air guide hole and the first air guide groove on the first surface.

[0018] ​​Optionally, one of the plurality of circular vent holes is arranged at the center of the disc-shaped body, and the rest of the circular vent holes are arranged in a plurality of concentric circles based on the center;

[0019] The plurality of circular vent holes on each concentric circle are equally spaced. The plurality of second vent holes on each concentric circle are equally spaced.

[0020] Optionally, the diameter of the circular vent hole at the center is greater than the diameter of the rest of the circular vent holes.

[0021] Optionally, the plurality of air guide holes are equally spaced in the interval region between the row of circular vent holes closest to the edge of the disc-shaped body.

[0022] Alternatively, the plurality of air guide holes are equally spaced in the interval region between the row of circular vent holes closest to the edge of the disc-shaped body and the row of circular vent holes next closest to the edge of the disc-shaped body.

[0023] The diameter of the circular vent hole is 3-10 times the hole diameter of the air guide hole.

[0024] Optionally, the second air guide groove is a straight-line type groove extending radially along the disc-shaped body, one end of the second air guide groove is connected to the air guide hole, and the other end is connected to the first air guide groove.

[0025] Optionally, the hole diameter of the air guide hole is greater than the width of the second air guide groove, and the width of the second air guide groove and the first air guide groove is the same.

[0026] Optionally, the depth of the first air guide groove is greater than or equal to the depth of the second air guide groove.

[0027] Optionally, the second surface of the disc-shaped body is provided with a compression ring, and the compression ring is used to connect with the central air inlet pipeline of the CMP polishing head.

[0028] The compression ring is arranged in the annular region where the plurality of circular vent holes are located, and the width of the compression ring is less than the diameter of the circular vent hole.

[0029] Optionally, the second surface of the disc-shaped body is provided with a connecting part.

[0030] The connecting part includes an annular side wall protruding from the second surface, one end of the connecting part is connected to the edge of the second surface, and the other end of the connecting part is used to sealingly connect with the base of the CMP polishing head and form a closed cavity for edge air inlet.

[0031] The utility model also provides a CMP polishing head, which comprises the film support piece.

[0032] The utility model discloses beneficial effect lies in:

[0033] The utility model discloses a membrane support spare is on the basis of traditional membrane support spare, has increased a plurality of gas guide holes, annular first gas guide groove and a plurality of second gas guide groove at its main body edge position, wherein first gas guide groove sets up at the edge position of the one side of membrane support spare towards wafer, and the communication of gas guide hole and annular first gas guide groove is through second gas guide groove, in the operation process of CMP polishing head, after gas injection CMP polishing head, gas reaches the central region of elastic membrane through the larger vent hole on membrane support spare, and gas can also rapidly through the second gas guide groove and make first gas guide groove of first surface edge to reach the edge region of elastic membrane, thereby the gas of such elastic membrane center and edge region can be injected simultaneously and extend outward, and the edge region can also have greater pressure, make the pressure distribution of elastic membrane whole to wafer more uniform, solve the problem of traditional CMP polishing head elastic membrane edge pressure deficiency, can be through the accurate control of adjusting pressure parameter to product edge appearance, thereby improve CPM after wafer edge appearance, improve wafer planarization material layer central region and edge region's thickness uniformity, and further improve device performance. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, the following will briefly introduce the drawing needed to be used in the embodiment or prior art description, and obviously, the drawing in the following description is only some embodiments of the utility model, and for ordinary skilled person in the art, other drawings can also be obtained according to these drawings without paying creative labor.

[0035] Figure 1 It is the section view of membrane support spare and elastic membrane cooperation in prior art CMP polishing head.

[0036] Figure 2 It is the schematic diagram of elastic membrane and wafer pressure exertion after prior art CMP polishing head gas inlet.

[0037] Figure 3 It is the thickness difference distribution diagram of wafer surface after prior art CMP polishing head CMP process.

[0038] Figure 4 It is the wafer surface thickness distribution diagram after prior art CMP polishing head CMP process to wafer.

[0039] Figure 5 It is the structure schematic diagram of a kind of membrane support spare of one embodiment of the utility model.

[0040] Figure 6 It is the section structure schematic diagram of a kind of membrane support spare of one embodiment of the utility model.

[0041] Figure 7 This is a schematic diagram of a membrane support component and an elastic membrane in one embodiment of the present invention.

[0042] Figure 8 This is a schematic diagram of applying pressure to a wafer by venting air through an elastic membrane in one embodiment of the present invention.

[0043] Figure 9 This is a thickness distribution diagram of the wafer surface after CMP using the CMP polishing head with the film support of this utility model.

[0044] Figure 10 This is a thickness difference distribution diagram of the wafer surface after CMP using the CMP polishing head with the film support of this utility model. Detailed Implementation

[0045] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of a filter chip packaging structure and its wafer-level packaging method according to the present invention. The advantages and features of the present invention will become clearer from the following description and drawings. However, it should be noted that the concept of the present invention can be implemented in many different forms and is not limited to the specific embodiments described herein. The accompanying drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0046] The terms “first,” “second,” etc., used in the specification and claims are used to distinguish between similar elements and are not necessarily used to describe a particular order or chronological sequence. It should be understood that these terms, used so in this way, may be replaced where appropriate, for example, to allow embodiments of the invention described herein to operate in a different order than that described or shown herein. Similarly, if the methods described herein comprise a series of steps, and the order of these steps presented herein is not necessarily the only possible order in which these steps can be performed, and some described steps may be omitted and / or some other steps not described herein may be added to the method. If a component in one figure is identical to a component in another figure, although these components are readily identifiable in all figures, this specification will not label all identical components in every figure for the sake of clarity. Example 1

[0047] like Figure 5 and Figure 6 As shown, this embodiment provides a film support 100 for a CMP polishing head, the film support 100 comprising:

[0048] A disc-shaped body 110 having a first surface 101, a second surface, and an annular sidewall between the first surface 101 and the second surface, the first surface 101 being a working surface matched with an elastic film;

[0049] The central region of the disc-shaped body 110 is provided with a plurality of circular ventilation holes 102 spaced apart and penetrating through the disc-shaped body 110;

[0050] The edge region of the disc-shaped body 110 is provided with a plurality of air guide holes 103, a first air guide groove 104, and a plurality of second air guide grooves 105;

[0051] The plurality of air guide holes 103 penetrate through the disc-shaped body 110 and are spaced apart along the circumference of the disc-shaped body 110;

[0052] The first air guide groove 104 is annular and distributed along the circumference of the disc-shaped body 110 at the edge of the first surface 101;

[0053] The air guide holes 103 are located inside the first air guide groove 104, and each second air guide groove 105 communicates one air guide hole 103 and the first air guide groove 104 at the first surface 101.

[0054] Among them, one of the plurality of circular ventilation holes 102 is arranged at the center of the disc-shaped body 110, and the remaining circular ventilation holes 102 are arranged into a plurality of concentric circles based on the center; the plurality of circular ventilation holes 102 on each concentric circle are equally spaced. The diameter of the circular ventilation hole 102 located at the center is greater than that of the remaining circular ventilation holes 102.

[0055] Specifically, as shown in the embodiment, the plurality of circular ventilation holes 102 include a first ventilation hole 121, a plurality of second ventilation holes 122, and a plurality of third ventilation holes 123; Figure 5

[0056] The first ventilation hole 121 is located at the center of the disc-shaped body 110, and the first ventilation hole 121 is concentric with the disc-shaped body 110;

[0057] The plurality of second ventilation holes 122 are equally spaced around the outer periphery of the first ventilation hole 121, and the plurality of third ventilation holes 123 are equally spaced around the outer periphery of the plurality of second ventilation holes 122. That is, the plurality of second ventilation holes 122 and the plurality of third ventilation holes 123 form two concentric circles concentric with the first ventilation hole 121.

[0058] ​In this embodiment, preferably, the diameter of the first vent 121 is larger than the diameter of the second vent 122, and the diameter of the second vent 122 is the same as that of the third vent 123.

[0059] Optionally, the plurality of air guide holes 103 are equally spaced in the interval region between the row of circular air vents 102 (located in the outermost concentric circle) closest to the edge of the disc-shaped body 110; or, the plurality of air guide holes 103 are equally spaced in the interval region between the row of circular air vents closest to the edge of the disc-shaped body 110 and another row of circular air vents (i.e., the concentric circle closest to the outermost concentric circle) closest to the edge of the disc-shaped body 110.

[0060] In this embodiment, a plurality of the air guide holes 103 are preferably distributed at equal intervals in the interval area between a row of circular air vents 102 (located in the outermost concentric circle) closest to the edge of the disc-shaped main body 110.

[0061] Specifically, such as Figure 5 As shown, in this embodiment, a plurality of air guide holes 103 are evenly distributed along the circumference of the disc-shaped main body 110. An air guide hole 103 is provided in the interval region between any two adjacent third air guide holes 123 on the outermost concentric circle. Placing the air guide hole 103 in the interval region between the outermost third air guide holes 123 shortens the distance between the air guide hole 103 and the first air guide groove 104, reduces the length of the second air guide groove 102, and thus improves the inflation speed at the edge of the elastic membrane 200. Preferably, the diameter of the circular air guide hole 102 is 3-10 times the diameter of the air guide hole, such as the diameter of the third air guide hole 123 being 3-10 times the diameter of the air guide hole 103.

[0062] In this embodiment, the second air guide groove 105 is a straight groove extending radially along the disc-shaped body 110. One end of the second air guide groove 105 is connected to the air guide hole 103, and the other end is connected to the first air guide groove 104.

[0063] In this embodiment, the diameter of the air guide hole 103 is greater than the width of the second air guide groove 105, and the widths of the second air guide groove 105 and the first air guide groove 104 are the same.

[0064] Preferably, the depth of the first air guide groove 104 is greater than or equal to the depth of the second air guide groove 105.

[0065] In this embodiment, the second surface of the disc-shaped body 110 is provided with a pressure ring 106, which is used to connect to the central air intake pipe of the CMP polishing head.

[0066] The compression ring 106 is arranged in the annular area where the plurality of circular air holes 102 are located, and is preferably arranged in the annular area where the third air hole 123 is located, and the width of the compression ring 106 is smaller than the diameter of the third air hole 123.

[0067] In the embodiment, the second surface of the disc-shaped body 110 is provided with a connecting part 107.

[0068] The connecting part 107 includes an annular side wall protruding from the second surface, one end of the connecting part 107 is connected with the edge of the second surface, and the other end of the connecting part 107 is used for sealingly connecting with the base of the CMP polishing head and forming a sealed cavity for edge air inlet.

[0069] The state of the film support 100, the elastic film 200 and the fixing ring 300 after being mounted and matched in the embodiment is shown in Figure 7 When air is supplied to the polishing head, the gas can quickly pass through the larger circular air holes 102 on the film support 100 to reach the central area of the elastic film 200, and the gas can also quickly pass through the gas guide hole 103, pass through the second gas guide groove 105 and reach the first gas guide groove 104 at the edge of the first surface 101, so as to quickly reach the edge area of the elastic film 200 and inflate it, as shown in Figure 8 Thus, the central and edge areas of the elastic film 200 can be synchronously pushed and extended outward by the injected gas, and the edge area can also have a larger pressure, so that the pressure distribution of the elastic film 200 on the wafer 400 is more uniform.

[0070] After the CMP polishing head with the film support 100 of the utility model is used to perform CMP on the wafer 400, the thickness distribution and thickness difference distribution of the surface of the wafer 400 are shown in Figure 9 and Figure 10 It can be seen that the thickness difference between the central area and the edge area of the wafer after CMP is smaller, the overall thickness distribution of the wafer 400 is more uniform, and the edge appearance is better, which solves the problem of insufficient pressure of the elastic film at the edge of the traditional CMP polishing head, thereby improving the edge appearance of the wafer 400 after CPM, improving the thickness uniformity of the central area and the edge area of the planarization material layer of the wafer 400, and further improving the device performance. Embodiment 2

[0071] The CMP polishing head provided in the embodiment includes the film support 100 as described in Embodiment 1.

[0072] The CMP polishing head of the embodiment further includes a polishing head base, a fixing ring for fixing the elastic film, an elastic film, a central air inlet pipeline, an edge air inlet pipeline and other matching mechanisms, the above-mentioned matching mechanisms are the same as those of the existing CMP polishing head, and the embodiment will not be described herein.

[0073] The CMP polishing head of the embodiment adopts the film support 100 of the embodiment 1, because the film support 100 increases the air guide holes and the air guide grooves at the edge, the greater pressure can be applied to the edge area of the elastic film, the pressure distribution of the whole elastic film to the wafer is more uniform, thereby improving the CMP effect of the polishing head to the wafer, improving the wafer edge topography after CPM, improving the thickness uniformity of the center area and the edge area of the wafer planarization material layer, and further improving the device performance.

[0074] It should be noted that each of the embodiments in the specification is described in a related manner, and the same and similar parts between each of the embodiments can be referred to each other, and each of the embodiments focuses on the difference from other embodiments. Especially, for the structural embodiments, because they are basically similar to the method embodiments, the description is relatively simple, and the related parts can refer to the part of the method embodiments.

[0075] The above description is only the description of the preferred embodiment of the utility model, and does not limit the scope of the utility model, and any change and modification of the above disclosure by the ordinary skilled in the art belongs to the protection scope of the claims.

Claims

1. A membrane support for a CMP polishing head, characterized by The film support comprises: a disc-shaped body having a first surface, a second surface and an annular sidewall between the first surface and the second surface, the first surface being a working surface matched with an elastic film; a plurality of circular vent holes are arranged in the central region of the disc-shaped body and penetrating through the disc-shaped body; a plurality of air guide holes, a first air guide groove and a plurality of second air guide grooves are arranged in the edge region of the disc-shaped body; the plurality of air guide holes penetrating through the disc-shaped body and being arranged in the interval along the circumference of the disc-shaped body; the first air guide groove is annular and arranged along the circumference of the disc-shaped body at the edge of the first surface; the air guide holes are located inside the first air guide groove, and each second air guide groove is in communication with one air guide hole and the first air guide groove at the first surface.

2. The membrane support of claim 1, wherein, one of the plurality of circular vent holes is arranged at the center of the disc-shaped body, and the remaining circular vent holes are arranged into a plurality of concentric circles based on the center; the plurality of circular vent holes on each concentric circle are arranged at equal intervals.

3. The membrane support of claim 2, wherein, the diameter of the circular vent hole at the center is greater than that of the remaining circular vent holes.

4. The membrane support of claim 2, wherein, the plurality of air guide holes are arranged at equal intervals in the interval region between the circular vent holes closest to the edge of the disc-shaped body; alternatively, the plurality of air guide holes are arranged at equal intervals in the interval region between the circular vent holes closest to the edge of the disc-shaped body and the circular vent holes next closest to the edge of the disc-shaped body; the diameter of the circular vent hole is 3-10 times the diameter of the air guide hole.

5. The membrane support of claim 4, wherein, the second air guide groove is a straight-line type groove extending radially along the disc-shaped body, one end of the second air guide groove is connected to the air guide hole, and the other end is connected to the first air guide groove.

6. The membrane support of claim 5, wherein, the diameter of the air guide hole is greater than the width of the second air guide groove, and the width of the second air guide groove is the same as that of the first air guide groove.

7. The membrane support of claim 6, wherein, the depth of the first air guide groove is greater than or equal to the depth of the second air guide groove.

8. The membrane support of claim 3, wherein, the second surface of the disc-shaped body is provided with a compression ring for connecting with the central air inlet pipeline of the CMP polishing head; the compression ring is arranged in the annular region where the plurality of circular vent holes are located, and the width of the compression ring is less than the diameter of the circular vent hole.

9. The membrane support of claim 8, wherein, the second surface of the disc-shaped body is provided with a connecting part; the connecting part includes an annular sidewall protruding from the second surface, one end of the connecting part is connected to the edge of the second surface, and the other end of the connecting part is used for sealing connection with the base of the CMP polishing head and forms a sealed cavity for edge air inlet.

10. A CMP polishing head, characterized by, The film support comprises: a disc-shaped body having a first surface, a second surface and an annular sidewall between the first surface and the second surface, the first surface being a working surface matched with an elastic film; a plurality of circular vent holes are arranged in the central region of the disc-shaped body and penetrating through the disc-shaped body; a plurality of air guide holes, a first air guide groove and a plurality of second air guide grooves are arranged in the edge region of the disc-shaped body; the plurality of air guide holes penetrating through the disc-shaped body and being arranged in the interval along the circumference of the disc-shaped body; the first air guide groove is annular and arranged along the circumference of the disc-shaped body at the edge of the first surface; the air guide holes are located inside the first air guide groove, and each second air guide groove is in communication with one air guide hole and the first air guide groove at the first surface. one of the plurality of circular vent holes is arranged at the center of the disc-shaped body, and the remaining circular vent holes are arranged into a plurality of concentric circles based on the center; the plurality of circular vent holes on each concentric circle are arranged at equal intervals. the diameter of the circular vent hole at the center is greater than that of the remaining circular vent holes. the plurality of air guide holes are arranged at equal intervals in the interval region between the circular vent holes closest to the edge of the disc-shaped body; alternatively, the plurality of air guide holes are arranged at equal intervals in the interval region between the circular vent holes closest to the edge of the disc-shaped body and the circular vent holes next closest to the edge of the disc-shaped body; the diameter of the circular vent hole is 3-10 times the diameter of the air guide hole. the second air guide groove is a straight-line type groove extending radially along the disc-shaped body, one end of the second air guide groove is connected to the air guide hole, and the other end is connected to the first air guide groove. the diameter of the air guide hole is greater than the width of the second air guide groove, and the width of the second air guide groove is the same as that of the first air guide groove. the depth of the first air guide groove is greater than or equal to the depth of the second air guide groove. the second surface of the disc-shaped body is provided with a compression ring for connecting with the central air inlet pipeline of the CMP polishing head; the compression ring is arranged in the annular region where the plurality of circular vent holes are located, and the width of the compression ring is less than the diameter of the circular vent hole. the second surface of the disc-shaped body is provided with a connecting part; the connecting part includes an annular sidewall protruding from the second surface, one end of the connecting part is connected to the edge of the second surface, and the other end of the connecting part is used for sealing connection with the base of the CMP polishing head and forms a sealed cavity for edge air inlet. The film support comprises:

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