Grinding waste collecting device and wafer thinning apparatus

Abstract

The application discloses a grinding waste collecting device and a wafer thinning equipment, the device is installed on the base of the wafer thinning equipment and is used for collecting the waste produced by wafer grinding; the grinding waste collecting device comprises an upper filter tank and a lower filter tank, the upper filter tank is located above the lower filter tank, the lower filter tank is communicated with a collecting and discharging module located below the lower filter tank, and waste liquid is discharged from the collecting and discharging module through the upper filter tank and the lower filter tank; and the grinding waste collecting device is connected with a driving mechanism.

Description

Technical Field

[0001] This invention relates to the field of ultra-precision wafer grinding technology, and in particular to a grinding waste collection device and a wafer thinning equipment. Background Technology

[0002] Currently, the semiconductor industry manufactures semiconductor chips by forming electronic circuits such as ICs (Integrated Circuits) or LSIs (Large Scale Integrations) on the surface of semiconductor wafers. Before the wafer is diced into semiconductor chips, the back side of the wafer is ground using a grinding and thinning process. This back side refers to the side opposite to the device side where the electronic circuits are formed. Wafer back side thinning refers to the high-precision grinding of various materials such as silicon wafers or compound semiconductors before packaging, reducing their thickness to a suitable ultra-thin profile.

[0003] Typically, grinding and thinning removes approximately 700 μm or more of the substrate material. Backside thinning primarily removes substrate material, and due to this significant thickness removal, a large amount of powder, such as silicon powder, is generated during the grinding and polishing process. Furthermore, once the total wafer thickness is reduced to a certain level, such as below 7 μm, some chipping occurs at the wafer edges, resulting in debris (commonly known as edge chipping). Additionally, abrasive grains from the grinding wheel surface also detach. In short, grinding and thinning processes generate a large amount of waste, including large fragments, small particles, and grinding waste fluid. This waste needs to be promptly discharged to prevent accumulation and leakage. Summary of the Invention

[0004] This invention provides a grinding waste collection device and a wafer thinning device, which aim to solve at least one of the technical problems existing in the prior art.

[0005] A first aspect of the present invention provides a grinding waste collection device, installed on the base of a wafer thinning equipment, for collecting waste generated during wafer grinding; the grinding waste collection device includes an upper filter tank and a lower filter tank, the upper filter tank being located above the lower filter tank, the lower filter tank being connected to a collection and discharge module located below it, and waste liquid being discharged from the collection and discharge module through the upper filter tank and the lower filter tank; the grinding waste collection device is connected to a drive mechanism.

[0006] In one embodiment, multiple grinding waste collection devices are provided, each located in the area corresponding to the workstation of each chuck in the wafer thinning equipment.

[0007] In one embodiment, the upper filter tank and the lower filter tank are separately configured, with the upper filter tank nested inside the lower filter tank.

[0008] In one embodiment, the upper filter tank and the lower filter tank are integrally connected.

[0009] In one embodiment, the base includes a bottom surface and sidewalls, the bottom surface being used to mount a grinding table, and the sidewalls being used to collect and block waste generated during grinding.

[0010] In one embodiment, the driving mechanism includes a lifting mechanism, the fixed end of which is mounted on the side wall of the base, and the movable end of which is connected to the upper filter tank.

[0011] In one embodiment, the grinding waste collection device further includes a detection module for detecting the liquid level inside the grinding waste collection device or the base.

[0012] In one embodiment, the detection module includes a liquid level sensor mounted on the side wall of the base.

[0013] In one embodiment, when the detection module detects that the drainage is obstructed, it causes the drive mechanism to move the upper filter tank, and the waste liquid continues to be discharged from the lower filter tank.

[0014] A second aspect of the present invention provides a wafer thinning apparatus, comprising:

[0015] The equipment front-end module is used to realize the entry and exit of wafers, and the equipment front-end module is set at the front end of the wafer thinning equipment;

[0016] A grinding module is used to grind the wafer, and the grinding module is located at the end of the wafer thinning equipment;

[0017] A polishing module is used to perform chemical mechanical polishing on the wafer after grinding and to transfer the wafer between the three modules. The polishing module is located between the front-end module of the equipment and the grinding module.

[0018] The grinding module base is equipped with a grinding waste collection device as described above.

[0019] The beneficial effects of this invention include: it can quickly handle the drainage blockage caused by waste materials such as wafer fragments, avoid equipment downtime, and improve efficiency. Attached Figure Description

[0020] The advantages of the present invention will become clearer and easier to understand through the following detailed description in conjunction with the accompanying drawings, but these drawings are merely illustrative and do not limit the scope of protection of the present invention, wherein:

[0021] Figure 1 This invention illustrates a wafer thinning apparatus according to an embodiment of the present invention;

[0022] Figures 2 to 5 The grinding waste collection device provided in Embodiment 1 is shown;

[0023] Figures 6 to 9 The grinding waste collection device provided in Embodiment 2 is shown. Detailed Implementation

[0024] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods and scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein. It should be understood that, unless specifically stated otherwise, for ease of understanding, the following description of specific embodiments of the present invention is based on the premise that the relevant equipment, devices, components, etc., are in their original static state and are not given external control signals or driving forces.

[0025] Furthermore, it should be noted that the terms used in this application to indicate orientation, such as front, back, up, down, left, right, top, bottom, front, back, horizontal, and vertical, are merely for ease of explanation and to aid in the understanding of relative position or direction, and are not intended to limit the orientation of any device or structure.

[0026] To illustrate the technical solution described in this invention, the following description will be provided with reference to the accompanying drawings and embodiments.

[0027] In this application, a wafer is also referred to as a wafer, silicon wafer, substrate, or substrate, etc., which have the same meaning and practical function.

[0028] The wafer thinning equipment provided in this embodiment is mainly used for back-side thinning of wafers. The back-side refers to the side of the wafer where no devices are laid, which is generally a substrate. The substrate material can be silicon, silicon oxide, silicon nitride, silicon carbide, sapphire, etc.

[0029] Figure 1 An embodiment of the present invention provides a wafer thinning apparatus, comprising:

[0030] Equipment front-end module 1 is used to realize the entry and exit of wafers. Equipment front-end module 1 is set at the front end of the wafer thinning equipment. Equipment front-end module 1 is a transition module that realizes the transfer of wafers from the outside to the inside of the equipment, so as to realize the "dry entry and dry exit" of wafers.

[0031] Grinding module 3 is used to grind the wafer, the grinding including rough grinding and fine grinding, and grinding module 3 is located at the end of the wafer thinning equipment;

[0032] The polishing module 2 is used to perform chemical mechanical polishing on the wafer after the grinding is completed. It also has the function of transferring the wafer between the three modules (equipment front-end module 1, grinding module 3 and polishing module 2). The polishing module 2 is located between the equipment front-end module 1 and the grinding module 3.

[0033] Device front-end module 1:

[0034] The front-end module 1 of the equipment includes a wafer storage unit 11 and a first transmission unit 12. The wafer storage unit 11 is located on one side of the front end of the wafer thinning equipment, and the first transmission unit 12 is located between the wafer storage unit 11 and the polishing module 2 to realize the transmission of the wafer between the wafer storage unit 11 and the polishing module 2.

[0035] The wafer storage unit 11 consists of multiple front-opening unified pods (FOUPs), specifically two, three, or more. A front-opening unified pod is a container used in semiconductor manufacturing to protect, transport, and store wafers. Its main components are a front-opening container that can hold the wafer and a front-opening door structure. This front-opening door structure is hermetically connected to the outer wall of the wafer thinning equipment, allowing communication between the front-opening container and the equipment's interior.

[0036] The first transfer unit 12 includes a wafer pick-and-place robot. The pick-and-place robot can rotate, extend, or fold and retract, and can also move along a transfer track. The pick-and-place robot is a drying robot used to pick up and place dry and clean wafers. The pick-and-place robot can retrieve wafers to be processed from the wafer storage unit 11 through the door structure of the wafer transfer box and send them to the polishing module 2. It can also receive processed wafers from the polishing module 2 and place them into the wafer transfer box.

[0037] Polishing Module 2:

[0038] The polishing module 2 includes a second transmission unit 21, a third transmission unit 22, a chemical mechanical polishing unit 23, and a post-processing unit 24. The second transmission unit 21, the chemical mechanical polishing unit 23, and the post-processing unit 24 occupy the edges of the polishing module 2, respectively, while the third transmission unit 22 is located in the center.

[0039] Specifically, the second transfer unit 21 is located on one edge of the polishing module 2 and distributed along the length of the device, connecting the front-end module 1 and the grinding module 3. The chemical mechanical polishing unit 23 is located on the other edge of the polishing module 2 and is adjacent to the grinding module 3 and the second transfer unit 21, respectively. The post-processing unit 24 is located on another edge of the polishing module 2 and is adjacent to the front-end module 1, the second transfer unit 21, and the chemical mechanical polishing unit 23, respectively. The third transfer unit 22 is located near the center of the polishing module 2 and is surrounded by the second transfer unit 21, the chemical mechanical polishing unit 23, and the post-processing unit 24, used to realize the mutual transfer of wafers between the second transfer unit 21, the chemical mechanical polishing unit 23, and the post-processing unit 24.

[0040] In one embodiment, the second transmission unit 21 includes a temporary storage section and a moving buffer section for temporarily storing and transporting wafers. The temporary storage section is located near the front-end module 1 of the device and is used for temporarily storing or transferring wafers. The moving buffer section is arranged along the direction from the front-end module 1 of the device to the grinding module 3 and is bidirectionally movable.

[0041] In one embodiment, the third transfer unit 22 includes a central robot arm for transferring the ground wafer from the moving buffer section to the chemical mechanical polishing unit 23, transferring the polished wafer from the chemical mechanical polishing unit 23 to the post-processing unit 24, and transferring the cleaned wafer from the post-processing unit 24 to the temporary storage section.

[0042] After the wafer is taken out from the front-end module 1 of the equipment, it is transported to the grinding module 3 via the second transmission unit 21 for grinding. After the wafer is ground in the grinding module 3, it is transported to the chemical mechanical polishing unit 23 via the second transmission unit 21 and the third transmission unit 22 for polishing. After polishing and cleaning, the wafer is then transferred back to the front-end module 1 of the equipment via the third transmission unit 22 and the second transmission unit 21.

[0043] The post-processing unit 24 is used to clean and dry the polished wafer, and may include a horizontal brushing device and a single-chamber cleaning device.

[0044] Grinding Module 3:

[0045] The grinding module 3 includes a grinding unit 31, a cleaning unit, and a fourth transmission unit.

[0046] The grinding unit 31 is used to perform wafer grinding and thickness measurement. For example... Figure 1 As shown, the grinding unit 31 includes a base 32, a worktable 33 mounted on the base 32, a chuck 34 disposed on the worktable 33, and a grinding wheel 35 corresponding to the position of the chuck 34. The worktable 33 is rotatable about its vertical central axis. Figure 1As shown, in one embodiment, three suction cups 34 are provided, which can rotate between the rough grinding station, the fine grinding station, and the loading / unloading station. Two grinding wheels 35 respectively perform rough grinding and fine grinding. It is understood that... Figure 1 This is just one example; the number of suction cups 34 and grinding wheels 35 can also be other values. For example, the number of suction cups 34 can be 1, 2, 4, 5, etc., and correspondingly, the number of grinding wheels 35 can be 1, 3, 4, etc.

[0047] like Figure 1 As shown, in one embodiment, three independently rotatable suction cups 34 are evenly distributed on the worktable 33, namely the first suction cup, the second suction cup, and the third suction cup. The three suction cups 34 are porous ceramic suction cups with identical structures to achieve vacuum adsorption of the substrate, and the lines connecting the centers of the three suction cups 34 and the center of the worktable 33 form a 120° angle with each other. The three suction cups 34 correspond to three work stations, namely the rough grinding station, the fine grinding station, and the loading and unloading station. The two work stations opposite the grinding wheel 35 are used for rough grinding and fine grinding, respectively, and the remaining work station is used for loading, unloading, and cleaning of the substrate. The rotation of the worktable 33 can drive the three suction cups 34 to switch between these three work stations, so that the suction cups 34 carrying the substrate can move cyclically in the order of loading and unloading station—rough grinding station—fine grinding station—loading and unloading station.

[0048] The worktable 33 is mounted on the base 32, which includes a bottom surface and side walls. The side walls extend upward from the bottom surface and surround the worktable 33, enclosing it within the base 32. The bottom surface is used to mount the grinding worktable 33, and the side walls are used to collect and block waste generated during grinding.

[0049] like Figure 1 As shown, the area corresponding to each chuck 34 in the wafer thinning equipment refers to the area on the base 32 corresponding to the fan-shaped outward radiation of each chuck 34 on the worktable 33. The workstations mentioned here can be understood as the rough grinding station, fine grinding station, and loading / unloading station mentioned above. For example, the area where the rough grinding station is located is... Figure 1 The lower left part of the middle base 32, where the fine grinding station is located is Figure 1 The upper left part of the central base 32 has a loading and unloading station located at... Figure 1 The right side of the middle section.

[0050] The cleaning unit is used to perform suction cup 34 cleaning, polishing and wafer cleaning.

[0051] The fourth transfer unit includes a simple robotic arm. The simple robotic arm picks up the wafer from the second transfer unit 21 and sends it to the grinding unit 31 for grinding. After grinding and cleaning are completed, the simple robotic arm picks up the wafer from the grinding unit 31 and places it in the second transfer unit 21 to facilitate the subsequent transfer of the wafer.

[0052] like Figure 1 As shown, one embodiment of the present invention provides a grinding waste collection device 4, which is installed on the base 32 of a wafer thinning equipment for collecting waste generated during wafer grinding.

[0053] like Figure 1 As shown, in one embodiment, multiple grinding waste collection devices 4 are provided, each located in the area corresponding to the workstation of each chuck 34 in the wafer thinning equipment. Specifically, the number of grinding waste collection devices 4 is equal to the number of chucks 34.

[0054] like Figures 2 to 9 As shown, the grinding waste collection device 4 includes an upper filter tank 41 and a lower filter tank 42. The upper filter tank 41 is located above the lower filter tank 42. The lower filter tank 42 is connected to the collection and discharge module 44 located below it. Waste liquid is discharged from the collection and discharge module 44 through the upper filter tank 41 and the lower filter tank 42.

[0055] In one embodiment, the grinding waste collection device 4 is connected to the drive mechanism 43. When abnormal drainage is detected (manually or automatically), the grinding waste collection device 4 is moved to discharge the liquid. The drive mechanism 43 can be connected to the upper filter tank 41 or the lower filter tank 42. In this embodiment, the action can be performed automatically to clear blockages after the upper filter tank 41 becomes clogged.

[0056] In one embodiment, the grinding waste collection device 4 includes a detection module for detecting the liquid level inside the grinding waste collection device 4 or the base 32. Specifically, the detection module includes a liquid level sensor mounted on the side wall of the base 32. When the grinding waste collection device 4 becomes clogged, and waste liquid overflows and reaches a certain height, the liquid level sensor detects the liquid, indicating a drainage problem and notifying the grinding waste collection device 4 to take measures. This embodiment can detect accumulated liquid and automatically take unblocking measures.

[0057] The grinding waste collection device 4 can be implemented in various ways. Two specific embodiments of the grinding waste collection device 4 are described below.

[0058] Example 1:

[0059] like Figures 2 to 5 As shown in Embodiment 1, the grinding waste collection device 4 includes an upper filter tank 41 and a lower filter tank 42 that are nested together. The upper filter tank 41 and the lower filter tank 42 are separately arranged, with the upper filter tank 41 located above the lower filter tank 42 and fitted inside the lower filter tank 42. The bottom or side surfaces of the upper filter tank 41 and the lower filter tank 42 are provided with drainage holes. The drainage holes of the upper filter tank 41 and the lower filter tank 42 are at least partially aligned.

[0060] The upper filter tank 41 is connected to the drive mechanism 43 to move the upper filter tank 41, and the lower filter tank 42 is connected to the collection and discharge module 44 located below it. Waste liquid is discharged from the collection and discharge module 44 through the upper filter tank 41 and the lower filter tank 42.

[0061] The collection and discharge module 44 includes a collection tank 441 and a discharge pipe connected below the collection tank 441. A lower filter tank 42 is placed inside the collection tank 441, and the collection tank 441 is connected to the discharge pipe. Waste generated during the grinding process is filtered through the upper filter tank 41 and the lower filter tank 42, and the waste liquid flows into the collection tank 441 and then flows away through the discharge pipe.

[0062] like Figures 2 to 5 As shown, in one embodiment, the drive mechanism 43 includes a lifting mechanism for raising or lowering the upper filter tank 41. The fixed end of the lifting mechanism is mounted on the side wall of the base 32, and the moving end of the lifting mechanism is connected to the upper filter tank 41, enabling it to lift the upper filter tank 41 upwards. The lifting mechanism can be implemented using a cylinder or a motor.

[0063] The working process of Example 1 includes: Figure 2 and Figure 4 As shown, the upper filter tank 41 and the lower filter tank 42 are normally nested together, and the liquid passes through the two filters and is discharged from the collection tank 441; as Figure 3 and Figure 5 As shown, when the detection module detects obstructed drainage, the drive mechanism 43 moves the upper filter tank 41, lifting it and separating it from the lower filter tank 42. The lower filter tank 42 remains stationary in the collection tank 441, and the waste liquid continues to drain away from the lower filter tank 42. Specifically, the lifting mechanism raises the upper filter tank 41, lifting away debris. The debris no longer obstructs the drainage process, and the waste liquid continues to drain away from the outer leakage tank, restoring smooth drainage. During regular equipment maintenance, the debris in the upper filter tank 41 is cleaned, reducing the number of equipment downtimes.

[0064] Example 2:

[0065] like Figures 6 to 9 As shown, in Embodiment 2, the grinding waste collection device 4 includes an upper filter tank 41 and a lower filter tank 42 integrally connected. In other words, the upper filter tank 41 and the lower filter tank 42 are fixed together and move simultaneously. Figures 7 to 9As shown, the upper filter tank 41 and the lower filter tank 42 are fixed together to form a large tank. This large tank is divided into an upper layer and a lower layer, separated by a filter plate. Both the bottom and sides of the upper filter tank 41 and the lower filter tank 42 are provided with drainage holes. The upper filter tank 41 is located above the lower filter tank 42, and the lower filter tank 42 is connected to the collection and discharge module 44 located below it. Waste liquid is discharged from the collection and discharge module 44 through the upper filter tank 41 and the lower filter tank 42.

[0066] Additionally, the grinding waste collection device 4 is connected to the drive mechanism 43. Specifically, the upper filter tank 41 or the lower filter tank 42 can be connected to the drive mechanism 43, and the drive mechanism 43 moves the upper filter tank 41 and the lower filter tank 42 together. In one embodiment, such as Figure 7 and Figure 9 As shown, the fixed end of the lifting mechanism is installed on the side wall of the base 32, and the moving end of the lifting mechanism is connected to the upper filter tank 41. When the lifting mechanism raises the upper filter tank 41, the lower filter tank 42 is also raised at the same time.

[0067] The working process of Example 2 includes: Figure 6 and Figure 8 As shown, normally the upper filter tank 41 and the lower filter tank 42 are placed in the collection tank 441, and the waste liquid is discharged from the collection tank 441 after passing through the two layers of filtration; as Figure 7 and Figure 9 As shown, when the detection module detects that the drainage is obstructed (such as the upper filter tank 41 being blocked by waste), the lifting mechanism raises the upper filter tank 41, and the lower filter tank 42 is also lifted at the same time. Since there is no accumulated waste in the lower filter tank 42, the waste liquid can flow into the collection tank 441 through the side of the lower filter tank 42 and then be discharged. When the equipment is regularly maintained, the debris in the upper filter tank 41 will be cleaned in a unified manner to ensure that the efficiency of the equipment is not reduced due to cleaning debris.

[0068] Based on the above-described structure of the grinding waste collection device 4, an embodiment of the present invention also provides a processing method, including:

[0069] S1, when the drainage in the base 32 is blocked or the liquid level rises, the detection module outputs an alarm signal;

[0070] S2, the drive mechanism 43 drives the grinding waste collection device 4 to rise and discharge the waste liquid;

[0071] S3, wait for a period of time and then check if the liquid level has dropped;

[0072] S4, if the liquid level drops, the equipment continues to process the wafer;

[0073] S5. If the liquid level does not drop, shut down the equipment and notify the operator for maintenance. During maintenance, clean the debris in the grinding waste collection device 4, check and clear other blockages, and handle products that need to be reprocessed due to malfunction.

[0074] The above-described embodiments of the present invention can quickly resolve drainage blockage issues caused by waste materials such as wafer fragments, preventing equipment downtime and improving efficiency.

[0075] The accompanying drawings in this specification are schematic diagrams used to illustrate the concept of the invention and to schematically show the shapes of the various parts and their interrelationships. It should be understood that, in order to clearly show the structure of the various components of the embodiments of the invention, the drawings are not drawn to the same scale, and the same reference numerals are used to indicate the same parts in the drawings.

[0076] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0077] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these 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 grinding debris collection device characterized by, Installed on the base of the wafer thinning equipment, it is used to collect waste generated during wafer grinding; The grinding waste collection device includes an upper filter tank and a lower filter tank. The upper filter tank is located above the lower filter tank, and the lower filter tank is connected to the collection and discharge module located below it. Waste liquid is discharged from the collection and discharge module through the upper filter tank and the lower filter tank. The side of the upper filter tank is provided with a leakage hole. The upper filter tank and the lower filter tank are set separately. The upper filter tank is fitted inside the lower filter tank and connected to the drive mechanism. The drive mechanism includes a lifting mechanism. The fixed end of the lifting mechanism is installed on the side wall of the base, and its moving end is connected to the upper filter tank. The grinding waste collection device also includes a detection module for detecting the liquid level inside the grinding waste collection device or base. When drainage is obstructed, the drive mechanism lifts the upper filter tank and separates it from the lower filter tank. The upper filter tank lifts up the debris, and the debris no longer obstructs the drainage process. The waste liquid continues to be discharged from the lower filter tank.

2. The grinding waste collecting device according to claim 1, characterized in that, Multiple grinding waste collection devices are provided, each located in the area corresponding to the workstation of each chuck in the wafer thinning equipment.

3. The grinding waste collecting device according to claim 1, wherein The base includes a bottom surface and a side wall. The bottom surface is used to mount a grinding worktable, and the side wall is used to collect and block waste generated during grinding.

4. The grinding waste collecting device according to claim 3, wherein The detection module includes a liquid level sensor, which is mounted on the side wall of the base.

5. A wafer thinning apparatus, comprising: include: The equipment front-end module is used to realize the entry and exit of wafers, and the equipment front-end module is set at the front end of the wafer thinning equipment; A grinding module is used to grind the wafer, and the grinding module is located at the end of the wafer thinning equipment; A polishing module is used to perform chemical mechanical polishing on the wafer after grinding and to transfer the wafer between the three modules. The polishing module is located between the front-end module of the equipment and the grinding module. The grinding module is equipped with a grinding waste collection device as described in any one of claims 1 to 4 on its base.

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