Monolithic wafer wet etching apparatus

Abstract

The application discloses a single wafer wet etching device, which comprises a wafer supporting table with a rotating function, an etching liquid spraying device and a baffle arranged at the periphery of the wafer supporting table. The baffle comprises an anti-back-splashing structure for slowing down the etching liquid splashed on the wafer. The anti-back-splashing structure comprises a first vertical plate, the length direction of which is perpendicular to the surface of the wafer and the inner side surface of which has a spacing from the wafer; a first opening transversely passing through the first vertical plate, the first opening being arranged on the movement track of the etching liquid splashed from the surface of the wafer; a second horizontal plate, the first end of which is fixedly arranged on the outer side surface of the first vertical plate; and the top surface of the second horizontal plate is horizontal and lower than or equal to the bottom surface of the first opening, so that the etching liquid passing out of the first opening flows on the top surface of the second horizontal plate and is slowed down. The application can prevent the splashed etching liquid from back-splashing on the wafer.

Description

Technical Field

[0001] This invention relates to a semiconductor integrated circuit manufacturing equipment, and more particularly to a single-wafer wet etching apparatus. Background Technology

[0002] like Figure 1 The diagram shown is a structural schematic of an existing monolithic wafer wet etching apparatus; the existing monolithic wafer wet etching apparatus includes:

[0003] A wafer carrier stage 101 with a rotation function is used to place a wafer 103 and rotate the wafer 103.

[0004] Multiple clamps 102 are provided on the wafer carrier stage 101. The clamps 102 fix the wafer 103 by clamping the edge of the wafer 103.

[0005] The wafer carrier stage 101 is connected to a motor via bearings, and the motor drives the wafer carrier stage 101 to rotate.

[0006] Typically, heating and cooling devices are also provided on the wafer carrier stage 101 to control the etching temperature.

[0007] An etching solution spraying device is used to inject etching solution onto the surface of the wafer 103.

[0008] In the present invention, the etching fluid jetting device includes a nozzle and an arm 104. Figure 1 The image shows two nozzles, designated 105a and 105b, used to spray different etching solutions. Figure 1 Two etching solutions are shown, designated 106a and 106b respectively. The nozzle is mounted on the arm 104 and connected to the etching solution delivery line 107, which is connected to the etching solution source.

[0009] A baffle is disposed around the wafer carrier stage 101. Typically, different etchants require different baffles. Figure 1 The image also shows baffles corresponding to two different etching solutions, labeled 108a and 108b respectively.

[0010] The functions of the outer baffle include: preventing chemical solutions, i.e., etching solutions, from splashing everywhere; blocking and recycling the etching solutions, such as enabling the discharge of acid, alkali, and organic liquids.

[0011] but Figure 1 The baffle shown, however, cannot completely prevent splashing. Figure 1As shown, the baffles 108a and 108b have the same structure, both consisting of a vertical plate, and an extension section extending inward to the side of the wafer 103 is provided at the top of the vertical plate. Figure 1 The dashed arrows in the diagram represent the trajectory of the etching fluid ejected from the wafer 103. It can be seen that the high-speed etching fluid will collide with the baffle. Due to the high incident velocity of the etching fluid, the velocity of the reflection after the collision will also be high, eventually resulting in splashing as shown by dashed arrow 109. The etching fluid corresponding to dashed arrow 109 will eventually return to the surface of the wafer 103, thereby etching the surface of the wafer 103 and forming defects, which will ultimately affect the product yield.

[0012] Existing improvements for reducing solution splashing include increasing the spacing between the baffle and the wafer, or using a fan filter unit (FFU) to reduce splashing. Summary of the Invention

[0013] The technical problem to be solved by the present invention is to provide a single-wafer wet etching apparatus that can reduce the speed of the etching solution ejected from the wafer, thereby preventing the ejected etching solution from splashing back onto the wafer.

[0014] To solve the above-mentioned technical problems, the single-wafer wet etching apparatus provided by the present invention includes: a wafer carrier stage with a rotation function, used to place the wafer and rotate the wafer.

[0015] An etching solution spraying device is used to inject etching solution onto the surface of the wafer.

[0016] A baffle plate is disposed around the wafer carrier stage.

[0017] The baffle includes a splash-proof structure for slowing down the etching fluid ejected from the wafer.

[0018] The anti-splash structure includes:

[0019] A first vertical plate, the length direction of which is perpendicular to the surface of the wafer, and the inner side of the first vertical plate and the wafer having a gap.

[0020] The first opening passes laterally through the first vertical plate. The first opening is located on the trajectory of the etching solution ejected from the wafer surface, so that the etching solution passes through the first opening.

[0021] The second horizontal plate has its first end fixedly disposed on the outer side of the first vertical plate; the top surface of the second horizontal plate is horizontal and the top surface of the second horizontal plate is lower than or equal to the bottom surface of the first opening, and the etching fluid passing through the first opening flows on the top surface of the second horizontal plate, thereby slowing down the etching fluid for the first time.

[0022] A further improvement is that the anti-splash structure also includes:

[0023] The third inclined plate has its first end fixedly mounted on the second end of the second horizontal plate. The top surface of the third inclined plate has a sloping structure, and the lowest end of the top surface of the third inclined plate is level with the top surface of the second horizontal plate. The etching solution flows from the top surface of the second horizontal plate to the lowest end of the top surface of the third inclined plate and then gradually rises along the sloping structure to achieve a second deceleration.

[0024] A further improvement is that the anti-splash structure also includes:

[0025] The fourth arc-shaped plate has its first end fixedly mounted on the second end of the third inclined plate. The top surface of the fourth arc-shaped plate has an arc-shaped structure, and the lowest point of the top surface of the fourth arc-shaped plate is level with the highest point of the top surface of the third inclined plate. The etching solution flows from the top surface of the third inclined plate to the lowest point of the top surface of the fourth arc-shaped plate and then moves along the arc-shaped slope structure, thereby achieving a third deceleration.

[0026] A further improvement is that the trajectory of the arc-shaped structure is a semicircle or a semiellipse.

[0027] A further improvement is that, in the lateral direction, the second end of the arc-shaped structure is located between the first and second ends of the third inclined plate, so that the etching fluid, after being decelerated by the arc-shaped structure, flows back to the third inclined plate.

[0028] A further improvement is that the baffle also includes a recovery structure for collecting the etching solution; the recovery structure includes:

[0029] The etching fluid, after being decelerated, flows through the second opening of the second horizontal plate and downwards to achieve recycling.

[0030] A further improvement is that the recycling structure also includes:

[0031] The fifth vertical plate has its top end fixedly disposed on the bottom surface of the second horizontal plate between the second opening and the second end of the second horizontal plate.

[0032] A further improvement is that the height of the first vertical plate above the first opening is greater than or equal to the maximum height formed by the backsplash of the etching solution flowing back from the arc structure to the third inclined plate, in order to prevent the backflowing etching solution from splashing onto the edge of the wafer.

[0033] A further improvement is that the etching fluid spraying device includes a nozzle and an arm, the nozzle being disposed on the arm, the nozzle being connected to an etching fluid delivery pipeline, and the etching fluid delivery pipeline being connected to an etching fluid source.

[0034] A further improvement is that the etching solution includes an acid solution, an alkaline solution, or an organic liquid.

[0035] A further improvement is that each of the etching solutions is provided with a baffle.

[0036] A further improvement is that the number of baffles includes multiple baffles;

[0037] Each of the baffles enables the recovery of one or more of the etching solutions.

[0038] A further improvement is that the first vertical plate of a portion of the baffle is provided with two or more first openings, and each first opening is located at a different height position along the length of the first vertical plate;

[0039] A corresponding anti-splash structure and a recycling structure are provided at each of the first openings;

[0040] The first vertical plate can move up and down. When the first opening moves to a position on the trajectory of the etching solution ejected from the wafer surface, the anti-splashing structure and the recycling structure corresponding to the first opening are used to recycle the etching solution. The anti-splashing structure and the recycling structure corresponding to each first opening realize the recycling of one type of etching solution.

[0041] The present invention features a specially designed baffle that controls the flow path of the ejected etching solution and decelerates the etching solution along the flow path, thereby preventing the ejected etching solution from splashing back onto the wafer and further preventing the splashed etching solution from forming defects on the wafer, thus improving product yield.

[0042] This invention controls the flow path of the ejected etching fluid, and also allows the decelerated etching fluid to flow back to the recycling point, thereby achieving the recycling of the etching fluid.

[0043] This invention can be achieved by improving the baffle based on the flow characteristics of the etching solution. Therefore, this invention also has the characteristics of simple structure, low cost and easy implementation. Attached Figure Description

[0044] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0045] Figure 1 This is a schematic diagram of an existing monolithic wafer wet etching apparatus;

[0046] Figure 2 This is a schematic diagram of the structure of a single-wafer wet etching apparatus according to an embodiment of the present invention. Detailed Implementation

[0047] like Figure 2 The diagram shown is a structural schematic of a single-wafer wet etching apparatus according to an embodiment of the present invention; the single-wafer wet etching apparatus according to an embodiment of the present invention includes:

[0048] A wafer carrier stage 201 with a rotation function is used to place a wafer 203 and rotate the wafer 203.

[0049] In this embodiment of the invention, a plurality of clamps 202 are provided on the wafer carrier stage 201, and the clamps 202 fix the wafer 203 by clamping the edge of the wafer 203.

[0050] The wafer carrier stage 201 is connected to a motor via bearings, and the motor drives the wafer carrier stage 201 to rotate.

[0051] Typically, heating and cooling devices are also provided on the wafer carrier stage 201 to control the etching temperature.

[0052] An etching solution jetting device is used to inject etching solution onto the surface of the wafer 203.

[0053] In this embodiment of the invention, the etching fluid jetting device includes a nozzle and an arm 204. Figure 2 The image shows two nozzles, designated 205a and 205b, used to spray different etching solutions. Figure 2 Two etching solutions are shown, designated 206a and 206b respectively. The nozzle is mounted on the arm 204 and connected to the etching solution delivery line 207, which is connected to the etching solution source.

[0054] A baffle 208 is disposed around the wafer carrier stage 201.

[0055] The baffle 208 includes a splash-proof structure for slowing down the etching fluid ejected from the wafer 203.

[0056] The anti-splash structure includes:

[0057] A first vertical plate 301 is perpendicular to the surface of the wafer 203 along its length, and the inner side of the first vertical plate 301 is spaced from the wafer 203.

[0058] A first opening 302 extends laterally through the first vertical plate 301. The first opening 302 is positioned on the trajectory of the etching solution ejected from the surface of the wafer 203, allowing the etching solution to pass through the first opening 302. The trajectory of the etching solution ejected from the surface of the wafer 203 is shown by the dashed arrow 401.

[0059] A second horizontal plate 303 is fixedly mounted at its first end on the outer surface of the first vertical plate 301. The top surface of the second horizontal plate 303 is horizontal and lower than or equal to the bottom surface of the first opening 302. The etching fluid exiting the first opening 302 flows on the top surface of the second horizontal plate 303, thereby causing the etching fluid to decelerate for the first time. The path of the etching fluid flowing on the top surface of the second horizontal plate 303 is shown by the dashed arrow 402. The friction between the top surface of the second horizontal plate 303 and the etching fluid causes the etching fluid to achieve the first deceleration. In some embodiments, by increasing the length of the second horizontal plate 203, the speed of the etching fluid can be reduced to a level that prevents backsplashing simply through this first deceleration.

[0060] In this embodiment of the invention, the anti-splash structure further includes:

[0061] The third inclined plate 305 has its first end fixedly mounted on the second end of the second horizontal plate 303. The top surface of the third inclined plate 305 has a sloping structure, and the lowest end of the top surface of the third inclined plate 305 is level with the top surface of the second horizontal plate 303. The etching solution flows from the top surface of the second horizontal plate 303 to the lowest end of the top surface of the third inclined plate 305 and then gradually rises along the sloping structure to achieve a second deceleration. Figure 2 The dashed arrow 403 illustrates the etching fluid climbing from the top surface of the second horizontal plate 203 to the top surface of the third inclined plate 305. It can be seen that the third inclined plate 305 not only slows down the etching fluid through friction but also through the gravity of the etching fluid itself. Therefore, the resistance encountered in the second deceleration is greater, resulting in a better deceleration effect. In some embodiments, the second deceleration by the third inclined plate 305 can reduce the velocity of the etching fluid to a level that prevents backsplashing.

[0062] In this embodiment of the invention, the anti-splash structure further includes:

[0063] A fourth arc-shaped plate 306 is provided, with its first end fixedly mounted on the second end of the third inclined plate 305. The top surface of the fourth arc-shaped plate 306 has an arc-shaped structure, and the lowest point of its top surface is level with the highest point of the top surface of the third inclined plate 305. The etching solution flows from the top surface of the third inclined plate 305 to the lowest point of the top surface of the fourth arc-shaped plate 306, then moves along the arc-shaped ramp structure, thereby achieving a third deceleration. Figure 2 As shown, the fourth arc-shaped plate 306 also decelerates the etching fluid through surface friction and the gravity of the etching fluid itself. Therefore, the resistance encountered in the third deceleration is also relatively large. Figure 2 As shown by the dashed arrow 404, the direction of movement of the etching fluid will change significantly, eventually resulting in a backflow along the dashed arrow 404.

[0064] In this embodiment of the invention, the trajectory of the arc-shaped structure is a semicircle or a semiellipse.

[0065] In the transverse direction, the second end of the arc-shaped structure is located between the first and second ends of the third inclined plate 305, allowing the etching solution, after being decelerated by the arc-shaped structure, to flow back onto the third inclined plate 305. As shown by the dashed arrow 405, the flowing etching solution will generate a certain amount of backsplash; the dashed arrow 406 also represents the backsplash generated by the etching solution during its movement. In this embodiment of the invention, the height of the first vertical plate 301 above the first opening 302 is greater than or equal to the maximum height formed by the backsplash of the etching solution flowing back from the arc-shaped structure to the third inclined plate 305, to prevent the flowing etching solution from splashing onto the edge of the wafer 203.

[0066] In this embodiment of the invention, the baffle 208 further includes a recovery structure for collecting the etching solution; the recovery structure includes:

[0067] The etching fluid, after being decelerated, passes vertically through the second opening 304 of the second horizontal plate 303 and flows downwards for recycling. The dashed arrow 407 shows the recycling path of the etching fluid. A recycling bin is placed below the dashed arrow 407, and the etching fluid flows downwards along the dashed arrow 407 into the recycling bin.

[0068] The recycling structure also includes:

[0069] The fifth vertical plate 307 has its top end fixedly disposed on the bottom surface of the second horizontal plate 303 between the second opening 304 and the second end of the second horizontal plate 303.

[0070] The etching solution includes acid solutions, alkaline solutions, or organic liquids.

[0071] In this embodiment of the invention, the number of baffles 208 includes multiple baffles;

[0072] Each of the baffles 208 enables the recovery of one or more of the etching solutions.

[0073] In some embodiments, the first vertical plate 301 of the baffle 208 is provided with two or more first openings 302, and each first opening 302 is located at a different height position along the length direction of the first vertical plate 301. Figure 2 In the diagram, the baffle, marked with 208a, has two first openings, and the two first openings are marked with 302a and 302b respectively.

[0074] A corresponding anti-splash structure and a recycling structure are provided at each of the first openings 302. Figure 2 The image shows only the first vertical plate 301 of the baffle 208a; other structures are omitted. In some embodiments, each first opening of the baffle 208a corresponds to the anti-splash structure and the recycling structure, and can... Figure 2 The anti-splash structure of the baffle 208 is the same as the recycling structure, for example, a structure can be provided at the first opening 302a. Figure 2 The structure of the second horizontal plate 303, the third inclined plate 305, the fourth arc-shaped plate 306, the second opening 304, and the fifth vertical plate 307 in the baffle 208 described above; and the structure of the baffle 208 described above; and the structure of the baffle 208 described above; and the structure of the baffle 208 described above. Figure 2 The baffle 208 described herein has the same structure as the second horizontal plate 303, the third inclined plate 305, the fourth arc-shaped plate 306, the second opening 304, and the fifth vertical plate 307. In other embodiments, each of the first openings of the baffle 208a can correspond to the anti-splash structure and the recovery structure. Figure 2 The anti-splash structure and the recycling structure of the baffle 208 are different.

[0075] The first vertical plate 301 of the baffle 208a can move up and down. When the first opening 302 moves to a position on the trajectory of the etching solution ejected from the wafer surface, the anti-splashing structure and the recovery structure corresponding to the first opening 302 are used to recover the etching solution. Each anti-splashing structure and recovery structure corresponding to the first opening 302 enables the recovery of one type of etching solution. For example, when acid solution needs to be recovered, the position of the first opening 302a needs to be moved to the trajectory of the etching solution ejected from the wafer surface; when alkaline solution needs to be recovered, the position of the first opening 302b needs to be moved to the trajectory of the etching solution ejected from the wafer surface.

[0076] In this embodiment of the invention, the baffle 208 is specially designed to control the flow path of the ejected etching solution and decelerate the etching solution along the flow path, thereby preventing the ejected etching solution from splashing back onto the wafer 203. For example, the outermost edge area of ​​the wafer 203 with a width of 2cm to 3cm will not be splashed back by the etching solution. Therefore, this embodiment of the invention can prevent the splashed etching solution from forming defects on the wafer 203, thereby improving product yield.

[0077] This invention, through controlling the flow path of the ejected etching fluid, can also enable the decelerated etching fluid to flow back to the recycling point, thereby achieving the recycling of the etching fluid.

[0078] The present invention can be implemented by improving the baffle 208 in combination with the flow characteristics of the etching solution. Therefore, the present invention also has the characteristics of simple structure, low cost and easy implementation.

[0079] The present invention has been described in detail above through specific embodiments, but these are not intended to limit the invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A single wafer wet etching apparatus, characterized by comprising: The application relates to a wafer carrier table with a rotating function, which is used for placing and rotating a wafer. The wafer carrier table comprises an etching liquid injection device, which is used for injecting etching liquid onto the surface of the wafer. A baffle plate is arranged on the periphery of the wafer carrier table. The baffle plate comprises an anti-splashing structure, which is used for decelerating the etching liquid splashed on the wafer. The anti-splashing structure comprises a first vertical plate, which is perpendicular to the surface of the wafer in the length direction, and the inner side of the first vertical plate has a spacing from the wafer. A first opening is arranged on the movement track of the etching liquid splashed from the surface of the wafer, and the etching liquid passes through the first opening. A second horizontal plate is fixedly arranged on the outer side of the first vertical plate at the first end. The top surface of the second horizontal plate is horizontal, and the top surface of the second horizontal plate is lower than or equal to the bottom surface of the first opening. The etching liquid passing through the first opening flows on the top surface of the second horizontal plate to decelerate the etching liquid for the first time.

2. The single wafer wet etch apparatus of claim 1, wherein The anti-splashing structure further comprises a third inclined plate, which is fixedly arranged on the second end of the second horizontal plate at the first end. The top surface of the third inclined plate is in a slope structure, and the lowest end of the top surface of the third inclined plate is level with the top surface of the second horizontal plate.

3. The single wafer wet etch apparatus of claim 2, wherein the etch chamber is a single wafer etch chamber. The etching liquid flows from the top surface of the second horizontal plate to the lowest end of the top surface of the third inclined plate, gradually rises along the slope structure to decelerate the etching liquid for the second time. The anti-splashing structure further comprises a fourth arc-shaped plate, which is fixedly arranged on the second end of the third inclined plate at the first end.

4. The single wafer wet etch apparatus of claim 3, wherein: The top surface of the fourth arc-shaped plate is in an arc structure, and the lowest end of the top surface of the fourth arc-shaped plate is level with the highest end of the top surface of the third inclined plate.

5. The single wafer wet etch apparatus of claim 3, wherein: The etching liquid flows from the top surface of the third inclined plate to the lowest end of the top surface of the fourth arc-shaped plate, moves along the arc structure to decelerate the etching liquid for the third time.

6. The single wafer wet etch apparatus of claim 5, wherein: The track of the arc structure is a semicircle or a half-ellipse. In the transverse direction, the second end of the arc structure is located between the first end and the second end of the third inclined plate, so that the etching liquid decelerated through the arc structure flows back to the third inclined plate.

7. The single wafer wet etch apparatus of claim 6, wherein: The baffle plate further comprises a recovery structure for collecting the etching liquid. The recovery structure comprises a second opening vertically passing through the second horizontal plate.

8. The single-wafer wet etching apparatus as described in claim 5, characterized in that: The etching liquid decelerated passes through the second opening and flows downward to realize recovery. The recovery structure further comprises a fifth vertical plate, which is fixedly arranged on the bottom surface of the second horizontal plate between the second opening and the second end of the second horizontal plate. The height of the first vertical plate above the first opening is greater than or equal to the maximum height of the etching liquid splashed from the arc structure back to the third inclined plate, so as to prevent the etching liquid flowing back from splashing onto the edge of the wafer.

9. The single-wafer wet etching apparatus as described in claim 7, characterized in that: The etching liquid spraying device comprises a nozzle and an arm, the nozzle is arranged on the arm, the nozzle is connected with an etching liquid conveying pipeline, and the etching liquid conveying pipeline is connected with an etching liquid source.

10. The single wafer wet etch apparatus of claim 9, wherein: The etching liquid comprises an acid solution, an alkali solution or an organic liquid.

11. The single wafer wet etch apparatus of claim 10, wherein: The number of the baffles comprises a plurality of baffles. Each of the baffles is used for recycling one or more kinds of etching liquid.

12. The single wafer wet etch apparatus of claim 11, wherein: Two or more first openings are arranged on the first vertical plate of some of the baffles, and each of the first openings is located at a different height position in the length direction of the first vertical plate. A corresponding anti-splashing structure and a recycling structure are arranged at each of the first openings. The first vertical plate is movable up and down, when the first opening moves to a position located on the movement track of the etching liquid splashed from the wafer surface, the anti-splashing structure and the recycling structure corresponding to the first opening are used for recycling the etching liquid, and the anti-splashing structure and the recycling structure corresponding to each of the first openings are used for recycling one kind of etching liquid.

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