Substrate processing equipment
The substrate processing apparatus addresses non-uniform processing by separating liquid flows and using a bubble nozzle to promote uniform distribution, ensuring efficient and uniform substrate processing.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KIOXIA CORP
- Filing Date
- 2022-08-12
- Publication Date
- 2026-06-08
AI Technical Summary
Existing substrate processing apparatuses struggle to uniformly distribute processing solutions across semiconductor substrates, leading to non-uniform processing and accumulation of reaction products.
A substrate processing apparatus with an inner wall and processing liquid nozzle configuration that separates downward and upward flows of processing liquid, promoting uniform distribution and suppressing interference, combined with a bubble nozzle to enhance upward flow and prevent stagnation.
Ensures uniform processing of semiconductor substrates by maintaining consistent flow velocity and preventing reaction product accumulation, resulting in efficient and uniform application of processing solutions across the entire substrate surface.
Smart Images
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Abstract
Description
Technical Field
[0001] Embodiments of the present invention relate to a substrate processing apparatus.
Background Art
[0002] In the manufacturing process of semiconductor devices, a process of etching various films formed on a semiconductor substrate is carried out. For example, in a three-dimensional stacked non-volatile memory device in which memory cells are stacked three-dimensionally, when forming a stacked body in which an insulating film and a conductive film are stacked around a memory hole, a stacked body in which a silicon oxide film and a silicon nitride film are alternately stacked is formed. A process of selectively etching the silicon nitride film is carried out. In the etching process, for example, a substrate processing apparatus that performs the etching process by immersing a plurality of semiconductor substrates in a processing tank containing an etching solution is used. In such a substrate processing apparatus, it is required to equalize the circulation flow of a processing solution such as an etching solution with respect to the entire semiconductor substrate disposed in the processing tank, and to equalize the processing of the semiconductor substrate with the processing solution.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0004] The problem to be solved by the present invention is to provide a substrate processing apparatus that enables equalization of processing of a substrate such as a semiconductor substrate with a processing solution.
Means for Solving the Problems
[0005] The substrate processing apparatus of the embodiment includes a processing tank for storing a processing liquid and for accommodating a plurality of substrates to be processed with the processing liquid, arranged in a predetermined direction with their substrate surfaces facing substantially horizontally; an inner wall provided inside the processing tank that covers at least a portion of the substrate surface on one end of the plurality of substrates along the arrangement direction, and the side surface of the plurality of substrates along the arrangement direction, and that a space exists between the inner wall and the bottom surface of the processing tank for the processing liquid to flow through; and a device provided inside the processing tank at a position outside the inner wall. It has a plurality of openings that extend in the direction of the arrangement and are opened toward the bottom surface of the processing tank so that the processing liquid is discharged toward the bottom surface of the processing tank. A processing liquid nozzle and a device provided to cover the bottom of the inner wall , having a plurality of openings that extend in the direction of the arrangement and allow the processing liquid to flow through. It is equipped with a base plate. [Brief explanation of the drawing]
[0006] [Figure 1] This is an example of a front view showing a partial cross-section of the substrate processing apparatus of the embodiment. [Figure 2] Figure 1 is a side view showing a partial cross-section of the substrate processing apparatus. [Figure 3] This figure shows the flow of the processing liquid in the substrate processing apparatus shown in Figure 1. [Figure 4] This is another example of a front view showing a partial cross-section of the substrate processing apparatus of the embodiment. [Figure 5] This figure shows the flow of the processing liquid in the substrate processing apparatus shown in Figure 4. [Figure 6] This is a front view showing a partial cross-section of a first modified example of the substrate processing apparatus of the embodiment. [Figure 7] This is a front view showing a second modified example of the substrate processing apparatus of the embodiment in a partial cross-sectional view. [Figure 8] This figure shows the flow rate distribution of the processing liquid in the substrate processing apparatus shown in Figure 7. [Figure 9] This figure shows the silica concentration distribution in the substrate processing apparatus shown in Figure 7. [Figure 10] This figure shows the flow rate distribution of the processing liquid in a substrate processing apparatus for comparison. [Figure 11] This figure shows the silica concentration distribution in a substrate processing apparatus for comparison. [Figure 12] This figure shows the silica concentration distribution in a substrate processing apparatus for comparison. [Figure 13] Figure 4 is a front view showing a modified example of the substrate processing apparatus in a partial cross-section. [Modes for carrying out the invention]
[0007] The substrate processing apparatus of the embodiment will be described below with reference to the drawings. In each embodiment, substantially identical components are denoted by the same reference numerals, and their descriptions may be partially omitted. The drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of thickness of each part, etc., may differ from those in reality.
[0008] Figure 1 is a front view showing a partial cross-section of the substrate processing apparatus of the embodiment, and Figure 2 is a side view showing a partial cross-section of the substrate processing apparatus shown in Figure 1. The substrate processing apparatus 1 shown in Figures 1 and 2 is a batch-type processing apparatus that processes multiple substrates W at once with a processing liquid, and comprises a processing tank 2 for storing the processing liquid, an inner wall 3 provided inside the processing tank 2, and a processing liquid nozzle 4 provided outside the inner wall 3 inside the processing tank 2.
[0009] The processing tank 2 stores the processing solution and accommodates multiple substrates W to be processed with the processing solution, arranged in a predetermined direction with their substrate surfaces (the processing surface on which the device is formed or the back surface thereof) facing approximately horizontally. The processing solution is selected according to the processing of the substrates W. When etching a semiconductor substrate used as the substrate W, an etching solution is used. Various known etching solutions are stored in the processing tank 2. For example, when etching a silicon nitride film provided on a semiconductor substrate, an aqueous phosphoric acid solution heated to around 150°C is used.
[0010] For the phosphoric acid aqueous solution used as an etching solution for silicon nitride films, an aqueous solution of inorganic phosphoric acid (orthophosphoric acid), commonly represented by H3PO4, is used. Instead of H3PO4, or in addition to H3PO4, H4P2O7 (pyrophosphoric acid) or the like may be used. The phosphoric acid aqueous solution may contain additives to increase the etching rate of the silicon nitride. For example, phosphates such as alkali metal salts of phosphoric acid or organic phosphoric acids may be added. This explanation primarily describes the case where the substrate processing apparatus 1 is applied to a wet etching apparatus, but the substrate processing apparatus 1 is not limited to this and may also be a substrate cleaning apparatus, etc.
[0011] Multiple substrates W are arranged in a predetermined direction (first direction A) on the lifter 5, supported so as to be leaning upright in a substantially vertical direction, and housed in the processing tank 2. A predetermined process such as etching is performed in the processing liquid stored in the processing tank 2. The lifter 5 is made capable of being raised and lowered between a processing position (processing area) where the substrates W are immersed in the processing liquid stored in the processing tank 2 and a standby position above the processing tank 2 by a lifting unit (not shown). When the lifter 5 is lowered to the processing position, the multiple substrates W are immersed in the processing liquid and a predetermined process such as etching is performed while supported by the lifter 5. The lifter 5 has a central support member 6 that supports the center of the lower edge of the multiple substrates W, and a pair of side support members 7A and 7B that support the sides of the multiple substrates W, which are provided to support the multiple substrates W at predetermined intervals.
[0012] The processing tank 2 is provided with a circulation system having an overflow section 8 for circulating the processing liquid, a circulation pump 9, a processing liquid nozzle 4 for discharging the processing liquid, a first pipe 10 connecting the overflow section 8 and the circulation pump 9, and a second pipe 11 connecting the circulation pump 9 and the processing liquid nozzle 4. Although not shown in the figure, the processing tank 2 may be provided with a processing liquid supply section for supplying the processing liquid, and further a processing liquid temperature adjustment section for adjusting the temperature of the processing liquid as required. A filter for removing solid reaction products and the like in the processing liquid may be provided in the circulation system. The overflow section 8 is provided at the upper edge of the processing tank 2 and recovers the processing liquid that has overflowed from the upper edge of the processing tank 2 due to the circulation of the processing liquid. The processing liquid recovered by the overflow section 8 is sent to the circulation pump 9 through the first pipe 10. The processing liquid discharged from the circulation pump 9 is sent to the processing liquid nozzle 4 through the second pipe 10. The processing liquid is discharged from the processing liquid nozzle 4.
[0013] Inside the processing tank 2, an inner wall 3 is provided that separates the processing area of a plurality of substrates W supported by the lifter 5 from the outer area inside the processing tank 2 where the processing liquid nozzle 4 is disposed. The inner wall 3 is provided so as to cover at least a part of the substrate surface on one end side along the arrangement direction (first direction A) of the plurality of substrates W and the height direction of the side surface along the arrangement direction of the plurality of substrates W. That is, the inner wall 3 is provided such that a space (lower circulation space) through which the processing liquid can flow exists between the bottom surface of the processing tank 2 and the inner wall 3. Further, below the arrangement of the plurality of substrates W, the inner wall 3 does not have a bottom surface. The inner wall 3 is arranged such that a circulation space (upper circulation space) for the processing liquid exists in its upper part.
[0014] One surface at the other end along the arrangement direction of the plurality of substrates W on the inner wall 3 is joined to the inner wall surface of the processing tank 2 and has a shape surrounding three surfaces of the processing region of the substrate W. That is, the inner wall 3 has a first surface 3A, a second surface 3B, and a third surface 3C arranged so as to surround three surfaces of the processing region of the substrate W. The first surface 3A is arranged so as to cover at least a part in the height direction of the substrate surface on one end side along the arrangement direction (first direction A) of the plurality of substrates W. One end of the second surface 3B is joined to one end in the direction (second direction B) intersecting the first direction A of the first surface 3A. One end of the third surface 3C is joined to the other end in the second direction B of the first surface 3A. The other end of the second surface 3B and the other end of the third surface 3C are joined to the inner wall surface of the processing tank 2. Further, between the second surface 3B and the third surface 3C on the inner wall 3 and the inner wall surface of the processing tank 2 facing these, a support portion 23 that connects between the inner wall 3 and the processing tank 2 and reinforces the inner wall 3 is provided.
[0015] By installing the inner wall 3 having such a shape in the processing tank 2, the processing liquid flows in the depth direction (third direction C intersecting the first direction A) of the processing tank 2 between the three surfaces of the inner wall 3 and the three inner wall surfaces of the processing tank 2, and the lower flow space between the bottom surface of the processing tank 2 and the inner wall 3 and the upper flow space between the upper part of the processing tank 2 and the inner wall 3 are configured such that the processing liquid flows. Further, in the three surfaces of the inner wall 3 and the inner wall surface on the other end side of the arrangement of the plurality of substrates W in the processing tank 2 or in the processing region of the substrate W surrounded by the back plate of the lifter 5, the processing liquid is also configured to flow in the depth direction (third direction C) of the processing tank 2.
[0016] Figure 3 shows the flow of the processing liquid in the substrate processing apparatus 1 of the embodiment. In the processing tank 2 having the inner wall 3 as described above, the processing liquid nozzle 4 is positioned between the inner wall 3 and the inner wall surface of the processing tank 2 outside of it, as shown in Figure 3, and opens toward the bottom surface of the processing tank 2. A downward flow is formed between the inner wall 3 and the inner wall surface of the processing tank 2 by the processing liquid discharged from the processing liquid nozzle 4. Furthermore, the processing liquid flows into the processing area of the substrate W surrounded by the inner wall 3 through the flow space for the processing liquid between the bottom surface of the processing tank 2 and the inner wall 3. An upward flow of the processing liquid is formed in the processing area of the substrate W. Preferably, the height of the inner wall 3 is set so that its upper end is higher than half the height of the multiple substrates W and higher than the installation position of the processing liquid nozzle 4. This makes it possible to suppress interference between the downward flow of the processing liquid between the inner wall 3 and the inner wall surface of the processing tank 2 and the upward flow of the processing liquid in the processing area of the substrate W surrounded by the inner wall 3.
[0017] In this way, by providing an inner wall 3 in the processing tank 2 and installing a processing liquid nozzle 4 with an opening facing downwards between the inner wall 3 and the inner wall surface of the processing tank 2, a downward flow of processing liquid is formed between the inner wall 3 and the inner wall surface of the processing tank 2, and an upward flow of processing liquid is formed in the processing area of the substrate W. By separating the region where the downward flow of processing liquid is formed from the region where the upward flow is formed, it is possible to suppress interference between the downward and upward flows of processing liquid at the same location. As a result, the velocity of the upward flow of processing liquid in the processing area of the substrate W is kept constant, and the processing of the substrate W can be made uniform. Furthermore, reaction products such as silica formed by etching the silicon nitride film, for example, can flow uniformly, and the accumulation of reaction products in areas where the flow is stagnant can be suppressed. As a result, it is possible to supply the processing liquid uniformly to the entire surface of the substrate W and to make the processing of the substrate W by the processing liquid uniform.
[0018] In Figures 1, 2, and 3, the processing liquid nozzle 4 is installed with its opening facing downwards, but the opening direction of the processing liquid nozzle 4 is not limited to this. The processing liquid nozzle 4 only needs to be opened in such a way that an upward flow of processing liquid is formed in the inner region of the inner wall 3, i.e., the processing region of the substrate W, and a downward flow of processing liquid is formed between the inner wall 3 and the inner wall surface of the processing tank 2. Figure 4 is a front view showing a partial cross-section of another substrate processing apparatus of the embodiment, and Figure 5 shows the flow of processing liquid in another substrate processing apparatus of the embodiment. For example, as shown in Figure 4, the processing liquid nozzle 4 may be installed between the inner wall 3 and the inner wall surface of the processing tank 2, and the processing liquid nozzle 4 may be opened toward the lower flow space between the bottom surface of the processing tank 2 and the inner wall 3. With such a processing liquid nozzle 4, as shown in Figure 5, an upward flow of processing liquid can be formed in the processing region of the substrate W within the inner wall 3, and a downward flow of processing liquid can be formed between the inner wall 3 and the inner wall surface of the processing tank 2. The opening direction of the processing liquid nozzle 4 should be such that it forms an upward flow of processing liquid in the processing area of the substrate W as described above, and does not hinder the formation of a downward flow of processing liquid between the inner wall 3 and the inner wall surface of the processing tank 2.
[0019] Figures 1 and 2 show a state in which the inner wall 3 does not have a bottom surface, but the shape of the inner wall 3 is not limited to this. Figure 6 is a front view showing a partial cross-section of a first modified example of the substrate processing apparatus of the embodiment. For example, as shown in Figure 6, a bottom plate 13 having a plurality of openings 12 may be further provided at the bottom of the inner wall 3. In this case, a downward flow of processing liquid is formed between the inner wall 3 and the inner wall surface of the processing tank 2, and this downward flow flows along the bottom plate 13 and flows into the processing area of the substrate W through the plurality of openings 12. The processing liquid that has flowed into the processing area of the substrate W forms an upward flow within the processing area of the substrate W. Therefore, similar to the substrate processing apparatus 1 shown in Figures 1 and 2, interference between the downward flow and upward flow of processing liquid at the same location is suppressed. As a result, the velocity of the upward flow of processing liquid in the processing area of the substrate W is kept constant, and the processing of the substrate W can be made uniform. Furthermore, the accumulation of reaction products in areas where the flow is stagnant can be suppressed. These measures enable the uniform supply of the processing solution to the entire surface of the substrate W, thereby ensuring uniform processing with the processing solution.
[0020] As shown in Figure 6, when a bottom plate 13 having a plurality of openings 12 is provided at the bottom of the inner wall 3, it is preferable to provide a bubble nozzle (bubbler) 14 on the bottom plate 13. Figure 7 is a front view showing a partial cross-section of a second modified example of the substrate processing apparatus of the embodiment. For example, as shown in Figure 7, a bubble nozzle 14 can be provided on the bottom plate 13 having a plurality of openings 12 to perform bubbling in the processing liquid. Although not shown, the bubble nozzle 14 is connected to a compressed gas supply device such as a compressor. The gas discharged from the bubble nozzle 14 may be air or the like, or an inert gas such as nitrogen gas or argon gas may be used. The bubble nozzle 14 is open toward the substrate W above. This allows bubbling in the processing liquid in the processing area of the substrate W to promote the upward flow of the processing liquid. By promoting the upward flow of the processing liquid in the processing area of the substrate W, the processing liquid is supplied more uniformly and efficiently to the entire surface of the substrate W, making it possible to make the processing of the entire surface of the substrate W with the processing liquid more uniform and efficient.
[0021] Figure 8 shows the flow velocity distribution of the processing liquid when using the substrate processing apparatus 1 shown in Figure 7. Figure 9 shows the concentration distribution of silica, a reaction product, when using the substrate processing apparatus 1 shown in Figure 7. For comparison with Figures 8 and 9, Figures 10 and 11 show the flow velocity distribution of the processing liquid and the concentration distribution of silica when using a comparative substrate processing apparatus installed with the processing liquid nozzle and bubble nozzle facing upwards on the lower side of the lifter. Figures 8 to 11 all show a state in which phosphoric acid is used as the processing liquid and it is bubbled with nitrogen gas (N2). As shown in Figure 8, when using the substrate processing apparatus 1 of the embodiment, it can be seen that the variation in the flow velocity of the processing liquid is small, and it is unlikely that there will be any parts with fast or slow flow velocities. Furthermore, as shown in Figure 9, when using the substrate processing apparatus 1 of the embodiment, the variation in the concentration distribution of silica, a reaction product, is also small. From these, it can be seen that the substrate processing apparatus 1 of the embodiment makes it possible to uniformly and efficiently process the entire surface of the substrate W with the processing liquid.
[0022] In contrast, as shown in Figure 10, the comparative substrate processing apparatus exhibits a high-velocity region in the center, while the surrounding area exhibits a slower velocity. This is because the high-velocity region in the center facilitates the formation of a downward flow around it, resulting in opposing upward and downward flows in the surrounding area. Consequently, the flow velocity in the surrounding area tends to be slower. As a result, the comparative substrate processing apparatus exhibits a tendency for the flow velocity of the processing solution to vary across the entire substrate W. This reduces the uniformity of the processing solution across the entire substrate W. This is also evident from the silica concentration distribution shown in Figure 11, where the variation in flow velocity leads to significant variation in the concentration distribution of the reaction products. It can be seen that the comparative substrate processing apparatus cannot achieve uniform processing of the entire substrate W with the processing solution.
[0023] Furthermore, Figure 12 shows the concentration distribution of silica, a reaction product, when a comparative substrate processing apparatus having the same configuration as Figure 7, except that the bottom plate 13 provided at the bottom of the inner wall 3 is not opened, is used in the substrate processing apparatus 1 shown in Figure 7. As is clear from Figure 12, when the bottom plate 13 is not opened, the processing liquid stagnates within the inner wall 3 where the bottom plate 13 is provided, impairing the flow of the processing liquid. As a result, there is a large variation in the concentration distribution of silica, a reaction product, and the concentration distribution is particularly high within the inner wall 3. This also shows that it is effective to provide an opening 12 in the bottom plate 13 and to arrange a bubble nozzle 14 to promote the flow (upward flow) of the processing liquid within the inner wall 3.
[0024] The modified configuration, in which a bubble nozzle 14 is provided on a bottom plate 13 having multiple openings 12 and bubbles are applied to the processing liquid, is not limited to the substrate processing apparatus 1 shown in Figure 7. Figure 13 is a front view showing a modified configuration of the substrate processing apparatus shown in Figure 4 in a partial cross-section. For example, as shown in Figure 13, a substrate processing apparatus 1 equipped with a combination of a processing liquid nozzle 4 opening toward the lower flow space shown in Figure 4 and a bubble nozzle 14 installed on a bottom plate 13 having multiple openings 12, which is provided at the bottom of the inner wall 3 shown in Figure 7, is also effective. The substrate processing apparatus 1 shown in Figure 13 is installed between the inner wall 3 and the inner wall surface of the processing tank 2 and is equipped with a processing liquid nozzle 4 opening toward the lower flow space between the bottom surface of the processing tank 2 and the inner wall 3, and a bubble nozzle 14 provided on a bottom plate 13 having multiple openings 12, so as to form an upward flow of processing liquid in the processing area of the substrate W. The basic configuration of the substrate processing apparatus 1 shown in Figure 13 is the same as that of the substrate processing apparatus 1 shown in Figure 7. According to the substrate processing apparatus 1 shown in Figure 13, similar to the substrate processing apparatus 1 shown in Figure 7, bubbling of the processing liquid can promote the formation of an upward flow of the processing liquid. Therefore, since the processing liquid is supplied more uniformly and efficiently to the entire surface of the substrate W, it becomes possible to make the processing of the entire surface of the substrate W with the processing liquid more uniform and efficient.
[0025] According to the substrate processing apparatus 1 of the above-described embodiment, a downward flow of processing liquid is mainly formed between the inner wall 3 and the inner wall surface of the processing tank 2, and an upward flow of processing liquid is mainly formed in the processing area of the substrate W, thereby suppressing interference between the downward and upward flows of processing liquid at the same location. Furthermore, by providing a bubble nozzle 14 on the bottom plate 13 having a plurality of openings 12, the formation of an upward flow of processing liquid in the processing area of the substrate W can be promoted. As a result, the velocity of the upward flow of processing liquid in the processing area of the substrate W is kept constant, and the processing of the substrate W can be made uniform. Furthermore, it is possible to suppress variations in processing by the processing liquid due to the accumulation of reaction products formed by the processing of the substrate W. As a result, it is possible to uniformly supply the processing liquid to the entire surface of the substrate W and to make the processing of the substrate W by the processing liquid uniform.
[0026] The configurations of each embodiment described above can be applied in combination, and some can also be replaced. Although several embodiments of the present invention have been described here, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as described in the claims. [Explanation of Symbols]
[0027] 1...Substrate processing device, 2...Processing tank, 3...Inner wall, 4...Processing liquid nozzle, 5...Lifter, 8...Overflow section, 9...Circulation pump, 10,11...Piping, 12...Opening, 13...Bottom plate, 14...Bubble nozzle.
Claims
1. A processing tank for storing a processing liquid and for accommodating a plurality of substrates to be processed with the processing liquid, arranged in a predetermined direction with their substrate surfaces facing substantially horizontally, An inner wall is provided inside the processing tank, covering at least a portion of the substrate surface at one end of the plurality of substrates along the arrangement direction, and the side surface of the plurality of substrates along the arrangement direction, and such that a space exists between the inner wall and the bottom surface of the processing tank through which the processing liquid flows. A processing liquid nozzle is provided inside the processing tank at a position outside the inner wall, extending in the direction of arrangement, and having a plurality of openings that open toward the bottom surface of the processing tank so that the processing liquid is discharged toward the bottom surface of the processing tank. A bottom plate is provided to cover the bottom of the inner wall, and has a plurality of openings that extend in the direction of arrangement and allow the processing liquid to flow through. A substrate processing apparatus comprising the following:
2. Furthermore, the substrate processing apparatus according to claim 1, comprising a bubble nozzle positioned between the bottom surface of the processing tank and the plurality of substrates, positioned on the inside of the inner wall and opening upward.
3. Furthermore, an overflow tank for collecting the processing liquid that overflows from the processing tank, A circulation pipe for returning the processed liquid recovered in the overflow tank to the processing tank, The system comprises a circulation pump installed in the aforementioned circulation piping, The substrate processing apparatus according to claim 1 or claim 2, wherein the circulation piping is connected to the processing liquid nozzle.
4. Furthermore, the processing tank is equipped with a bubble nozzle positioned between the bottom surface and the plurality of substrates, which is located inside the inner wall and opens upward. The substrate processing apparatus according to claim 1, wherein the bubble nozzle is provided on the bottom plate.
5. The plurality of substrates are housed in the processing tank by a support member, The substrate processing apparatus according to claim 1, wherein the support member is immersed in the processing tank so as to be located above the bottom plate.
6. The substrate processing apparatus according to claim 5, wherein the processing liquid nozzle is provided above the support member with respect to the bottom surface of the processing tank.