A carrier head and polishing system for chemical mechanical polishing

Abstract

The application discloses a carrier head and a polishing system for chemical mechanical polishing, the carrier head comprises a base, a carrier disc arranged below the base, an elastic film arranged below the carrier disc, a retaining ring arranged below the carrier disc and located at the outer circumferential side of the elastic film, a gland arranged above the carrier disc, and a protective cover connected to the base and covering the outer circumferential side of the gland, wherein the outer circumferential side of the gland is provided with a liquid blocking structure to prevent liquid from being transmitted upward through the gap between the protective cover and the gland.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of chemical mechanical polishing, and particularly relates to a carrier head for chemical mechanical polishing and a polishing system. BACKGROUND

[0002] The integrated circuit industry is the core of the information technology industry and plays a key role in promoting the transformation and upgrading of the manufacturing industry to digitalization and intelligence. Chips are the carriers of integrated circuits, and chip manufacturing involves integrated circuit design, wafer manufacturing, wafer processing, electrical measurement, cutting and packaging, and testing processes. Among them, chemical mechanical polishing is one of the five core processes in the wafer manufacturing process.

[0003] Chemical mechanical polishing (CMP) is a global planarization ultra-precision surface processing technology. Chemical mechanical polishing usually attracts the wafer to the bottom surface of the carrier head, the side of the wafer with the deposited layer abuts against the upper surface of the polishing pad, and the carrier head rotates with the polishing pad in the same direction under the actuation of the driving assembly and gives the wafer a downward load; the polishing liquid is supplied to the upper surface of the polishing pad and distributed between the wafer and the polishing pad, so that the wafer completes the chemical mechanical polishing of the wafer under the joint action of chemical and mechanical.

[0004] During the polishing process, the polishing liquid and the particles generated by the polishing will extend upward along the outer sidewall of the carrier head and be transmitted to the connection between the base and the carrier disc. The long-term accumulation of the polishing liquid and the particles at the connection will cause damage to the parts, thereby affecting the service life of the corresponding parts. SUMMARY

[0005] The present application provides a carrier head for chemical mechanical polishing and a polishing system, which aims to at least solve one of the technical problems existing in the prior art.

[0006] In a first aspect, the present application provides a carrier head for chemical mechanical polishing, comprising:

[0007] a base;

[0008] a carrier disc arranged below the base;

[0009] an elastic film arranged below the carrier disc;

[0010] a retaining ring arranged below the carrier disc and located at the outer peripheral side of the elastic film;

[0011] a gland arranged above the carrier disc;

[0012] a protective cover connected to the base and covering the outer peripheral side of the gland;

[0013] The outer periphery of the gland is provided with a liquid blocking structure to prevent liquid from being transported upward through the gap between the protective cover and the gland.

[0014] In some embodiments, the liquid blocking structure is a liquid blocking groove, which is arranged downwardly inclined.

[0015] In some embodiments, the number of liquid blocking grooves is at least one, which is arranged spaced along the height direction of the gland.

[0016] In some embodiments, the longitudinal section of the liquid blocking groove is a quadrilateral opening outwardly.

[0017] In some embodiments, the transverse and longitudinal width of the liquid blocking groove is greater than or equal to the gap between the protective cover and the gland.

[0018] In some embodiments, the liquid blocking structure is a liquid blocking groove, which is arranged horizontally outwardly.

[0019] In some embodiments, the liquid blocking groove is an outwardly opening notch structure, which includes an inclined surface extending upwardly and inclined from the side wall of the gland.

[0020] In some embodiments, the angle between the inclined surface and the horizontal plane is 30-60°.

[0021] In some embodiments, the inner side wall of the protective cover is provided with a liquid blocking structure, which is a protruding structure arranged extending toward the outer side wall of the gland.

[0022] The second aspect of the embodiments of the present application provides a polishing system, which includes a polishing disc, a dressing part, a liquid supply part, and the carrier head as described above.

[0023] The beneficial effects of the present application include:

[0024] a. The interior of the carrier head is provided with a liquid blocking structure, which effectively prevents fluid such as polishing liquid from entering the interior of the carrier head through the gap between the protective cover and the gland;

[0025] b. The liquid blocking structure can be arranged on the inner side wall of the gland and / or the outer side wall of the protective cover to form a combined liquid blocking effect. BRIEF DESCRIPTION OF DRAWINGS

[0026] The advantages of the present application will become more apparent and more readily appreciated when considered in connection with the following detailed description, considered in conjunction with the accompanying drawings, which are merely illustrative and not restrictive, wherein:

[0027] Figure 1 is a schematic view of a carrier head for chemical mechanical polishing provided by an embodiment of the present application;

[0028] Figure 2 is Figure 1 is a partial enlarged view of A in

[0029] Figure 3 is a schematic view of a carrier head according to another embodiment of the present application.

[0030] Figure 4 is Figure 3 is a partial enlarged view of B in

[0031] Figure 5 is a schematic view of a carrier head according to another embodiment of the present application.

[0032] Figure 6 is Figure 5 is a partial enlarged view of C in

[0033] Figure 7 is a schematic view of a polishing system according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] The technical solutions of the present application will be described in detail below with reference to specific embodiments and the accompanying drawings. The embodiments described herein are specific embodiments of the present application, which are used to illustrate the concept of the present application; these descriptions are all explanatory and exemplary, and should not be understood as limiting the embodiments of the present application and the protection scope of the present application. In addition to the embodiments described herein, those skilled in the art can also employ other technical solutions that are obvious based on the content disclosed in the claims and the specification of the present application, which include technical solutions that make any obvious substitutions and modifications to the embodiments described herein.

[0035] The drawings of the present specification are schematic drawings that assist in illustrating the concept of the present application, and schematically represent the shape of each part and the relationship between them. It should be understood that, in order to clearly show the structure of each component of the embodiments of the present application, the drawings are not drawn according to the same scale, and the same reference numerals are used to represent the same parts in the drawings.

[0036] In the present application, "Chemical Mechanical Polishing (CMP)" is also referred to as "Chemical Mechanical Planarization (CMP)", and "Wafer (W)" is also referred to as "Substrate", which have the same meaning and actual effect.

[0037] Embodiments of the present disclosure generally relate to a chemical mechanical polishing (CMP) unit used in the semiconductor device manufacturing industry.

[0038] In chemical mechanical polishing, a polishing liquid composed of sub-micron or nano abrasive particles and chemical solution flows between the wafer and the polishing pad, and the polishing liquid is uniformly distributed under the action of the transmission of the polishing pad and the rotation centrifugal force to form a thin liquid film between the wafer and the polishing pad. The chemical components in the liquid react with the wafer to convert insoluble substances into soluble substances, which are then removed from the wafer surface by the micromechanical friction of the abrasive particles and dissolved into the flowing liquid, that is, the surface material is removed in the alternating process of chemical film formation and mechanical film removal to achieve surface planarization treatment, thereby achieving the purpose of global planarization.

[0039] Figure 1 is a schematic view of a carrier head 100 for chemical mechanical polishing provided by an embodiment of the present application, the carrier head 100 comprising:

[0040] a base 10, an upper part of the base 10 being configured with a connecting flange to connect a rotary driving device and drive the carrier head 10 to rotate around its axis;

[0041] a carrier disc 20 arranged below the base 10; specifically, the carrier disc 20 is connected concentrically to the lower part of the base 10 through a diaphragm 70, and a shaft part is arranged at the middle position of the carrier disc 20, which is slidingly connected to the hole part at the center position of the base 10, so that the carrier disc 20 and the base 10 can move relatively vertically to adjust the vertical position of the carrier disc 20;

[0042] an elastic film 30 arranged below the carrier disc 20 for loading the wafer to be polished;

[0043] a retaining ring 40 arranged below the carrier disc 20 and located at the outer peripheral side of the elastic film 30 to limit the position of the wafer and prevent the polished wafer from flying out of the inside of the carrier head 100 to cause debris;

[0044] a gland 50 arranged above the carrier disc 20; the gland 50 is annular in structure and is arranged at the outer peripheral side of the carrier disc 20;

[0045] a protective cover 60 connected to the base 10 and covering the outer peripheral side of the gland 50 to protect the internal structure of the carrier head 100 from the polishing liquid and the particulate matter generated during polishing from entering the inside of the carrier head 100.

[0046] During chemical mechanical polishing, the polishing liquid and the particulate matter generated during polishing will follow the outer sidewall of the retaining ring 40, enter the gap between the protective cover 60 and the gland 50, and be transmitted along the outer sidewall of the gland 50 to the upper part of the carrier disc 20. The polishing liquid and the particulate matter generated during polishing may accumulate near the diaphragm 70 in front of the carrier disc 20 and the base 10. Since the polishing liquid has a certain corrosive property, it will cause damage to the diaphragm 70 and the connected parts, to some extent affecting the service life of the carrier head 100.

[0047] To solve the above problems, in the present application, the outer peripheral side of the gland 50 is provided with a liquid blocking structure, such as Figure 1 as shown, to prevent the liquid from being transmitted upward through the gap between the protective cover 60 and the gland 50.

[0048] Figure 2 is Figure 1 A partial enlarged view of A in the figure, the liquid blocking structure provided on the outer side wall of the gland 50 is a liquid blocking groove 51, which prevents the polishing liquid and other liquids from being transmitted upward along the outer side wall of the gland 50.

[0049] Further, the liquid blocking groove 51 is a ring-shaped groove, and the opening thereof is inclined downward. Specifically, the longitudinal section of the liquid blocking groove 51 is a quadrilateral opening outward, so that the liquid entering the liquid blocking groove 51 along the outer side wall of the gland 50 is turned inside the liquid blocking structure and transmitted downward, to prevent the liquid from entering the inside of the carrier head 100 along the gland 50.

[0050] Figure 2 In the figure, the number of liquid blocking grooves 51 is a pair, which are arranged in the height direction of the gland 50. In this way, the liquid entering through the gap between the protective cover 60 and the gland 50 can be formed into multiple layers of barriers, avoiding or reducing the liquid from entering the inside of the carrier head 100.

[0051] It should be noted that the number of liquid blocking grooves 51 is at least one, to prevent the liquid from entering the inside of the carrier head 100. It can be understood that the liquid blocking groove 51 can also be three, four or other numbers.

[0052] As an embodiment of the present application, the width of the liquid blocking groove 51 in the transverse and longitudinal directions is greater than or equal to the gap between the protective cover 60 and the gland 50, so that the liquid blocking groove 51 can buffer part of the liquid, and the liquid is turned inside the liquid blocking groove 51 and transmitted downward.

[0053] Figure 3 is a schematic view of the carrier head 100 provided by another embodiment of the present application, which is similar to Figure 1 the structure of the carrier head shown in the figure, and only the differences between the two will be described below.

[0054] The outer peripheral side of the gland 50 is provided with a liquid blocking structure, which is a liquid blocking groove 51, and the liquid blocking groove 51 is arranged horizontally outward.

[0055] Further, the liquid blocking groove 51 is a notch structure with an outward opening, so that the liquid entering between the protective cover 60 and the gland 50 flows downward after entering the liquid blocking groove 51.

[0056] Figure 4In the embodiment, the liquid blocking groove 51 comprises an inclined surface 51a extending upwardly from the sidewall of the cover 50.

[0057] Further, the angle between the inclined surface 51a and the horizontal plane is 30-60°. Preferably, the angle between the inclined surface 51a and the horizontal plane is 45°, so that the liquid can enter the interior of the liquid blocking groove 51 via the inclined surface 51a, and the liquid changes the transmission direction in the interior of the liquid blocking groove 51 to avoid entering the interior of the carrier head 100.

[0058] Figure 5 is a schematic view of the carrier head 100 provided by an embodiment of the present application, which comprises:

[0059] a base 10;

[0060] a carrier disc 20 arranged below the base 10;

[0061] an elastic film 30 arranged below the carrier disc 20 and used for loading the wafer to be polished;

[0062] a retaining ring 40 arranged below the carrier disc 20 and located at the outer circumferential side of the elastic film 30;

[0063] a cover 50 arranged above the carrier disc 20; the outer circumferential wall of the cover 50 is provided with a liquid blocking groove 51;

[0064] a protective cover 60 connected to the base 10 and covering the outer circumferential side of the cover 50 to protect the internal structure of the carrier head 100.

[0065] Further, the inner sidewall of the protective cover 60 is provided with a liquid blocking structure, which is a protruding structure 61 extending towards the outer sidewall of the cover 50, as shown in Figure 6 .

[0066] Figure 6 In the embodiment, the number of the protruding structures 61 arranged on the inner sidewall of the protective cover 60 is one pair, which are arranged at the lower side of the liquid blocking groove 51. In the embodiment, the protruding structure 61 and the liquid blocking groove 51 are combined with each other to form a barrier to the fluid between the protective cover 60 and the cover 50, so as to reduce or avoid the fluid entering the interior of the carrier head 100 via the gap, prevent the polishing liquid from accumulating at the connecting part between the base 10 and the carrier disc 20, prolong the service life of the corresponding components of the carrier head 100, and ensure the stability of the carrier head 100.

[0067] It should be noted that the transverse dimension of the protruding structure 61 is related to the gap dimension between the protective cover 60 and the cover 50, so as to avoid the protruding structure 61 from forming a capillary effect to transport the liquid towards the interior of the carrier head 100.

[0068] It can be understood that the carrier head 100 can not be configured with the grommet 50, and the liquid blocking structure described above can be arranged on the outer sidewall of the carrier disc 20 to prevent or reduce the fluid from entering the interior of the carrier head 100 via the gap between the protective cover 60 and the carrier disc 20.

[0069] Figure 7 FIG. 1 is a schematic view of a polishing system 1000 according to an embodiment of the present application, which comprises the carrier head 100, the polishing disc 300, the polishing pad 200, the dresser 400 and the liquid supply 500.

[0070] The polishing pad 200 is arranged on the upper surface of the polishing disc 300, and the polishing pad 200 rotates together with the polishing disc 300 around the Ax axis. The horizontally movable carrier head 100 is arranged above the polishing pad 200, and the bottom of the carrier head 100 is attracted to the wafer to be polished. The dresser 400 swings around a fixed point, and the dresser head arranged thereon rotates by itself and applies a downward load to dress the surface of the polishing pad 200. The liquid supply 500 is arranged above the polishing pad 200 to spread the polishing liquid on the surface of the polishing pad 200.

[0071] During the polishing operation, the carrier head 100 abuts the surface of the polishing pad 200 with the wafer to be polished, and the carrier head 100 rotates and reciprocates along the radial direction of the polishing disc 300, so that the surface of the wafer in contact with the polishing pad 200 is gradually polished. At the same time, the polishing disc 300 rotates, and the liquid supply 500 sprays the polishing liquid on the surface of the polishing pad 200 to supply the polishing liquid between the wafer and the polishing pad 200. Under the chemical action of the polishing liquid, the wafer is rubbed with the polishing pad 200 through the relative motion of the carrier head 100 and the polishing disc 300 to achieve global polishing.

[0072] The interior of the carrier head 100 is configured with the liquid blocking structure to effectively prevent the polishing liquid and other fluids from entering the interior of the carrier head via the gap between the protective cover and the grommet.

[0073] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0074] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the application. The scope of the application is not to be limited by the embodiments shown and described, but only by the claims and their equivalents.

Claims

1. A carrier head for chemical mechanical polishing, characterized by, The application relates to a carrier head, comprising: a base; a carrier disc arranged below the base; an elastic film arranged below the carrier disc; a retaining ring arranged below the carrier disc and located at the outer periphery of the elastic film; a cover arranged above the carrier disc; a protective cover connected to the base and covering the outer periphery of the cover; the outer periphery of the cover is provided with a liquid blocking groove to prevent liquid from being transported upward through the gap between the protective cover and the cover; the liquid blocking groove is arranged obliquely downward, the number of the liquid blocking grooves is at least one, and the liquid blocking grooves are arranged at intervals in the height direction of the cover; and the longitudinal section of the liquid blocking groove is a quadrilateral opening outward.

2. The load head of claim 1 wherein, The transverse and longitudinal widths of the liquid blocking groove are greater than or equal to the gap between the protective cover and the cover.

3. The load head of claim 1 wherein, The inner side wall of the protective cover is provided with a liquid blocking structure, which is a protruding structure extending towards the outer side wall of the cover.

4. A polishing system characterized by, The application further relates to a polishing disc, a dressing part, a liquid supply part and the carrier head according to any one of claims 1 to 3.

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