TWI815675B - A system for detecting silicon wafers - Google Patents

Abstract

An embodiment of the present invention discloses a system for detecting silicon wafers. The system includes: a plurality of bearing members for carrying the silicon wafers by contacting corresponding multiple parts of the silicon wafers; a detection device, for detecting defects in different parts of the silicon chip by moving relative to the silicon chip; a sensing device for sensing the position of the detection device and when sensing that the detection device is in contact with the silicon chip A first command signal is generated when the contact position of the corresponding bearing member is detected; the driving device is used to move the corresponding bearing member from a contact position in contact with the silicon chip to a position not in contact with the silicon chip based on the first command signal The distance position is such that the silicon chip is carried by other bearing members in the plurality of bearing members except the corresponding bearing member.

Description

A system for detecting silicon wafers

The invention belongs to the field of semiconductor manufacturing, and in particular relates to a system for detecting silicon wafers.

Due to various reasons, the silicon wafer contains impurities and causes defects. Due to the complex interaction between the above steps, defects are often more likely to occur in the edge area of the silicon wafer, causing unstable film accumulation at the edge of the silicon wafer. During the steps, defects may occur in part or all of these films, and these defects may be transferred to the device area of the silicon wafer. With the global development of informatization, the size of devices in silicon chip applications continues to decrease, and the impact of the above defects has gradually become more significant. As a result, the edge of the silicon wafer has become one of the major sources of yield limitations in semiconductor manufacturing. During the device manufacturing process, effectively removing these films accumulated at the edges of the silicon wafer can reduce defects and achieve higher device yields.

The use of automatic detection devices for silicon wafer appearance defects is now very common. It mainly photographs the surface of the silicon wafer and uses the obtained surface image to identify particles, scratches, chemical contamination, edge damage, etc. on the surface of the silicon wafer. After the defect is detected, the information processing module digitizes the results to evaluate the quality of the silicon wafer and determine whether it can meet quality requirements, thereby preventing defective products from flowing into subsequent processing steps, resulting in waste of production capacity and low yield. reduce.

In related technologies, commonly used detection methods for monitoring silicon wafer appearance defects include back contact detection and edge contact detection. When using the back contact defect detection method, the silicon wafer can be fixed by adsorption to the back of the silicon wafer. Thus, the edge of the silicon wafer and the defects on the upper surface can be accurately photographed. However, the back adsorption device makes it impossible to obtain a complete image of the back of the silicon wafer. At the same time, because the back surface contact will leave stains that contaminate the back of the silicon wafer, affecting product quality. This increases the burden of the cleaning steps in the subsequent steps, and at the same time, it is not guaranteed to completely remove the above-mentioned residual stains in the subsequent cleaning steps. When using the edge contact defect detection method, the silicon wafer is fixed by a silicon wafer edge clamping device, and the surface of the silicon wafer is photographed through a camera. Since the clamp used to clamp the silicon wafer will block part of the surface of the silicon wafer when photographing Silicon wafer, so in order to obtain a complete image of the edge of the silicon wafer, it is necessary to loosen the clamp after taking a shot of the silicon wafer surface, rotate the silicon wafer to a predetermined angle and then re-clamp it to take a second shot of the silicon wafer surface. This is This makes the detection efficiency of edge contact detection in the related art low, and repeated clamping actions will cause additional contamination to the edge of the silicon wafer.

In order to solve the above technical problems, embodiments of the present invention are expected to provide a system for detecting silicon wafers, by controlling the corresponding carrier to avoid detection when the detection device is in a position to detect the part of the silicon wafer that is in contact with any carrier. The configuration of the device ensures the integrity of edge defect detection of silicon wafers and avoids missed detections.

The technical solution of the present invention is implemented as follows: A system for detecting silicon wafers, the system includes: a plurality of carriers, used to carry the silicon wafers by contacting with corresponding multiple parts of the silicon wafers; a detection device, used to pass relative to the silicon wafers The chip moves to detect defects in different parts of the silicon chip; the sensing device is used to sense the position of the detection device and when it senses that the detection device is in contact with the corresponding bearing member of the silicon chip, A first command signal is generated when the detected position is detected; a driving device is used to move the corresponding carrier from a contact position in contact with the silicon chip to a distant position not in contact with the silicon chip based on the first command signal, so that the silicon chip The sheet is carried by other carriers in the plurality of carriers except the corresponding carrier.

Embodiments of the present invention provide a system for detecting silicon wafers. The position of the detection device is sensed by a sensing device. When the detection position is at a position for detecting the portion of the silicon wafer that is in contact with the corresponding carrier, the corresponding carrier is driven. The components are not in contact with the silicon wafer, so that the detection device can completely obtain the image of the edge of the silicon wafer. At the same time, through the configuration of multiple carriers that can independently switch between the contact position and the away position, it is ensured that when the corresponding carrier is not When in contact with the silicon chip, the silicon chip can be stably held by other bearing members.

In order to help the review committee understand the technical features, content and advantages of the present invention and the effects it can achieve, the present invention is described in detail below in the form of embodiments with the accompanying drawings and attachments, and the drawings used therein are , its purpose is only for illustration and auxiliary description, and may not represent the actual proportions and precise configurations after implementation of the present invention. Therefore, the proportions and configuration relationships of the attached drawings should not be interpreted or limited to the actual implementation of the present invention. The scope shall be stated first.

In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical" The orientations or positional relationships indicated by "horizontal", "top", "bottom", "inner", "outer", etc. 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 the description. , rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be construed as a limitation of the present invention.

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

In the embodiments of the present invention, unless otherwise expressly stipulated and limited, the terms "installation", "connection", "connection", "fixing" and other terms should be understood in a broad sense. For example, it can be a fixed connection or a removable connection. Disassembly and connection, or integration; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interaction between two elements. For those with ordinary knowledge in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

The edge contact defect detection method in the related art cannot obtain a complete image of the silicon wafer surface under the premise of only one inspection, because the silicon wafer edge clamp used to fix the silicon wafer will block the part where the clamp contacts the edge of the silicon wafer. , there is a risk of missed detection of edge defects. In order to avoid the above risks, in the related art, the upper and lower surfaces of the silicon wafer are obtained, the silicon wafer is rotated, and then the silicon wafer is re-clamped for defect detection. However, this method will increase the process time and reduce the overall efficiency. Based on this, the inventor proposed a system for detecting silicon wafers. Through this system, the edge clamp of the silicon wafer can be prevented from blocking the edge of the silicon wafer during the detection of the silicon wafer, so that the edge of the silicon wafer can be completely detected through one inspection. Defect detection, while also being able to stably hold the silicon wafer during the entire process of detecting surface defects on the silicon wafer.

Referring to Figure 1, the above-mentioned system for detecting silicon wafers includes: a plurality of carriers G, which cooperate with each other to stably hold the silicon wafer W. Referring to Figure 1, there are 8 optional carriers G. The multiple carriers G carry the silicon wafer W in a manner that they are in contact with corresponding multiple parts of the silicon wafer W. The parts in contact with the silicon wafer W of a single carrier G are fixed, that is, during the entire silicon wafer detection process, the single carrier G carries the silicon wafer W. The position where the carrier G is in contact with the silicon chip W always remains unchanged, and the single carrier G can move from the contact position with the silicon chip W to the away position where the silicon chip W is released, that is, the single carrier G can move away from the silicon. The sheet W is not in contact with the silicon sheet W, wherein each carrier G can move independently from the contact position to the away position. Optionally, the carrier G moves against the silicon sheet W by contacting the periphery of the back side of the silicon sheet W. Support, thereby reducing the area of the silicon chip W blocked by the carrier G during the detection process; A detection device D used to detect defects in the silicon wafer W. During the detection process, the detection device D moves relative to the silicon wafer W. During the movement, the detection device D can acquire the silicon wafers located within the detection range of the detection device D. The surface image of W is analyzed by the image processing unit to detect defects in different parts of the surface of the silicon wafer W. Optionally, the detection device D is a camera used to capture an image of the silicon chip W, such as a CCD camera.

During the entire detection process, the multiple carriers G can cooperate with each other to hold the silicon wafer W stably. In order to solve the above technical problems, the system proposed by the inventor moves the detection device D to the silicon wafer W. When any part of the carrier G is in contact, the corresponding carrier G can move from the contact position to the far away position, so that the part of the silicon chip W that is in contact with the corresponding carrier G is exposed within the detection range of the detection device D without being detected by the detection device D. The corresponding carrier G is blocked. The system for detecting the silicon wafer W includes a sensing device S. The sensing device S is used to sense the position of the detection device D. When the detection device D detects any contact between the silicon wafer W and the silicon wafer W, The sensing device S can generate a first command signal when detecting the part in contact with the carrier G. That is to say, the sensing device S can generate a first command when any carrier G appears within the detection range of the detection device D. signal; At the same time, the system for detecting the silicon wafer W also includes a driving device M, which can receive the first command signal and drive the corresponding carrier located within the detection range of the detection device D based on the first command signal. G moves from the contact position to the away position, so that the portion of the silicon chip W blocked by the corresponding carrier G is exposed within the detection range of the detection device D. The driving device M can be selected as a stepper motor. At the same time, the silicon wafer W is still carried by a plurality of other carriers G that are not located within the detection range of the detection device D and is stably held. Optionally, the corresponding carrier G moves along the radial direction of the supported silicon chip W to prevent the carrier G from colliding with other devices of the system during movement.

When defects are detected on the surface of different parts of the silicon wafer W through the above-mentioned system for detecting the silicon wafer W, when the detection device D moves to the part of the silicon wafer W that is in contact with any carrier G, the sensing device S moves toward The driving device M sends a first command signal, and the driving device M drives the corresponding carrier G away from the silicon chip W and exits the detection range of the detection device D, thereby completely exposing the portion of the silicon chip W that is blocked by the corresponding carrier G. Within the detection range of the detection device D, the technical problem of incomplete detection due to the carrier G blocking the edge of the silicon wafer W during the surface defect detection process of the silicon wafer W is solved. Optionally, the detection device D includes a front detector and a back detector that move on both sides of the carried silicon chip W to detect the front and back sides of the silicon chip W respectively. Corresponding detectors are respectively provided on the back side, so that the detection device D can simultaneously detect the upper and lower surfaces of the same part of the silicon wafer W during movement.

The above-mentioned sensing device S can also generate a second control signal when sensing that the detection device D is detecting a portion of the silicon wafer W that is not in contact with the corresponding carrier G, that is, on the surface of the silicon wafer W During the defect detection process, the detection device D continues to move relative to the silicon wafer W after completing the detection of the parts of the surface of the silicon wafer W that are blocked by any carrier G. When the surface of the silicon wafer W located within the detection range no longer has the ability to communicate with When the corresponding bearing member G is in contact with the position, the sensing device S sends a second command signal to the driving device M. The driving device M drives the corresponding bearing member G to return from the away position to the contact position based on the second command signal to realize the alignment. For the clamping of the edge part of the silicon chip W, since the detection device D has completed the detection of this part at this time, the corresponding carrier G does not block the surface of the silicon chip W when it carries the silicon chip W at the contact position. In another embodiment, the sensing device S includes a distance meter for measuring the distance between the detection device D and its fixed position in the direction of movement, so as to obtain the position of the detection device D according to the distance. The distance meter includes a laser transmitter disposed at the fixed position and a laser receiver disposed on the detection device D and moving together with the detection device D, wherein the laser transmitter and the laser receiver are optionally disposed at the same location. Horizontal height.

Specifically, during the actual detection process, see Figure 2, before the silicon wafer detection starts, multiple carriers G are in contact positions to carry the silicon wafer W, and the detection device D moves from the initial position along the radial direction of the silicon wafer W. When the detection device D moves to the position Q1 for detecting the part P1 of the silicon chip W that is in contact with the carrier G1, since the part P1 of the silicon chip W that is in contact with the carrier G1 is fixed, when the detection device D is at the position Q1 It can be seen that the silicon chip W within the detection range of the detection device D exists in contact with the carrier G1, so when the sensing device S senses that the detection device D is located at the detection position Q1, the first command signal is generated, and the driving device M is based on the first command signal. A command signal drives the carrier G1 to move from the contact position to the away position, so that the part P1 of the silicon wafer W is completely exposed within the detection range of the detection device D. The detection device D obtains a complete image of the edge part P1 of the silicon wafer W. At this time, multiple carriers G other than the carrier G1 are in contact positions to stably carry the silicon chip W; when the detection device D completes the detection of the part P1 of the silicon chip W and continues to move, the part P1 of the silicon chip W moves away relatively The detection range of the detection device D, that is, the detection device D is in a position to detect the part of the silicon chip W that is not in contact with the carrier G1. At this time, the sensing device S generates a second command signal, and the driving device M is based on the second command signal. The carrier G1 is driven to move from the away position to the contact position, and the carrier G1 contacts the edge portion P1 of the silicon chip W to support the silicon chip W. The above process is repeated when the detection device D moves to a position for detecting the portion of the silicon chip W that is in contact with the carrier G2.

In another embodiment, the detection device D moves along the radial direction of the silicon chip W, a plurality of carriers G are arranged in pairs, and the connecting lines between two carriers G in each pair of carriers G are parallel to each other and are perpendicular to the radial direction. With the above configuration, the detection device D can simultaneously detect the parts of the silicon chip W that are in contact with the two carriers G in each pair of carriers G. Further, the carriers G located on the same side in the radial direction are evenly distributed in the circumferential direction of the silicon chip W being carried. Referring to Figure 3, the carriers G located on the same side in the radial direction are evenly distributed along the circumferential direction of the silicon chip W. Circumferentially equally spaced, two load bearing members G in each pair of load bearing members G can switch between the contact position and the distance position simultaneously, and each pair of load bearing members G is configured such that when any pair of load bearing members G When in the distanced position, the remaining pairs of bearing members G are in contact positions to achieve stable bearing of the silicon wafer W.

Specifically, during the actual detection process, see Figure 4, before the silicon wafer detection starts, multiple carriers G are in contact positions to carry the silicon wafer W, and the detection device D moves along the radial direction of the silicon wafer W from the initial position. When the detection device D moves to the position Q1 for detecting the parts P1 and P1' of the silicon chip W that are in contact with the pair of carriers G1, since the parts of the pair of carriers G1 that are in contact with the silicon chip W are fixed, When the detection device D is located at the position Q1, it can be seen that the surface of the silicon chip W within the detection range of the detection device D has a portion P1 and a portion P1' that are in contact with a pair of carriers G1, so the sensing device S senses that the detection device D is located at the detection range. The first command signal is generated at the position Q1, and the driving device M drives the pair of carriers G1 to move from the contact position to the away position based on the first command signal, so that the parts P1 and P1' of the silicon chip W are completely exposed to the detection device D. Within the detection range, the detection device D obtains a complete image of the edge portion P1 and P1' of the silicon wafer W. At this time, multiple pairs of carriers G other than the pair of carriers G1 are in contact positions to stably carry the silicon wafer W; When the detection device D completes the detection of the parts P1 and P1' of the silicon wafer W, it continues to move. The parts P1 and P1' of the silicon wafer W relatively leave the detection range of the detection device D, that is, the detection device D is in the position of detecting the silicon wafer W. The position of W that is not in contact with the pair of carriers G1 is detected. At this time, the sensing device S generates a second command signal, and the driving device M drives the carrier G1 to move from the away position to the contact position based on the second command signal. The supporting member G1 contacts the portion P1 and the portion P1' of the silicon chip W to support the silicon chip W. The above process is repeated when the detection device D moves to a position for detecting the portion of the silicon chip W that is in contact with the other pair of carriers G2.

It should be noted that the technical solutions recorded in the embodiments of the present invention can be combined arbitrarily as long as there is no conflict. The proportions between the various components shown in the reference numerals are not fixed and are mainly intended to facilitate understanding of the scheme.

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

M: drive device W: silicon chip S: sensing device D:Detection device G: Bearing part G1: Bearing part G2: Bearing part Q1: Location P1: Part P1': Part

Figure 1 is a schematic diagram of a system for detecting silicon wafers according to an embodiment of the present invention; Figure 2 is a working diagram of a system for detecting silicon wafers according to an embodiment of the present invention; Figure 3 is a schematic diagram of a system for detecting silicon wafers according to another embodiment of the present invention; FIG. 4 is a working diagram of a system for detecting silicon wafers according to another embodiment of the present invention.

M: drive device

W: silicon chip

S: sensing device

D:Detection device

G: Bearing part

Claims (10)

A system for detecting silicon wafers, the system includes: A plurality of bearing members, used to carry the silicon chip by contacting corresponding multiple parts of the silicon chip; A detection device used to detect defects in different parts of the silicon wafer by moving relative to the silicon wafer; a sensing device, configured to sense the position of the detection device and generate a first command signal when it is sensed that the detection device is in a position for detecting the portion of the silicon chip that is in contact with the corresponding carrier; A driving device for moving the corresponding carrier from a contact position in contact with the silicon chip to a remote position not in contact with the silicon chip based on the first command signal, so that the silicon chip is removed from the plurality of carriers. The load is carried by other load-bearing members than the corresponding load-bearing member. The system for detecting silicon wafers as described in claim 1, wherein the sensing device is also used to detect parts of the silicon wafer that are not in contact with the corresponding carrier when it is sensed that the detection device is in a position. When generating a second command signal, the driving device is also used to move the corresponding bearing member from the away position to the contact position based on the second command signal. The system for detecting silicon wafers as described in claim 1 or 2, wherein the detection device moves along the radial direction of the silicon wafer being carried, the plurality of carriers are arranged in pairs, and the carriers in each pair The connection lines between the two carriers are parallel to each other and perpendicular to the radial direction, so that the detection device simultaneously detects the portions of the silicon chip that are in contact with the two carriers in each pair of carriers. The system for detecting silicon wafers as described in claim 3, wherein the carriers located on the same side of the radial direction are evenly distributed in the circumferential direction of the silicon wafer being carried. The system for detecting silicon wafers as described in claim 3, wherein the sensing device includes a distance meter for measuring the distance between the detecting device and the fixed position in the radial direction, so as to obtain the distance based on the distance. The location of the detection device. The system for detecting silicon wafers as described in claim 5, wherein the rangefinder includes a laser transmitter arranged at the fixed position and a laser receiver arranged on the detection device to move together with the detection device . The system for detecting silicon wafers as claimed in claim 1, wherein the plurality of carriers support the silicon wafer by contacting the periphery of the back side of the silicon wafer. The system for detecting silicon wafers as described in claim 7, wherein the corresponding bearing member moves along the radial direction of the supported silicon wafer. The system for detecting silicon wafers as described in claim 1, wherein the detection device includes a front detector and a back side that move on both sides of the carried silicon wafer to respectively detect the front and back sides of the silicon wafer. detector. The system for detecting silicon wafers as described in claim 1, wherein the detection device is a camera used to take images of the silicon wafers.