TW202245981A - Double-sided polishing device and double-sided polishing method - Google Patents

Abstract

The invention relates to a double-sided grinding device, which is used for grinding two opposite surfaces of a silicon wafer, and comprises an annular bearing structure, a grinding device and a grinding device, and is characterized in that the annular bearing structure is used for supporting the silicon wafer from the peripheral side in the radial direction; the two static pressure supporting pieces are oppositely arranged, are respectively positioned on two sides of the silicon wafer, and are used for supporting the silicon wafer in a non-contact manner through fluid static pressure; the two grinding wheels are oppositely arranged and used for grinding the two opposite faces of the silicon wafer, the two static pressure supporting pieces comprise the first static pressure supporting piece and the second static pressure supporting piece, and the first static pressure supporting piece is used for adsorbing the ground silicon wafer; and the cleaning structure is used for cleaning the first static pressure supporting piece. The invention further relates to a double-sided grinding method. Through the arrangement of the cleaning structure, the static pressure supporting piece used for adsorbing the silicon wafer is cleaned, and the smoothness of the wafer is prevented from being influenced.

Description

Double-side grinding device and double-side grinding method

The invention belongs to the technical field of semiconductors, in particular to a double-side grinding device and a double-side grinding method.

The processing technology of silicon wafers is developing rapidly, and the double-side grinding technology is developing day by day. As the diameter of silicon wafers becomes larger and the feature size of integrated circuits becomes smaller and smaller, the flatness of the wafer surface, the cleanliness of the surface, and the degree of damage are raised. higher requirements.

Double Disk Surface Grinding (DDSG) is adopted. The grinding method includes: placing the wafer vertically on the ring carrier and between two opposite static pressure supports. The wafer is balanced by hydrostatic pressure and The annular carrier rotates together at a low speed, while two grinding wheels facing each other rotate at a high speed to grind both surfaces of the wafer simultaneously. During the grinding process, the two grinding wheels are fed in the axial direction until the final target thickness of the wafer is reached. After the grinding process is completed, one side of the wafer will be vacuum-adsorbed to the static pressure support on one side, and after the mechanical arm absorbs the wafer from the other side, the static pressure support will desorb.

There are a large number of pit-like defects on the wafer surface on the side where the wafer and the static pressure support are adsorbed. The main reasons are: ①Silicon slag is sputtered onto the static pressure support during processing; ②The back of the wafer is generally dirty, and the Contacting the hydrostatic supports may contaminate the hydrostatic supports. However, the static pressure support does not have a self-cleaning function, resulting in pit-shaped defects on the side of the wafer contacting the static pressure support when the adsorption is completed.

In order to achieve the above object, the technical solution adopted in the embodiment of the present invention is: a double-sided grinding device, which is used to grind the opposite sides of the silicon wafer, including: A ring-shaped bearing structure, used to support the silicon wafer from the outer peripheral side in the radial direction; Two static pressure supports arranged opposite to each other, the two static pressure supports are respectively located on both sides of the silicon wafer, and the silicon wafer is supported non-contact by hydrostatic pressure; Two grinding wheels oppositely arranged are used for grinding the opposite two sides of the silicon wafer, The two static pressure supports include a first static pressure support and a second static pressure support, and the first static pressure support is used for absorbing the polished silicon wafer; The double-sided grinding device also includes a cleaning structure for cleaning the first static pressure support.

Optionally, the cleaning structure includes a cleaning brush, and a first driving structure, configured to control the cleaning brush to move in a direction close to the first static pressure support, and to be in contact with the adsorption surface of the first static pressure support, to clean the adsorption surface.

Optionally, the second static pressure support is provided with a first through hole, and the cleaning brush can pass through the first through hole to clean the adsorption surface.

Optionally, a second driving structure is also included for controlling the cleaning brush or the first static pressure support to rotate in a plane parallel to the adsorption surface, so as to clean the adsorption surface.

Optionally, the second driving structure includes a rotating shaft, the cleaning brush is connected to one end of the rotating shaft, and the cleaning brush is a bar-shaped structure, and the extending direction of the bar-shaped structure is perpendicular to the axial direction of the rotating shaft.

Optionally, the area on the first static pressure support for absorbing the silicon wafer is the first area, and the length of the cleaning brush in its extending direction is greater than that of the first area parallel to the extending direction of the cleaning brush. The maximum length in the direction.

Optionally, it also includes a cleaning liquid supply device, the edge of the second static pressure support is provided with a plurality of second through holes along its circumference, the second through holes are connected with the cleaning liquid supply device, and the cleaning brush When cleaning the adsorption surface, the cleaning liquid supply device supplies cleaning liquid to the adsorption surface through the second through hole.

Optionally, the cleaning structure further includes an air knife for blowing the adsorption surface after cleaning.

Optionally, the air knife is integrated with the cleaning brush, the cleaning brush includes a body and bristles disposed on the first surface of the body, the air knife includes a through hole extending from the first surface and penetrating the body .

The embodiment of the present invention also provides a double-sided grinding method, which is carried out by using the above-mentioned double-sided grinding device, including: cleaning the first hydrostatic support with a cleaning structure; Carrying the silicon wafer through the annular bearing structure, and placing it between the first static pressure support and the second static pressure support, and non-contact supporting the silicon wafer through hydrostatic pressure; Two grinding wheels rotate at high speed to grind the opposite sides of the silicon wafer.

Optionally, the cleaning structure includes a cleaning brush to clean the first static pressure support through the cleaning structure, specifically including: controlling the cleaning brush to move in a direction close to the first static pressure support, and contact with the adsorption surface of the first static pressure support; The cleaning brush is controlled to rotate clockwise or counterclockwise, and at the same time, the second static pressure support is controlled to provide cleaning liquid to the first static pressure support, so as to clean the adsorption surface.

Optionally, the cleaning structure further includes an air knife, and the first static pressure support is cleaned through the cleaning structure, and further includes: After the cleaning brush stops cleaning, the suction surface is blown by an air knife.

The beneficial effect of the invention is: through the setting of the cleaning structure, the static pressure support used for absorbing the silicon chip is cleaned, so as to avoid affecting the smoothness of the wafer.

In order for the Ligui Examiner to understand the technical features, content and advantages of the present invention and the effects it can achieve, the present invention is hereby combined with the accompanying drawings and appendices, and is described in detail in the form of embodiments as follows, and the drawings used therein , the purpose of which is only for illustration and auxiliary instructions, and not necessarily the true proportion and precise configuration of the present invention after implementation, so it should not be interpreted based on the proportion and configuration relationship of the attached drawings, and limit the application of the present invention in actual implementation The scope is described first.

In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical ", "horizontal", "top", "bottom", "inner", "outer" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying Describes, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and operate in a specific orientation, and therefore should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of said features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

In the embodiments of the present invention, terms such as "installation", "connection", "connection" and "fixation" should be interpreted in a broad sense unless otherwise clearly specified and limited. Disassembled connection, or integration; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those with ordinary knowledge in the art can understand the specific meanings of the above terms in the embodiments of the present invention according to specific situations.

With reference to Fig. 1-Fig. 3, present embodiment provides a kind of double-sided grinding device, is used for grinding the relative two sides of silicon wafer 10, comprises: An annular bearing structure, used to support the silicon wafer 10 from the outer peripheral side in the radial direction; Two static pressure supports arranged opposite to each other, the two static pressure supports are respectively located on both sides of the silicon wafer 10, and support the silicon wafer 10 non-contact through hydrostatic pressure; The two grinding wheels 3 oppositely arranged are used for grinding the opposite two sides of the silicon wafer 10, The two static pressure supports include a first static pressure support 1 and a second static pressure support 2, and the first static pressure support 1 is used to absorb the polished silicon wafer 10; The double-sided grinding device also includes a cleaning structure for cleaning the first static pressure support 1 .

The setting of this cleaning structure can realize the cleaning of the first static pressure support 1 used to absorb the silicon wafer 10, avoiding the smoothness of the silicon wafer 10 due to the pollution on the first static pressure support 1, and the silicon wafer 10 resulting in pit-like defects.

It should be noted that, in this embodiment, the first static pressure support 1 is cleaned before the silicon wafer 10 is placed between the two static pressure supports, so as to effectively avoid Contamination causes defects on the silicon wafer 10.

Exemplarily in this embodiment, the cleaning structure includes a cleaning brush 4, and a first driving structure, used to control the cleaning brush 4 to move toward the direction close to the first static pressure support 1, and The adsorption surface of the support member 1 is in contact to clean the adsorption surface.

The cleaning structure can be installed independently or integrated with the corresponding static pressure support. In this embodiment, the second static pressure support 2 is provided with a first through hole 21, and the cleaning brush 4 can penetrate Through the first through hole 21 to clean the adsorption surface.

In the non-cleaning working state, the cleaning brush 4 can be accommodated in the first through hole 21, and in the cleaning working state, the cleaning brush 4 protrudes from the first through hole 21 to the first static pressure support. 1 until it contacts the adsorption surface of the first static pressure support 1 to clean it, simplify the structure and save space.

Exemplarily in this embodiment, the double-sided grinding device further includes a second driving structure, which is used to control the rotation of the cleaning brush 4 or the first static pressure support 1 in a plane parallel to the adsorption surface, so as to The adsorption surface is clean.

Exemplarily, the second drive structure includes a rotating shaft 5, the cleaning brush 4 is connected to one end of the rotating shaft 5, and the cleaning brush 4 is a bar-shaped structure, and the extending direction of the bar-shaped structure is in line with the axis of the rotating shaft 5 perpendicular to the direction.

The cleaning brush 4 includes a body, one side of the body is provided with bristles, and the bristles are arranged facing the adsorption surface of the first static pressure support member 1 .

The cleaning brush 4 has a strip structure, and is rotated to clean the adsorption surface, which saves space and facilitates the integrated arrangement of the cleaning brush 4 and the second static pressure support member 2 .

Exemplarily in this embodiment, the area on the first static pressure support 1 for absorbing the silicon wafer 10 is the first area, and the length of the cleaning brush 4 in the direction of its extension is greater than that of the first area in relation to the cleaning. The maximum length in a direction parallel to the extension direction of the brush 4 .

The length of the cleaning brush 4 in its extending direction is greater than or equal to the maximum length of the first region in a direction parallel to the extending direction of the cleaning brush 4 . In this way, the comprehensive cleaning of the adsorption surface can be realized only through the rotating action, without moving in other directions, which simplifies the structure and the cleaning process.

Exemplarily in this embodiment, the double-sided grinding device further includes a cleaning liquid supply device, and the edge of the second static pressure support 2 is provided with a plurality of second through holes 22 along its circumference, and the second through holes 22 Connected with the cleaning liquid supply device, when the cleaning brush 4 cleans the adsorption surface, the cleaning liquid supply device provides cleaning liquid to the adsorption surface through the second through hole 22 .

With the aid of the cleaning solution, the adsorption surface can be effectively cleaned.

The type of cleaning fluid can be set according to actual needs. Exemplarily, the hydrostatic support realizes the non-contact support of the silicon wafer 10 through fluid balance. Cleaning liquid, for example, the fluid that this static pressure support adopts is water, then this cleaning liquid also can be water, so long as the corresponding fluid passage hole on the first static pressure support 1 (that is, this second through hole 22) Just open it.

In this embodiment, the second through hole 22 is disposed on the edge of the second static pressure support 2 , and a plurality of second through holes 22 are arranged at intervals along the circumferential direction of the second static pressure support 2 . The silicon wafer 10 is generally circular, and the second static pressure support member 2 is circular in structure conforming to the shape of the silicon wafer 10. The second static pressure support member 2 is provided with a through hole for the grinding wheel 3 to pass through ( The third through hole 23 ), the second through hole 22 is located outside the first through hole 21 , so that the cleaning liquid can better cooperate with the cleaning brush 4 .

It should be noted that the number and size of the second through holes 22 can be set according to actual needs.

Exemplarily in this embodiment, the cleaning structure further includes an air knife for blowing the adsorption surface after cleaning.

After the adsorption surface is cleaned by the cleaning brush 4, due to the use of the cleaning liquid, the surface of the adsorption surface remains with cleaning liquid. The setting of the air knife can dry the adsorption surface to avoid contamination of the silicon wafer 10 by the cleaning liquid. .

The specific structure of the air knife can be arranged in various ways. Exemplarily in this embodiment, the air knife is integrated with the cleaning brush 4. The cleaning brush 4 includes a body and bristles arranged on the first surface of the body. The knife includes a through hole extending from the first surface and extending through the body.

The air knife is connected with high-pressure clean air to ensure the cleanliness of the adsorption surface.

The embodiment of the present invention also provides a double-sided grinding method, which is carried out by using the above-mentioned double-sided grinding device, including: cleaning the first hydrostatic support 1 through the cleaning structure; The silicon wafer 10 is carried by a ring-shaped supporting structure, and placed between the first static pressure support 1 and the second static pressure support 2, and the silicon wafer 10 is supported non-contact by hydrostatic pressure; The two grinding wheels 3 rotate at high speed to grind the opposite sides of the silicon wafer 10 .

Exemplarily, the cleaning structure includes a cleaning brush 4, and the first static pressure support 1 is cleaned through the cleaning structure, specifically including: Controlling the cleaning brush 4 to move in a direction close to the first static pressure support 1, and contact with the adsorption surface of the first static pressure support 1; The cleaning brush 4 is controlled to rotate clockwise or counterclockwise, and at the same time, the second static pressure support 2 is controlled to provide cleaning fluid to the first static pressure support 1 to clean the adsorption surface.

It should be noted that, providing the cleaning liquid to the first static pressure support 1 may also be performed before cleaning by the cleaning brush 4, and it is not limited here to provide the cleaning liquid to the first static pressure support 1 and control the The sequence in which the cleaning brush 4 moves to clean the first static pressure support 1 .

Exemplarily, the cleaning structure further includes an air knife, which cleans the first static pressure support 1 through the cleaning structure, and further includes: After the cleaning brush 4 stops cleaning, the adsorption surface is blown by an air knife.

The following points need to be explained: (1) The drawings of the embodiment of the present invention are only related to the structure related to the embodiment of the present invention, other structures can refer to the general design; (2) For the sake of clarity, in the drawings used to describe the embodiments of the present invention, the thicknesses of layers or regions are enlarged or reduced, that is, these drawings are not drawn according to actual scale. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, that element can be "directly on" or "under" the other element. or there may be intermediate elements; (3) In the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

The above are only preferred embodiments of the present invention, and are not used to limit the implementation scope of the present invention. If the present invention is modified or equivalently replaced without departing from the spirit and scope of the present invention, it shall be covered by the protection of the patent scope of the present invention. in the range.

1: The first hydrostatic support 2: The second hydrostatic support 3: grinding wheel 4: Cleaning brush 5: Rotation axis 10: Silicon wafer 21: The first through hole 22: Second through hole 23: The third through hole

Fig. 1 shows the structural representation of double-sided grinding device in the embodiment of the present invention; Fig. 2 shows the schematic structural view of the hydrostatic support in the embodiment of the present invention; Fig. 3 shows a schematic structural view of the second static pressure support in the embodiment of the present invention.

1: The first hydrostatic support

2: The second hydrostatic support

3: grinding wheel

10: Silicon wafer

Claims (12)

A double-sided lapping device for lapping opposite sides of a silicon wafer, comprising: A ring-shaped bearing structure, used to support the silicon wafer from the outer peripheral side in the radial direction; Two static pressure supports arranged opposite to each other, the two static pressure supports are respectively located on both sides of the silicon wafer, and the silicon wafer is supported non-contact by hydrostatic pressure; Two grinding wheels opposite to each other are used to grind the opposite sides of the silicon wafer; The two static pressure supports include a first static pressure support and a second static pressure support, and the first static pressure support is used for absorbing the polished silicon wafer; The double-sided grinding device also includes a cleaning structure for cleaning the first static pressure support. The double-sided grinding device as claimed in claim 1, wherein the cleaning structure includes a cleaning brush, and a first driving structure, which is used to control the cleaning brush to move towards the direction close to the first static pressure support, and to communicate with the second The adsorption surface of a static pressure support is contacted to clean the adsorption surface. The double-sided grinding device as claimed in claim 2, wherein the second static pressure support is provided with a first through hole, and the cleaning brush can pass through the first through hole to clean the adsorption surface. The double-sided grinding device as claimed in claim 2, further comprising a second drive structure for controlling the rotation of the cleaning brush or the first static pressure support in a plane parallel to the adsorption surface, so as to face clean. The double-sided grinding device as described in claim 4, wherein the second drive structure includes a rotating shaft, and the cleaning brush is connected to one end of the rotating shaft, and the cleaning brush is a bar-shaped structure, and the extending direction of the bar-shaped structure is in line with the The axial directions of the rotating shafts are perpendicular. The double-sided grinding device according to claim 5, wherein the area on the first static pressure support for absorbing the silicon wafer is the first area, and the length of the cleaning brush in its extending direction is greater than that of the first area. The maximum length in a direction parallel to the direction of extension of the cleaning brush. The double-sided grinding device according to claim 3, further comprising a cleaning liquid supply device, the edge of the second static pressure support is provided with a plurality of second through holes along its circumference, and the second through holes are connected to the The cleaning liquid supply device is connected, and when the cleaning brush cleans the adsorption surface, the cleaning liquid supply device provides cleaning liquid to the adsorption surface through the second through hole. The double-sided grinding device according to claim 2, wherein the cleaning structure further includes an air knife for blowing the cleaned adsorption surface. The double-sided grinding device as claimed in claim 8, wherein the air knife is integrated with the cleaning brush, the cleaning brush includes a body and bristles arranged on the first surface of the body, and the air knife includes The through hole that extends and runs through the body. A double-sided grinding method, carried out by using the double-sided grinding device described in any one of claims 1 to 9, comprising: cleaning the first hydrostatic support with a cleaning structure; Carrying the silicon wafer through the annular bearing structure, and placing it between the first static pressure support and the second static pressure support, and non-contact supporting the silicon wafer through hydrostatic pressure; Two grinding wheels rotate at high speed to grind the opposite sides of the silicon wafer. The double-sided grinding method according to claim 10, wherein the cleaning structure includes a cleaning brush, and the first static pressure support is cleaned by the cleaning structure, specifically including: controlling the cleaning brush to move in a direction close to the first static pressure support, and contact with the adsorption surface of the first static pressure support; The cleaning brush is controlled to rotate clockwise or counterclockwise, and at the same time, the second static pressure support is controlled to provide cleaning liquid to the first static pressure support, so as to clean the adsorption surface. The double-sided grinding method according to claim 11, wherein the cleaning structure further includes an air knife, and the first static pressure support is cleaned by the cleaning structure, further comprising: After the cleaning brush stops cleaning, the suction surface is blown by an air knife.

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