CN216657548U

CN216657548U - Double-sided adsorption device used as connecting piece in wafer planarization process

Info

Publication number: CN216657548U
Application number: CN202122945408.4U
Authority: CN
Inventors: 于海超; 汪松; 李尧尧; 周明
Original assignee: Strong Half Conductor Shanghai Co ltd; Hubei Jiangcheng Laboratory
Current assignee: Strong Half Conductor Shanghai Co ltd; Hubei Jiangcheng Laboratory
Priority date: 2021-11-26
Filing date: 2021-11-26
Publication date: 2022-06-03
Anticipated expiration: 2031-11-26

Abstract

A double-sided adsorption device used as a connecting piece in a wafer planarization process comprises an adsorption body with a certain thickness and an upper end face and a lower end face. The upper end surface of the adsorption body is used as an upper adsorption area of the adsorption polishing head, and the lower end surface of the adsorption body is used as a lower adsorption area for adsorbing the wafer; an air flow channel is arranged inside the air inlet pipe. The upper adsorption area is provided with a plurality of groups of concentric circular grooves which are communicated with the airflow channel; the lower adsorption area is provided with a plurality of adsorption holes which are communicated with the airflow channel; the adsorption holes are distributed in a concentric circle shape, the distance between two adjacent adsorption holes on the same ring is the same, and the distance is gradually decreased from the inner ring to the outer ring; the edge of the lower adsorption area is provided with a sealing ring, the lower end surface of the lower adsorption area protrudes downwards to serve as a positioning ring of the wafer, the protruding section and the lower adsorption area define a space for mounting the wafer together, and the lower end surface of the protruding section is higher than or level to the lower end surface of the wafer; an isolation groove is arranged between the sealing ring and the outermost layer adsorption hole and is communicated with the airflow channel.

Description

Double-sided adsorption device used as connecting piece in wafer planarization process

Technical Field

The utility model relates to the technical field of semiconductors, in particular to a double-sided adsorption device serving as a connecting piece in a wafer planarization process.

Background

Silicon wafers are widely used as substrate materials for semiconductor devices. A silicon wafer is produced by sequentially performing the following steps for a single crystal silicon ingot: peripheral grinding, slicing, lapping (lapping), etching, double-sided polishing, single-sided polishing, cleaning, and the like. Flatness is a variety of parameters used to characterize the wafer topography, thickness, etc., and specifically includes: warp (BOW), deformation (Warp), deformation with respect to a fitting Surface (SORI), maximum thickness variation (TTV), and the like.

The single-side Polishing step is a step necessary for improving flatness by removing irregularities or undulations on the surface of the wafer, and is a mirror-surface Polishing process using a CMP (Chemical Mechanical Polishing) method. The chemical mechanical polishing technology has two functions of mechanical polishing with polishing property and chemical polishing with acid and alkali resistant solution, so that the surface of the wafer can be completely flattened, and the subsequent film deposition can be carried out.

CMP polishing apparatuses are used in the substrate sheet industry, window sheet industry, ic fabrication industry, and MEMS planarization fabrication processes. CMP polishing apparatuses typically include a polishing platen to which a polishing pad is attached, over which a polishing head is disposed. In the polishing process, a wafer is pressed by a polishing head to be close to a polishing pad, while a polishing solution is dripped on the polishing pad, a polishing disk and the polishing head are respectively rotated, and the chemical corrosion and the mechanical friction are alternately and cyclically performed, thereby polishing one side of the wafer.

The wafer and the polishing head are relatively fixed through a wafer carrier such as a ceramic disc, and the wafer is fixed between the wafer and the ceramic disc in a solid wax coating and melting and then solidifying mode, but the mode has long processing time and inconvenient operation, and the uniformity of a wax layer cannot be ensured by pasting the solid wax, so that the wafer is bent and deformed, the surface of the wafer is uneven, and the condition of excessive polishing is easily caused. And subsequently, wax removal is needed, which easily causes wafer breakage. For wafers of different sizes, polishing heads in the polishing device need to be replaced by polishing heads of corresponding sizes, meanwhile, the wafers need to be waxed, if the wafers are not non-standard parts and are of special sizes, the wax pasting machine may need to be replaced, and cost is high.

In addition, the surface of the wafer is distorted, and a warpage (BOW) value exists, particularly, the warpage is higher at the edge of the wafer, and the flatness of the wafer is influenced. Before polishing, the surface of the wafer to be polished is flat by filling solid wax in a concave part of the surface of the wafer facing the ceramic disc, but the solid wax cannot ensure the uniformity of a wax layer, so that the surface quality of the wafer cannot be ensured, and a wax removing link is required to be added, so that the operation is inconvenient.

In view of the above, the present invention is to design a device for connecting and fixing a wafer, which is dedicated for the single-side polishing process of wafer planarization, and has the advantages of no damage to the wafer, convenient operation, and low cost.

Disclosure of Invention

The utility model aims to provide a double-sided adsorption device used as a connecting piece in a wafer planarization process.

In order to achieve the purpose, the utility model adopts the technical scheme that:

a double-sided adsorption device used as a connecting piece in a wafer planarization process comprises an adsorption body with a certain thickness, wherein the thickness direction of the adsorption body is defined as the vertical direction; the adsorption body is provided with an upper end face and a lower end face.

The upper end surface of the adsorption body is used as an upper adsorption area of the adsorption polishing head, and the lower end surface of the adsorption body is used as a lower adsorption area for adsorbing the wafer; an airflow channel is arranged in the adsorption body, and the airflow channel is provided with a vacuumizing port for communicating with a vacuum generator.

The upper adsorption area is provided with a plurality of groups of concentric circular grooves, and each circular groove is communicated with the airflow channel;

the lower adsorption area is provided with a plurality of adsorption holes, and each adsorption hole is communicated with the airflow channel; the adsorption holes are distributed on the lower adsorption area in a concentric circle shape, the distance between two adjacent adsorption holes on the same ring is the same, and the distance is gradually reduced from the inner ring of the concentric circle to the outer ring; the air flow channel, the round groove and the adsorption hole jointly define a vacuum cavity;

a sealing ring is arranged at the edge of the lower adsorption area, the lower end face of the sealing ring protrudes downwards relative to the lower adsorption area, the protruding section of the sealing ring is used as a positioning ring of the wafer, the protruding section of the sealing ring and the lower adsorption area define a space for mounting the wafer together, and the lower end face of the protruding section of the sealing ring is higher than or level to the lower end face of the wafer; an isolation groove is arranged between the sealing ring and the outermost layer adsorption hole and communicated with the airflow channel.

The relevant content in the above technical solution is explained as follows:

1. in the above scheme, the application process of the technical scheme is as follows: the adsorption body is firstly turned over, the lower adsorption area is arranged towards the upper side, the wafer is embedded into the protruding section of the sealing ring and then fixed, and the wafer is attached to the lower adsorption area. Then the adsorption body is turned over to make the lower adsorption area face downwards, and the wafer is fixed by the sealing ring and cannot fall off. The upper adsorption area faces upwards and is aligned and attached to the lower surface of the polishing head, and then the polishing head is vacuumized. The wafer is adsorbed and fixed in the lower adsorption area of the adsorption device, the adsorption device and the wafer are taken as a whole and adsorbed and fixed on the polishing head, namely the adsorption device is used as a connecting piece between the wafer and the polishing head. And then polishing treatment is carried out. And after polishing is finished, vacuumizing is stopped, the adsorption device and the wafer are integrally taken down from the polishing head, the adsorption device is turned over, the lower adsorption area is arranged towards the upper side, and the wafer is taken out.

In the scheme, the adsorption devices with different sizes are designed and processed according to the diameter sizes of different wafers, the density of holes can be customized according to the warping degree of the wafers, and the adsorption devices can be directly replaced when the wafers with different sizes need to be fixed. However, for the existing wafers with different sizes, the polishing heads in the polishing device need to be replaced and the polishing heads with the corresponding sizes need to be replaced, and for the wafers with special sizes, even the polishing heads need to be customized, so that the cost is high and the time consumption is long. Meanwhile, the wafer needs to be waxed, if the wafer is not a non-standard part and is of a special size, the wax pasting machine may need to be replaced, and the cost is high. In addition, the adsorption device of the technical scheme has strong universality and is suitable for the single-side polishing, grinding and MEMS planarization manufacturing process in the planarization process. In conclusion, the technical scheme has the advantages of convenience in operation, low cost, strong universality and stable connection, and facilitates the realization of a non-standard system.

3. Among the above-mentioned scheme, this technical scheme adopts adsorption equipment to adsorb fixedly to the wafer, and combines a sealing washer on the lower adsorption zone to assist fixedly to the wafer, convenient operation, fixed stable, can realize exempting from the waxing, avoid the wax, follow-up wafer adopt the pure water wash get rid of the polishing solution can, need not wash the wax removal specially again, can accomplish and fix the wafer harmlessly. In addition, the adsorption holes in the lower adsorption area are distributed in a non-uniform mode, the outer layer is dense, the inner layer is sparse, the wafer can be stretched and flattened on the surface of the adsorption device, the warping degree (BOW) is reduced, and the wafer is prevented from being over-polished.

4. In the scheme, the adsorption holes are distributed on the lower adsorption area in a concentric circle shape, the distance between two adjacent adsorption holes on the same ring is the same, and the distance is gradually decreased from the inner ring to the outer ring of the concentric circle. The adsorption holes are distributed non-uniformly, the distance between every two adjacent adsorption holes on the outer layer is smaller than that between every two adsorption holes on the inner layer, namely the adsorption holes on the outer layer are distributed more densely, the corresponding adsorption force is stronger, the adsorption holes on the inner layer are more sparse, and the corresponding adsorption force is weaker. The edge part of wafer is more warp than the middle part, and the wafer adsorbs in lower adsorption zone, and then the adsorption affinity that its edge received is stronger, and the adsorption affinity that receives in the middle is weaker, makes the wafer stretch to the edge from the center to reduce the angularity of wafer. The spacing between layers and the spacing between adsorption holes on the same layer can be customized and adjusted according to the warping degree of the wafer.

5. In the above scheme, this technical scheme designs the adsorption equipment of two-sided punching and groove mode, and the higher authority adsorbs the burnishing head, adsorbs the wafer below. The upper adsorption area is provided with a circular groove, the lower adsorption area is provided with an adsorption hole, the circular groove and the adsorption hole are communicated with the airflow channel, namely the circular groove, the adsorption hole and the airflow channel jointly form a vacuum cavity, and when the vacuum is pumped, the upper adsorption area and the lower adsorption area simultaneously generate adsorption force. The circular groove has a larger air exhaust area relative to the adsorption hole, and aims to ensure that the adsorption force of the upper adsorption area is larger. Adsorption zone and lower adsorption zone adopt a sharing airflow channel on this technical scheme, because of the size of wafer is less, light in weight, its required adsorption affinity is less, be 50 microns to between 5 millimeters usually, so sharing airflow channel can not influence the adsorption affinity to the wafer, if adopt mutually independent airflow channel, then the structure is comparatively complicated, need carry out the concatenation connection with two parts, this technical scheme adopts a public airflow channel, the simplified structure, processing is simple, and in the polishing process, the operation is also comparatively simple.

6. In the above scheme, a sealing ring is arranged at the edge of the lower adsorption area, the lower end face of the sealing ring protrudes downwards relative to the lower adsorption area, the protruding section of the sealing ring is used as a positioning ring of the wafer, and the protruding section of the sealing ring and the lower adsorption area jointly define a space for mounting the wafer. The sealing ring is used for sealing a lower adsorption area of the adsorption device, and prevents polishing liquid from entering an adsorption hole of the lower adsorption area, so that the adsorption force is reduced, and even the wafer falls off. And the protruding section of the sealing ring is also used as a positioning ring of the wafer, the diameter of the sealing ring is generally slightly smaller than that of the wafer, and the wafer is clamped in the protruding section of the sealing ring to perform auxiliary positioning on the wafer.

7. In the above scheme, an isolation groove is arranged between the sealing ring and the outermost layer adsorption hole, and the isolation groove is communicated with the airflow channel. When the polishing solution flows into the lower adsorption area, the polishing solution is discharged through the isolation groove, so that the polishing solution is prevented from entering the adsorption holes to influence the adsorption force.

8. In the scheme, the number of the adsorption holes in the outer ring is 5-15 more than that of the adsorption holes in the inner ring.

9. In the above scheme, the bottom of the circular groove is provided with a plurality of vent holes, and the circular groove is communicated with the airflow channel through the vent holes.

10. In the above scheme, the vacuum pumping port is located on the side surface of the adsorption body.

11. In the above solution, the airflow channel is arranged along the radial direction of the adsorption body.

12. In the above scheme, the edge of lower adsorption zone is equipped with a seal groove, the sealing washer embedding is this seal groove. The lower end face of the outer groove wall of the sealing groove is lower than the lower end face of the inner groove wall of the sealing groove.

The working principle of the utility model is as follows: the utility model uses the adsorption device as a connecting piece between the wafer and the polishing head. The adsorption body is firstly turned over, the lower adsorption area is arranged towards the upper side, the wafer is embedded into the protruding section of the sealing ring and then fixed, and the wafer is attached to the lower adsorption area. Then the adsorption body is turned over to make the lower adsorption area face downwards, and the wafer is fixed by the sealing ring and cannot fall off. The upper adsorption area faces upwards and is aligned and attached to the lower surface of the polishing head, and then the polishing head is vacuumized. The wafer is adsorbed and fixed on the lower adsorption area of the adsorption device, and the adsorption device and the wafer are adsorbed and fixed on the polishing head as a whole. The wafer and the polishing head are relatively fixed through the double-sided adsorption of the adsorption device, and then polishing treatment is carried out. And after polishing is finished, vacuumizing is stopped, the adsorption device and the wafer are integrally taken down from the polishing head, the adsorption device is turned over, the lower adsorption area is arranged towards the upper side, and the wafer is taken out.

Due to the application of the technical scheme, compared with the prior art, the utility model has the following advantages:

1. the utility model adopts a double-sided adsorption device in the planarization process to relatively connect and fix the wafer and the polishing head. The adsorption devices with different specifications can be customized for wafers with different sizes, wafers with different warping degrees and even wafers with special sizes, and the cost is low. Avoiding replacement of the polishing heads, or customization of the polishing heads, is costly and time consuming. In conclusion, the double-sided adsorption device is convenient to operate, low in cost, high in universality and stable in connection, and non-standard systems are conveniently realized.

2. The wafer is mainly fixed by adsorption, and is combined with a sealing ring to be fixed in an auxiliary manner, so that the wafer fixing device is convenient to operate and stable in fixing, wax-free and wax-free wafer fixing can be realized, the wafer fixing device is convenient to clean, and the wafer can be fixed without damage.

3. Because the adsorption holes for adsorbing the wafer are in non-uniform distribution, the outer layer is dense, the inner layer is sparse, the adsorption force of the outer layer is stronger, the adsorption force of the inner layer is weaker, the adsorption force on the edge of the wafer is stronger, the adsorption force on the middle layer is weaker, the wafer is stretched and extended from the center to the edge, the warping degree (BOW) of the wafer is reduced, the flatness is improved, and the condition that the wafer is over-polished is avoided. And the distance between layers of the adsorption holes and the distance between the adsorption holes on the same layer can be customized and adjusted according to the warping degrees of wafers in different batches.

4. The sealing ring is arranged, so that polishing liquid can be prevented from entering the adsorption holes of the lower adsorption area, the adsorption force is ensured, and the sealing ring can be used as a positioning ring of the wafer to assist in fixing the wafer, so that the wafer can be conveniently loaded and fixed on the adsorption device.

Drawings

FIG. 1 is a perspective view of an upper adsorption region of an adsorption apparatus according to an embodiment of the present invention;

FIG. 2 is a perspective view of a lower adsorption region of an adsorption apparatus according to an embodiment of the present invention;

FIG. 3 is a perspective cross-sectional view of an upper adsorption region of an adsorption apparatus according to an embodiment of the present invention;

FIG. 4 is a perspective cross-sectional view of a lower adsorption zone view of an adsorption apparatus according to an embodiment of the present invention;

FIG. 5 is a cross-sectional view of an adsorption apparatus according to an embodiment of the present invention;

FIG. 6 is a diagram illustrating a usage of an adsorption apparatus as a connection member between a wafer and a polishing head according to an embodiment of the present invention.

In the above drawings: 1. an adsorption body; 2. an upper adsorption zone; 3. a lower adsorption zone; 4. a polishing head; 5. a wafer; 6. an air flow channel; 7. a vacuum pumping port; 8. a circular groove; 9. an adsorption hole; 10. a seal ring; 11. an isolation trench; 12. a sealing groove; 13. a polishing pad; 14. and (7) polishing the disc.

Detailed Description

The utility model is further described with reference to the following figures and examples:

example 1: double-sided adsorption device used as connecting piece in wafer planarization process

Referring to fig. 1-2, the double-sided adsorption device includes an adsorption body 1 having a certain thickness, and the thickness direction of the adsorption body 1 is defined as the vertical direction; the adsorption body 1 has an upper end face and a lower end face.

Referring to fig. 3 to 5, the upper end surface of the adsorption body 1 serves as an upper adsorption area 2 for adsorbing a polishing head 4, and the lower end surface of the adsorption body 1 serves as a lower adsorption area 3 for adsorbing a wafer 5; an airflow channel 6 is arranged in the adsorption body 1, and the airflow channel 6 is provided with a vacuum pumping port 7 for communicating a vacuum generator; the vacuumizing port 7 is positioned on the side surface of the adsorption body 1. The gas flow channels 6 are arranged in the radial direction of the adsorption body 1.

Go up adsorption zone 2 and seted up multiunit concentric circle recess 8, every circle recess 8 all with airflow channel 6 intercommunication. A plurality of vent holes are formed in the bottom of the circular groove 8, and the circular groove 8 is communicated with the airflow channel 6 through the vent holes.

The lower adsorption zone 3 is provided with a plurality of adsorption holes 9, and each adsorption hole 9 is communicated with the airflow channel 6; the adsorption holes 9 are distributed on the lower adsorption area 3 in a concentric circle shape, the distance between two adjacent adsorption holes 9 on the same ring is the same, and the gradient of the distance is gradually decreased from the inner ring to the outer ring of the concentric circle; the gas flow channel 6, the circular groove 8 and the adsorption hole 9 together define a vacuum cavity. Two adjacent circles adsorb hole 9, the number of outer lane adsorb hole 9 is 5~15 more than the number of inner circle adsorb hole 9.

A sealing ring 10 is arranged at the edge of the lower adsorption area 3, the lower end surface of the sealing ring 10 protrudes downwards relative to the lower adsorption area 3, the protruding section of the sealing ring 10 is used as a positioning ring of the wafer 5, the protruding section of the sealing ring 10 and the lower adsorption area 3 define together to form a space for mounting the wafer 5, and the lower end surface of the protruding section of the sealing ring 10 is higher than or level to the lower end surface of the wafer 5; an isolation groove 11 is arranged between the sealing ring 10 and the outermost layer adsorption hole 9, and the isolation groove 11 is communicated with the airflow channel 6. The edge of the lower adsorption area 3 is provided with a sealing groove 12, and the sealing ring 10 is embedded into the sealing groove 12.

The feeding process of the embodiment is as follows: firstly, the adsorption body 1 is turned over, the lower adsorption area 3 is arranged towards the upper part, the wafer 5 is embedded into the protruding section of the sealing ring 10 and then fixed, and the wafer 5 is attached to the lower adsorption area 3. The adsorption body 1 is turned over to make the lower adsorption area 3 face downward, and the wafer 5 is fixed by the seal ring 10 and will not fall off. The upper adsorption zone 2 faces upwards and is aligned and attached to the lower surface of the polishing head 4, and then the vacuum is pumped. The wafer 5 is sucked and fixed to the lower suction area 3 of the suction device, and the suction device and the wafer 5 are sucked and fixed to the polishing head 4 as a whole. The wafer 5 and the polishing head 4 are relatively fixed through the double-sided adsorption of the adsorption device, and then polishing treatment is carried out. And after polishing is finished, vacuumizing is stopped, the adsorption device and the wafer 5 are integrally taken down from the polishing head 4, then the adsorption device is turned over, the lower adsorption area 3 is arranged towards the upper side, and then the wafer 5 is taken out.

Referring to fig. 6, in operation of this embodiment, the adsorption device adsorbs both sides, the lower adsorption region 3 adsorbs and fixes the wafer 5, the upper adsorption region 2 adsorbs and fixes the polishing head 4, and the adsorption device serves as a connecting member to connect and fix the wafer 5 and the polishing head 4. The polishing pad 13 is attached to the polishing pad 14, the wafer 5 is pressed by the polishing head 4 against the polishing pad 13, the polishing pad 13 is dropped with the polishing liquid, the polishing pad 14 and the polishing head 4 are rotated, and the chemical etching and the mechanical rubbing are alternately and cyclically performed, thereby polishing the lower surface of the wafer 5.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. The utility model provides a two-sided adsorption equipment as connecting piece in wafer planarization process which characterized in that: the double-sided adsorption device comprises an adsorption body (1) with a certain thickness, and the thickness direction of the adsorption body (1) is defined as the vertical direction; the adsorption body (1) is provided with an upper end face and a lower end face;

the upper end face of the adsorption body (1) is used as an upper adsorption area (2) of the adsorption polishing head (4), and the lower end face of the adsorption body (1) is used as a lower adsorption area (3) for adsorbing a wafer (5); an airflow channel (6) is arranged in the adsorption body (1), and the airflow channel (6) is provided with a vacuum pumping port (7) for communicating a vacuum generator;

a plurality of groups of concentric circular grooves (8) are formed in the upper adsorption area (2), and each circular groove (8) is communicated with the airflow channel (6);

the lower adsorption area (3) is provided with a plurality of adsorption holes (9), and each adsorption hole (9) is communicated with the airflow channel (6); the adsorption holes (9) are distributed on the lower adsorption area (3) in a concentric circle shape, the distance between two adjacent adsorption holes (9) on the same ring is the same, and the distance is gradually decreased from the inner ring to the outer ring of the concentric circle; the air flow channel (6), the round groove (8) and the adsorption hole (9) jointly define a vacuum cavity;

a sealing ring (10) is arranged at the edge of the lower adsorption area (3), the lower end face of the sealing ring (10) protrudes downwards relative to the lower adsorption area (3), the protruding section of the sealing ring (10) is used as a positioning ring of the wafer (5), the protruding section of the sealing ring (10) and the lower adsorption area (3) define together to form a space for mounting the wafer (5), and the lower end face of the protruding section of the sealing ring (10) is higher than or level to the lower end face of the wafer (5); an isolation groove (11) is arranged between the sealing ring (10) and the outermost layer adsorption hole (9), and the isolation groove (11) is communicated with the airflow channel (6).

2. The double-sided adsorption device as a connector in a wafer planarization process as claimed in claim 1, wherein: two adjacent circles adsorb hole (9), the number of outer lane adsorb hole (9) is 5~15 more than the number of inner circle adsorb hole (9).

3. The double-sided adsorption device as a connector in a wafer planarization process as claimed in claim 1, wherein: the bottom of the round groove (8) is provided with a plurality of vent holes, and the round groove (8) is communicated with the airflow channel (6) through the vent holes.

4. The double-sided adsorption device as a connector in a wafer planarization process as claimed in claim 1, wherein: the vacuumizing port (7) is positioned on the side surface of the adsorption body (1).

5. The double-sided adsorption device as a connector in a wafer planarization process as claimed in claim 1, wherein: the gas flow channel (6) is arranged in the radial direction of the adsorption body (1).

6. The double-sided adsorption device as a connector in a wafer planarization process as claimed in claim 1, wherein: the edge of lower adsorption zone (3) is equipped with a seal groove (12), this seal groove (12) of sealing washer (10) embedding.

7. The double-sided suction apparatus as a connecting member in a wafer planarization process as recited in claim 6, wherein: the lower end face of the outer groove wall of the sealing groove (12) is lower than the lower end face of the inner groove wall of the sealing groove (12).