Wafer polishing apparatus and wafer polishing method

Abstract

The application relates to the technical field of semiconductors, and discloses a wafer grinding device and a wafer grinding method. The wafer grinding device is characterized in that a baffle is arranged between two adjacent grinding discs to separate the grinding chambers where the two grinding discs are arranged, so as to directly block the grinding liquid splashed by the grinding discs, avoid the influence of the grinding liquid and wafer fragments on the grinding process in other grinding chambers, and avoid the lifting of the baffle during use, so that the phenomenon of occupying the running time of the machine is avoided, and the efficiency of the machine running is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a wafer grinding apparatus and a wafer grinding method. Background Technology

[0002] In integrated circuit manufacturing, chemical mechanical polishing (CMP) is the most effective process for achieving global planarization of the substrate. This method utilizes a chemical reaction to etch the substrate surface, while simultaneously using the friction between the polishing pad and the substrate to remove the etched and softened material, thus achieving planarization.

[0003] To better control the substrate polishing process, multiple polishing steps are typically required, involving multiple polishing pads, each using a different polishing slurry. However, with the polishing pads rotating at high speed, the polishing slurry can be flung out, easily splashing onto other pads and causing polishing abnormalities. To address this, a baffle ring is commonly added around the polishing pads to catch the splashed slurry. For effective interception, the baffle ring needs to be slightly higher than the polishing pads. However, this higher baffle ring can interfere with the polishing head's entry and exit from the polishing pads. Therefore, the baffle ring needs to be lowered when the polishing head enters or exits the polishing pads. The time required for raising and lowering the baffle ring reduces machine operating time and decreases machine efficiency. Summary of the Invention

[0004] In view of this, the present invention provides a wafer grinding apparatus and a wafer grinding method to solve the problem of low machine operating efficiency caused by adding a retaining ring outside the grinding disc.

[0005] In a first aspect, the present invention provides a wafer polishing apparatus, which includes a polishing table, a plurality of polishing discs, and baffles. The polishing disc assembly includes a plurality of polishing discs, which are circumferentially spaced around the central axis of the polishing table to form a plurality of polishing chambers. At least one baffle is provided between any two adjacent polishing chambers to separate them. The baffles are fixed in the height direction; the top height of the baffle projected in the height direction is lower than or equal to the top height of the rotating part; the bottom height of the baffle projected in the height direction should be lower than the upper edge height of the baffle ring after it is raised, and higher than or equal to the lower edge height of the polishing head after it is raised.

[0006] Beneficial effects: By placing the baffle between two adjacent grinding discs, the grinding chambers containing the two grinding discs are separated, which facilitates the direct blocking of the grinding fluid splashed from the grinding discs, preventing the grinding fluid and wafer fragments from affecting the grinding process in other grinding chambers. At the same time, by fixing the baffle and ensuring that the top height of the baffle is lower than or equal to the top height of the rotating part, and that the bottom height of the baffle is lower than the upper edge height after the retaining ring is raised, but higher than or equal to the lower edge height after the grinding head is raised, the baffle does not need to be raised or lowered during use, thus avoiding the phenomenon of occupying machine running time and improving the efficiency of machine operation.

[0007] In one optional embodiment, the wafer polishing apparatus further includes a rotating support and a polishing head. The rotating support has a rotating portion and a mounting portion. The rotating portion is rotatably mounted on the polishing table and is located at the center of the polishing table. The mounting portion is radially arranged outside the rotating portion along the central axis of the polishing table. Multiple mounting portions are evenly distributed around the central axis of rotation of the rotating portion. The polishing head is mounted on the mounting portion, and each polishing head corresponds to one of the mounting portions. The polishing head is used to adsorb and polish the wafer.

[0008] Beneficial effects: By providing a rotating part and evenly distributing multiple mounting parts around the rotation center axis of the rotating part, it is convenient to move the wafer between multiple grinding discs. Compared with the phenomenon that a single wafer needs to be moved back to the stage after each adsorption when using a single mounting part to complete the picking and placing of multiple wafers, the moving time of the mounting part can be reduced, and multiple wafers can be ground at the same time, thus improving grinding efficiency.

[0009] In one alternative embodiment, one end of any of the baffles is connected to the rotating part in a driving connection, and the other end of any of the baffles extends radially away from the rotating part along the central axis of the rotating part.

[0010] Beneficial effects: By connecting one end of the baffle to the rotating part, the baffle can be rotated under the drive of the rotating part. Furthermore, by extending the other end of the baffle radially away from the rotating part along the central axis of the rotating part, the grinding liquid splashed during the grinding process can be blocked, thus avoiding affecting the grinding work in other grinding chambers.

[0011] In one alternative embodiment, the wafer polishing apparatus further includes a moisturizing component. The moisturizing component includes a first flow guide installed on the rotating part. One end of the first flow guide has an inlet communicating with the outlet of a water storage component, and the other end of the first flow guide extends to the baffle. The other end of the first flow guide has an outlet on one side wall of the baffle with the spray direction facing it.

[0012] Beneficial effects: By installing the first guide component on the rotating part, it is easy to make the first guide component rotate with the rotating bracket. Furthermore, by connecting the inlet of the first guide component with the outlet of the water storage component and facing the outlet of the first guide component toward one of the side walls of the baffle, it is easy to guide water to the side wall of the baffle, keep the surface of the baffle moist, and rinse the surface of the baffle to prevent crystallization and residue at the grinding fluid.

[0013] In one alternative embodiment, at least two first guide members are provided, wherein the outlets of the two first guide members are respectively facing the two side walls of the baffle.

[0014] In one optional embodiment, the first flow guide is located on the side of the baffle; the moisturizing component further includes a second flow guide, which is located on the top of the baffle, one end of the second flow guide is provided with an inlet communicating with the liquid outlet of the water storage component, and the other end of the second flow guide extends to the side wall of the baffle.

[0015] Beneficial effects: The second guide component facilitates further improvement in the flushing and moisturizing capabilities of the baffle, enhancing the ability to remove crystals.

[0016] In one optional embodiment, the wafer polishing apparatus further includes retaining rings, which are configured to correspond one-to-one with the polishing discs and are used to fit over the polishing discs.

[0017] In one alternative embodiment, the bottom of the baffle has a gap between it and the grinding disc in the height direction.

[0018] Beneficial effect: By leaving a gap between the bottom of the baffle and the grinding disc in the height direction, the baffle is prevented from rubbing against the grinding disc during rotation.

[0019] Secondly, the present invention also provides a wafer polishing method, applied to a wafer polishing apparatus. The wafer polishing method includes: Step S1: A polishing head adsorbs a wafer and moves it to the surface of one of the polishing pads, where polishing is performed; Step S2: A first flow guide and / or a second flow guide disposed between the polishing pad and an adjacent polishing pad are opened to keep the baffle surface moist and to rinse the baffle surface; Step S3: When the wafer is finished being processed at the polishing pad, the first flow guide and / or the second flow guide disposed between the polishing pad and an adjacent polishing pad are closed; Step S4: Steps S1 to S3 are repeated until processing is completed.

[0020] Beneficial effects: Since the wafer grinding method is applied to the wafer grinding equipment, it has the same effect as the wafer grinding equipment, so it will not be elaborated here.

[0021] In one alternative embodiment, the baffle is made of a hydrophobic material.

[0022] Beneficial effects: By using a hydrophobic material for the baffle, water on the baffle can be separated from the baffle in a timely manner. At the same time, under the impact of water, residual crystals on the baffle can be separated from the baffle in a timely manner. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the specific embodiments of the present invention, the drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a top view of the wafer grinding apparatus provided by the present invention;

[0025] Figure 2 This is a partial structural schematic diagram of the wafer grinding apparatus provided by the present invention;

[0026] Figure 3 This is a partial structural schematic diagram of the wafer grinding apparatus provided by the present invention;

[0027] Figure 4 This is a schematic flowchart of the wafer grinding method provided by the present invention;

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Grinding table;

[0030] 2. Grinding disc;

[0031] 3. Baffle;

[0032] 4. Rotating bracket; 401. Rotating part; 402. Mounting part;

[0033] 5. Grinding head;

[0034] 61. First flow guide; 62. Second flow guide;

[0035] 7. Retaining ring. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] The following is combined Figures 1 to 4 The following describes embodiments of the present invention.

[0038] According to an embodiment of the present invention, in a first aspect, a wafer grinding apparatus is provided, such as... Figures 1 to 3 As shown, the grinding device includes a grinding table 1, a grinding disc assembly, and a baffle 3. The grinding disc assembly includes multiple grinding discs 2, preferably three, which are circumferentially spaced around the central axis of the grinding table 1 to form multiple grinding chambers. At least one baffle 3 is provided between any two adjacent grinding chambers to separate them. It can be noted that in this embodiment, the baffle 3 is positioned in the height direction (…). Figure 2 The z-direction is fixed to prevent the baffle 3 from occupying the machine's allowed time due to lifting and lowering.

[0039] By using the technical solution of this embodiment, the baffle 3 is placed between two adjacent grinding discs 2, separating the grinding chambers where the two grinding discs 2 are located. This facilitates the direct blocking of the grinding fluid splashed out by the grinding discs 2, preventing the grinding fluid and wafer fragments from affecting the grinding process in other grinding chambers. At the same time, by fixing the baffle 3, and ensuring that the top height of the baffle 3 is lower than or equal to the top height of the rotating part 401, and that the bottom height of the baffle 3 is lower than the upper edge height of the baffle ring 7 after it is raised, and higher than or equal to the lower edge height of the grinding head 5 after it is raised, the baffle 3 is not raised or lowered during use, thus avoiding the phenomenon of occupying the machine's running time and improving the efficiency of the machine's operation.

[0040] It can be noted that one, two or more baffles 3 are provided between any two adjacent grinding chambers. Preferably, in this embodiment, a total of four grinding chambers are provided, of which three grinding chambers contain grinding discs 2, and the empty grinding chambers serve as wafer pick-and-place chambers. A baffle 3 is provided between any two adjacent grinding chambers, and a baffle 3 is placed between the grinding chambers and the pick-and-place chambers.

[0041] In one embodiment, such as Figures 1 to 3 As shown, the wafer polishing apparatus also includes a rotating support 4 and a polishing head 5. The rotating support 4 has a rotating part 401 and a mounting part 402. The rotating part 401 is rotatably mounted on the polishing table 1 and is located at the center of the polishing table 1. The mounting parts 402 are radially arranged outside the rotating part 401 along the central axis of the polishing table 1. Multiple mounting parts 402 are provided, preferably four, and are evenly distributed around the rotational central axis of the rotating part 401. The polishing head 5 is mounted on the mounting part 402, and each polishing head 5 corresponds to one of the mounting parts 402. The polishing head 5 is used to adsorb and polish the wafer.

[0042] By utilizing the technical solution of this embodiment, a rotating part 401 is provided, and multiple mounting parts 402 are evenly distributed around the rotation center axis of the rotating part 401, which facilitates the movement of wafers between multiple grinding discs 2. Compared with the phenomenon that a single wafer needs to be moved back to the stage after being picked up and placed using a single mounting part 402 to complete the picking and placing of multiple wafers, the movement time of the mounting part 402 can be reduced, and multiple wafers can be ground at the same time, thus improving grinding efficiency.

[0043] In one embodiment, such as Figures 1 to 3 As shown, one end of any baffle 3 is connected to the rotating part 401 in a transmission manner, or in a fixed manner, and the other end of any baffle 3 extends radially away from the rotating part 401 along the central axis of the rotating part 401.

[0044] By using the technical solution of this embodiment, by fixing one end of the baffle 3 to the rotating part 401, the baffle 3 can be rotated under the drive of the rotating part 401. Furthermore, by extending the other end of the baffle 3 radially away from the rotating part 401 along the central axis of the rotating part 401, the grinding liquid splashed during the grinding process can be blocked, thus avoiding affecting the grinding work in other grinding chambers.

[0045] In one embodiment, such as Figures 1 to 3 As shown, the wafer polishing apparatus also includes a moisturizing component. The moisturizing component includes a first flow guide 61, which is installed on the rotating part 401. One end of the first flow guide 61 has an inlet that communicates with the liquid outlet of the water storage component, and the other end of the first flow guide 61 extends to the baffle 3. The other end of the first flow guide 61 has an outlet on one side wall of the baffle 3 facing the direction of liquid spraying.

[0046] Using the technical solution of this embodiment, by installing the first guide member 61 on the rotating part 401, it is easy to make the first guide member 61 rotate with the rotating bracket 4. Furthermore, by connecting the inlet of the first guide member 61 to the outlet of the water storage device and directing the outlet of the first guide member 61 toward one of the side walls of the baffle 3, it is easy to guide water to the side wall of the baffle 3, keep the surface of the baffle 3 moist, and restart the surface of the baffle 3 to prevent crystallization and residue at the grinding fluid.

[0047] In one embodiment, such as Figures 1 to 3 As shown, at least two first guide members 61 are provided, with the outlets of the two first guide members 61 facing the two side walls of the baffle 3 respectively.

[0048] In one embodiment, such as Figures 1 to 3As shown, the first guide member 61 is located on the side of the baffle 3; the moisturizing component also includes a second guide member 62, which is located on the top of the baffle 3. One end of the second guide member 62 is provided with an inlet that communicates with the liquid outlet of the water storage component, and the other end of the second guide member 62 extends to the side wall of the baffle 3.

[0049] By utilizing the technical solution of this embodiment, the setting of the second guide member 62 facilitates further improvement in the rinsing and moisturizing ability of the baffle 3, and enhances the ability to clean up crystals.

[0050] In one embodiment, such as Figures 1 to 3 As shown, the wafer polishing apparatus also includes a retaining ring 7, which is configured in a one-to-one correspondence with the polishing disk 2, and the retaining ring 7 is used to fit around the polishing disk 2.

[0051] In one embodiment, such as Figures 1 to 3 As shown, the bottom of the baffle 3 has a gap between it and the grinding disc 2 in the height direction. The gap should not be too large and should be controlled within the range of 1 to 5 mm, preferably 1 mm, to avoid the inability to effectively block the splashing grinding liquid when the gap is too large.

[0052] By using the technical solution of this embodiment, a gap is left between the bottom of the baffle 3 and the grinding disk 2 in the height direction, so as to avoid the baffle 3 rubbing against the grinding disk 2 during the rotation process.

[0053] It can be explained that when installing baffle 3, baffle 3 is positioned in the height direction ( Figure 2 The top height obtained by projecting the inner Z-direction is lower than or equal to the top height of the rotating part 401; let the baffle 3 be in the height direction ( Figure 2 The bottom height obtained by the inward (Z-direction) projection should be slightly lower than the upper edge height of the baffle ring 7 after it is raised, and higher than or equal to the lower edge height of the grinding head 5 after it is raised. Preferably, since the baffle ring 7 will be 3-5mm higher than the grinding disc after it is raised, the bottom of the baffle 3 should coincide with the lower edge of the grinding head 5 after it is raised by 1mm-2mm to effectively prevent the grinding liquid from splashing.

[0054] Similarly, the distance between the far end of the baffle 3 (the end away from the central axis of the rotating part 401) and the central axis of the rotating part 401 is defined as the first distance d1, the distance between the center of the grinding disc 2 and the central axis of the rotating part 401 is defined as the second distance d2, and the radius of the grinding disc 2 is r. The first distance is made greater than or equal to the second distance, and the first distance is made less than or equal to the sum of the second distance and r, that is, d2≤d1≤(d2+r), ​​to avoid problems such as difficulty in installation, cleaning and deformation during installation.

[0055] According to an embodiment of the present invention, in another aspect, a wafer polishing method is also provided, applied to the wafer polishing apparatus of the first aspect. For example... Figure 4As shown, the polishing method includes: Step S1: The polishing head 5 picks up the wafer and moves it to the surface of one of the polishing pads 2, where polishing is performed; Step S2: The first guide 61 and / or the second guide 62 provided between the polishing pad 2 and the adjacent polishing pad 2 are opened to keep the surface of the baffle 3 moist and to rinse the surface of the baffle 3; Step S3: When the wafer is finished being processed at the polishing pad 2, the first guide 61 and / or the second guide 62 provided between the polishing pad 2 and the adjacent polishing pad 2 are closed; Step S4: Steps S1 to S3 are repeated until the processing is completed.

[0056] It can be explained that before proceeding to step S4, the grinding head 5 should also perform the process of adsorbing the wafer and the rotating part 401 should rotate. Specifically, after the grinding work in the current grinding pad 2 is completed, the first guide 61 and / or the second guide 62 should be closed, and the grinding head 5 should be allowed to adsorb the wafer. Then, the rotating part 401 should rotate, moving the wafer to the next grinding pad 2. Then, the adsorption force of the adsorbed wafer should be removed, and when grinding is performed again, the first guide 61 and / or the second guide 62 should be opened until the grinding is completed, and then step S3 should be performed.

[0057] It can be noted that steps S1 and S2 can be performed simultaneously, sequentially, or alternately. Preferably, when the grinding head 5 picks up the wafer and moves it to the surface of one of the grinding pads 2, the first guide 61 and / or the second guide 62 provided between the grinding pad 2 and the adjacent grinding pad 2 are opened, and then the wafer is ground.

[0058] In one embodiment, the baffle 3 is made of a hydrophobic material.

[0059] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A wafer grinding apparatus, characterized in that, include: Grinding table (1); The grinding disc assembly includes multiple grinding discs (2), which are circumferentially spaced around the central axis of the grinding table (1) to form multiple grinding chambers. At least one baffle (3) is provided between any two adjacent grinding chambers to separate the two adjacent grinding chambers. A rotating bracket (4) is provided with a rotating part (401) and a mounting part (402). The rotating part (401) is rotatably mounted on the grinding table (1) and the rotating part (401) is located at the center of the grinding table (1). The mounting part (402) is located radially on the outside of the rotating part (401) along the central axis of the grinding table (1). A grinding head (5) is mounted on the mounting part (402) and is used to adsorb and grind the wafer. A retaining ring (7) is provided in a one-to-one correspondence with the grinding disc (2), and the retaining ring (7) is used to fit around the grinding disc (2); Among them, the baffle (3) is fixed in the height direction; the top height of the baffle (3) projected in the height direction is lower than or equal to the top height of the rotating part (401); the bottom height of the baffle (3) projected in the height direction is lower than the upper edge height of the retaining ring (7) after it is raised, and higher than or equal to the lower edge height of the grinding head (5) after it is raised; a gap is left between the bottom of the baffle (3) and the grinding disc (2) in the height direction.

2. The wafer grinding apparatus according to claim 1, characterized in that, Also includes: The mounting part (402) is provided in multiple ways, and the multiple mounting parts (402) are evenly distributed around the rotation center axis of the rotating part (401); Furthermore, the grinding head (5) and the mounting part (402) are arranged in a one-to-one correspondence.

3. The wafer grinding apparatus according to claim 2, characterized in that, One end of any of the baffles (3) is connected to the rotating part (401) in a transmission connection, and the other end of any of the baffles (3) extends radially away from the rotating part (401) along the central axis of the rotating part (401).

4. The wafer grinding apparatus according to any one of claims 1-3, characterized in that, Also includes: The moisturizing component includes a first guide member (61), which is installed on the rotating part (401). One end of the first guide member (61) is provided with an inlet communicating with the outlet of the water storage component. The other end of the first guide member (61) extends to the baffle (3). The other end of the first guide member (61) is provided with an outlet on one side wall of the baffle (3) facing the direction of the spray.

5. The wafer grinding apparatus according to claim 4, characterized in that, The first guide (61) is provided in at least two, wherein the outlets of the two first guides (61) are respectively facing the two side walls of the baffle (3).

6. The wafer grinding apparatus according to claim 4, characterized in that, The first guide member (61) is located on the side of the baffle (3); The moisturizing component also includes a second guide (62), which is located on the top of the baffle (3). One end of the second guide (62) is provided with an inlet that communicates with the outlet of the water storage component, and the other end of the second guide (62) extends to the side wall of the baffle (3).

7. A wafer grinding method, applied to the wafer grinding apparatus according to any one of claims 1-6, characterized in that, The grinding method includes: Step S1: The grinding head (5) picks up the wafer and moves it to the surface of one of the grinding disks (2), where it is ground. Step S2: Open the first guide (61) and / or the second guide (62) set between the grinding disc (2) and the adjacent grinding disc (2), keep the surface of the baffle (3) moist and rinse the surface of the baffle (3); Step S3: When the wafer is finished at the grinding pad (2), close the first flow guide (61) and / or the second flow guide (62) provided between the grinding pad (2) and the adjacent grinding pad (2). Step S4: Repeat steps S1 to S3 above until the processing is completed.

8. The wafer grinding method according to claim 7, characterized in that, The baffle (3) is made of a hydrophobic material.

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