Wafer post-processing device

Abstract

The present invention discloses a wafer post-processing device, which comprises: a driving mechanism, which vertically clamps the wafer; a driving mechanism, which drives the driving mechanism and the wafer to rotate; a supply arm, which swings on the side of the wafer and supplies liquid to the surface of the wafer through a nozzle thereon; a retaining ring, which is arranged on the outer peripheral side of the driving mechanism to prevent the liquid from splashing; and a guide structure is provided on the edge of the retaining ring to prevent the liquid from accumulating and dripping on the edge of the retaining ring.

Description

Technical Field

[0001] The invention belongs to the technical field of wafer drying, and in particular relates to a wafer post-processing device. Background Art

[0002] Wafer manufacturing is a key link in the development of the integrated circuit (IC) industry. As the feature size of integrated circuits continues to shrink, the requirements for wafer surface quality are getting higher and higher, so the control of defect size and quantity in the wafer manufacturing process is becoming more and more stringent. In the logic chip process, when the feature size develops from 28nm to 7nm, the control range of contaminants above 19nm is also reduced from 100 to 50, gradually approaching the limits of cleaning technology and measurement technology. Contaminants are an important factor that causes the quality of the wafer surface to deteriorate and even cause defects. Therefore, cleaning technology is needed to desorb contaminants on the wafer surface to obtain an ultra-clean surface, especially in the post-cleaning and drying of chemical mechanical polishing (CMP), liquid mark defects are easily encountered, which will lead to local changes in oxide thickness and seriously affect the chip manufacturing qualification rate.

[0003] Patent CN111540702B discloses a vertical Marangoni wafer processing device, which adopts a semi-annular retaining ring structure with an arc-shaped inner wall. The retaining ring is hydrophilic and can catch the liquid thrown out from the edge of the wafer and guide the liquid toward the two ends of the retaining ring to prevent the liquid from being thrown onto the wall surfaces at higher positions such as the top wall of the chamber, thereby avoiding the fine droplets caused by the liquid colliding and sputtering at these positions to contaminate the front space and surface of the wafer.

[0004] When the liquid is thrown from the wafer to the inner arc surface of the semi-annular retaining ring, most of the liquid will flow along the inner wall of the retaining ring towards the two terminal directions of the semi-annular outer retaining ring; but there is also a small amount of liquid that will flow along the inner wall of the retaining ring away from the backplane, thereby accumulating into droplets at the edge of the retaining ring and randomly dripping onto the wafer surface, affecting the processing effect of the wafer surface. Summary of the invention

[0005] The present invention aims to solve one of the technical problems existing in the prior art to at least some extent.

[0006] To this end, an embodiment of the present invention provides a wafer post-processing device, which includes:

[0007] A driving mechanism that vertically clamps the wafer and drives the wafer to rotate;

[0008] a supply arm that swings at the side of the wafer and supplies liquid to the wafer surface via a nozzle thereon;

[0009] A retaining ring, which is arranged on the outer peripheral side of the driving mechanism to prevent the liquid from splashing;

[0010] The edge of the retaining ring is provided with a flow guiding structure to prevent the liquid on the edge of the retaining ring from accumulating and dripping.

[0011] As a preferred embodiment, the retaining ring is an annular structure, which is covered on the outer peripheral side of the driving mechanism.

[0012] As a preferred embodiment, the retaining ring is made of a hydrophilic material to form a flow-guiding structure at the edge of the retaining ring.

[0013] As a preferred embodiment, the flow-guiding structure is made of a porous material and is detachably arranged on the edge of the retaining ring.

[0014] As a preferred embodiment, the guide structure is a guide groove arranged along the contour of the retaining ring, and the number of the guide grooves is not less than one.

[0015] As a preferred embodiment, the guide groove is arranged on the inner side surface and / or the outer end surface of the edge of the retaining ring.

[0016] As a preferred embodiment, the guide groove is arranged perpendicular to the side surface of the edge of the retaining ring.

[0017] As a preferred embodiment, the cross section of the guide groove is a long strip, and the width thereof matches the capillary force of the attached liquid.

[0018] As a preferred embodiment, the width of the guide groove is 0.02 mm to 8 mm.

[0019] As a preferred embodiment, the guide groove is arranged to be inclined relative to the side surface of the edge of the retaining ring.

[0020] As a preferred embodiment, the retaining ring includes an outer retaining ring and an inner retaining ring located inside the outer retaining ring.

[0021] As a preferred embodiment, the inner wall of the outer retaining ring includes a liquid receiving surface for receiving liquid thrown out by the wafer and a liquid guiding surface for guiding the liquid to the bottom of the inner wall, and both the liquid receiving surface and the liquid guiding surface are planes.

[0022] The beneficial effects of the present invention include:

[0023] A guide structure is provided at the edge of the retaining ring to prevent the droplets accumulated on the upper side of the retaining ring from falling onto the surface of the wafer, thereby effectively ensuring the cleaning and drying effect of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The advantages of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings, which are only schematic and do not limit the scope of protection of the present invention, wherein:

[0025] Figure 1 A wafer post-processing device provided by an embodiment of the present invention is shown;

[0026] Figure 2 The wafer post-processing device provided in the first embodiment is shown;

[0027] Figure 3 The outer retaining ring provided in the second embodiment is shown;

[0028] Figure 4 and Figure 5 The flow guiding structure provided by the fourth embodiment is shown;

[0029] Figures 6 to 8 The flow guiding structure provided in the fifth embodiment is shown. DETAILED DESCRIPTION

[0030] The technical scheme of the present invention is described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments recorded herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limitations on the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments recorded herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments recorded herein.

[0031] The drawings of this specification are schematic diagrams, which assist in explaining the concept of the present invention and schematically show the shapes of various parts and their mutual relationships. It should be understood that in order to clearly show the structures of various components of the embodiments of the present invention, 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.

[0032] In the present invention, "Chemical Mechanical Polishing (CMP)" is also called "Chemical Mechanical Planarization (CMP)", and the wafer is also called substrate, and their meanings and actual functions are equivalent.

[0033] Figure 11 is a schematic diagram of the structure of a wafer post-processing device 100 according to the present invention, which includes a driving mechanism 10 and a supply arm 20, both of which are arranged in a box. The driving mechanism 10 is a disc-shaped structure, and its outer edge is provided with a claw to reliably clamp the wafer w; the rear side of the driving mechanism 10 is provided with a driving motor to drive the wafer w to rotate in a vertical plane. Driven by the motor assembly, the supply arm 20 swings in a vertical plane parallel to the plane where the wafer w is located. The supply arm 20 is provided with a nozzle at its free end, so that liquid can be supplied to the global surface of the rotating wafer w through the nozzle moving with the supply arm 20.

[0034] The wafer post-processing device 100 also includes a retaining ring 30, which is arranged on the outer peripheral side of the driving mechanism 10 to prevent liquid thrown out by centrifugal force on the surface of wafer w from falling onto the top wall of the box chamber, thereby preventing fine droplets caused by liquid impact and sputtering at these positions from contaminating the front space and surface of wafer w, and preventing droplets formed by liquid accumulation on the top wall of the chamber from dripping downward and contaminating wafer w.

[0035] Embodiment 1

[0036] like Figure 2 As shown, the retaining ring 30 includes an outer retaining ring 41 and an inner retaining ring 47 located inside the outer retaining ring 41, and both the outer retaining ring 41 and the inner retaining ring 47 are mounted on the chamber back plate 50. The outer retaining ring 41 is used to block the liquid thrown out of the wafer w and guide it to the bottom thereof, and the inner retaining ring 47 is used to block the liquid flowing out from the bottom of the outer retaining ring 41 to prevent the liquid from falling back onto the surface of the wafer w.

[0037] In one embodiment, the outer retaining ring 41 is connected to the chamber back plate 50 through a telescopic mechanism 48, and the telescopic mechanism 48 drives the outer retaining ring 41 away from or close to the chamber back plate 50, so that the outer retaining ring 41 moves to different positions in different process steps. For example, the outer retaining ring 41 moves to an initial position close to the chamber back plate 50 to facilitate the placement of the wafer, and the outer retaining ring 41 moves to a working position away from the chamber back plate 50 to surround the wafer w and block the sputtered liquid when the wafer w is cleaned. In this embodiment, the outer retaining ring 41 is set to be movable to meet the needs of different process steps.

[0038] In one embodiment, Figure 1 As shown, the outer retaining ring 41 is a full ring structure, which can completely block the liquid thrown out by the wafer w, so as to prevent the liquid thrown out from the position not blocked by the outer retaining ring 41 from splashing onto the side wall of the chamber, splashing and rebounding to the space in front of the wafer w, thereby avoiding that some of the splashed droplets will contaminate the wafer w. Furthermore, a drainage hole 46 is provided at the bottom of the outer retaining ring 41 to drain the liquid received by the outer retaining ring 41 in time.

[0039] Embodiment 2

[0040] like Figure 3 As shown, the inner wall of the outer retaining ring 41 includes a liquid receiving surface 42 for receiving the liquid thrown out by the wafer w and a liquid guiding surface 43 for guiding the liquid to the bottom of the inner wall, wherein the liquid receiving surface 42 and the liquid guiding surface 43 are both planes, and the liquid receiving surface 42 and the liquid guiding surface 43 are transitioned by a smooth arc surface. Figure 3 As shown, the liquid receiving surface 42 extends upwardly from the top of the extension 44 toward the chamber back plate 50. The angle between the liquid receiving surface 42 and the vertical plane is less than 45°. The liquid guiding surface 43 extends upwardly from the bottom of the inner wall toward the liquid receiving surface 42. The angle between the liquid guiding surface 43 and the horizontal plane is less than 45°.

[0041] like Figure 3 As shown, when the angle between the liquid thrown out of the wafer w and the tangent of the liquid receiving surface 42 is very small, the position where the two meet is effectively sputter-proof. Compared with the inner wall of the arc-shaped outer retaining ring 41 in the past, the planar liquid receiving surface 42 provided in this embodiment effectively extends the anti-sputtering width L0 of the outer retaining ring 41. In addition, the planar liquid guide surface 43 is provided, and the characteristic of the small angle between the liquid guide surface 43 and the horizontal direction is conducive to reducing the possibility of the droplets sputtered from the liquid receiving surface 42 being sputtered again toward the front direction of the wafer w through the liquid guide surface 43, reducing the possibility of sputtering contamination of the wafer w, while retaining the function of draining the liquid to the inner retaining ring 47 to prevent it from directly dripping to the driving mechanism 10.

[0042] Embodiment 3

[0043] Since some liquid droplets will accumulate on the upper side of the retaining ring 30, these liquid droplets will affect the post-processing of the wafer w. In order to solve the above technical problems, the retaining ring 30 of the present invention is equipped with a guide structure 30a, such as Figure 1 As shown, the guide structure 30 a is disposed along the edge of the contour of the retaining ring 30 , and the guide structure 30 a guides the liquid thrown out by the wafer w to the lower part of the retaining ring 30 .

[0044] As an embodiment of the present invention, the retaining ring 30 is an annular structure, such as Figure 1 As shown, the cover is arranged on the outer peripheral side of the driving mechanism 10, and the guide structure 30a is arranged on the edge of the retaining ring 30. The droplets accumulated on the top of the inner wall of the retaining ring 30 can flow toward the lower part of the retaining ring 30 under the guidance of the guide structure 30a to avoid the droplets from dripping onto the surface of the wafer w under the action of gravity.

[0045] In one embodiment, the retaining ring 30 is made of a hydrophilic material, and the various components of the retaining ring 30 can be made of materials with different hydrophilicities. A hydrophilic gradient is formed on the inner wall of the retaining ring 30 to form a guide structure 30a to guide the fluid accumulated on the inner wall of the retaining ring 30 to move toward the lower part of the retaining ring 30. Specifically, the edge of the retaining ring 30 can be made of a super-hydrophilic material with good hydrophilicity, while the other parts of the retaining ring 30 can be made of ordinary hydrophilic materials to improve the hydrophilicity of the edge of the retaining ring 30.

[0046] Embodiment 4

[0047] like Figure 4 As shown, the flow guiding structure 30a includes a porous material 45, which is used to collect and guide the liquid gradually accumulated on the top of the outer retaining ring 41, and is detachably arranged on the edge of the retaining ring 30 through rivets. The porous material 45 attaches the liquid flow / liquid droplet from the top of the outer retaining ring 41 by capillary action, and discharges the liquid from the bottom end of the porous material 45 by siphon action, so that the top of the porous material 45 is always in an unsaturated state, and the liquid flow can be continuously accumulated and the liquid can be guided away from the inside, which solves the problem of dripping on the top of the outer retaining ring 41 and prevents the contamination and defects of the wafer w caused by the accumulated dripping liquid.

[0048] In one embodiment, Figure 4 As shown, the edge of the outer retaining ring 41 away from the chamber back plate 50 is provided with a protruding portion 44, and the protruding portion 44 is parallel to the chamber back plate 50, so as to facilitate the liquid on the inner wall of the outer retaining ring 41 to flow to the protruding portion 44. Figure 4 As shown, the extension 44 is covered with a porous material 45, and the liquid accumulated on the top of the outer retaining ring 41 can be collected by the porous material 45 under the capillary action. The porous material 45 is a hydrophilic material and can be made of a thin sheet of PVA sponge.

[0049] In one embodiment, Figure 5 As shown, the porous material 45 is disposed on the edge of the outer retaining ring 41, and the porous material 45 is symmetrically distributed. The coverage area of ​​the porous material 45 exceeds 50% of the edge of the outer retaining ring 41, preferably 60% to 75%. Figure 5 As shown, the liquid flows inside the porous material 45 and is discharged at the bottom end of the porous material 45, so that the droplets accumulated on the top of the inner wall of the outer retaining ring 41 can flow toward the lower part of the outer retaining ring 41 under the guidance of the porous material 45 to prevent the droplets from dripping onto the surface of the wafer w under the action of gravity.

[0050] In one embodiment, the extension portion 44 is provided with a through hole for fixing the porous material 45, and the porous material 45 is detachably fixed to the through hole by rivets and is thus arranged on the edge of the outer retaining ring 41, so as to facilitate regular replacement of the porous material 45 to ensure the post-processing effect of the wafer w.

[0051] Embodiment 5

[0052] As another embodiment of the present invention, the guide structure 30a is a guide groove arranged along the contour of the retaining ring 30, such as Figure 6 As shown, there are two guide grooves, which are arranged at intervals along the radial direction of the retaining ring 30. The liquid droplets on the liquid receiving surface 42 of the inner wall of the retaining ring 30 slide toward the edge of the retaining ring and slide into the interior of the guide groove.

[0053] Furthermore, the cross-section of the guide groove is a long strip, and the ratio of its depth to width matches the capillary force of the attached liquid. Specifically, the width of the guide groove is set so that it can provide a suitable capillary force to accumulate the liquid in the guide groove and reliably limit the liquid to flow in the guide groove. It is understandable that the capillary force of the guide groove should not be too strong, as too strong capillary force will make it difficult for the liquid to be discharged from the end of the guide groove by gravity and siphon action.

[0054] The width of the guide groove can be determined comprehensively based on the working conditions of the wafer post-processing device 100, such as the water flow rate of cleaning and drying; preferably, the width of the guide groove is between 0.02 mm and 8 mm.

[0055] To ensure that the guide groove has sufficient water storage capacity without affecting its capillary force, the ratio of the depth to the width of the guide groove is 0.1 to 50. Preferably, the ratio of the depth to the width of the guide groove is 0.5 to 10.

[0056] During wafer post-processing, the droplets gradually accumulated on the inner top of the retaining ring 30 will move along the liquid receiving surface 42 toward the edge of the retaining ring 30 away from the chamber back plate under the action of gravity; when the droplets touch the opening position of the guide groove, they will be quickly pulled into the guide groove due to the capillary action of the narrow slit structure of the guide groove.

[0057] If the liquid in the guide groove where liquid accumulates continues to increase, the newly added liquid will remain in the guide groove due to capillary action and be transported along the guide groove to both sides or one side of the position; when the adhesion force between the liquid and the inner wall of the guide groove is not sufficient to offset the gravity of the liquid, the liquid will flow downward along the guide groove to the end of the guide groove.

[0058] When the liquid at the end of the guide groove accumulates to the critical discharge height in the vertical direction, the additional liquid at the end will flow out from the end of the guide groove because the capillary force of the guide groove cannot withstand the gravity. This forms a cycle of guide groove adhesion liquid flow and guide drainage, thereby continuously and smoothly draining away the excess liquid on the top to prevent droplets from falling and contaminating the wafer w.

[0059] Figure 6In the embodiment shown, two guide grooves perpendicular to the side of the edge are provided on the edge of the retaining ring 30: a first guide groove 30a-1 and a second guide groove 30a-2. The depth and width of the guide groove are in the millimeter level to form a groove structure with a large cross-sectional area, thereby ensuring the guide capacity of the guide groove and realizing fast and efficient guide.

[0060] When the liquid flow rate to be guided locally is greater than the accumulation capacity of the first guide groove 30a-1, the overflowed liquid will be accumulated and guided by the second guide groove 30a-2. It can be understood that the second guide groove 30a-2 near the lower end surface of the edge of the retaining ring 30 is equivalent to the second line of defense, which effectively prevents the droplets accumulated on the top of the retaining ring 30 from falling.

[0061] Furthermore, the geometric dimensions of the guide groove are at the millimeter level, which is conducive to ensuring the structural strength; at the same time, the millimeter-level groove structure is convenient for selecting the processing form and is conducive to controlling the processing cost.

[0062] It is understandable that the guide groove of the retaining ring 30 may be provided with one, three, or more numbers, as long as the guide capacity of the retaining ring 30 matches the process technology of the wafer post-processing device 100 .

[0063] As an embodiment of the present invention, the guide groove is arranged on the inner side surface 33 and the outer end surface 34 of the edge of the retaining ring 30, such as Figure 7 As shown. The retaining ring 30 has multiple guide grooves, and the width and depth of the guide grooves may be different when viewed from the longitudinal section. A guide groove with a smaller width has a stronger capillary suction, but the decrease in cross-sectional area will reduce its flow-conducting capacity. Using multiple such guide grooves can supplement the flow-conducting capacity. Liquid that one guide groove does not have time to accumulate and guide will be accumulated and guided by the adjacent guide grooves. Since the width and depth of the guide grooves used in this embodiment are relatively small, there is no need to significantly thicken the outer edge of the retaining ring 30 away from the back plate of the box body due to the provision of the guide grooves, so as to avoid occupying other working space inside the box body chamber.

[0064] Figure 8 Schematic diagram of another embodiment of the guide groove of the present invention. The structure can guide a relatively small liquid flow and is suitable for scenes with small liquid flow. The guide groove is located at the lower end surface 34 of the edge of the retaining ring 30. Such a configuration is conducive to designing a steeper profile line of the liquid contact surface 42 of the retaining ring 30, so that the angle between the direction of the wafer w ejecting the liquid and the liquid contact surface 42 is smaller, so as to enhance the anti-sputtering capability.

[0065] As Figure 6 As a variation of the embodiment, the guide groove may also be inclined relative to the side of the edge of the retaining ring 30, so as to ensure the guiding effect of the guide groove and prevent the accumulation and dripping of droplets on the top of the inner wall of the retaining ring 30 and affect the post-processing effect of the wafer w.

[0066] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0067] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A wafer post-processing device, characterized in that: include: A driving mechanism that vertically clamps the wafer and drives the wafer to rotate; a supply arm that swings at the side of the wafer and supplies liquid to the wafer surface via a nozzle thereon; A retaining ring, which is arranged on the outer peripheral side of the driving mechanism to prevent the liquid from splashing; The edge of the retaining ring is provided with a guide structure to prevent the liquid on the edge of the retaining ring from accumulating and dripping; The guide structure is a guide groove arranged along the contour of the retaining ring, and the number of guide grooves arranged is not less than one; the cross section of the guide groove is a long strip, and the width thereof matches the capillary force of the attached liquid; the ratio of the depth to the width of the guide groove is 0.1 to 50; The retaining ring is made of hydrophilic material, and its various components are made of materials with different hydrophilicities, so that the inner wall of the retaining ring forms a hydrophilicity gradient to guide the liquid accumulated on the inner wall of the retaining ring to move toward the lower part of the retaining ring.

2. The wafer post-processing device according to claim 1, characterized in that: The retaining ring is an annular structure, and is disposed on the outer peripheral side of the driving mechanism.

3. The wafer post-processing device according to claim 1, characterized in that: The retaining ring is made of a hydrophilic material to form a flow guiding structure at the edge of the retaining ring.

4. The wafer post-processing device according to claim 1, characterized in that: The flow-guiding structure comprises a porous material, which is detachably arranged on the edge of the retaining ring.

5. The wafer post-processing device according to claim 1, characterized in that: The guide groove is arranged on the inner side surface and / or the outer end surface of the edge of the retaining ring.

6. The wafer post-processing device according to claim 1, characterized in that: The guide groove is arranged perpendicular to the side surface of the edge of the retaining ring.

7. The wafer post-processing device according to claim 1, characterized in that: The width of the guide groove is 0.02 mm to 8 mm.

8. The wafer post-processing device according to claim 1, characterized in that: The guide groove is arranged obliquely relative to the side surface of the edge of the retaining ring.

9. The wafer post-processing device according to claim 1, characterized in that: The retaining ring comprises an outer retaining ring and an inner retaining ring located inside the outer retaining ring.

10. The wafer post-processing device according to claim 9, characterized in that: The inner wall of the outer retaining ring includes a liquid receiving surface for receiving liquid thrown out by the wafer and a liquid guiding surface for guiding the liquid to the bottom of the inner wall, and both the liquid receiving surface and the liquid guiding surface are planes.

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