Wet etching equipment

Abstract

A wet etching device includes a process tank having an inner space configured to receive an etchant and having a support unit, on which a wafer is disposed to contact the etchant. A laser unit is disposed above the process tank and is configured to direct a laser beam toward the wafer and thereby heat the wafer. An etchant supply unit is configured to supply the etchant to the inner space of the process tank.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Korean Patent Application No. 10-2018-0105518 filed on September 4, 2018 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to etching, and more particularly, to a wet etching apparatus. Background Art

[0004] In the semiconductor device manufacturing process, a wet etching process, which generally uses an etchant, may be performed to selectively remove a portion of a film, thereby leaving a desired pattern unetched or etching only a desired pattern. In order to perform a smooth etching process, a high temperature may be maintained during etching. For example, in the case of etching nitride, a high temperature of 160° C. or more may be maintained.

[0005] During high temperature etching, the etchant may be heated to a desired temperature. However, due to the boiling point of the etchant or the heat resistance of other devices, it may be difficult to heat the etchant to a sufficiently high process temperature, and depending on the region of the wafer being etched (e.g., whether it is the center of the wafer being etched or the edge of the wafer), the problem of uneven etching rate may occur due to uneven flow rate of the etchant, uneven temperature, etc. Summary of the invention

[0006] A wet etching device includes: a process tank having an inner space configured to receive an etchant, and having a support unit on which a wafer is disposed to contact the etchant. A laser unit is disposed above the process tank and is configured to direct a laser beam toward the wafer and thereby heat the wafer. An etchant supply unit is configured to supply the etchant to the inner space of the process tank.

[0007] A wet etching device includes: a process tank having an internal space configured to receive an etchant, and having a support unit arranged in the internal space. The support unit is configured to support a wafer in contact with the etchant. A laser unit is arranged above the process tank and has a laser light source that emits a laser beam, and an optical system that expands the area of ​​the laser beam and is configured to expose the wafer using the expanded laser beam. An etchant supply unit has an etchant injection unit and an etchant discharge unit respectively arranged on opposite sides of the process tank. A pipeline connects the etchant injection unit and the etchant discharge unit. A circulation pump is installed on the pipeline.

[0008] A wet etching device includes: a process tank having an internal space configured to receive an etchant and including an opening recessed into the internal space. A support portion is arranged around the opening and supports the outer periphery of a wafer. The wafer is arranged on the support portion to contact the etchant. A laser unit is arranged above the process tank and projects a laser beam onto a surface of the wafer opposite to a surface to be processed of the wafer, so that the wafer is heated. An etchant supply unit is configured to supply an etchant to the internal space of the process tank. An exhaust unit is configured to exhaust the etchant from the internal space of the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A more complete understanding of the present disclosure and its many attendant aspects will be more readily obtained, and likewise the present disclosure and its many attendant aspects will become better understood, by reference to the following detailed description taken in conjunction with the accompanying drawings, in which:

[0010] Figure 1 is a schematic cross-sectional view showing a wet etching apparatus according to an exemplary embodiment of the present disclosure;

[0011] Figure 2 is a schematic cross-sectional view showing a wet etching apparatus according to an exemplary embodiment of the present disclosure;

[0012] Figure 3 It is shown Figure 1 An enlarged cross-sectional view of a wafer support unit (part "A") in a wet etching apparatus;

[0013] Figure 4 It is shown Figure 1 A plan view of a wafer support unit (part "A") in a wet etching apparatus;

[0014] Figure 5 is a schematic perspective view showing a wet etching apparatus according to an exemplary embodiment of the present disclosure;

[0015] FIG. 6A to FIG. 11A is a plan view showing a method of manufacturing a semiconductor device using a wet etching apparatus according to an exemplary embodiment of the present disclosure;

[0016] FIG. 6B to FIG. 11B are respectively along FIG. 6A to FIG. 11A A cross-sectional view taken along line II' of ; and

[0017] Figures 12 to 15 is a perspective view illustrating a method of manufacturing a semiconductor device using a wet etching process according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0018] In describing the exemplary embodiments of the present disclosure shown in the drawings, specific terms are used for clarity. However, the present disclosure is not intended to be limited to the specific terms so selected, and it will be understood that each specific element includes all technical equivalents that operate in a similar manner.

[0019] Figure 1 is a schematic cross-sectional view illustrating a wet etching apparatus according to an exemplary embodiment of the present disclosure.

[0020] Reference Figure 1 According to an exemplary embodiment of the present disclosure, the wet etching device 100 includes an inner space 20S (see Figure 2 ), a process tank 20 having a plurality of etchants, a laser unit 40 disposed above the process tank 20, and an etchant supply unit 35 that supplies the etchant 10 to the inner space 20S of the process tank 20. The laser unit 40 may be a device configured to provide a laser beam.

[0021] The process tank 20 includes a support unit 25, and the wafer W is placed on the support unit 25 to contact the etchant 10. Figure 1 As shown, the support unit 25 is located in the inner space 20S of the process tank 20, and may be configured so that the wafer W disposed thereon is immersed in the etchant 10. The wafer W may be positioned so that the surface P1 to be processed (eg, etched) faces upward.

[0022] In such an arrangement, the laser beam LB emitted from the laser unit 40 may be projected onto the surface P1 of the wafer W to be processed.

[0023] As described above, the laser beam LB may be directly projected onto the surface to be processed P1 while the surface to be processed P1 is in contact with the etchant 10. Therefore, a portion to be etched by the etchant is exposed.

[0024] The process tank 20 may include a transparent window 22 for projecting the laser beam LB to the wafer W disposed on the support unit 25. In addition, the transparent window 22 may be hingedly connected to the process tank 20 to open and close the inner space 20S of the process tank 20. The transparent window 22 may be opened to place the wafer W on the support unit 25. In the process of placing the wafer W, the laser unit 40 may be detached from the process tank 20. The process tank 20 may alternatively have a separate entrance instead of the transparent window 22.

[0025] The laser unit 40 is disposed above the process tank 20 and is configured to project a laser beam LB onto the surface to be processed P1 of the wafer W. For smooth etching, an appropriate process temperature is used. In this exemplary embodiment, the laser beam LB can be used as a means to heat the wafer W to obtain a desired high process temperature.

[0026] In some approaches, the etchant 10 may be used as a heating means, but this approach may be limited in how high the process temperature can be, and depending on the heat resistance of other devices such as the process tank 20, thermal deformation and / or damage may occur.

[0027] In order to solve such a problem, in an exemplary embodiment of the present disclosure, a laser beam LB is projected directly to a wafer W to be processed using a laser unit 40 to heat the wafer W to a desired process temperature.

[0028] In some exemplary embodiments of the present disclosure, the wafer W may include a stacked nitride film (e.g., a silicon nitride film) and an oxide film (e.g., a silicon oxide film), and a wet etching process may be introduced to selectively etch the nitride film on the wafer W (see Fig. 10A and Fig. 10B ). In this case, the etchant 10 for etching the nitride film may have an etching selectivity relative to the oxide film. For example, the etching rate of the oxide film by the etchant 10 may be lower than the etching rate of the nitride film by the etchant 10.

[0029] For example, in order to etch nitride, phosphoric acid may be used as the etchant 10, and the etching process temperature is set to a high temperature of 160° C. or higher (e.g., 163° C.). However, since the desired etching process temperature is higher than the boiling point of phosphoric acid (e.g., 158° C.), there is a problem in achieving the desired etching process temperature by directly heating the etchant 10 (e.g., boiling the etchant 10).

[0030] As described above, instead of heating the etchant 10, the wafer W may be heated to a desired process temperature using the laser unit 40 disposed above the process tank 20. In some exemplary embodiments of the present disclosure, the laser unit 40 may be used together with a heating method for the etchant 10 (ie, heating the etchant 10 to a temperature lower than the desired etching process temperature).

[0031] The laser unit 40 includes a laser light source 45 that emits a laser beam LB and an optical system 47 disposed between the laser light source 45 and the process tank 20. The optical system 47 is configured to expand the area of ​​the laser beam LB.

[0032] The laser light source 45 may be configured to emit a laser beam LB having a wavelength in the range of 10 nm to 1 mm (or more preferably, 200 nm to 900 nm) (which may span from ultraviolet light to infrared light). The wavelength of the laser beam LB may be appropriately selected according to the substance to be etched and used. In addition, the laser power condition may be appropriately selected according to the heating temperature.

[0033] The optical system 47 may include an arrangement of a plurality of lenses configured to expand the area of ​​the laser beam LB generated from the laser light source 45. For example, the arrangement of the plurality of lenses may be an arrangement of various lenses such as concave lenses and / or convex lenses, etc. The area of ​​the laser beam LB expanded by the optical system 47 may have an area capable of substantially covering the surface P1 to be processed of the wafer W.

[0034] The laser unit 40 may include a housing 41 that seals a laser light source 45 and an optical system 47. The sealed space of the housing 41 may be connected to a vacuum pump 49. The sealed space of the housing 41 may be depressurized or maintained at a near vacuum by operating a valve VO associated with the vacuum pump 49. By depressurizing / vacuuming operations, the laser may be prevented from being partially blocked or otherwise disturbed by dust, smoke, etc. that may be generated during the etching process.

[0035] The wet etching apparatus 100 may include an etchant supply unit 35 that supplies the etchant 10 to the inner space 20S of the process tank 20. The etchant supply unit 35 may be configured to allow the etchant 10 to flow into the inner space 20S of the process tank 20 at a speed within a predetermined range. For example, the etchant supply unit 35 may supply the etchant at a flow rate within a range of 0.1 m / sec to 1 m / sec.

[0036] The etchant supply unit 35 may include a first connector 35A of an etchant injection unit disposed at a first side of the process tank 20 and injecting the etchant 10 into the internal space 20S, and a second connector 35B of an etchant discharge unit disposed at a second side of the process tank 20 and discharging the etchant 10 from the internal space 20S. The first side and the second side of the process tank may be disposed to face each other.

[0037] In addition, since the first connector 35A of the etchant injection unit and the second connector 35B of the etchant discharge unit each have a plurality of connectors arranged along corresponding opposite side surfaces of the process tank 20, the flow rate of the etchant 10 can be relatively uniformly maintained throughout the entire area of ​​the internal space 20S.

[0038] The process tank 20 may have a volume sufficient to submerge the wafer W and a structure in which the height is smaller than the width. The process tank 20 may have a relatively small inner space 20S so that only a sufficient amount of the etchant 10 for etching one wafer may be received.

[0039] For example, when a 300 mm diameter wafer is used, the process tank 20 may have an inner space 20S with a slightly larger area (eg, 310 mm×310 mm). In addition, the volume of the inner space 20S may be in the range of 1 liter to 10 liters.

[0040] Figure 2 is a schematic cross-sectional view of a wet etching apparatus according to an exemplary embodiment of the present disclosure, Figure 3 and Figure 4 They are shown respectively Figure 1 An enlarged cross-sectional view and a plan view of a wafer support unit (part "A") in a wet etching apparatus.

[0041] Reference Figure 2 , except that the structure of the support unit 25' is different and the etchant supply unit 30 also includes an etchant circulation system and a concentration detection system, the wet etching device 100A can be the same as Figure 1 Therefore, unless otherwise specifically stated, Figure 1 The illustrated description may be combined with the description regarding this exemplary embodiment.

[0042] The supporting unit 25 ′ may include an opening OP located at an upper portion of the process tank 20 and recessed in the internal space 20S, and a supporting portion 25T located around the opening OP and in which the outer peripheral portion of the wafer W is disposed.

[0043] like Figure 3 As shown, the wafer W may be arranged so that the surface P1 to be processed is directed toward the inner space 20S at the support portion 25T. The surface P2 opposite to the surface P1 to be processed of the wafer W is oriented upward by such arrangement of the wafer W, and the laser beam LB may irradiate the surface P2 located on the opposite side.

[0044] With the wafer W thus arranged, the laser beam LB is projected onto the surface P2 opposite to the surface to be processed P1, which is in contact with the etchant 10 to be etched. In particular, when the portion to be etched by the etchant 10 is not exposed to the outside but is located quite deep inside (for example, a three-dimensional semiconductor element such as V-NAND, refer to FIGS. 6 to 10), uniform heating in the thickness direction can be ensured by irradiating and heating the opposite surface.

[0045] In addition, if Figure 4 As shown, the recessed opening OP may be formed corresponding to the shape and size of the wafer W, so that the support portion 25T of the opening OP is located at the outer periphery of the wafer W.

[0046] A separate input window covering the opening OP of the process tank 20 may be provided, but as in this exemplary embodiment of the present disclosure, it may be configured to cover the opening OP by the wafer W to be etched without a separate input window. The peripheral portion of the wafer W may be in close contact with the support portion 25T, so that while the surface P1 to be processed of the wafer W is in contact with the etchant 10, the wafer W may close and substantially seal the internal space 20S of the process tank 20 through the opening OP. The peripheral portion of the wafer W may be in close contact with the support portion 25T by the etchant having a predetermined viscosity, so that while the surface P1 to be processed of the wafer W is in contact with the etchant 10, the wafer W may close the opening OP to substantially seal the internal space 20S of the process tank 20.

[0047] The etchant supply unit 30 may include an etchant injection unit 30A and an etchant exhaust unit 30B. The wet etching apparatus 100A may further include an etchant circulation unit 60 connected to the etchant injection unit 30A and the etchant exhaust unit 30B to circulate the etchant 10 together with the etchant injection unit 30A and the etchant exhaust unit 30B.

[0048] The etchant circulation unit 60 may include a pipe 61 connecting the etchant injection unit 30A and the etchant discharge unit 30B and a circulation pump 65 installed on the pipe 61. The etchant 10 flowing into the inner space 20S of the process tank 20 at a constant speed may be circulated and supplied by the operation of the circulation pump 65.

[0049] The etchant injection unit 30A and the etchant exhaust unit 30B may include first and second sub-tanks 31A and 31B, respectively, which can temporarily accommodate the etchant 10 therein together with first and second connectors 35A and 35B connected to the inner space 20S of the process tank 20 .

[0050] Therefore, the etchant circulation unit 60 can maintain the flow rate of the etchant 10 to ensure uniform and smooth etching. As the number of cycles of the etchant increases during the etching process, the characteristics of the etchant 10 may change (for example, it may be contaminated), resulting in degradation or failure of etching performance. To prevent this, the wet etching apparatus 100A may include concentration detection units 70A and 70B to detect at least one characteristic of the etchant 10, for example, the concentration of the etchant 10 and the concentration of the element to be etched.

[0051] The wet etching apparatus 100A may include a first concentration detection unit 70A that detects the concentration of an element to be etched and a second concentration detection unit 70B that detects the concentration of the etchant 10. A constant amount of the etchant 10 may be sampled at a desired point by selectively operating the first detection valve V2a and the second detection valve V2b to detect the concentration of the element to be etched and the concentration of the etchant 10.

[0052] The first concentration detection unit 70A may be connected to the pipe 61 and may detect the concentration of the element to be etched discharged from the process tank 20. Similarly, the second concentration detection unit 70B may be connected to the pipe 61 and may detect the concentration of the etchant 10 discharged from the process tank 20.

[0053] In this exemplary embodiment of the present disclosure, the etchant 10 may be detected from a portion of the duct 61 adjacent to the etchant discharge unit 35B, but alternatively, the first concentration detection unit 70A and the second concentration detection unit 70B may be directly connected to the etchant discharge unit 35B.

[0054] The wet etching apparatus 100A may further include an etchant storage unit 90A which is connected to the etchant circulation unit 60 and supplies pure etchant according to the detected concentration of the element to be etched.

[0055] Similarly, the wet etching apparatus 100A may further include a deionized water storage unit 90B that is connected to the etchant circulation unit 60 and supplies deionized (DI) water to the etchant according to the detected concentration of the etchant 10 .

[0056] When the concentration of the element to be etched detected by the first concentration detection unit 70A exceeds a predetermined value, the process control unit 80 can discharge the etchant 10 through the etchant discharge pipe 51 and can resupply pure (e.g., uncontaminated) etchant from the etchant storage unit 90A to the process tank 20.

[0057] The etchant discharge pipe 51 may be configured to discharge the etchant 10 from the inner space 20S of the process tank 20 to the outside. The etchant discharge pipe 51 may be connected to the discharge pump 55, and the process control unit 80 may control the discharge valve V1 to use the discharge pump 55 to discharge the used etchant 10 from the etchant discharge pipe 51. Next, the process control unit 80 may supply new pure etchant from the etchant storage unit 90A through the pipe 61 by operating the first supply valve V3a.

[0058] Similarly, when the concentration of the etchant 10 detected by the second concentration detection unit 70B exceeds a predetermined value, the process control unit 80 may control the resupply of deionized water to the etchant 10. The process control unit 80 may operate the second supply valve V3b to resupply an appropriate amount of deionized water from the deionized water storage unit 90B through the pipe 61.

[0059] In some exemplary embodiments of the present disclosure, the etchant 10 may include phosphoric acid for etching silicon nitride, and the element to be etched may include silicon (Si).

[0060] In this case, the etchant 10 may include silicon (Si) generated by etching the silicon nitride film, and the silicon concentration in the etchant 10 may increase as the etching process proceeds. When the silicon concentration in the etchant 10 reaches a predetermined value (e.g., a threshold value), oxide may grow on the surface of the silicon oxide film to increase the thickness of the silicon oxide film.

[0061] In order to suppress this abnormal growth phenomenon, the first concentration detection unit 70A is used to measure the concentration of silicon in the etchant 10, and when the concentration of the element to be etched (for example, silicon) detected by the first concentration detection unit 70A exceeds a predetermined value, the process control unit 80 can discharge the etchant 10 through the etchant discharge pipe 51 and can re-supply pure etchant from the etchant storage unit 90A to the process tank 20.

[0062] Similarly, since the etchant 10 is used in a heated state, moisture may evaporate as the etching process proceeds and the concentration of phosphoric acid may gradually increase. When the concentration of the etchant 10 reaches a predetermined value (eg, a threshold), the viscosity becomes too high, so that workability may be extremely deteriorated.

[0063] In order to solve such a problem, the concentration of the etchant 10 is measured using a second concentration detection unit 70B, and when the concentration of the etchant 10 detected by the second concentration detection unit 70B exceeds a predetermined value, the process control unit 80 can resupply deionized water from the deionized water storage unit 90B to the pipeline 61, thereby stabilizing the concentration of the etchant.

[0064] Figure 5 is a schematic perspective view illustrating a wet etching apparatus according to an exemplary embodiment of the present disclosure.

[0065] Reference Figure 5 , except that the laser unit 40' is implemented by a scanning method and only except the structure of the support unit 25' and the etchant supply unit 30, the wet etching apparatus 100B can be understood as Figure 1 Therefore, unless otherwise specifically stated, Figure 1 The description of the illustrated exemplary embodiment may be combined with the description of this exemplary embodiment.

[0066] The laser unit 40' may include a laser light source 45' that emits a linear laser beam and a scanning unit that moves the laser beam so that the wafer W is irradiated therewith. The moving direction SD of the scanning unit may be the width direction of the linear laser beam. For example, when a wafer having a diameter of 300 mm is used, the length of the linear laser beam may be at least 300 mm. Therefore, almost the entire area of ​​the wafer W may be irradiated by scanning to ensure relatively uniform heating.

[0067] In an exemplary embodiment of the present disclosure, the scanning unit may be configured to physically move the laser light source. In an exemplary embodiment of the present disclosure, the scanning unit may move the laser beam by fixing the laser light source and operating the optical system.

[0068] The laser unit 40 ′ includes a housing 41 having a closed space where a path of the laser beam is located, and the closed space can be decompressed or maintained in a vacuum state.

[0069] The supporting unit 25' and the etchant supply unit 30 may have Figure 2 The supporting unit 25' and the etchant supply unit 30 of the wet etching apparatus 100A shown in FIG. Figure 5 In the embodiment, the etchant circulation system and the concentration detection system are not shown, but the wet etching apparatus 100B may adopt the etchant circulation system and the concentration detection system.

[0070] The wet etching equipment can be used in various semiconductor device manufacturing methods. Hereinafter, a manufacturing process of a three-dimensional semiconductor device such as V-NAND (particularly, a silicon nitride removal process) and a manufacturing process of a logic device (particularly, a replacement process for a gate structure) will be described.

[0071] FIG. 6A to FIG. 11A is a plan view showing a method of manufacturing a semiconductor device (eg, V-NAND) using a wet etching process according to an exemplary embodiment of the present disclosure, FIG. 6B to FIG. 11B Along FIG. 6A to FIG. 11A A cross-sectional view taken along line II'.

[0072] Reference FIG. 6A to FIG. 6B , a lower insulating film 302 may be formed on a substrate 300. For example, the substrate 300 may be a silicon substrate, a germanium substrate, or a silicon germanium substrate. The lower insulating film 302 may be a silicon oxide film formed by a thermal oxidation process or a silicon oxide film formed using a deposition technique. The thin film structure TS may be formed by alternately and repeatedly depositing a sacrificial film 304 and an insulating film 306 on the lower insulating film 302.

[0073] In some exemplary embodiments of the present disclosure, the sacrificial films 304 may have the same thickness. In other exemplary embodiments of the present disclosure, the sacrificial films 304 of the bottom layer and the top layer of the thin film structure TS may be formed to be thicker than the sacrificial film 304 located therebetween. The insulating films 306 may have the same thickness, or a portion of the insulating films 306 may have different thicknesses. The lower insulating film 302 may have a smaller thickness than the sacrificial film 304 and the insulating film 306 formed thereon.

[0074] In some exemplary embodiments of the present disclosure, the sacrificial film 304 and the insulating film 306 may include materials having different etching selectivities. In this method, the sacrificial film 304 may be formed of a silicon nitride film, and the insulating film 306 may be formed of a silicon oxide film.

[0075] Reference FIG. 7A to FIG. 7B , a penetration hole H exposing the substrate 300 through the thin film structure TS may be formed. The penetration hole H may be formed in the thin film structure TS in plurality, and the plurality of penetration holes H may be two-dimensionally formed on the upper surface of the thin film structure TS. According to some example embodiments, the penetration holes H may be arranged to form a row along the first direction D1. In other exemplary embodiments of the present disclosure, the penetration holes H may be arranged in a zigzag manner in the first direction D1.

[0076] The penetration hole H may be formed by forming a first mask pattern having an opening defining a region where the penetration hole H is to be formed on the thin film structure TS, and may be formed by anisotropically etching the thin film structure TS using the first mask pattern as an etching mask. The first mask pattern may be formed of a material having an etching selectivity with respect to the sacrificial film 304 and the insulating film 306. The upper surface of the substrate 300 is overetched by the etching process, so that the upper portion of the substrate 300 may be recessed. Therefore, the penetration hole H may penetrate at least a portion of the substrate 300.

[0077] Reference Fig. 8A and Figure 8B , a semiconductor pattern 322 may be formed in the penetration hole H. In some exemplary embodiments of the present disclosure, the semiconductor pattern 322 may be formed in a pillar shape penetrating at least a portion of the substrate 300. The semiconductor pattern 322 may be formed by forming a semiconductor film filling the penetration hole H on the thin film structure TS and then planarizing the semiconductor film until the upper surface of the thin film structure TS is exposed. The semiconductor film may include a semiconductor material (e.g., a polycrystalline silicon film, a single crystal silicon film, or an amorphous silicon film) formed by atomic layer deposition (ALD) or chemical vapor deposition (CVD). The semiconductor pattern 322 may be locally formed in the penetration hole H by a planarization process.

[0078] Reference Fig. 9A and Fig. 9B, the thin film structure TS may be patterned to form a trench T exposing the substrate 300 between adjacent semiconductor patterns 322. The trench T may be formed by forming a second mask pattern defining a plane position on which the trench T is to be formed on the thin film structure TS, and then anisotropically etching the thin film structure TS using the second mask pattern as an etching mask. The trench T may be spaced apart from the semiconductor pattern 322, and may be formed to expose the sidewalls of the sacrificial film 304 and the insulating film 306. During the etching process, the upper portion of the substrate 300 is overetched, so that the upper portion of the substrate 300 may be recessed. When the trench T is formed, the thin film structure TS may have a line shape extending in one direction (e.g., the first direction D1). The thin film structure TS in the form of a single line shape may be penetrated by a plurality of semiconductor patterns 322.

[0079] Reference Fig. 10A and Fig. 10B , the sacrificial film 304 exposed by the trench T may be removed so that a recessed region R may be formed between the insulating films 306. The recessed region R may be formed by isotropically etching the sacrificial film 304 using an etching condition having an etching selectivity with respect to the insulating film 306, the semiconductor pattern 322, the lower insulating film 302, and the substrate 300. The sacrificial film 304 may be completely removed by the isotropic etching process. For example, when the sacrificial film 304 is a silicon nitride film and the insulating film 306 is a silicon oxide film, the etching process may be a wet etching process using an etchant containing phosphoric acid.

[0080] As described above, in the etching process using an etchant containing phosphoric acid, silicon (Si) is generated by the etching process of the sacrificial film 304, and the silicon concentration in the etchant may increase as the etching process proceeds. When the silicon concentration in the etchant reaches a threshold value, as shown in FIG. Fig. 10B As indicated by “I” in FIG. 1 , an abnormal growth oxide DS grows on the surface of the silicon oxide film, which may result in reduced reliability and cause failure. However, according to this method, Figure 2 As shown, the first concentration detection unit 70A is used to measure the concentration of the element to be etched, and when the concentration of the element to be etched detected from the first concentration detection unit 70A exceeds a predetermined value, the process control unit 80 can discharge the etchant through the etchant discharge pipe 51, and resupply pure phosphoric acid as an etchant from the etchant storage unit 90A to the process tank 20, thereby preventing failure caused by abnormal growth of oxide.

[0081] Reference Fig.11A and Fig. 11BAfter forming the recessed region R, a horizontal insulator 360 covering the inner surface of the recessed region R and a gate electrode 350 filling the remaining space of the recessed region R may be formed. The horizontal insulator 360 and the gate electrode 350 may be formed by respectively forming a horizontal insulating film and a conductive film sequentially covering the recessed region R, and then locally forming the horizontal insulator 360 and the gate electrode 350 in the recessed region R by removing the horizontal insulating film and the conductive film in the trench T. The horizontal insulating film may be composed of one thin film or a plurality of thin films.

[0082] In some exemplary embodiments of the present disclosure, the horizontal insulating film may include a tunnel insulating film adjacent to the semiconductor pattern 322, a blocking insulating film adjacent to the gate electrode 350, and a charge storage film between the tunnel insulating film and the blocking insulating film. The conductive film may be formed to conformally cover the inner wall of the trench T while filling the recessed region R. In this case, forming the gate electrode 350 may include removing the conductive film in the trench T by an isotropic etching method. The gate electrode 350 and the insulating film 306 interposed therebetween may be defined as a stacked structure SS.

[0083] After forming the gate electrode 350 , a common source region 370 may be formed on the substrate 300 . The common source region 370 may be formed by performing an ion implantation process on the substrate 300 exposed by the trench T. The common source region 370 may have a different conductivity type from that of the semiconductor pattern 322 .

[0084] Alternatively, the region of the substrate 300 in contact with the semiconductor pattern 322 may have the same conductivity type as the semiconductor pattern 322. Each of the plurality of common source regions 370 may be connected to each other to be in an equipotential state. However, in other exemplary embodiments of the present disclosure, each of the plurality of common source regions 370 may be electrically separated to have different potentials.

[0085] An electrode separation pattern 375 filling the trench T may be formed on the common source region 370. For example, the electrode separation pattern 375 may include a silicon oxide film, a silicon nitride film, or a silicon oxynitride film.

[0086] Next, a desired three-dimensional semiconductor device may be manufactured by forming a conductive pad connected to the semiconductor pattern 322 , a contact plug, and a bit line connected to the contact plug.

[0087] Figures 12 to 15 is a perspective view illustrating a method of manufacturing a semiconductor device using a wet etching process according to an exemplary embodiment of the present disclosure.

[0088] Reference Fig.12, an active pin 505 is formed on the semiconductor substrate 501 , and a source / drain region 510 including a crystalline semiconductor region 510A is formed on the active pin 505 exposed at both sides of a dummy gate electrode 535 formed above the semiconductor substrate 501 .

[0089] The crystalline semiconductor region 510A may be formed by a selective epitaxial growth (SEG) process. The crystalline semiconductor regions 510A on the active pin 505 may be fused with each other during the growth process. The cross-sectional shape of the source / drain region 510 is not limited thereto, for example, the cross-sectional shape cut along the YZ plane of the source / drain region 510 may be shaped as a polygon such as a quadrilateral, a hexagon, a circle, or an ellipse. The source / drain region 510 may have an upper surface higher than the upper surface of the active pin 505. The source / drain region 510 may be formed by a semiconductor layer doped with impurities. In some exemplary embodiments of the present disclosure, the source / drain region 510 may be composed of Si, SiGe, or SiC doped with impurities.

[0090] Reference Fig.13 , a gate inter-insulating layer 562 may be formed on the source / drain region 510 .

[0091] The inter-gate insulating layer 562 may cover the source / drain region 510, the dummy gate electrode 535, and the insulating spacer 550 to a sufficient thickness. For example, the inter-gate insulating layer 562 may include an oxide, a nitride, and / or an oxynitride. Then, a local portion (dashed line portion) of the inter-gate insulating layer 562 is planarized to expose the dummy gate electrode 535. The mask pattern layer 536 may be removed, and the upper surface of the dummy gate electrode 535 may be exposed in this planarization process.

[0092] Reference Fig.14 , the dummy gate insulating film 532 and the dummy gate electrode 535 may be removed to provide an open region E for forming a gate structure.

[0093] The dummy gate insulating film 532 and the dummy gate electrode 535 may be selectively removed relative to the lower device separation layer 507 and the active pin 505, so that the open area E may expose the lower device separation layer 507 and the active pin 505. The removal process of the dummy gate insulating film 532 and the dummy gate electrode 535 may use a dry etching process and / or a wet etching process. In the peripheral circuit, the dummy gate insulating film 532 may be retained to form a gate insulator.

[0094] In some exemplary embodiments of the present disclosure, the etching process may be performed using Figures 1 to 5 For example, the wet etching process may be performed using the wet etching equipment shown. Figure 1 The wet etching device 100 shown in FIG. Figure 1As shown, the support unit 25 used in this exemplary embodiment is located in the internal space 20S of the process tank 20, and the wafer W set thereon is exposed to the etchant flow EC, and the surface to be processed P1 in contact with the etchant flow is directed upward, so the laser beam LB emitted from the laser unit 40 can be projected onto the surface to be processed P1 of the wafer W. Therefore, the device described herein is used when the portion to be etched (e.g., the dummy gate electrode 535) is exposed to the surface to be processed. Here, the etchant flow EC is shown as the X direction, but it can be another direction (e.g., the Y direction) located in the XY plane.

[0095] Reference Fig.15 , a gate insulating film 542 and first and second gate electrodes 545 a and 545 b (gate electrodes 545 ) may be formed in the open region E to form a gate structure 540 .

[0096] A gate insulating film 542 may be formed substantially conformally along the sidewalls and lower surface of the open region E. The gate insulating film 542 may include an oxide, a nitride, or a high-k film. As used herein, "high-k" means having a dielectric constant higher than that of silicon dioxide. The first gate electrode 545a and the second gate electrode 545b may include a metal or a semiconductor material. Then, a desired semiconductor device may be manufactured by forming an interlayer insulating layer and forming a contact plug connected to the source / drain region 510 while penetrating the interlayer insulating layer.

[0097] As described above, according to an exemplary embodiment of the present disclosure, by uniformly heating the wafer using a laser unit disposed above the process tank, a uniform etching rate can be ensured in the entire region. For example, a thick layer to be etched that requires a high processing temperature in various types of three-dimensional semiconductor devices can be effectively removed at a uniform etching rate.

[0098] The various features and aspects of the present invention are not limited to the above description and can be more readily understood in the course of describing specific embodiments of the present invention.

[0099] While exemplary embodiments of the present disclosure have been shown and described above, it will be apparent to those skilled in the art that modifications and variations may be made without departing from the scope of the inventive concept.

Claims

1. A wet etching device, include: a process tank having an inner space configured to receive an etchant and having a support unit on which a wafer is disposed to contact the etchant; a laser unit disposed above the process tank and configured to direct a laser beam toward the wafer to heat the wafer; as well as an etchant supply unit configured to supply the etchant to an inner space of the process tank, The supporting unit includes: an opening, which is arranged at the upper part of the process tank and is recessed into the internal space; and a supporting portion, which is arranged around the opening and supports the outer periphery of the wafer. wherein the surface to be processed of the wafer points toward the inner space, and the laser beam irradiates the surface opposite to the surface to be processed of the wafer, so that the laser beam directly heats the wafer without irradiating the etchant, and The wafer and the support part are in contact with each other, so that the wafer closes the opening while the surface to be processed of the wafer is in contact with the etchant.

2. The wet etching device according to claim 1, in, The laser unit includes: a laser light source configured to emit the laser beam; and an optical system disposed between the laser light source and the process tank and configured to expand a region of the laser beam.

3. The wet etching apparatus according to claim 2, in, The area of ​​the laser beam expanded by the optical system has a size large enough to cover the area of ​​the wafer.

4. The wet etching apparatus according to claim 1, in, The laser unit includes: a laser light source that emits a linear laser beam; and a scanning unit that moves the laser beam so that the wafer is irradiated. 5 . The wet etching apparatus according to claim 1 , further comprising a housing having a closed space, wherein the laser unit is disposed in the closed space, and the closed space is configured to be decompressed or maintained in a vacuum state.

6. The wet etching apparatus according to claim 1, in, The etchant supply unit supplies the etchant at a flow rate within a range of 0.1 m / sec to 1.0 m / sec.

7. The wet etching apparatus according to claim 1, in, The etchant supply unit includes: an etchant injection unit, which is arranged on a first side of the process tank and is configured to inject the etchant into the internal space of the process tank; and an etchant discharge unit, which is arranged on a second side of the process tank and is configured to discharge the etchant from the internal space of the process tank.

8. The wet etching apparatus according to claim 7, further comprising: include: An etchant circulation unit is connected to the etchant injection unit and the etchant exhaust unit and is configured to circulate the etchant.

9. The wet etching apparatus according to claim 1, further comprising: include: A concentration detection unit is configured to detect the concentration of the etchant and / or the concentration of the element to be etched.

10. The wet etching apparatus according to claim 9, in, The etchant is phosphoric acid, and the element to be etched includes silicon.

11. The wet etching apparatus according to claim 1, in, The process tank includes a discharge unit configured to discharge the etchant received in the inner space.

12. A wet etching device, include: a process tank having an inner space configured to receive an etchant, and having a support unit disposed in the inner space, the support unit being configured to support a wafer in contact with the etchant; a laser unit disposed above the process tank and having a laser light source emitting a laser beam, and an optical system that expands an area of ​​the laser beam and is configured to expose the wafer using the expanded laser beam; as well as an etchant supply unit, which has an etchant injection unit and an etchant discharge unit respectively arranged on opposite sides of the process tank, a pipeline connecting the etchant injection unit and the etchant discharge unit, and a circulation pump installed on the pipeline, The support unit includes: an opening, which is arranged at the upper part of the process tank and is recessed into the internal space; and a support portion, which is arranged around the opening and supports the outer periphery of the wafer so that the surface to be processed of the wafer points to the internal space, and wherein the laser beam irradiates a surface of the wafer opposite to the surface to be processed of the wafer, and The wafer and the support part are in contact with each other, so that the wafer closes the opening while the surface to be processed of the wafer is in contact with the etchant.

13. The wet etching apparatus according to claim 12, further comprising: include: a first concentration detection unit connected to the etchant discharge unit or the pipeline and configured to detect the concentration of the element to be etched discharged from the process tank; and an etchant storage unit connected to the etchant supply unit and configured to supply pure etchant according to the detected concentration of the element to be etched.

14. The wet etching apparatus according to claim 12, further comprising: include: a second concentration detection unit connected to the etchant discharge unit or the pipeline and configured to detect the concentration of the etchant discharged from the process tank; and a deionized water storage unit connected to the etchant supply unit and supplying deionized water to the etchant according to the detected concentration of the etchant.

15. A wet etching device, include: A process tank having an inner space configured to receive an etchant, and including an opening recessed into the inner space and a support portion disposed around the opening and supporting an outer peripheral portion of a wafer, the wafer being disposed on the support portion to contact the etchant; a laser unit disposed above the process tank and projecting a laser beam onto a surface of the wafer opposite to a surface to be processed of the wafer, so that the wafer is heated; A first sub-tank, which is disposed on a first side of the process tank and has a first temporary accommodation space; A second sub-trough, which is disposed on a second side of the process tank and has a second temporary accommodation space, the second side of the process tank facing the first side of the process tank; a plurality of etchant injection units, the plurality of etchant injection units being arranged at a first side of the process tank along a width direction of the process tank and connecting the inner space to the first temporary accommodation space; a plurality of etchant exhaust units arranged at a second side of the process tank along a width direction of the process tank and connecting the inner space to the second temporary accommodation space; a circulation pipe connecting the first sub-tank with the second sub-tank; as well as A circulation pump is installed on the circulation pipe and circulates the etchant to contact the wafer in the internal space while the laser beam is irradiated to the wafer.

16. The wet etching apparatus according to claim 15, further comprising: include: a first concentration detection unit configured to detect the concentration of an element to be etched from the etchant; and a process control unit, which controls the discharge of the etchant and the resupply of pure etchant when the detected concentration of the element to be etched exceeds a predetermined value.

17. The wet etching apparatus according to claim 15, further comprising: include: a second concentration detection unit configured to detect the concentration of the etchant; and a process control unit configured to control the resupply of deionized water to the etchant when the detected concentration of the etchant exceeds a predetermined value.

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