Method for improving wafer film uniformity in a slot machine

Abstract

The application provides a method for improving wafer film uniformity in a slot machine, characterized in that the method comprises the following steps: S01: setting a mark point on a wafer, and setting a chemical solution in a slot body; S02: making the mark point on the wafer finally immerse in the chemical solution; S03: rotating the wafer in a first predetermined time period of etching, so that the mark point rotates 170-190 degrees; making the wafer swing in a preset angle in a second predetermined time period of etching, and the first predetermined time period is 1 / 3-2 / 3 of a total etching time period; S04: taking the wafer out of the chemical solution, and making the mark point finally move out of the chemical solution. The method can make the time of immersion of each position of the wafer in the chemical solution basically consistent through a time compensation mechanism, ensures that the film etching amount of each position on the wafer surface is basically the same, and effectively improves the film uniformity after wafer etching.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a method for improving the uniformity of wafer film layers in a slotted machine. Background Technology

[0002] In semiconductor wet lithography, multiple wafers are typically immersed simultaneously in a chemical solution using a tank immersion apparatus for processes such as film removal and cleaning. When the wafers enter the chemical solution, the front end contacts the solution first, resulting in a faster reaction time for the front end compared to the back end. Upon exiting the solution, the back end is preferentially exposed to air, while the front end remains immersed. This time difference (the front end immersing for a longer time than the back end) leads to different film loss rates between the two ends, resulting in poor uniformity of the film after wet etching.

[0003] Therefore, for those skilled in the art, designing a method to improve the uniformity of wafer film layers within a slotted wafer rig is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] This invention provides a method for improving the uniformity of wafer film layers in a slotted wafer etcher. This method uses a time compensation mechanism to ensure that the immersion time of the wafer in the chemical solution is basically the same at all positions in the circumference, thus ensuring that the amount of film etching at each position on the wafer surface is approximately the same and effectively improving the uniformity of the film layer after wafer etching.

[0005] To achieve the above objectives, this application provides a method for improving the uniformity of wafer film layers within a slotted wafer rig, the method comprising the following steps:

[0006] S01: Marking points are set on the wafer, and a chemical solution is placed in the tank;

[0007] S02: The marked points on the wafer are finally immersed in the chemical solution;

[0008] S03: During the first predetermined etching time period, rotate the wafer to rotate the marking point by 170°~190°; during the second predetermined etching time period, swing the wafer within a preset angle, wherein the first predetermined time period is 1 / 3~2 / 3 of the total etching time period.

[0009] S04: Remove the wafer from the chemical solution and finally remove the marked point from the chemical solution.

[0010] Optionally, the second preset time period includes 1 / 8 to 3 / 8 of the total etching time period, or the second preset time period includes 5 / 8 to 7 / 8 of the total etching time period.

[0011] Optionally, the preset angle is 5°~15°.

[0012] Optionally, in S03, the wafer is rotated 180° during the first predetermined time period of etching.

[0013] Optionally, in S03, the wafer is oscillated for the first time within the preset angle during the second predetermined time period, where the second predetermined time period is 1 / 8 to 3 / 8 of the total etching time period;

[0014] Step S03 also includes:

[0015] During the third predetermined time period of etching, the wafer is oscillated a second time within the preset angle, and the third predetermined time period is 5 / 8 to 7 / 8 of the total etching time period.

[0016] Optionally, the oscillation speed of the first oscillation is 1°~5° / s, the rotation speed of the wafer is 5°~10° / s, and the oscillation speed of the second oscillation is less than 3° / s.

[0017] Optionally, in S03, the specific steps of oscillating the wafer within the preset angle during the second or third predetermined time period of etching include:

[0018] The wafer is swung sequentially to the left and right sides of the vertical direction by half of the preset angle.

[0019] Optionally, a gas bubbling device is provided on the side wall of the tank;

[0020] The specific steps of S03 include: during the rotation or oscillation of the wafer, opening the gas bubbling device, and using the bubbles generated by the gas bubbling device to disturb the liquid flow on the surface of the wafer.

[0021] Optionally, the diameter of the bubble is 0.3~3mm, and the flow rate of the bubble is 5~50L / min.

[0022] Optionally, step S03 further includes: turning on the gas bubbling device before the wafer starts to rotate or oscillate; and turning off the gas bubbling device within 1 to 5 seconds after the wafer finishes rotating or oscillating.

[0023] This invention provides a method for improving the uniformity of wafer film layers in a trough etching machine. The method involves rotating the wafer midway through the etching process, moving the wafer's marker points from top to bottom. At this time, the marker points are the last to be immersed in the chemical solution when entering the trough and the last to be removed from the chemical solution when exiting the trough. This setup ensures that the immersion time of each position on the wafer in the chemical solution is essentially the same, effectively solving the problem of inconsistent total reaction time on both sides of the wafer. This ensures that the amount of film etched at each position on the wafer surface is approximately the same, averaging the total process time of the entire wafer and effectively improving the uniformity of the film layer after etching.

[0024] Furthermore, when the wafer rotates and oscillates, the liquid flow direction on the wafer surface changes, breaking the boundary layer formed on the wafer surface due to long-term unidirectional flow. When the wafer rotates and oscillates at large angles, the change in liquid direction can remove particles attached to the surface, thereby improving the wafer's performance and lifespan. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a wafer after it enters the tank at time T0 in one embodiment of this application, where arrow a indicates the direction in which the wafer enters the tank.

[0026] Figure 2 This is a schematic diagram of the structure in which the wafer performs its first oscillation at time T / 4 of the etching process in one embodiment of this application.

[0027] Figure 3 This is a schematic diagram of the structure of a wafer after it is rotated at etching time T / 2 in one embodiment of this application.

[0028] Figure 4 This is a schematic diagram of the structure in which the wafer performs a second oscillation at the 3T / 4 time point during etching, according to one embodiment of this application.

[0029] Figure 5 This is a schematic diagram of the structure of a wafer before it is removed from the etching tank at time T in one embodiment of this application. Arrow b indicates the direction in which the wafer is removed from the etching tank.

[0030] The reference numerals in the attached figures are explained as follows:

[0031] 1. Wafer; 2. Marker point; 3. Tank; 4. Gas bubbling device. Detailed Implementation

[0032] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present application will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present application.

[0033] The terms “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the mechanism or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0034] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "fixation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; they can refer to a direct connection or a connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Unless otherwise specified, the following embodiments and features can complement or combine with each other.

[0036] like Figures 1-5 As shown, one embodiment of this application provides a method for improving the uniformity of wafer film layers within a slot etching machine, applied to semiconductor etching processes. The method includes the following steps:

[0037] S01: Marking point 2 (e.g., Notch port) is set on wafer 1, and chemical solution is placed in tank 3.

[0038] S02: Make the marker point 2 on wafer 1 finally immersed in the chemical solution.

[0039] S03: During the first predetermined etching time period T1, rotate wafer 1 to rotate marker 2 by 170°~190°. During the second predetermined etching time period T2, swing wafer 1 within a preset angle β. The first predetermined time period T1 is 1 / 3 to 2 / 3 of the total etching time period T.

[0040] S04: Remove wafer 1 from the chemical solution and make mark 2 the last part of the chemical solution to be removed.

[0041] Reference Figure 1As shown, in this application, the marking point 2 of wafer 1 is located at the top (the highest point or nearby area), so that wafer 1 is vertically immersed into the chemical solution along the first direction a by a flipping mechanism (not shown), so that the marking point 2 of wafer 1 is finally entered into the chemical solution.

[0042] Reference Figure 3 As shown, during the middle of the etching process (1 / 3 to 2 / 3 of the etching time), wafer 1 is rotated, causing marker point 2 on wafer 1 to move from top to bottom. At this time, marker point 2 on wafer 1 will be the last to be immersed in the chemical solution when entering the tank and the last to be removed from the chemical solution when exiting the tank. Conversely, the opposite side of marker point 2 on wafer 1 will be the first to be immersed in the chemical solution when entering the tank and the first to be removed from the chemical solution when exiting the tank. This setting ensures that the immersion time of each position on wafer 1 in the chemical solution is basically the same, effectively solving the problem of inconsistent total reaction time on both sides of wafer 1. This ensures that the etching amount of the film layer at each position on the surface of wafer 1 is approximately the same, averaging the total process time of the entire wafer 1 and effectively improving the uniformity of the film layer after etching.

[0043] Furthermore, when wafer 1 rotates, the liquid flow direction on the surface of wafer 1 changes, breaking the boundary layer formed on the surface of wafer 1 due to long-term unidirectional flow. When wafer 1 rotates and oscillates at large angles, the change in liquid direction can remove particles attached to the surface, thereby improving the performance and lifespan of wafer 1.

[0044] Furthermore, this application oscillates wafer 1 within a preset angle β before or after rotation. This configuration enhances the synergistic effect of chemical reaction mass transfer by transiently disturbing the surface of wafer 1 through oscillation, causing the particles on the surface of wafer 1 to be in an unstable state. At this time, the direction of force on wafer 1 changes, and the particles on the surface of wafer 1 are carried away along with the change in liquid flow direction during the "oscillation," thereby improving particle removal efficiency.

[0045] For example, in S03, the wafer 1 is rotated 180° within a first predetermined time period T1 of etching, so as to rotate the mark point 2 on the wafer 1 from the highest point to the lowest point, thereby equalizing the immersion time of each region of the wafer 1 in the chemical solution.

[0046] It should be noted that the current tank-type machine uses a flipping mechanism to grab wafer 1 and gradually introduce it into the chemical solution. The flipping mechanism should drive wafer 1 to rotate at least 190° to meet the rotation requirements of wafer 1.

[0047] In a preferred embodiment, the second preset time period T2 includes 1 / 8 to 3 / 8 of the total etching time period T, or the second preset time period T2 includes 5 / 8 to 7 / 8 of the total etching time period T. That is, the wafer 1 can be oscillated before or after large-angle rotation to achieve effective removal of particles from the surface of the wafer 1.

[0048] As a preferred embodiment, the preset angle β is 5°~15°, which means that during the second preset time period T2 of etching, only a small angle of oscillation is needed to remove the particles on the surface of the wafer 1.

[0049] In an optional example, wafer 1 can be oscillated back and forth by 10° during the second preset time period T2 of etching.

[0050] Meanwhile, the number of oscillations of wafer 1 can be set as needed. For example, the number of oscillations of wafer 1 can be limited to 3 to 10 times, or the number of oscillations of wafer 1 can be limited to a dozen or several dozen times, in order to improve the particle removal effect of wafer 1.

[0051] In a preferred embodiment, in S03, the wafer 1 is oscillated for the first time within a preset angle β during a second predetermined time period T2. The second predetermined time period T2 is 1 / 8 to 3 / 8 of the total etching time period T, i.e., 1 / 8T ≤ T2 ≤ 3 / 8T. During the first predetermined etching time period T1, the wafer 1 is rotated, causing the marker point 2 to rotate 170° to 190° (e.g., 180°). The first predetermined time period T1 is 1 / 3 to 2 / 3 of the total etching time period T, i.e., 1 / 3T ≤ T2 ≤ 1 / 2T.

[0052] With this configuration, wafer 1 can be rotated 170°~190° within the first preset time period T1. After the rotation is completed, the marker point 2 of wafer 1 is located at the bottom, and the marker point 2 is removed from the chemical solution last when exiting the tank. According to the time compensation mechanism, the additional reaction during exiting the tank can be reduced after the wafer 1 is rotated, the total process time of the whole wafer 1 is averaged, and the uniformity of the film layer after wet etching of wafer 1 is improved.

[0053] Meanwhile, wafer 1 also oscillates within a preset angle β during the second preset time period T2 before rotation, using transient disturbance to enhance chemical reaction mass transfer, making the particles on the surface of wafer 1 in an unstable state, causing the force direction of the particles to change, and the particles will be carried away along the change of liquid flow direction during the oscillation of wafer 1, thereby improving the removal efficiency.

[0054] Furthermore, step S03 also includes:

[0055] During the third predetermined time period T3 of etching, wafer 1 is oscillated a second time within a preset angle β. The third predetermined time period T3 is the 5 / 8 to 7 / 8 time period in the total etching time period T, i.e., 5 / 8T≤T2≤7 / 8T, for further processing.

[0056] With this setup, wafer 1 undergoes two oscillations, one before and one after a large-angle rotation, to further enhance particle desorption from the surface of wafer 1 and increase particle removal efficiency. After the etching process is completed, wafer 1 is lifted out of the chemical solution, thus completing the entire etching process.

[0057] Reference Figure 1 In a specific example, the mark point 2 of wafer 1 is positioned at the top, and at time T0, wafer 1 is inserted into tank 3 along the first direction a by a flipping mechanism, and the mark point 2 of wafer 1 is finally immersed in the chemical solution.

[0058] Reference Figure 2 After wafer 1 is fully immersed, wafer 1 is oscillated within a range of 10° at the 4 / T etching time of the total etching time T to disturb the chemical solution on the surface of wafer 1. The chemical solution can change the boundary layer formed by the long-term unidirectional flow on the surface of wafer 1 and remove the particles attached to the surface of wafer 1.

[0059] Reference Figure 3 This causes wafer 1 to rotate 180° at 1 / 2T of the total etching time T, thereby moving the marker point 2 on wafer 1 to the bottom.

[0060] Reference Figure 4 This allows wafer 1 to oscillate a second time within a 10° range at 3 / 4T of the total etching time T, further removing particles from the surface of wafer 1 and preventing liquid turbulence from causing particles to redeposit on the surface of wafer 1.

[0061] Reference Figure 5 At time T, the wafer 1 is moved out of the tank 3 along the second direction b by the flipping mechanism. The mark point 2 of the wafer 1 is finally removed from the chemical solution. At this time, the time for each position of the wafer 1 to be immersed in the chemical solution is basically the same, which can ensure the uniformity and consistency of the film layer after etching on the surface of the wafer 1.

[0062] Furthermore, the oscillation speed of the first oscillation is preferably 1°~5° / s, that is, the first oscillation has a small oscillation speed and a small oscillation angle, so as to avoid the chemical solution from causing impact damage to wafer 1 and better protect the surface pattern of wafer 1.

[0063] Meanwhile, the rotation speed of wafer 1 is preferably 5°~10° / s, so that wafer 1 rotates at a constant speed of 5°~10° / s for 170°~190°. This not only completes the large-angle rotation of wafer 1 and shortens the rotation time of wafer 1, but also increases the impact effect of the chemical solution on wafer 1 and improves the removal effect of particles on the surface of wafer 1.

[0064] Furthermore, the oscillation speed of the second oscillation is preferably less than 3° / s, meaning the second oscillation has a smaller oscillation speed and angle. Since the particles on the surface of wafer 1 have been substantially removed during the first preset time period T1 and the second preset time period T2, rotating wafer 1 at a smaller speed during the second oscillation can protect the surface structure of wafer 1 on the one hand, and prevent the turbulence of the chemical solution during the oscillation of wafer 1 from causing redeposition of particles on the surface of wafer 1, thus reducing particle residue in the boundary layer of wafer 1.

[0065] Reference Figures 2-4 As shown, in a preferred embodiment, in S03, the specific steps of oscillating wafer 1 within a preset angle β during the second predetermined time period T2 or the third predetermined time period T3 of etching include:

[0066] The wafer 1 is swung sequentially to the left and right sides of the vertical direction by half a preset angle β, so as to realize the swaying of the wafer 1 within the preset angle β.

[0067] In an optional example, the specific steps of oscillating wafer 1 in S03 include:

[0068] First, rotate wafer 1 clockwise (or counterclockwise) by 5°, then rotate wafer 1 counterclockwise (or clockwise) by 10°, and then rotate wafer 1 clockwise (or counterclockwise) by 10° again. Repeat the above steps to make wafer 1 swing 3 to 10 times in order to remove particles from the surface of wafer 1.

[0069] Reference Figures 2-4 As shown, in another preferred embodiment, in S03, the specific steps of oscillating wafer 1 within a preset angle β during the second predetermined time period T2 or the third predetermined time period T3 of etching include:

[0070] The wafer 1 is oscillated successively in the clockwise and counterclockwise directions at a preset angle β, so as to realize the oscillation of the wafer 1 within the preset angle β.

[0071] In another alternative example, the specific steps of oscillating wafer 1 in S03 include:

[0072] First, rotate wafer 1 clockwise (or counterclockwise) by 10°, then rotate wafer 1 counterclockwise (or clockwise) by 10°. Repeat the above steps to make wafer 1 swing 3 to 10 times in order to remove particles from the surface of wafer 1.

[0073] Continue to refer to Figures 2-4 A gas bubbling device 4 is preferably provided on the side wall of the tank 3. The exhaust port of the bubble bubbling device 4 faces the wafer 1 and is used to output gas toward the surface of the wafer 1.

[0074] Further, the specific steps of S03 include: during the rotation or oscillation of wafer 1, opening the gas bubbling device 4, and using the bubbles generated by the gas bubbling device 4 to disturb the liquid flow on the surface of wafer 1. After the gas is output, bubbles can be generated on the surface of wafer 1, which can cool the surface of wafer 1 to ensure that the etching temperature at various locations on the surface of wafer 1 is basically uniform; on the other hand, the bubbles can disturb the chemical solution around wafer 1, and further remove particles from the surface of wafer 1 through the chemical solution.

[0075] More specifically, since the reaction of wafer 1 in the chemical solution is exothermic, and the tank 3 lacks a heat dissipation mechanism, it will cause local high temperature in wafer 1, and the etching rate will be faster than in other areas.

[0076] This application incorporates a gas bubbling device 4 on the inner wall of the tank 3. Utilizing gas bubbling technology, the device introduces an inert gas (e.g., nitrogen) while the wafer 1 rotates to generate a bubble cluster. As the bubbles rise, they facilitate liquid exchange on the surface of the wafer 1, dissipating heat, balancing the temperature distribution within the tank 3, and uniformizing the etching rate of the wafer 1. Simultaneously, the rising bubble cluster generates continuous micro-fluid disturbances, causing additional momentum exchange at the boundary layer of the wafer 1, improving transfer efficiency, and preventing the accumulation of byproducts and particles within the microstructure of the wafer 1.

[0077] It should be noted that the tank body 3, the tilting mechanism, and the gas bubbling device 4 of the trough-type machine must all meet the requirements for corrosion resistance.

[0078] As an optional example, step S03 further includes: turning on the gas bubbling device 4 before the wafer 1 begins to rotate or oscillate. After the wafer 1 completes its rotation or oscillation, the gas bubbling device 4 is turned off within 1 to 5 seconds to achieve the purpose of heat dissipation on the surface of the wafer 1 and preventing particle redeposition.

[0079] In a preferred embodiment, the bubble diameter can be set to 0.3~3mm, and the bubble flow rate can be set to 5~50L / min.

[0080] In summary, this application provides a method for improving the uniformity of the wafer film layer in a trough etching machine. This method involves rotating the wafer 1 during the middle of the etching process (1 / 3 to 2 / 3 of the etching time), causing the marker point 2 on the wafer 1 to move from top to bottom. At this time, the marker point 2 on the wafer 1 is the last to be immersed in the chemical solution when entering the trough and the last to be removed from the chemical solution when exiting the trough. This setup ensures that the immersion time of each position on the wafer 1 in the chemical solution is basically the same, effectively solving the problem of inconsistent total reaction time on both sides of the wafer 1. This ensures that the etching amount of the film layer at each position on the surface of the wafer 1 is approximately the same, averaging the total process time of the entire wafer 1, and effectively improving the uniformity of the film layer after etching the wafer 1.

[0081] Furthermore, when wafer 1 rotates and oscillates, the liquid flow direction on the surface of wafer 1 changes, breaking the boundary layer formed on the surface of wafer 1 due to long-term unidirectional flow. When wafer 1 rotates and oscillates at large angles, the change in liquid direction can remove particles attached to the surface, thereby improving the performance and lifespan of wafer 1.

[0082] The above description is only a description of the preferred embodiments of this application and is not intended to limit the scope of this application in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of this application.

Claims

1. A method for improving the uniformity of wafer film layers within a slotted wafer assemblies, characterized in that, The method includes the following steps: S01: Marking points are set on the wafer, and a chemical solution is placed in the tank; S02: The marked points on the wafer are finally immersed in the chemical solution; S03: During the first predetermined etching time period, rotate the wafer to rotate the marking point by 170°~190°; during the second predetermined etching time period, swing the wafer within a preset angle, wherein the first predetermined time period is 1 / 3~2 / 3 of the total etching time period. S04: Remove the wafer from the chemical solution and finally remove the marked point from the chemical solution.

2. The method for improving the uniformity of wafer film layers in a slotted mill as described in claim 1, characterized in that, The second preset time period includes 1 / 8 to 3 / 8 of the total etching time period, or the second preset time period includes 5 / 8 to 7 / 8 of the total etching time period.

3. The method for improving the uniformity of wafer film layers in a slotted mill as described in claim 1, characterized in that, The preset angle is 5°~15°.

4. The method for improving the uniformity of wafer film layers in a slotted mill as described in claim 1, characterized in that, In S03, the wafer is rotated 180° during the first predetermined time period of etching.

5. The method for improving the uniformity of wafer film layers in a slotted mill as described in claim 1, characterized in that, In S03, the wafer is oscillated for the first time within the preset angle during the second predetermined time period, where the second predetermined time period is 1 / 8 to 3 / 8 of the total etching time period. Step S03 also includes: During the third predetermined time period of etching, the wafer is oscillated a second time within the preset angle, and the third predetermined time period is 5 / 8 to 7 / 8 of the total etching time period.

6. The method for improving the uniformity of wafer film layers in a slotted mill as described in claim 5, characterized in that, The speed of the first oscillation is 1°~5° / s, the speed of the wafer rotation is 5°~10° / s, and the speed of the second oscillation is less than 3° / s.

7. The method for improving the uniformity of wafer film layers in a slotted mill as described in claim 5, characterized in that, In S03, the specific steps for the wafer to oscillate within the preset angle during the second or third predetermined time period of etching include: The wafer is swung sequentially to the left and right sides of the vertical direction by half of the preset angle.

8. The method for improving the uniformity of wafer film layers in a slotted mill as described in claim 5, characterized in that, A gas bubbling device is provided on the side wall of the tank; The specific steps of S03 include: during the rotation or oscillation of the wafer, opening the gas bubbling device, and using the bubbles generated by the gas bubbling device to disturb the liquid flow on the surface of the wafer.

9. The method for improving the uniformity of wafer film layers in a slotted mill as described in claim 8, characterized in that, The diameter of the bubble is 0.3~3mm, and the flow rate of the bubble is 5~50L / min.

10. The method for improving the uniformity of wafer film layers in a slotted mill as described in claim 8, characterized in that, Step S03 further includes: turning on the gas bubbling device before the wafer starts to rotate or oscillate; and turning off the gas bubbling device within 1 to 5 seconds after the wafer finishes rotating or oscillating.

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