CN114944344A

CN114944344A - Wafer post-processing device

Info

Publication number: CN114944344A
Application number: CN202111676177.XA
Authority: CN
Inventors: 曹自立; 李长坤; 李灯; 赵德文
Original assignee: Huahaiqingke Co Ltd
Current assignee: Huahaiqingke Co Ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-08-26

Abstract

The invention discloses a wafer post-processing device, which comprises: a driving mechanism for vertically clamping the wafer; the driving mechanism drives the driving mechanism and the wafer to rotate; a supply arm which swings at a side surface of the wafer and supplies liquid to a surface of the wafer through a nozzle thereon; a stopper ring provided on an outer peripheral side of the drive mechanism to prevent the liquid from splashing; the edge of the retainer ring is provided with a flow guide structure so as to prevent liquid at the edge of the retainer ring from accumulating and dripping.

Description

Wafer post-processing device

Technical Field

The invention belongs to the technical field of wafer drying, and particularly relates to a wafer post-processing device.

Background

Wafer fabrication is a key link in the development of the Integrated Circuit (IC) industry. As integrated circuit feature sizes continue to shrink, wafer surface quality requirements become higher and higher, and thus wafer fabrication processes have tighter and tighter control over the size and number of defects. In the logic chip process, when the feature size is increased from 28nm to 7nm, the control range of contaminants above 19nm is also reduced from 100 to 50, and the limit of the cleaning technique and the measurement technique is gradually approached. Contaminants are important factors causing the quality of the wafer surface to be reduced and even causing defects, so that the contaminants on the wafer surface need to be desorbed by adopting a cleaning technology so as to obtain an ultra-clean surface, and particularly in post-cleaning drying of Chemical Mechanical Polishing (CMP), liquid mark defects are easily encountered, which cause local variation of oxide thickness and seriously affect the chip manufacturing yield.

Patent CN111540702B discloses a vertical marangoni wafer processing apparatus, which adopts a semicircular retaining ring structure with an arc-shaped inner wall surface, wherein the retaining ring has hydrophilicity, and can receive the liquid thrown out from the edge of the wafer and guide the liquid towards the two ends of the retaining ring, so as to prevent the liquid from being thrown to the wall surface of the upper position such as the top wall of the chamber, and avoid the liquid from polluting the front space of the wafer and the surface of the wafer by the tiny liquid drops caused by the impact and sputtering of the liquid at the positions.

When liquid is thrown from the wafer onto the inner arc surface of the semi-ring-shaped check ring, most of the liquid flows away along the inner wall of the check ring towards the two terminal directions of the semi-ring-shaped outer check ring; however, a small amount of liquid exists and flows along the inner wall of the retaining ring in the direction away from the back plate, so that liquid drops are accumulated at the edge of the retaining ring and randomly drop onto the surface of the wafer, and the treatment effect of the surface of the wafer is affected.

Disclosure of Invention

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

To this end, an embodiment of the present invention provides a wafer post-processing apparatus, which includes:

the driving mechanism vertically clamps the wafer and drives the wafer to rotate;

a supply arm which swings at a side surface of the wafer and supplies liquid to a surface of the wafer through a nozzle thereon;

a stopper ring provided on an outer peripheral side of the drive mechanism to prevent the liquid from splashing;

the edge of the retainer ring is provided with a flow guide structure so as to prevent liquid at the edge of the retainer ring from accumulating and dripping.

In a preferred embodiment, the retainer ring has an annular structure and covers an outer circumferential side of the drive mechanism.

In a preferred embodiment, the retainer ring is made of a hydrophilic material to form a flow guiding structure at the edge of the retainer ring.

As a preferred embodiment, the flow guiding structure is made of a porous material, and is detachably arranged on the edge of the retainer ring.

In a preferred embodiment, the flow guide structure is a flow guide groove arranged along the contour of the retainer ring, and the number of the flow guide groove is not less than one.

In a preferred embodiment, the diversion trench is disposed on the inner side surface and/or the outer end surface of the retainer ring edge.

In a preferred embodiment, the diversion trench is arranged perpendicular to the side surface of the retainer ring edge.

In a preferred embodiment, the cross section of the flow guide groove is in a long strip shape, and the width of the flow guide groove is matched with the capillary force of the hydrophilic liquid.

In a preferred embodiment, the width of the diversion trench is 0.02mm to 8 mm.

In a preferred embodiment, the diversion trench is obliquely arranged relative to the side surface of the retainer ring edge.

In a preferred embodiment, the retainer ring comprises an outer retainer ring and an inner retainer ring located inside the outer retainer ring.

In a preferred embodiment, the inner wall of the outer retainer ring comprises 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 the liquid receiving surface and the liquid guiding surface are both flat surfaces.

The beneficial effects of the invention include:

the edge of the retainer ring is provided with the flow guide structure to prevent liquid drops accumulated on the upper side of the retainer ring from falling to the surface of the wafer, and the cleaning and drying effects of the wafer are effectively guaranteed.

Drawings

The advantages of the invention will become clearer and more readily appreciated from the detailed description given with reference to the following drawings, which are given by way of illustration only, and which do not limit the scope of protection of the invention, wherein:

FIG. 1 illustrates a wafer post-processing apparatus according to an embodiment of the present invention;

FIG. 2 illustrates a wafer post-processing apparatus according to an exemplary embodiment;

FIG. 3 shows an outer retainer ring provided in the second embodiment;

fig. 4 and 5 show a flow guide structure provided in the fourth embodiment;

fig. 6 to 8 illustrate a flow guide structure provided in the fifth embodiment.

Detailed Description

The technical solution of the present invention is described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific embodiments of the present invention for the purpose of illustrating the concepts of the invention; the description is intended to be illustrative and exemplary and should not be taken to limit the scope of the invention. In addition to the embodiments described herein, those skilled in the art will be able to employ other embodiments that are obvious based on the disclosure of the claims and their description, including those that employ any obvious substitutions and modifications to the embodiments described herein.

The drawings in the present specification are schematic views to assist in explaining the concept of the present invention, and schematically show the shapes of respective portions and their mutual relationships. It should be understood that the drawings are not necessarily to scale, the same reference numerals being used to identify the same elements in the drawings in order to clearly show the structure of the elements of the embodiments of the invention.

In the present invention, "Chemical Mechanical Polishing (CMP)" is also referred to as "Chemical Mechanical Planarization (CMP)", and Wafer (Wafer) is also referred to as Substrate (Substrate), which means equivalent to actual effects.

Fig. 1 is a schematic structural diagram of a wafer post-processing apparatus 100 according to the present invention, which includes a driving mechanism 10 and a supply arm 20, both of which are disposed in a box. Wherein, the driving mechanism 10 is a disk-shaped structure, and the outer edge thereof is configured 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 the vertical plane. The feed arm 20 is driven by a motor assembly to oscillate in a vertical plane parallel to the plane of the wafer w, the feed arm 20 being provided with a nozzle at its free end so that liquid can be supplied to the global surface of the rotating wafer w via the nozzle moving with the feed arm 20.

The wafer post-processing apparatus 100 further includes a retaining ring 30 disposed at the outer periphery of the driving mechanism 10 to prevent the liquid thrown off by the centrifugal force on the surface of the wafer w from falling to the top wall of the chamber of the box body, so as to prevent the liquid from impacting and sputtering at these positions to cause fine liquid droplets to contaminate the front space of the wafer w and the surface of the wafer w, and prevent the liquid droplets formed by the accumulation of the liquid on the top wall of the chamber from falling downward to contaminate the wafer w.

Example one

As shown in fig. 2, the retainer ring 30 includes an outer retainer ring 41 and an inner retainer ring 47 located inside the outer retainer ring 41, and both the outer retainer ring 41 and the inner retainer ring 47 are mounted on the chamber back plate 50. The outer retainer ring 41 is used to block the liquid thrown off by the wafer w and guide the liquid to the bottom thereof, and the inner retainer ring 47 is used to block the liquid flowing out from the bottom of the outer retainer ring 41 to prevent the liquid from falling back to the surface of the wafer w.

In one embodiment, the outer retainer ring 41 is attached to the chamber backing plate 50 by a telescoping mechanism 48, and the telescoping mechanism 48 drives the outer retainer ring 41 away from or adjacent to the chamber backing plate 50 to move the outer retainer ring 41 to different positions during different process steps. For example, the outer retainer 41 is moved to an initial position near the chamber back plate 50 to facilitate the wafer pick-and-place, and the outer retainer 41 is moved to an operating position away from the chamber back plate 50 to surround the wafer w and to block the splashed liquid when the wafer w is cleaned. In this embodiment, the outer retainer 41 is movable to meet the requirements of different process steps.

In one embodiment, as shown in fig. 1, the outer retaining ring 41 is a full ring structure, which can completely shield the liquid thrown off by the wafer w, so as to prevent the liquid thrown off at a position not shielded by the outer retaining ring 41 from splashing on the sidewall surface of the chamber, splashing and rebounding to the space on the front surface of the wafer w, thereby preventing a part of the splashed liquid droplets from polluting the wafer w. Further, the bottom of the outer retainer 41 is provided with a drain hole 46 for draining the liquid received by the outer retainer 41 in time.

Example two

As shown in fig. 3, the inner wall of the outer retainer 41 includes a liquid receiving surface 42 for receiving the liquid thrown from the wafer w and a liquid guiding surface 43 for guiding the liquid to the bottom of the inner wall, wherein both the liquid receiving surface 42 and the liquid guiding surface 43 are flat surfaces, and the liquid receiving surface 42 and the liquid guiding surface 43 are transited by a smooth arc surface. As shown in fig. 3, the liquid-receiving surface 42 extends obliquely upward from the top end of the projection 44 toward the chamber back plate 50. The angle between the liquid-receiving surface 42 and the vertical surface is less than 45 deg.. The liquid guiding surface 43 extends obliquely upward 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 degrees.

As shown in fig. 3, when the included angle between the liquid thrown off by the wafer w and the tangent line of the liquid-receiving surface 42 is small, the position where the liquid-receiving surface 42 and the liquid-receiving surface are connected is effectively splash-proof, and the liquid-receiving surface 42 provided with the plane in the present embodiment effectively extends the splash-proof width L0 of the outer retainer 41 compared with the inner wall of the conventional arc-shaped outer retainer 41. In addition, the planar liquid guiding surface 43 is arranged, and the characteristic that the included angle between the liquid guiding surface 43 and the horizontal direction is small is matched, so that the possibility that liquid drops sputtered from the liquid receiving surface 42 are sputtered by the liquid guiding surface 43 and then shoot to the front side of the wafer w again is reduced, the possibility that the wafer w is polluted by sputtering is reduced, the function of guiding the liquid to the inner check ring 47 is kept, and the liquid is prevented from directly dropping to the driving mechanism 10.

EXAMPLE III

Since the upper side of the retainer ring 30 may accumulate some droplets, these droplets may have an influence on the post-processing of the wafer w. In order to solve the above technical problem, the baffle 30 of the present invention is configured with a flow guiding structure 30a, as shown in fig. 1, the flow guiding structure 30a is disposed along an edge of the outline of the baffle 30, and the flow guiding structure 30a guides the liquid thrown off by the wafer w to the lower portion of the baffle 30.

As an embodiment of the present invention, the retaining ring 30 is a ring-shaped structure, as shown in fig. 1, and is covered on the outer periphery of the driving mechanism 10, and the diversion structure 30a is disposed on the edge of the retaining ring 30, so that the liquid droplets accumulated on the top of the inner sidewall of the retaining ring 30 can flow toward the lower portion of the retaining ring 30 under the guidance of the diversion structure 30a, so as to avoid the liquid droplets from dropping onto the surface of the wafer w under the action of gravity.

In one embodiment, the retainer ring 30 is made of a hydrophilic material, and the components of the retainer ring 30 can be made of materials with different hydrophilicity. A hydrophilic gradient is formed on the inner sidewall of the retainer 30 to form a guide structure 30a that guides the inner wall accumulated in the retainer 30 to move toward the lower portion of the retainer 30. Specifically, the edge of the retainer ring 30 may be made of a super-hydrophilic material with good hydrophilicity, and the other portions of the retainer ring 30 are made of a common hydrophilic material to improve the hydrophilicity of the edge of the retainer ring 30.

Example four

As shown in fig. 4, the diversion structure 30a includes a porous material 45 for collecting and diverting liquid that gradually accumulates on the top of the outer retainer ring 41, which is detachably disposed at the edge of the retainer ring 30 by rivets. The porous material 45 adheres liquid flow/liquid drops from the top of the outer baffle 41 by virtue of capillary action, and liquid is discharged from the tail end of the bottom of the porous material 45 by utilizing siphon action, so that the top of the porous material 45 is always in an unsaturated state, liquid flow can be continuously accumulated and the liquid can be guided away from the inside, the problem of liquid dropping from the top of the outer baffle 41 is solved, and the pollution and the defect of the wafer w caused by the accumulated liquid dropping are prevented.

In one embodiment, as shown in fig. 4, the edge of the outer retainer 41 away from the chamber back plate 50 is provided with a protrusion 44, and the protrusion 44 is parallel to the chamber back plate 50 to facilitate guiding the liquid on the inner wall of the outer retainer 41 to the protrusion 44. As shown in fig. 4, the extension 44 is covered with a porous material 45, and the liquid accumulated on the top of the outer ring 41 can be completely 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 piece of PVA sponge.

In one embodiment, as shown in fig. 5, the porous material 45 is disposed at the edge of the outer retainer 41, the porous material 45 is distributed symmetrically, the coverage area of the porous material 45 exceeds 50%, preferably 60% to 75%, of the edge of the outer retainer 41, as shown in fig. 5, the liquid circulates inside the porous material 45 and is discharged at the bottom end of the porous material 45, so that the liquid drops accumulated on the top of the inner wall of the outer retainer 41 can flow toward the lower part of the outer retainer 41 under the guidance of the porous material 45, and the liquid drops are prevented from dropping onto the surface of the wafer w under the action of gravity.

In one embodiment, the extension 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 a rivet so as to be disposed at the edge of the outer retainer ring 41, thereby facilitating the periodic replacement of the porous material 45 to ensure the post-processing effect of the wafer w.

EXAMPLE five

As another embodiment of the present invention, the flow guiding structure 30a is a flow guiding groove disposed along the contour of the retainer 30, and as shown in fig. 6, the number of flow guiding grooves is two, and the flow guiding grooves are spaced apart along the radius direction of the retainer 30. The liquid drops on the liquid receiving surface 42 on the inner side wall of the retainer ring 30 slide toward the edge of the retainer ring and slide into the guide groove.

Furthermore, the section of the diversion trench is in a long strip shape, and the depth and width ratio of the diversion trench are matched with the capillary force of the hydrophilic liquid. In particular, the channels are provided with a width such that they provide a suitable capillary force to accumulate the liquid in the channels and to confine the liquid reliably within the channels. It will be appreciated that the capillary force of the channels should not be too strong, which would result in liquid not being easily drained from the ends of the channels by gravity and siphoning.

The width of the diversion trench can be determined comprehensively by combining the working conditions of the wafer post-processing device 100, such as the flow rate of cleaning and drying water; preferably, the width of the diversion trench is 0.02 mm-8 mm.

In order to ensure that the diversion trench has enough water storage capacity and does not influence the capillary force of the diversion trench, the ratio of the depth to the width of the diversion trench is 0.1-50. Preferably, the ratio of the depth to the width of the diversion trench is 0.5-10.

In the wafer post-processing process, the liquid drops accumulated gradually at the top of the inner side of the retainer ring 30 can move along the liquid receiving surface 42 to the edge of the side of the retainer ring 30 far away from the chamber back plate under the action of gravity; when the liquid drops contact the opening position of the diversion trench, the liquid drops are quickly pulled into the diversion trench due to the capillary action of the narrow slit structure of the diversion trench.

If the liquid in the diversion trench accumulated with liquid is continuously increased, the newly increased liquid is still in the diversion trench due to capillary action and is conveyed to two sides or one side of the diversion trench; when the adhesive force between the liquid and the inner wall surface of the diversion trench is not enough to counteract the gravity of the liquid, the liquid flows downwards along the diversion trench to the tail end of the diversion trench.

When the liquid at the tail end of the diversion trench accumulates to the critical discharge height in the vertical direction, the liquid newly added at the tail end cannot resist gravity due to the capillary force of the diversion trench and flows out from the tail end of the diversion trench, so that the circulation of the liquid flow and the diversion drainage of the diversion trench is formed, the redundant accumulated liquid at the top is continuously and smoothly discharged, and the phenomenon that the liquid drops fall to pollute the wafer w is avoided.

In the embodiment shown in fig. 6, the rim of the retainer 30 is provided with two channels perpendicular to the side of the rim: first guide grooves 30a-1 and second guide grooves 30 a-2. The depth and the width of the diversion trench are millimeter-sized to form a groove structure with a large sectional area, so that the diversion capability of the diversion trench is ensured, and the rapid and efficient diversion is realized.

When the flow rate of the liquid to be guided is locally larger than the accumulation capacity of the first guide groove 30a-1, the overflowed liquid will be accumulated and guided by the second guide groove 30 a-2. It can be understood that the second guiding grooves 30a-2 close to the lower end face of the edge of the retaining ring 30 are equivalent to a second defense line, and effectively prevent the liquid drops accumulated on the top of the retaining ring 30 from falling.

Furthermore, the geometric dimension of the diversion trench is millimeter level, which is beneficial to ensuring the structural strength; meanwhile, the millimeter-scale groove structure is convenient for selecting a processing form, and the processing cost is favorably controlled.

It is understood that the number of the diversion grooves of the baffle 30 may be one, three, or more, as long as the diversion capability of the baffle 30 matches the process of the wafer post-processing apparatus 100.

As an embodiment of the present invention, the channels are provided on the inner side 33 and the outer side 34 of the rim of the retainer 30, as shown in fig. 7. The retainer ring 30 has a plurality of guide grooves, and the width and depth of the guide grooves may be different from each other when viewed from a longitudinal section. Channels with smaller widths have stronger capillary suction, but the reduction of cross-sectional area reduces the flow conductivity. The flow guide capacity can be supplemented by using a plurality of flow guide grooves. One channel is shorter than the accumulated and guided liquid, and the accumulated and guided liquid is accumulated and guided by the adjacent channel. Because the width and the depth of the diversion trench used in the embodiment are smaller, the outer edge of the retainer ring 30 far away from the direction of the box body back plate does not need to be obviously thickened due to the arrangement of the diversion trench, so that other operation spaces in the box body cavity are avoided being occupied.

Fig. 8 is a schematic view of another embodiment of the guiding gutter of the present invention, which is capable of guiding a relatively small liquid flow rate, and is suitable for a scene with a small liquid flow rate. The diversion trench is located on the lower end face 34 of the edge of the check ring 30, and the arrangement is favorable for steeper section line design of the liquid receiving face 42 of the check ring 30, so that the included angle between the liquid throwing direction of the wafer w and the liquid receiving face 42 is smaller, and the anti-sputtering capacity is enhanced.

As a variation of the embodiment of fig. 6, the diversion trench may also be disposed obliquely with respect to the side surface of the edge of the retaining ring 30, so that the diversion effect of the diversion trench can also be ensured, and the post-processing effect of the wafer w is prevented from being affected by the accumulation and dropping of liquid drops on the top of the inner side wall of the retaining ring 30.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A wafer post-processing apparatus, comprising:

2. The wafer post-processing apparatus according to claim 1, wherein the retainer ring has an annular structure and covers an outer circumferential side of the driving mechanism.

3. The wafer post-processing apparatus as claimed in claim 1, wherein the retaining ring is made of a hydrophilic material to form a flow guiding structure at an edge of the retaining ring.

4. The wafer post-processing apparatus of claim 1, wherein the flow guide structure comprises a porous material detachably disposed at an edge of the retainer ring.

5. The wafer post-processing device according to claim 1, wherein the flow guide structure is a flow guide groove arranged along the contour of the retainer ring, and the number of the flow guide groove is not less than one.

6. The wafer post-processing device according to claim 5, wherein the diversion trench is disposed on an inner side surface and/or an outer side surface of the retainer ring edge.

7. The wafer post-processing device according to claim 5, wherein the diversion trench is disposed perpendicular to a side surface of the retainer ring edge.

8. The wafer post-processing apparatus as claimed in claim 5, wherein the guiding groove has a cross section of a long strip shape, and a width thereof is matched with a capillary force of the hydrophilic liquid.

9. The wafer post-processing device according to claim 8, wherein the width of the guiding groove is 0.02mm to 8 mm.

10. The wafer post-processing device according to claim 5, wherein the diversion trench is disposed obliquely with respect to a side surface of the retainer ring edge.

11. The wafer post-processing apparatus as claimed in claim 1, wherein the retaining ring comprises an outer retaining ring and an inner retaining ring located inside the outer retaining ring.

12. The wafer post-processing apparatus as recited in claim 11, wherein the inner wall of the outer retainer ring includes a liquid receiving surface for receiving liquid thrown off by the wafer and a liquid guiding surface for guiding the liquid toward the bottom of the inner wall, and the liquid receiving surface and the liquid guiding surface are both flat.