Cleaning apparatus for semiconductor wafer, cleaning method for semiconductor wafer, and manufacturing method for silicon wafer

Abstract

The present application provides a kind of semiconductor wafer cleaning device, which can inhibit the generation of particles on the back of semiconductor wafer.The semiconductor wafer cleaning device (1) includes: rotating table (11), with opening part (11a) in the center;Wafer holding part, set on the upper surface of rotating table (11), and hold semiconductor wafer (W) as cleaning object;Return part (21), set on the lower surface of rotating table;Nozzle head (14), with the recess (14a) arranged in the center and the horizontal part (14b) arranged on the radial outer side of the recess (14a);Lower part of liquid medicine supply nozzle (15), to the back of semiconductor wafer (W) supply liquid medicine;And wafer back flushing nozzle (16), to the back of semiconductor wafer (W) supply pure water, wherein, return part (21) is arranged near opening part (11a), and return part flushing nozzle (22) is arranged in the recess of nozzle head (14) to supply pure water to return part (21) to flush return part (21).

Description

Technical Field

[0001] This invention relates to a semiconductor wafer cleaning apparatus, a semiconductor wafer cleaning method, and a silicon wafer manufacturing method. Background Technology

[0002] Traditionally, silicon wafers have been used as substrates for semiconductor devices. Silicon wafers are obtained by processing single-crystal silicon ingots grown using methods such as the Czochralski (CZ) process. During this processing, the surface of the silicon wafer is covered with particles such as abrasive powder, so the silicon wafer is cleaned after processing to remove these particles.

[0003] In cleaning equipment for semiconductor wafers such as silicon wafers, there are batch cleaning equipment that cleans multiple semiconductor wafers simultaneously and single-wafer cleaning equipment that cleans semiconductor wafers one by one. Among these, single-wafer cleaning equipment has been more widely used in recent years due to its smaller required cleaning fluid volume, ability to avoid cross-contamination between semiconductor wafers, and the difficulty of processing multiple semiconductor wafers simultaneously due to its large diameter.

[0004] Figure 1 This represents an example of an existing semiconductor wafer cleaning device. Figure 1 The semiconductor wafer cleaning apparatus 100 shown includes a circular plate-shaped rotating stage 11 (also called a "decorative cup") and a wafer holding part 12. The rotating stage 11 has a circular opening 11a at the center and is horizontally arranged. The wafer holding part 12 is provided on the upper surface 11b of the rotating stage 11 and holds the semiconductor wafer W, which is to be cleaned.

[0005] Furthermore, the cleaning device 100 has a nozzle head 14 below the rotating table 11. The nozzle head 14 has a concave portion 14a and a horizontal portion 14b. The concave portion 14a is located at the center and tapers downwards in the vertical direction. The horizontal portion 14b is located radially outside the concave portion 14a and is horizontally positioned facing the lower surface of the rotating table 11. A drain port 14c is provided at the lower part of the concave portion 14a and is connected to a drain nozzle (not shown).

[0006] The recess 14a of the nozzle head 14 is provided with a lower liquid supply nozzle 15 and a wafer back rinse nozzle 16. The lower liquid supply nozzle 15 supplies liquid to the back of the semiconductor wafer W through the opening 11a, and the wafer back rinse nozzle 16 supplies pure water to the back of the semiconductor wafer W through the opening 11a.

[0007] On the other hand, an upper medicine supply nozzle 17 and a wafer surface rinsing nozzle 18 are provided above the semiconductor wafer W. The upper medicine supply nozzle 17 supplies medicine to the surface (front) of the semiconductor wafer W, and the wafer surface rinsing nozzle 18 supplies pure water to the surface (front) of the semiconductor wafer W.

[0008] The lower surface 11c of the rotary table 11 is provided with a cylindrical return section 13, which prevents the liquid medicine from flowing into the area between the lower surface 11c of the rotary table 11 and the nozzle head 14. Furthermore, the return section 13 is arranged along the inner wall 11d of the rotary table 11 that defines the opening 11a of the rotary table 11 (i.e., the inner wall 13a of the return section 13 and the inner wall 11d of the rotary table 11 form the same surface). Additionally, a rotating cup 19 is provided radially outward of the rotary table 11, which receives and recovers any liquid medicine or pure water that spills onto the outer side of the rotary table 11 during the cleaning and rinsing processes of the semiconductor wafer W.

[0009] The semiconductor wafer W using the cleaning apparatus 100 described above is cleaned in the following manner, for example. First, the rotating table 11 is rotated at a predetermined speed by a drive device (not shown), thereby rotating the semiconductor wafer W. Fluoric acid (HF) and other chemicals are supplied from the lower chemical supply nozzle 15 and the upper chemical supply nozzle 17, thereby removing polishing powder and the like adhering to the front and back sides of the semiconductor wafer W, such as the silicon wafer (cleaning process).

[0010] Next, while the semiconductor wafer W is rotating, the supply of liquid from the lower liquid supply nozzle 15 and the upper liquid supply nozzle 17 is stopped, and pure water is supplied from the back-side rinsing nozzle 16 and the surface rinsing nozzle 18 to rinse the front and back sides of the semiconductor wafer W (rinsing process).

[0011] Next, the supply of pure water from the back-side rinsing nozzle 16 and the surface rinsing nozzle 18 is stopped, causing the rotational speed of the semiconductor wafer W to increase. Nitrogen (N2) and other gases are supplied from the gas supply nozzle (not shown) to dry the front and back sides of the semiconductor wafer W (drying process). In this way, the semiconductor wafer W can be cleaned.

[0012] As described above, during the cleaning process of supplying HF or other cleaning solutions to the back side of the semiconductor wafer W, the solution may scatter onto the rotary table 11 or the nozzle head 14. However, during the subsequent drying process, sometimes the scattered solution may adhere to the back side of the semiconductor wafer W due to the airflow generated by the high-speed rotation of the rotary table 11. In this situation, etching marks or particles may appear on the back side of the wafer.

[0013] In order to suppress etching marks or particles on the back of such wafers, Patent Document 1 describes the following technology: when supplying a rinsing liquid such as pure water from a nozzle toward the lower surface of a semiconductor wafer, the jetting speed of the rinsing liquid ejected from the nozzle is changed by a speed control means, thereby cleaning the rotary table or nozzle head.

[0014] Existing technical documents Patent documents Patent document 1: Japanese Patent Application Publication No. 2005-217138. Summary of the Invention

[0015] The technical problem that the invention aims to solve However, after research, the inventors discovered that even using the technology described in Patent Document 1, particles are still generated on the back side of the semiconductor wafer, and therefore a technology that can suppress particle generation is desired.

[0016] The present invention was made in view of the above-mentioned technical problems, and its object is to provide a cleaning apparatus for semiconductor wafers, a cleaning method for semiconductor wafers, and a cleaning apparatus for silicon wafers that can suppress the generation of particles on the back side of semiconductors.

[0017] Solutions for solving technical problems To solve the above-mentioned technical problems, the present invention is as follows: [1] A cleaning apparatus for semiconductor wafers includes: a circular plate-shaped rotary table having a circular opening at the center and being horizontally arranged; A wafer holding section is provided on the upper surface of the rotary table and holds the semiconductor wafer that is to be cleaned; A cylindrical return section is provided on the lower surface of the rotary table; The nozzle head has a centrally located inverted conical recess and a horizontal portion that is radially outward from the recess and faces the lower surface of the rotary table and is horizontally arranged. A lower liquid supply nozzle is disposed in the recess of the nozzle head and supplies liquid to the back side of the semiconductor wafer through the opening; and A nozzle for rinsing the back of a wafer is disposed in the recess of the nozzle head and supplies pure water to the back of the semiconductor wafer through the opening. The semiconductor wafer cleaning apparatus is characterized in that, The return section is located near the opening. A return section rinsing nozzle is provided in the recess of the nozzle head to supply pure water to the return section for rinsing the return section.

[0018] [2] In the semiconductor wafer cleaning apparatus described in [1] above, the return section is disposed at a position radially outward from the inner wall of the rotary table that defines the opening.

[0019] [3] In the semiconductor wafer cleaning apparatus according to [2] above, the return section is disposed at a position 1 mm to 20 mm radially outward from the inner wall of the opening.

[0020] [4] The cleaning apparatus for semiconductor wafers according to any one of [1] to [3] above, wherein the return section rinsing nozzle is provided with a plurality of nozzles.

[0021] [5] In the semiconductor wafer cleaning apparatus according to [4] above, the plurality of return section rinsing nozzles are arranged such that they are separated from each other by more than 90 degrees in the circumferential direction of the recess.

[0022] [6] In the semiconductor wafer cleaning apparatus according to [4] or [5] above, the plurality of return section rinsing nozzles include a first return section rinsing nozzle and a second return section rinsing nozzle disposed radially inward of the first return section rinsing nozzle.

[0023] [7] In the semiconductor wafer cleaning apparatus described in [6] above, the nozzle for spraying pure water from the second return section rinsing nozzle protrudes from the surface of the recess.

[0024] [8] The cleaning apparatus for semiconductor wafers according to any one of [1] to [7] above further comprises: a gas supply nozzle disposed in the recess of the nozzle head and supplying gas to the back side of the semiconductor wafer via the opening, wherein the gas supply nozzle is arranged such that it is separated from the return rinsing nozzle by 90 degrees or more in the rotation direction of the rotary table.

[0025] [9] The cleaning apparatus for semiconductor wafers according to any one of [1] to [8] above, wherein the return section rinsing nozzle is configured to spray pure water onto the return section at an angle of 0 degrees to 30 degrees relative to the vertical direction.

[0026]

[10] A method for cleaning a semiconductor wafer, wherein the semiconductor wafer to be cleaned is cleaned using the semiconductor wafer cleaning apparatus described in any one of [1] to [9] above, characterized in that, While rinsing the back side of the semiconductor wafer by supplying pure water to the back side of the semiconductor wafer through the back-side rinsing nozzle, pure water is also supplied to the return section through the return section rinsing nozzle to rinse the return section.

[0027]

[11] In the semiconductor wafer cleaning method described in

[10] above, while supplying a chemical solution to the back side of the semiconductor wafer from the lower chemical solution supply nozzle, pure water is supplied to the return section from the return section rinsing nozzle to rinse the return section.

[0028]

[12] In the semiconductor wafer cleaning method according to

[10] or

[11] above, pure water is supplied to the return section simultaneously from the plurality of return section rinsing nozzles using the semiconductor wafer cleaning apparatus of any one of [4] to [7] above.

[0029]

[13] In the semiconductor wafer cleaning method described in

[12] above, the semiconductor wafer cleaning apparatus described in [6] or [7] above is used, and the flow rate of pure water from the first return section rinsing nozzle is greater than the flow rate of pure water from the second return section rinsing nozzle.

[0030]

[14] A method for cleaning a semiconductor wafer according to any one of

[10] to

[13] above, wherein, using the semiconductor wafer cleaning apparatus described in [8] above, gas is supplied to the back side of the semiconductor wafer from the gas supply nozzle at least during the rinsing of the back side of the semiconductor wafer with pure water.

[0031]

[15] The method for cleaning a semiconductor wafer according to any one of

[10] to

[14] above, wherein the semiconductor wafer is a silicon wafer.

[0032]

[16] A method for manufacturing a silicon wafer, wherein the silicon wafer is cleaned using the semiconductor wafer cleaning method described above

[15] , wherein the silicon wafer is obtained by performing wafer processing on a single crystal silicon ingot grown by a specified method.

[0033] Invention Effects According to the present invention, it is possible to suppress the generation of particles on the back side of a semiconductor wafer. Attached Figure Description

[0034] Figure 1 This diagram illustrates an example of a conventional semiconductor wafer cleaning apparatus.

[0035] Figure 2 The figure shows an example of a cleaning apparatus for semiconductor wafers based on the present invention. Figure 2 (a) is the overall diagram. Figure 2 (b) indicates that the person is... Figure 2 (a) is a diagram of the portion enclosed by the three-dot dashed line shown.

[0036] Figure 3 A diagram showing the positional relationship of the spray nozzles of the two return section flushing nozzles.

[0037] Figure 4 This is a top view of the nozzle head in the cleaning device used in the embodiment. Figure 4 (a) is a diagram relating to Invention Example 1. Figure 4 (b) is a diagram relating to Invention Example 2.

[0038] Figure 5 A diagram illustrating the cleaning effect of the concave portion of the nozzle head. Figure 5 (a) is a diagram relating to Invention Example 1. Figure 5 (b) is a diagram relating to Invention Example 2. Detailed Implementation

[0039] [Semiconductor wafer cleaning equipment] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The semiconductor wafer cleaning apparatus based on the present invention includes: a circular plate-shaped rotary table having a circular opening at its center and being horizontally arranged; a wafer holding portion disposed on the upper surface of the rotary table and holding the semiconductor wafer to be cleaned; a cylindrical return portion disposed on the lower surface of the rotary table; a nozzle head having a conical recess disposed at its center and a horizontal portion disposed radially outward of the recess and facing the lower surface of the rotary table; a lower chemical supply nozzle disposed in the recess of the nozzle head and supplying chemical solution toward the back side of the semiconductor wafer via the opening; and a wafer back side rinsing nozzle disposed in the recess of the nozzle head and supplying pure water toward the back side of the semiconductor wafer via the opening. The characteristic feature here is that the return portion is disposed near the opening, and the recess of the nozzle head is provided with a return portion cleaning nozzle for supplying pure water toward the return portion to rinse the return portion.

[0040] In order to suppress the generation of particles on the back side of the semiconductor wafer W, the inventors carefully studied the causes of this phenomenon. They discovered that the sprayed cleaning solution during the cleaning process not only adheres to the recess 14a of the nozzle head 14, but also to the return section 13 located on the lower surface 11c of the rotary table 11. In the subsequent drying process, the cleaning solution adhering to the return section 13 is carried by the airflow generated by the high-speed rotation of the rotary table 11 and adheres to the back side of the semiconductor wafer W.

[0041] Therefore, the inventors investigated the case of rinsing the return section 13 by supplying pure water to the return section 13 from the wafer backside rinsing nozzle 16. However, it is difficult to clean the return section 13 while rinsing the backside of the semiconductor wafer W using only the wafer backside rinsing nozzle 16. Therefore, the inventors conceived of providing a return section rinsing nozzle for supplying pure water to the return section 13 in the recess 14a of the nozzle head 14, and thus completed the present invention.

[0042] Figure 2The figure shows an example of a cleaning apparatus for semiconductor wafers based on the present invention. Figure 2 (a) is the overall diagram. Figure 2 (b) indicates that the person is... Figure 2 (a) shows the portion enclosed by the three dashed lines. Additionally, regarding... Figure 1 The same structural elements shown are labeled with the same reference numerals. Furthermore, on the recess 14a of the nozzle head 14, a lower liquid supply nozzle 15 and a wafer backside rinsing nozzle 16 are provided at a circumferential position in the recess 14a (not shown).

[0043] Figure 2 In the semiconductor wafer cleaning apparatus 1 shown, the return section 21 is disposed near the opening 11a of the rotary table 11. Specifically, as Figure 1 As shown, the return section 21 can be provided along the inner wall 11d of the rotary table 11, which defines the opening 11a of the rotary table 11. Furthermore, as... Figure 2 As shown in (b), the return section 21 can be positioned radially outward from the inner wall 11d of the rotary table 11 (i.e., the inner wall 21a of the return section 21 is positioned radially outward from the inner wall 11d of the rotary table 11). Of these two return sections 21, it is preferable that the return section 21 is positioned radially outward from the inner wall 11d of the rotary table 11. This forms a liquid accumulation area R between the lower surface 11c of the rotary table 11 and the inner wall 21a of the return section 21, where pure water supplied from the return section rinsing nozzle 22 accumulates. This allows the pure water held in the liquid accumulation area R to fall and clean the nozzle head 14.

[0044] When the return section 21 is positioned radially outward from the inner wall 11d of the rotary table 11, it is preferable to position the return section 21 at a position 1 mm to 20 mm radially outward from the inner wall 11d of the rotary table 11. By positioning the return section 21 at a position 1 mm or more radially outward from the inner wall 11d of the opening 11a, a pure water accumulation area R can be formed between the lower surface 11c of the rotary table 11 and the inner wall 21a of the return section 21, allowing the accumulated pure water to fall and effectively clean the nozzle head 14. Furthermore, by positioning the return section 21 at a position 20 mm or less radially outward from the inner wall 11d of the opening 11a, excessive diffusion of pure water within the accumulation area R, which could lead to uneven cleaning of the nozzle head 14, can be prevented. Moreover, by providing the return section rinsing nozzle 22 radially outward, the enlargement of the nozzle head 14, and even the cleaning device 1, can be prevented.

[0045] The return section rinsing nozzle 22 supplies pure water to the return section 21 to rinse it. The spraying of pure water from the return section rinsing nozzle 22 is preferably performed in such a way that the liquid falls onto the lower end 21b of the return section 21. Therefore, the return section rinsing nozzle 22 is preferably configured to spray pure water toward the return section 21 at an angle of 0 degrees or less and 30 degrees or less relative to the vertical direction. This disperses the pure water into both the radially outer and radially inner regions of the return section 21, effectively cleaning the entire return section 21.

[0046] The return section flushing nozzle 22 can also be provided with only one, but if Figure 2 As shown, multiple such units are preferably provided. This allows for efficient cleaning of the return section 21 and the recess 14a of the nozzle head 14, thereby improving the cleaning effect.

[0047] When multiple return rinsing nozzles 22 are provided, they are preferably arranged such that they are separated from each other by 90 degrees or more in the circumferential direction of the recess 14a of the nozzle head 14. This prevents pure water supplied from one return rinsing nozzle 22 from interfering with pure water supplied from the other return rinsing nozzles 22. More preferably, the multiple return rinsing nozzles 22 are arranged such that they are as far apart as possible from each other.

[0048] Furthermore, when multiple return rinsing nozzles 22 are provided, it is preferable that the radial positions of the return rinsing nozzles 22 are different. For example, when two return rinsing nozzles 22 are provided, it is preferable that the cleaning apparatus 1 has a first return rinsing nozzle 22a and a second return rinsing nozzle 22b disposed radially inward of the first return rinsing nozzle. This prevents the pure water supplied by the first return rinsing nozzle 22a and held in the liquid accumulation area R from being obstructed by the pure water supplied by the second return rinsing nozzle 22b. As a result, the pure water held in the liquid accumulation area R can fall more evenly onto the recess 14a of the nozzle head 14, thereby cleaning the recess 14a of the nozzle head 14 more evenly.

[0049] Furthermore, if two return section rinsing nozzles 22 (first return section rinsing nozzle 22a and second return section rinsing nozzle 22b) are provided, such as Figure 3 As shown, the positional relationship of the nozzles can be conceived in three ways: the nozzles of both protrude from the surface of the recess 14a. Figure 3 (a)); The nozzles of both are not protruding from the surface of the recess 14a ( Figure 3 (b)); and a pattern in which one nozzle protrudes from the surface of the recess 14a, while the other nozzle does not protrude from the surface of the recess 14a. Figure 3(c) Of these three configurations, it is preferable that the nozzle orifice of the second return section rinsing nozzle 22b, located radially inward, protrudes from the surface of the recess 14a of the nozzle head 14. This suppresses interference between the pure water sprayed from the second return section rinsing nozzle 22b and the pure water falling from the accumulation area R, resulting in more uniform cleaning of the recess 14a. Furthermore, "the nozzle orifice does not protrude from the surface of the recess 14a" means that the position of the upper end of the nozzle on the inclined side of the recess 14a (radially outward of the nozzle head 14) is the same as or lower than the height of the inclined surface of the recess 14a. Alternatively, the position of the upper end of the nozzle on the radially inward side may be higher than the height of the inclined surface of the recess 14a (see reference). Figure 3 (b) and Figure 3 (c) Nozzle 22a).

[0050] Furthermore, the cleaning apparatus 1 preferably includes a gas supply nozzle (not shown) in the recess 14a of the nozzle head 14, which supplies gas toward the back side of the semiconductor wafer W via the opening 11a of the rotary table 11. Preferably, this gas supply nozzle is arranged such that it is separated from the return rinsing nozzle 22 by at least 90 degrees in the rotation direction of the rotary table 11. This prevents interference from the gas supplied by the gas supply nozzle on the pure water supplied by the return rinsing nozzle 22 and held in the liquid accumulation area R.

[0051] [Semiconductor wafer cleaning methods] The semiconductor wafer cleaning method based on the present invention is a method for cleaning a semiconductor wafer that is to be cleaned using a semiconductor wafer cleaning apparatus based on the present invention described above. The method is characterized in that, while supplying pure water to the back side of the semiconductor wafer from a back side rinsing nozzle to rinse the back side of the semiconductor wafer, pure water is supplied to the return section from a return section rinsing nozzle to rinse the return section.

[0052] As described above, the semiconductor wafer cleaning apparatus 1 based on the present invention is provided with a return section rinsing nozzle 22, which cleans the return section 21 located near the opening 11a in the lower surface 11c of the rotating stage 11. In the present invention, while supplying pure water from the wafer backside rinsing nozzle 16 to the backside of the semiconductor wafer W to rinse the backside of the semiconductor wafer W, the return section rinsing nozzle 22 supplies pure water to the return section 21 to rinse the return section 21.

[0053] That is, in the rinsing process using pure water after the cleaning process of the semiconductor wafer using the cleaning solution, pure water is supplied to the return section 21 from the rinsing nozzle 22. As a result, the hydrogen fluoride and other cleaning solutions that adhered to the return section 21 during the cleaning process can be removed, and the generation of particles can be suppressed.

[0054] There are no particular limitations on the semiconductor wafer W that is to be cleaned, but silicon wafers can be cleaned appropriately.

[0055] In this invention, it is preferable to supply the liquid medicine from the lower liquid medicine supply nozzle 15 toward the back side of the semiconductor wafer W, while simultaneously supplying pure water from the return section rinsing nozzle 22 to the return section 21 to rinse the return section 21. That is, in the cleaning process using the liquid medicine, it is preferable to supply pure water from the return section rinsing nozzle 22 to the return section 21 to rinse the return section 21. This prevents the spread of liquid medicine from adhering to the return section 21 during the cleaning process and further suppresses the generation of particles.

[0056] Furthermore, in this invention, it is preferable to use a cleaning device 1 equipped with multiple return section rinsing nozzles 22, which simultaneously supply pure water to the return section 21 from the multiple return section rinsing nozzles 22. This further improves the cleaning effect on the return section 21 and the recess 14a of the nozzle head 14.

[0057] Furthermore, it is preferable to use a cleaning device 1 equipped with two return rinsing nozzles 22 (a first return rinsing nozzle 22a and a second return rinsing nozzle 22b), with the second return rinsing nozzle 22b positioned radially inward than the first return rinsing nozzle 22a, such that the flow rate of pure water from the first return rinsing nozzle 22a is greater than the flow rate of pure water from the second return rinsing nozzle 22b. This prevents the pure water supplied by the first return rinsing nozzle 22a and held in the liquid accumulation area R from being interfered with by the pure water supplied by the second return rinsing nozzle 22b, allowing the pure water held in the liquid accumulation area R to fall more evenly onto the recess 14a of the nozzle head 14, thus cleaning the recess 14a more evenly.

[0058] Furthermore, it is preferable to use a cleaning apparatus 1 equipped with a gas supply nozzle for supplying gas to the back side of the semiconductor wafer W, and the gas supply nozzle is arranged such that it is separated from the return rinsing nozzle 22 by at least 90 degrees in the rotation direction of the rotary table 11. At least during the rinsing of the back side of the semiconductor wafer W with pure water, gas is supplied from the gas supply nozzle 23 toward the back side of the semiconductor wafer W. As a result, it is possible to suppress interference from the gas supplied by the gas supply nozzle on the pure water supplied by the return rinsing nozzle 22 and held in the liquid accumulation area R.

[0059] [Silicon wafer manufacturing methods] The silicon wafer manufacturing method based on the present invention is characterized in that the silicon wafer is cleaned using the semiconductor wafer cleaning method based on the present invention described above, wherein the silicon wafer is obtained by performing wafer processing on a single crystal silicon ingot grown by a prescribed method.

[0060] As described above, in the semiconductor wafer cleaning method of the present invention, while pure water is supplied from the back-side rinsing nozzle 16 to rinse the back side of the semiconductor wafer W, pure water is supplied from the return rinsing nozzle 22 to rinse the return section 21. Therefore, by using the method of the present invention to clean the silicon wafer (pre-silicon wafer) obtained by wafer processing of a single-crystal silicon ingot grown by a prescribed method, a silicon wafer with reduced particle size can be obtained.

[0061] Methods for growing single-crystal silicon ingots include CZ method and floating zone (FZ) method. Example

[0062] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments.

[0063] [Example 1 of the invention] The front and back sides of the silicon wafer were cleaned using the semiconductor wafer cleaning apparatus 1 of the present invention. At this time, Figure 2 The cleaning apparatus 1 shown uses a single return rinsing nozzle 22. A top view of the nozzle head in the cleaning apparatus 1 used in Example 1 is shown below. Figure 4 (a). For example Figure 4 As shown in (a), a first lower liquid supply nozzle 15a for supplying ozone water (O3W) is provided at a position 45 degrees counterclockwise from the return section rinsing nozzle 22. A gas supply nozzle 23 for supplying N2 gas is provided at a position 90 degrees counterclockwise from the first lower liquid supply nozzle 15a. Furthermore, a second lower liquid supply nozzle 15b for supplying HF is provided at a position 90 degrees counterclockwise from the gas supply nozzle 23. A wafer backside rinsing nozzle 16 for supplying pure water (DIW) is positioned at a position 90 degrees counterclockwise from the second lower liquid supply nozzle 15b. The return section rinsing nozzle 22 is located directly below the return section 21. The heights of the liquid / pure water nozzles of the first lower liquid supply nozzle 15a, the second lower liquid supply nozzle 15b, and the wafer backside rinsing nozzle 16 are all the same. Figure 3 As shown in (b), it is positioned at the same height as the slope of the recess 14a of the nozzle head 14, and does not protrude from the recess 14a.

[0064] Using the cleaning apparatus 1 described above, the front and back sides of three silicon wafers were cleaned. Before this cleaning, a surface inspection apparatus (KLA-Tencor, SP1) was used to inspect the particles on the back side of each silicon wafer as light point defects (LPDs), and the number of LPDs with a size of 0.2 μm or larger was determined in advance.

[0065] The cleaning of each silicon wafer is performed as follows. First, in the cleaning process, the silicon wafer is rotated at 500 rpm, and O3W is supplied alternately and repeatedly from the first lower chemical supply nozzle 15a and the upper chemical supply nozzle 17, and HF is supplied from the second lower chemical supply nozzle 15b and the upper chemical supply nozzle 17. Next, in the rinsing process, while maintaining the silicon wafer rotation speed at 500 rpm, the supply of HF from the second lower chemical supply nozzle 15b and the upper chemical supply nozzle 17 is stopped, and DIW is supplied from the back side rinsing nozzle 16 and the surface rinsing nozzle 18 toward the front and back sides of the silicon wafer, respectively. DIW is also supplied from the return rinsing nozzle 22 toward the return rinsing section 21 to rinse the return section 21. Subsequently, during the drying process, the DIW supply from the back-side rinsing nozzle 16 and the surface rinsing nozzle 18 of the wafer, as well as the DIW supply from the return rinsing nozzle 22, is stopped. The silicon wafer is rotated at a high speed of 1500 rpm, and N2 gas is supplied from the gas supply nozzle 23 to dry the silicon wafer.

[0066] For each silicon wafer after cleaning, the particles on the back side of the silicon wafer are detected as LPDs, just as before cleaning. The number of LPDs with a size of 0.2μm or larger is investigated, and the increase in particles after cleaning is calculated.

[0067] [Example 2 of the invention] Similar to Example 1, the front and back sides of the silicon wafer are cleaned. However, as... Figure 4 As shown in (b), the cleaning apparatus 1 used is a cleaning apparatus in which two return section rinsing nozzles 22 are provided in the recess 14a of the nozzle head 14. Furthermore, the first return section rinsing nozzle 22a is located directly below the return section 21, and the second return section rinsing nozzle 22b is located 0.7 mm radially inward and 1 mm higher than the first return section rinsing nozzle 22a. All other conditions are the same as in Example 1. Similar to Example 1, after investigating the number of particles on the back side of the cleaned silicon wafer, the increase in the number of particles after cleaning is determined.

[0068] [Comparative Example] Similar to Example 1, the front and back sides of the silicon wafer are cleaned. However, as... Figure 1 As shown, a cleaning device without a return rinsing nozzle was used as the cleaning apparatus. All other conditions were the same as in Example 1 of the Invention. Similar to Example 1 of the Invention, the increase in the number of particles on the back side of the cleaned silicon wafer was determined after investigating the number of particles on the back side of the wafer.

[0069] <Increase in particle size after washing> First, for the silicon wafer of the comparative example, the number of particles (LPDs) increased by 10 to 40 after cleaning. In contrast, for the silicon wafer of Invention Example 1, the number of LPDs increased by only 2 to 3 after cleaning. Then, for the silicon wafer of Invention Example 2, the number of LPDs did not change after cleaning. Thus, according to the present invention, it is possible to suppress the generation of particles on the back side of the silicon wafer.

[0070] <Cleaning effect of the nozzle head recess> Figure 5 This figure illustrates the cleaning effect of the recess 14a of the nozzle head 14 with respect to Invention Examples 1 and 2. Figure 5 (a) represents Invention Example 1, Figure 5 (b) represents Invention Example 2. For example... Figure 5 As shown in (a), in Invention Example 1, which is equipped with a single return section rinsing nozzle 22, it is known that pure water will not flow evenly onto the recess 14a. In contrast, as... Figure 5 As shown in (b), in Invention Example 2, which is equipped with two return-section rinsing nozzles 22, it can be seen that pure water flows onto the recess 14a more evenly than in Invention Example 1. Therefore, it can be considered that Invention Example 2 is better able to clean the recess 14a of the nozzle head 14 than Invention Example 1.

[0071] Industrial availability According to the present invention, it is useful in the semiconductor wafer manufacturing industry because it can suppress the generation of particles on the back side of the semiconductor wafer.

[0072] Explanation of reference numerals in the attached figures 1. 100 - Semiconductor wafer cleaning apparatus; 11 - Rotary stage; 11a - Opening; 11b - Upper surface; 11c - Lower surface; 11d - Inner wall; 12 - Wafer holding section; 13, 21 - Return section; 14 - Nozzle head; 14a - Recess; 14b - Horizontal section; 14c - Drain outlet; 15 - Lower chemical supply nozzle; 15a - First lower chemical supply nozzle; 15b - Second lower chemical supply nozzle; 16 - Wafer backside rinsing nozzle; 17 - Upper chemical supply nozzle; 18 - Wafer surface rinsing nozzle; 19 - Rotating cup; 22 - Return section rinsing nozzle; 22a - First return section rinsing nozzle; 22b - Second return section rinsing nozzle; 23 - Gas supply nozzle; W - Semiconductor wafer.

Claims

1. A semiconductor wafer cleaning apparatus, comprising: A circular plate-shaped rotary table with a circular opening at the center and horizontally arranged; A wafer holding section is provided on the upper surface of the rotary table and holds the semiconductor wafer that is to be cleaned; A cylindrical return section is provided on the lower surface of the rotary table; The nozzle head has a centrally located inverted conical recess and a horizontal portion that is radially outward from the recess and faces the lower surface of the rotary table and is horizontally arranged. A lower liquid supply nozzle is disposed in the recess of the nozzle head and supplies liquid to the back side of the semiconductor wafer through the opening. as well as A nozzle for rinsing the back of a wafer is disposed in the recess of the nozzle head and supplies pure water to the back of the semiconductor wafer through the opening. The semiconductor wafer cleaning apparatus is characterized in that, The return section is disposed along the inner wall of the rotary table that defines the opening, or disposed at a position radially outward from the inner wall. In the recess of the nozzle head, in addition to the nozzle for rinsing the back side of the wafer, a return section rinsing nozzle is provided to supply pure water to the return section to rinse the return section.

2. The semiconductor wafer cleaning apparatus according to claim 1, characterized in that, The return section is positioned radially outward at a distance of 1 mm to 20 mm from the inner wall of the opening.

3. The semiconductor wafer cleaning apparatus according to claim 1 or 2, characterized in that, The return section has multiple flushing nozzles.

4. The semiconductor wafer cleaning apparatus according to claim 3, characterized in that, The plurality of return section flushing nozzles are arranged such that they are separated from each other by more than 90 degrees in the circumferential direction of the recess.

5. The semiconductor wafer cleaning apparatus according to claim 3, characterized in that, The plurality of return section flushing nozzles include a first return section flushing nozzle and a second return section flushing nozzle disposed radially inward of the first return section flushing nozzle.

6. The semiconductor wafer cleaning apparatus according to claim 5, characterized in that, The nozzle for spraying pure water from the second return section flushing nozzle protrudes from the surface of the recess.

7. The semiconductor wafer cleaning apparatus according to claim 1 or 2, characterized in that, It also includes: a gas supply nozzle disposed in the recess of the nozzle head, and supplying gas to the back side of the semiconductor wafer via the opening, the gas supply nozzle being arranged such that it is separated from the return section rinsing nozzle by more than 90 degrees in the rotation direction of the rotary table.

8. The semiconductor wafer cleaning apparatus according to claim 1 or 2, characterized in that, The return section rinsing nozzle is configured to spray pure water into the return section at an angle of 0 degrees to 30 degrees relative to the vertical direction.

9. A method for cleaning a semiconductor wafer, comprising using a semiconductor wafer cleaning apparatus to clean the semiconductor wafer to be cleaned, characterized in that, The semiconductor wafer cleaning device is, include: A circular plate-shaped rotary table with a circular opening at the center and horizontally arranged; A wafer holding section is provided on the upper surface of the rotary table and holds the semiconductor wafer that is to be cleaned; A cylindrical return section is provided on the lower surface of the rotary table; The nozzle head has a centrally located inverted conical recess and a horizontal portion that is radially outward from the recess and faces the lower surface of the rotary table and is horizontally arranged. A lower liquid supply nozzle is disposed in the recess of the nozzle head and supplies liquid to the back side of the semiconductor wafer through the opening; and A nozzle for rinsing the back of a wafer is disposed in the recess of the nozzle head and supplies pure water to the back of the semiconductor wafer through the opening. The return section is disposed along the inner wall of the rotary table that defines the opening, or disposed at a position radially outward from the inner wall. In the recess of the nozzle head, in addition to the nozzle for rinsing the back side of the wafer, a return section rinsing nozzle is provided to supply pure water to the return section for rinsing the return section. The cleaning method for semiconductor wafers is as follows: While rinsing the back side of the semiconductor wafer by supplying pure water to the back side of the semiconductor wafer through the back-side rinsing nozzle, pure water is also supplied to the return section through the return section rinsing nozzle to rinse the return section.

10. The semiconductor wafer cleaning method according to claim 9, characterized in that, While supplying liquid medicine to the back side of the semiconductor wafer from the lower liquid medicine supply nozzle, pure water is supplied to the return section from the return section rinsing nozzle to rinse the return section.

11. The semiconductor wafer cleaning method according to claim 9 or 10, characterized in that, In the semiconductor wafer cleaning apparatus, multiple return section rinsing nozzles are provided, and pure water is supplied to the return section simultaneously from multiple return section rinsing nozzles.

12. The semiconductor wafer cleaning method according to claim 11, characterized in that, The plurality of return section rinsing nozzles include a first return section rinsing nozzle and a second return section rinsing nozzle disposed radially inward of the first return section rinsing nozzle, such that the flow rate of pure water from the first return section rinsing nozzle is greater than the flow rate of pure water from the second return section rinsing nozzle.

13. The semiconductor wafer cleaning method according to claim 9 or 10, characterized in that, The semiconductor wafer cleaning apparatus further includes: a gas supply nozzle disposed in the recess of the nozzle head, and supplying gas to the back side of the semiconductor wafer via the opening, the gas supply nozzle being arranged such that it is separated from the return rinsing nozzle by more than 90 degrees in the rotation direction of the rotary table, and supplying gas to the back side of the semiconductor wafer from the gas supply nozzle at least during the rinsing of the back side of the semiconductor wafer with pure water.

14. The semiconductor wafer cleaning method according to claim 9 or 10, characterized in that, The semiconductor wafer is a silicon wafer.

15. A method for manufacturing a silicon wafer, characterized in that, The semiconductor wafer cleaning method of claim 14 is used to clean a silicon wafer, which is obtained by performing wafer processing on a single-crystal silicon ingot grown by a prescribed method.

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