Liquid treatment device, liquid treatment method, and liquid flow regulation member

Abstract

The purpose of the present invention is to prevent the occurrence of trouble with etching due to desorption of a noble metal layer with respect to a substrate on which a noble metal layer serving as a catalyst is formed when immersed in an etching liquid. This liquid treatment device is provided with: a substrate-holding unit that holds a substrate on the surface of which a noble metal layer serving as a catalyst for etching the substrate is formed when the substrate is immersed in the etching liquid; a storage tank in which a treatment liquid for treating the substrate is stored; a movement mechanism that moves the substrate-holding unit and the storage tank relatively to each other in order to move the substrate held by the substrate-holding unit inside and outside the storage tank; and a liquid flow regulation member that faces a regulation region in the storage tank in order to regulate the flow of the treatment liquid in the regulation region including the formation region of the noble metal layer on the surface of the substrate and the outer periphery of the formation region.

Description

Liquid treatment device, liquid treatment method, and liquid flow control member

[0001] The present disclosure relates to a liquid processing apparatus, a liquid processing method, and a liquid flow restricting member.

[0002] In manufacturing a semiconductor device, a substrate such as a semiconductor wafer (hereinafter referred to as a wafer) may be immersed in an etching solution to perform an etching process. Patent Document 1 describes an etching process using a technique called Mac Etch (Metal-Assisted Chemical Etching) method, in which a precious metal layer is formed on the surface of a semiconductor substrate, and then the substrate is immersed in an etching solution to etch the area covered by the precious metal layer using the precious metal layer as a catalyst.

[0003] Japanese Patent Application Laid-Open No. 2017-50378

[0004] The present disclosure provides a technique capable of preventing etching defects caused by detachment of a precious metal layer formed on a substrate that serves as a catalyst when the substrate is immersed in an etching solution.

[0005] The liquid processing apparatus of the present disclosure comprises: a substrate holding section that holds a substrate having a precious metal layer formed on its surface, the precious metal layer serving as a catalyst for etching the substrate when the substrate is immersed in an etching solution; a storage tank that stores a processing solution for processing the substrate; a movement mechanism that moves the substrate holding section and the storage tank relatively to each other to move the substrate held in the substrate holding section inside and outside the storage tank; and a liquid flow control member that faces a regulation area in the storage tank to control the flow of the processing solution in a regulation area that includes a formation area of ​​the precious metal layer on the surface of the substrate and the outer periphery of the formation area.

[0006] The present disclosure can prevent etching defects caused by detachment of a precious metal layer that acts as a catalyst when a substrate is immersed in an etching solution.

[0007] 1 is a perspective view showing an etching processing apparatus 1 of an embodiment; FIG. 2 is a configuration diagram of the etching processing apparatus; FIG. 3 is a longitudinal sectional side view of the etching processing apparatus; FIG. 4 is a longitudinal sectional side view of the etching processing apparatus; FIG. 5 is a schematic longitudinal sectional side view showing the operation of the etching processing apparatus; FIG. 6 is a schematic longitudinal sectional side view showing the operation of the etching processing apparatus; FIG. 7 is a schematic longitudinal sectional side view showing the operation of the etching processing apparatus; FIG. 8 is an enlarged longitudinal sectional side view showing the operation of the etching processing apparatus during stirring; FIG. 9 is a schematic view of a wafer surface showing the etching state; FIG. 10 is a schematic view of a wafer surface showing the etching state; FIG. 11 is a partial plan view of a rectifying plate of a modified example; FIG. 12 is a partial longitudinal sectional side view of a rectifying plate of a modified example; FIG. 13 is a longitudinal sectional side view of the rectifying plate of a modified example; FIG. 14 is a longitudinal sectional side view of the etching processing apparatus of a modified example; FIG. 15 is a plan view showing a substrate processing system.

[0008] (Embodiment) <Configuration of Etching Processing Apparatus> The configuration of an etching processing apparatus 1 of this embodiment will be described. The etching processing apparatus 1 performs etching processing on wafers W, which are circular substrates, by the Mac Etch method described above. FIG. 1 is a perspective view showing the etching processing apparatus 1. The etching processing apparatus 1 is a so-called batch processing apparatus in which a number of wafers W belonging to the same lot are loaded into a storage tank 11 and immersed in an etching liquid L1, which is a processing liquid, to process the wafers W collectively.

[0009] Regarding the wafer W, the surface of the wafer W to be etched is composed of a silicon (Si) layer W0. A precious metal layer M is formed by photolithography so as to cover a portion of this Si layer W0. The region of the Si layer W0 that contacts the precious metal layer M is the region where the precious metal layer is formed. Specifically, the precious metal layer M is composed of, for example, gold, silver, platinum, or ruthenium. This precious metal layer M is not embedded in the surface of the wafer W, but is provided so that its side surfaces are exposed.

[0010] Injection of the etching solution L1 into the reservoir tank 11 and agitation of the etching solution L1 stored in the reservoir tank 11 form a liquid flow along the surface of the wafer W. The etching solution L1 is a chemical solution that etches the area of ​​the wafer W that contacts the precious metal layer M formed on the wafer W through a catalytic reaction with the precious metal layer M. In other words, the etching solution L1 is a chemical solution that etches the area of ​​the wafer W that contacts the precious metal layer M through a MacEtch (Metal Assisted Chemical Etching) reaction. The etching solution L1 contains a corrosive and an oxidizing agent. Due to the characteristics of the MacEtch method, as will be described in detail later, adhesion of the precious metal layer M to the surface of the wafer W is relatively low during etching with the etching solution L1. Therefore, the flow of the etching solution L1 may cause the precious metal layer M to be detached from the surface of the wafer W.

[0011] In order to regulate the liquid flow and prevent the detachment of the precious metal layer M, a rectifying plate 60 is disposed on the front surface side of each wafer W in the storage tank 11. Therefore, a rectifying plate 60 is provided for each wafer W. When viewed in the thickness direction, the outline of the rectifying plate 60 is the same as the outline of the wafer W. Note that in FIG. 1 , the number of wafers W and rectifying plates 60 is shown fewer than the actual number to schematically illustrate the overall configuration, and the through-holes 63 provided in the rectifying plates 60 and the precious metal layer M of the wafer W are shown enlarged, while some of the components shown in FIG. 2 are omitted. In this embodiment, the etching liquid L1 is supplied to the storage tank 11 after the wafer W and the rectifying plate 60 are loaded into the storage tank 11. However, for convenience, FIG. 1 illustrates the etching liquid L1 being supplied before the loading.

[0012] 2 is a diagram illustrating the configuration of the etching processing apparatus 1. As shown in FIGS. 1 and 2, the etching processing apparatus 1 includes a storage tank 11, a substrate lifting mechanism 40 for holding a plurality of wafers W and a rectifying plate 60 and arranging them in the storage tank 11, an etching liquid supply unit 20, and a flow mechanism 30.

[0013] The reservoir tank 11 is open at the top so that the wafer W and the current plate 60 can be loaded and unloaded by the substrate lifting mechanism 40. A drain pipe 15 is connected to the bottom of the reservoir tank 11, and the etching liquid L1 can be discharged from the reservoir tank 11 by opening a valve V1 provided in the drain pipe 15.

[0014] The etching solution supply unit 20 will be described with reference to the longitudinal side view of the etching processing apparatus 1 in Fig. 3. The etching solution supply unit 20 includes a first supply unit 21 for supplying hydrofluoric acid (HF) as a corrosive agent, and hydrogen peroxide (H ２ O ２ The apparatus includes a second supply unit 22 for supplying nitric acid (HNO ３ ) may also be used.

[0015] The liquid supply pipe 23 is formed as a straight pipe with a closed tip, and is installed horizontally so as to extend in the front-to-back direction (the direction from the front to the back of the paper surface of FIG. 2 , the X direction). A plurality of supply ports 25 are opened in the liquid supply pipe 23 along the extension direction of the liquid supply pipe 23, and the supply ports 25 open upward. The lower part of the flow path forming member 24 is connected to the base end of the liquid supply pipe 23. The upper part of the flow path forming member 24 is extended outside the storage tank 11, and the liquid supplied to the upper part of the flow path forming member 24 is introduced into the liquid supply pipe 23 via a flow path provided in the flow path forming member 24, and is supplied into the storage tank 11 from the supply ports 25 (partially shown in FIG. 3 ) as indicated by the arrow in FIG. 3 .

[0016] The first supply unit 21 and the second supply unit 22 are connected to the upper part of the flow path forming member 24 via flow rate adjusting units M1 and M2, respectively, and supply liquid HF and H ２ O ２ The flow rate adjusting units M1 and M2 are configured by mass flow controllers, and can adjust the amount of HF and H supplied to the flow path forming member 24. ２ O ２ The flow rates of the etching solution L1 are adjusted. ２ O ２ HF and H from the first supply unit 21 and the second supply unit 22.２ O ２ By supplying the etching liquid L1, the etching liquid L1 can be stored in the storage tank 11. The dashed dotted line in Fig. 2 indicates the liquid surface of the etching liquid L1 during the etching process.

[0017] The flow mechanism 30 will now be described. The flow mechanism 30 includes a pipe 31, a pump 32, and a filter 33. One end of the pipe 31 is connected to the bottom of the storage tank 11. The pump 32 and the filter 33 are disposed toward the other end of the pipe 31. The other end of the pipe 31 is connected to the upper side of the flow path forming member 24. By operation of the pump 32, the etching liquid L1 in the storage tank 11 is filtered and purified by the filter 33, and can be introduced into the flow path forming member 24 and supplied into the storage tank 11 from the supply port 25 of the liquid supply pipe 23. In this way, the flow mechanism 30, together with the inside of the storage tank 11, forms a circulation path for the etching liquid L1. The circulation of the etching liquid L1 stirs the etching liquid L1 in the storage tank 11, and the HF and H in the etching liquid L1 at each part of the storage tank 11 are agitated. ２ O ２ The variation in each concentration is reduced.

[0018] The substrate lifting mechanism 40 will now be described. The substrate lifting mechanism 40 is composed of four substrate holding parts 41, a connection part 42, and a drive mechanism 43. The substrate holding parts 41 are configured as linear members extending in the front-to-rear direction, hold the wafer W and the rectifying plate 60, and are positioned within the storage tank 11 during etching processing. The four substrate holding parts 41 are provided two by two at the same height, and the two upper substrate holding parts 41 are arranged so as to sandwich the two lower substrate holding parts 41 from the left and right direction (Y direction) in a plan view.

[0019] Grooves 44 extending in the left-right direction are provided on the upper side of the substrate holding portion 41, spaced apart in the front-rear direction. The grooves 44 formed at the same position in the front-rear direction on four substrate holding portions 41 form a set. The peripheral edge of the wafer W and the peripheral edge of the rectifying plate 60 are fitted into the grooves 44 of the same set. This holds the wafer W and the rectifying plate 60 in an upright position. When the wafer W and the rectifying plate 60 are held in this manner, the surfaces of the wafers W on which the precious metal layers M are formed face in the same direction. The wafers W and the rectifying plates 60 are aligned in a line in the front-rear direction and alternately arranged in the front-rear direction so that the rectifying plates 60 are located on the front surface side of each wafer W. For example, 25 wafers W and 25 rectifying plates 60 are held by the substrate holding portion 41. Therefore, 50 grooves 44 are formed in one substrate holding portion 41.

[0020] For convenience, in the following description, the groove 44 for holding the wafer W may be referred to as 44A, and the groove for holding the rectifying plate 60 may be referred to as 44B. Therefore, the grooves 44A and 44B are alternately formed in the front-to-rear direction. The grooves 44A are formed at equal intervals in one substrate holding part 41, and the grooves 44B are formed at equal intervals in one substrate holding part 41. The wafer W is held on the substrate holding part 41 by the grooves 44A at intervals of, for example, 8 mm to 12 mm. The positional relationship between the wafer W and the rectifying plate 60 will be described in more detail later. In the following description, the side toward which the surface of the wafer W on which the precious metal layer M is provided faces in the front-to-rear direction is referred to as the front side.

[0021] One end of the substrate holding part 41 is connected to and supported by the connection part 42. At least a portion of this connection part 42 is located inside the storage tank 11 together with the substrate holding part 41 during the etching process. The connection part 42 is configured as a member extending vertically, and the upper side of the connection part 42 is connected to a drive mechanism 43 provided outside the storage tank 11. The drive mechanism 43 raises and lowers the connection part 42 and the substrate holding part 41 relative to the storage tank 11. The drive mechanism 43 moves the substrate holding part 41 between a standby position above the storage tank 11 and a processing position inside the storage tank 11 shown in FIGS. 2 and 3 , and the wafer W and the rectifying plate 60 held by the substrate holding part 41 can be carried in and out of the storage tank 11.

[0022] Next, the rectifying plate 60, which is a liquid flow regulating member, will be described in detail with reference to the vertical side view of Fig. 4. The rectifying plate 60 faces closely to the surface of the wafer W and is held by the substrate holding part 41 so as to form a narrow gap 61 between it and the surface of the wafer W. The rectifying plate 60 is detachable from the substrate holding part 41.

[0023] When the etching liquid L1 is injected into the storage tank 11 and when the pump 32 stirs the etching liquid L1 in the storage tank 11 after injection, a flow of the etching liquid L1 is formed along the surface of the wafer W. However, the flow rate of the etching liquid L1 passing over the surface of the wafer W is relatively small because the narrow width of the gap 61 results in high pressure loss. Therefore, the pressure that the side surface of the precious metal layer M receives from the etching liquid L1 is suppressed. As a result, detachment of the precious metal layer M from the surface of the wafer W is suppressed, as described above.

[0024] The rectifying plate 60 is made of, for example, a fluororesin that has high water repellency against the etchant L1 so that the inflow of the etchant L1 into the gap 61 is suppressed, thereby further suppressing the flow rate of the etchant L1 along the surface of the wafer W. Specific examples of such fluororesins include PFA (perfluoroalkoxyalkane) and PTFE (polytetrafluoroethylene). Note that in FIG. 4 , the opposing surface of the rectifying plate 60 that faces the surface of the wafer W across the gap 61 is shown as an opposing surface 62. With regard to the rectifying plate 60, only the opposing surface 62 may be made of a fluororesin, and the other portions may be made of, for example, a resin other than a fluororesin. In this example, the entire rectifying plate 60 is made of a fluororesin.

[0025] Mac Etch is an oxidation-reduction reaction catalyzed by a precious metal layer M. If the surface of the rectifying plate 60 is made of metal, there is a risk that an unnecessary reduction reaction will occur due to this metal, which will hinder the progress of the oxidation-reduction reaction caused by the precious metal layer M. For this reason, it is preferable that the surface of the rectifying plate 60 be made of a material other than metal, such as resin (i.e., it does not contain metal).

[0026] Furthermore, evaluation tests have confirmed that it is preferable to set the contact angle of the etching liquid L1 on the opposing surface 62 to, for example, 90° or more in order to prevent the etching liquid L1 from flowing into the gap 61. For example, by forming the opposing surface 62 from the above-mentioned fluororesin, it is possible to make the opposing surface 62 have such a contact angle.

[0027] The rectifying plate 60 has a large number of circular through-holes 63 formed on imaginary square lattice points. In this example, the diameter of the through-holes 63 is 1.0 mm, and the center-to-center distance between adjacent through-holes 63 vertically and horizontally along the square lattice is 1.8 mm. The gap formed between the backside of each wafer W held by the substrate holder 41 and the rectifying plate 60 is referred to as gap 64. Therefore, gap 64 is configured to be connected to gap 61 via through-hole 63, and when the etching liquid L1 is injected and stirred in the storage tank 11, the etching liquid L1 can flow from gap 64 into gap 61.

[0028] When the etching liquid L1 flows from the gap 64 into the gap 61 via the through-hole 63 in this manner, the flow rate of the etching liquid L1 flowing along the surface of the wafer W in the gap 61 is reduced by the effect of the liquid flow caused by the inflow. As a result, detachment of the precious metal layer M from the surface of the wafer W is more reliably suppressed. Note that even if the liquid flow of the etching liquid L1 flowing toward the surface of the wafer W via the through-hole 63 is directed toward the precious metal layer M, this liquid flow acts to press the precious metal layer M against the surface of the wafer W, and therefore, unlike the liquid flow of the etching liquid L1 flowing along the surface of the wafer W, does not detach the precious metal layer M.

[0029] The positional relationship between the wafer W and the flow rectifying plate 60 held by the substrate holding part 41 will be described in more detail. As described above, in order to suppress the liquid flow along the surface of the wafer W, the width H1 of the gap 61 is made relatively narrow. Specifically, the width H1 of the gap 61 is made smaller than the width H2 of the gap 64. That is, for two adjacent wafers W, the flow rectifying plate 60 located between the back surface of one wafer W and the front surface of the other wafer W is positioned closer to the front surface of the other wafer W than to the back surface of the first wafer W. Regarding the grooves 44 of the substrate holding part 41, the groove 44A provided between two adjacent grooves 44B in the front-rear direction is formed so that the distance from the front groove 44B is shorter than the distance from the rear groove 44B.

[0030] By making width H1<width H2 in this way, the pressure loss of the etching liquid L1 is lower in gap 64 than in gap 61, and therefore, the etching liquid L1 flows at a higher flow rate in gap 64 than in gap 61. Therefore, when viewed between gap 64 and gap 61, the etching liquid L1 is likely to flow from gap 64 to gap 61 via through-hole 63. That is, as described above, the flow of etching liquid L1 along the surface of wafer W in gap 61 is likely to be suppressed.

[0031] <Operation of Etching Treatment Apparatus> The operation of the etching treatment apparatus 1 will be described below in order with reference to the schematic vertical cross-sectional side views of the etching treatment apparatus 1 in Figures 5 to 8. This operation is performed by controlling the operation of each part of the apparatus by control signals transmitted from a control unit, which will be described later.

[0032] A total of 25 wafers W and 25 rectifying plates 60 are transferred to the substrate lifting mechanism 40 by a transfer mechanism (not shown). Then, the peripheral edge of each wafer W and the peripheral edge of each rectifying plate 60 are fitted into grooves 44A and 44B of the substrate holder 41 located outside the storage tank 11, respectively, thereby holding each wafer W and each rectifying plate 60 on the substrate holder 41 as described with reference to FIGS. 3 and 4 . Then, the substrate holder 41 is lowered from a standby position above the storage tank 11 to a processing position within the storage tank 11, and each wafer W and each rectifying plate 60 is transferred into the storage tank 11. In this embodiment, no etching liquid L1 is stored in the storage tank 11 during this transfer.

[0033] Then, HF and H are supplied from the first supply unit 21 and the second supply unit 22 to the liquid supply pipe 23. ２ O ２ As a result, the etching liquid L1, which is a mixture of these components, is supplied into the storage tank 11, and the liquid level of the etching liquid L1 rises ( FIG. 5 ). As the liquid level continues to rise, it reaches the gap 61 between the rectifying plate 60 and the front surface of the wafer W and the gap 64 between the rectifying plate 60 and the back surface of the wafer W, and the liquid level rises through these gaps 61 and 64. That is, the etching liquid L1 flows upward along each of the front and back surfaces of the wafer W. The flow rate of the etching liquid L1 through the gap 61 is suppressed due to the difference in pressure loss caused by the difference between the width H1 of the gap 61 and the width H2 of the gap 64, as described in FIG. 4 . As a result, the liquid level rises at a slower rate through the gap 61 than through the gap 64 ( FIG. 6 ). To eliminate the difference in liquid level between the gaps 61 and 64, a portion of the etching liquid L1 flowing through the gap 64 flows into the through-hole 63 of the rectifying plate 60 and is supplied to the gap 61 ( FIG. 7 ).

[0034] As the etching solution L1 continues to be stored in the storage tank 11 in this manner, the precious metal layer M on the surface of the wafer W is immersed in the etching solution L1. As the liquid level rises, the etching solution L1 flows from bottom to top in the gap 61, and the downward-facing side surface of the precious metal layer M is subjected to upward pressure by being exposed to this flow. However, as described above, the flow rate of the etching solution L1 flowing upward in the gap 61 is relatively slow, and therefore the pressure applied to the downward-facing side surface of the precious metal layer M is relatively small.

[0035] Furthermore, a lateral liquid flow is formed into the gap 61 via the through-holes 63. This lateral liquid flow pushes the liquid flow going upward through the gap 61, further reducing the flow rate of the upward liquid flow. In other words, the action of the through-holes 63 further reduces the flow rate of the etching liquid L1 going upward, and the pressure that the downward-facing side surface of the precious metal layer M receives becomes smaller. In this way, the supply of the etching liquid L1 to the storage tank 11 further progresses while preventing the precious metal layer M from being detached.

[0036] When the liquid level of the etching liquid L1 reaches a predetermined height higher than the upper ends of the wafers W and the rectifying plates 60, HF and H are supplied from the first supply unit 21 and the second supply unit 22. ２ O ２ The flow mechanism 30 then operates to suck the etching liquid L1 from the pipe 31 connected to the storage tank 11 and discharge the etching liquid L1 upward from the liquid supply pipe 23, thereby stirring the etching liquid L1 stored in the storage tank 11. The flow of the etching liquid L1 during this stirring is schematically shown by arrows in FIG.

[0037] During this stirring, as during storage, a liquid flow from below to above is formed in the gaps 61, 64, but because the gap 61 is narrow, the flow rate of the liquid flow in the gap 61 is low. The liquid flow flowing from the gap 64 to the gap 61 via the through-hole 63 acts to suppress the flow rate of the liquid flow upward in the gap 61. Therefore, even during this stirring, the pressure that the lower side surface of the precious metal layer M receives from the liquid flow of the etching liquid L1 is suppressed, and detachment of the precious metal layer M from the surface of the wafer W is prevented.

[0038] While the etching solution L1 is stored and stirred in the storage tank 11 as described above, the noble metal layer M immersed in the etching solution L1 causes Mac Etch to proceed on the Si layer W0 on the surface of the wafer W. This etching process will be described with reference to the schematic diagrams of the surface of the wafer W shown in FIGS. 10 to 12. The catalytic action of the noble metal layer M causes the H ２ O ２ is reduced, while the portion of the Si layer W0 on the surface of the wafer W that is in contact with the noble metal layer M is oxidized to form a silicon oxide film W2 (FIG. 10). This silicon oxide film W2 reacts with HF in the etching solution L1 that has penetrated from the periphery of the noble metal layer M to form water-soluble H ２ SiF ６ (hexafluorosilicic acid) and dissolves, and the portion in contact with the noble metal layer M is etched.

[0039] The liquid pressure from the etching solution L1 causes the noble metal layer M to ２ SiF ６The noble metal layer M is pressed against the surface of the new Si layer W0 that appears as a result of etching. The surface of this new Si layer W0 is then oxidized by the series of reactions described above (FIG. 11) and is then further etched. In this way, the noble metal layer M moves in the depth direction of the Si layer W0 while etching the contact portion of the Si layer W0.

[0040] As described above, in Mac Etch, the contact portion of the precious metal layer M with the Si layer W0 is etched, and therefore the adhesion of the precious metal layer M to the wafer W is relatively low. Therefore, when the precious metal layer M is subjected to lateral stress during etching, the precious metal layer M is likely to detach from the wafer W. However, as described above, due to the action of the rectifying plate 60, the pressure that the precious metal layer M receives from the lateral side due to the etching solution L1 flowing along the surface of the wafer W toward the precious metal layer M is relatively small, and therefore, etching proceeds while preventing the precious metal layer M from detaching.

[0041] Although it has been described above that the precious metal layer M is subjected to pressure due to the liquid flow from below, the agitation of the liquid in the storage tank 11 may cause the etching liquid L1 to flow toward the precious metal layer M along the surface of the wafer W from directions other than below, and the side surfaces of the precious metal layer M may be subjected to pressure from the liquid flow. However, the flow rate of such a liquid flow toward the precious metal layer M from directions other than below is also made relatively small by the straightening plate 60, and the pressure is relatively small, so that detachment of the precious metal layer M is prevented.

[0042] 12, when a recess of a predetermined depth is formed by etching, the substrate holder 41 rises to the standby position, the wafer W and the current plate 60 are removed from the storage tank 11, and the etching is completed. The used etching liquid L1 is removed from the storage tank 11.

[0043] As described above, the etching processing apparatus 1 using the rectifying plate 60 can prevent problems such as etching not being able to start or being stopped midway due to the precious metal layer M being detached from the wafer W.

[0044] Instead of using the rectifying plate 60, it is possible to form a recess on the surface of the wafer W and place the precious metal layer M in this recess to protect the precious metal layer M from the flow of the etching solution L1 along the surface of the wafer W. That is, it is possible to start etching by surrounding the precious metal layer M with another film without opening its sides. However, surrounding the precious metal layer M in this way may prevent the etching solution L1 from penetrating the contact area of ​​the precious metal layer M with the Si layer W0, which may result in a problem of preventing etching from progressing. Furthermore, forming such a film surrounding the precious metal layer M is time-consuming. Therefore, the etching processing apparatus 1 using the rectifying plate 60 has the advantage of eliminating the time-consuming process of forming such a film and ensuring reliable etching. However, forming such a film surrounding the precious metal layer M is not prohibited when performing etching using the rectifying plate 60 in the etching processing apparatus 1.

[0045] Incidentally, in the etching processing apparatus 1, in the previously described embodiment, the etching liquid L1 is supplied to and stored in the storage tank 11 after the wafer W and the rectifying plate 60 are carried into the storage tank 11, but the etching liquid L1 may be stored in advance in the storage tank 11. That is, in the previously described embodiment, the liquid level of the etching liquid L1 is raised relative to the wafer W and the rectifying plate 60, but the wafer W and the rectifying plate 60 may be lowered relative to the liquid level of the etching liquid L1. In this case, too, a liquid flow similar to that in the case where the liquid level of the etching liquid L1 is raised relative to the wafer W and the rectifying plate 60 occurs in the gaps 61, 64 and through-holes 63, and detachment of the precious metal layer M is prevented.

[0046] <Modifications> FIGS. 13 to 15 are diagrams showing modified examples of the rectifying plate 60. The arrangement of the through holes 63 of the rectifying plate 60 in the present disclosure is not limited to a lattice-like arrangement. For example, the plan view of the rectifying plate 60 in FIG. 13 shows an example in which the through holes 63 are arranged in multiple rows in both the vertical and horizontal directions, with the through holes 63 in adjacent rows in the vertical direction and the through holes 63 in adjacent rows in the horizontal direction being arranged in a staggered pattern. Three adjacent through holes 63 are located at the vertices of an equilateral triangle. In this case, as in the previously described example, the diameter of the through holes 63 may be approximately 1 mm, and the spacing between adjacent through holes 63 may be approximately 0.8 mm. While the main surface of the rectifying plate 60 is shown as being circular, the shape is not limited to this, and other shapes, such as a square, may also be used.

[0047] 14 shows a longitudinal side view of the flow rectifying plate 60A. The flow rectifying plate 60A differs from the flow rectifying plate 60 in that a plurality of recesses 66 are formed on an opposing surface 62 facing the front surface of the wafer W. The recesses 66 are provided for each through-hole 63, and the through-holes 63 open to the bottom surfaces of the recesses 66. As the etching liquid L1 flows through the gaps 61, as shown by the dashed arrows in the figure, a portion of the etching liquid L1 enters the recesses 66, where the flow direction is changed by the recesses 66 and moves out of the recesses 66. In other words, an obstacle is provided from the perspective of the etching liquid L1 flowing through the gaps 61, thereby further reducing the flow rate of the etching liquid L1.

[0048] 14, the recess 66 has a shape like a cut-out sphere, and the through-hole 63 opens in the center of the recess 66, but the shape of the recess 66 is arbitrary. The positional relationship between the recess 66 and the through-hole 63 is not limited to this example. Instead of the multiple recesses 66, multiple convex portions (projections) may be provided on the opposing surface 62. By making the etching liquid L1 flowing through the gap 61 along the surface of the wafer W collide with the convex portions, the flow rate of the etching liquid L1 can be further reduced.

[0049] Furthermore, although the current plate 60 has through holes 63 formed in a plate-like body, the current plate 60 may have a mesh-like structure formed by weaving linear materials. In such a current plate 60, the through holes 63 are formed in the areas where no linear materials are arranged, and the opposing surface 62 of the current plate 60 has an uneven surface due to the overlapping of the linear materials, thereby increasing the pressure loss of the etching liquid L1 in the gap 61. Furthermore, the liquid flow regulating member is not limited to being plate-shaped like the current plate 60, and may be a block-like member with a relatively large thickness.

[0050] As mentioned above, the flow rectifying plate 60 is provided close to the surface of the wafer W so that the pressure loss of the etching liquid L1 in the gap 61 is increased, and therefore the through hole 63 does not need to be formed as shown in FIG. 15 .

[0051] In the example described above, the drive mechanism 43 provided in the substrate lifting mechanism 40 serves as a moving mechanism for relatively moving the substrate holding part 41 and the storage tank 11, and moves the substrate holding part 41 up and down relative to the storage tank 11 to load and unload the wafer W and the rectifying plate 60 into and out of the storage tank 11. Instead of lifting and unloading the substrate holding part 41 in this way, a lifting mechanism for lifting and unloading the storage tank 11 may be provided as the moving mechanism described above, so that the wafer W and the rectifying plate 60 can be loaded and unloaded into and out of the storage tank 11.

[0052] The noble metal layer M does not have to be provided in contact with the Si layer W0; for example, etching may be performed with a metal layer interposed between the noble metal layer M and the Si layer W0. This metal layer is a metal other than a noble metal, such as titanium. However, since the etching rate decreases when a metal layer is interposed in this manner, it is preferable to provide the noble metal layer M so that it is in contact with the Si layer W0 to be etched. Furthermore, the etching target is not limited to the Si layer; for example, a layer other than a Si layer, such as germanium, gallium arsenide, gallium nitride, or silicon carbide, may also be etched.

[0053] 16 is a side view of an etching processing apparatus 1A, which is a modified example of the etching processing apparatus 1. In this etching processing apparatus 1A, a support portion 71 is provided that supports the peripheral edge of each current rectifying plate 60 from above, and the support portion 71 is attached to an elevating mechanism 72. The elevating mechanism 72 moves each current rectifying plate 60 in and out of the storage tank 11, and the current rectifying plate 60 is positioned outside the storage tank 11 so as not to interfere with the loading and unloading of the wafer W held by the substrate holding portion 41. When etching is performed, the current rectifying plate 60 is positioned inside the storage tank 11. As shown as an example of this etching processing apparatus 1A, the current rectifying plate 60 is not limited to being mounted on the substrate holding portion 41.

[0054] 16 , when the wafer W is held by the substrate holder 41, the precious metal layer M is located on a portion of the upper side of the wafer W. The rectifying plate 60 is formed in a semicircular shape so as to overlap only the upper side of the wafer W. As described above, the rectifying plate 60 only needs to face the formation region on the wafer W surface where the precious metal layer M is formed and the periphery of the formation region, and is not limited to a configuration in which it overlaps the entire surface of the wafer W. In other words, the regulated region on the wafer W surface where the liquid flow regulating member faces and regulates the liquid flow includes the formation region on the wafer W surface where the precious metal layer M is formed and the periphery of the formation region, and is not limited to the entire surface of the wafer W. Note that, regarding the rectifying plate 60 facing the regulated region, the portion of the rectifying plate 60 facing the regulated region may include a through-hole 63.

[0055] 16 , when the rectifying plate 60 faces only a portion of the surface of the wafer W, it is necessary to hold the wafer W in a specific orientation on the substrate holder 41 so that the precious metal layer M does not move away from the position facing the rectifying plate 60. For this reason, it is preferable to configure the rectifying plate 60 to face the entire surface of the wafer W, as shown in FIG.

[0056] The substrate holder 41 is not limited to holding a plurality of wafers W, but may be configured to hold only one wafer W. Furthermore, it is not limited to holding the wafer W in an upright position, but may be held in an inclined or horizontal position. Furthermore, the substrate to be etched is not limited to the wafer W, but may be a substrate (dummy substrate) for setting parameters of the device that is not intended for manufacturing semiconductor products.

[0057] <Configuration of Substrate Processing Apparatus> Next, the configuration of an example of a substrate processing system 100 in which the etching processing apparatus 1 of the present disclosure is incorporated as an etching apparatus 81 will be described with reference to the plan view of Fig. 17. Fig. 17 is a schematic plan view illustrating the substrate processing system 100. As shown in Fig. 17, the substrate processing system 100 includes a carrier load / unload unit 2, a lot formation unit 3, a lot placement unit 4, a lot transport unit 5, a lot processing unit 6, and the control device 7, which is the control unit described above.

[0058] The carrier loading / unloading section 2 includes a carrier stage 51, a carrier transport mechanism 52, carrier stocks 53 and 54, and a carrier mounting table 55. The carrier stage 51 mounts a plurality of carriers C transported from outside. The carriers C are, for example, front-opening unified pods (FOUPs), which are containers that accommodate a plurality of sets (e.g., 25 sets) of wafers W arranged vertically in a horizontal position, as described above. The rectifying plate 60 is stored in a carrier C that is separate from the carrier C that stores the wafers W. The carrier transport mechanism 52 transports the carriers C between the carrier stage 51, the carrier stocks 53 and 54, and the carrier mounting table 55. A substrate transport mechanism 56, which will be described later, transfers the wafers W and the rectifying plate 60 to the carriers C mounted on the carrier mounting table 55.

[0059] The lot formation unit 3 has a substrate transfer mechanism 56 and forms lots. Specifically, forming a lot involves removing wafers W to be collectively processed in the substrate processing system 100 from a carrier C and arranging and holding them on the lot mounting unit 4 waiting in the waiting area 50 within the substrate processing system 100. The wafers W collectively processed in this manner constitute one lot. One lot may include, for example, 25 wafers W housed in the same carrier C. The substrate transfer mechanism 56 also removes rectifying plates 60 from the carrier C and arranging and holding them on the lot mounting unit 4. The lot mounting unit 4 corresponds to the substrate holder 41 and the connection unit 42 described above. Therefore, as described with reference to FIGS. 1 to 4 , the wafers W and the rectifying plates 60 are alternately arranged in a line, and each wafer W faces the same direction.

[0060] The lot transport section 5 has a lot transport mechanism 74, which transports the lot mounting section 4 between the waiting area 50 and the lot processing section 6. The lot transport mechanism 74 includes rails 75, a movable body 76 that moves along the rails 75, and a holder 77. The holder 77 is provided on the movable body 76 and is configured to be able to detachably hold the lot mounting section 4.

[0061] The lot processing unit 6 collectively performs etching, cleaning, drying, and other processes on one lot of wafers W held on the lot mounting unit 4. Hereinafter, one lot of wafers W and the rectifying plate 60 may be simply referred to as a "lot." The lot processing unit 6 is provided with one etching device 81, four DIW supply devices 82a to 82d (sometimes collectively referred to as the DIW supply device 82), a pre-cleaning device 83, a post-cleaning device 84, and a drying device 85. Specifically, these are arranged in the following order along the rail 75: DIW supply device 82a, pre-cleaning device 83, DIW supply device 82b, etching device 81, DIW supply device 82c, post-cleaning device 84, DIW supply device 82d, and drying device 85, and the lot transport unit 5 transports and processes the lot mounting unit 4 in this order. That is, in the lot processing section 6, processing is performed in the following order: pre-wetting by supplying DIW (De-Ionized Water) → pre-cleaning → rinsing by supplying DIW → etching → rinsing by supplying DIW → post-cleaning → rinsing by supplying DIW → drying.

[0062] Each of the devices 82-84 has the same configuration as the etching processing device 1 (etching device 81), except that the processing liquid stored in the storage tank 11 is different from the etching liquid L1, and is configured to perform processing in the same procedure as that in the etching processing device 1. That is, each process from the pre-wet process to the rinse process after post-cleaning is performed by transferring the lot mounting unit 4 to each of the storage tanks 11 of the devices 81-84 in the order described above, and immersing the wafer W and the flow rectifying plate 60 together with the lot mounting unit 4 in the processing liquid in each storage tank 11. Each of the devices 81-84 also includes a drive mechanism 43, as shown in FIG. 3 and other figures. This drive mechanism 43 can transfer the lot mounting unit 4 to and from the holder 77, and raises and lowers the received lot mounting unit 4 as described above to load and unload it from and into the storage tank 11.

[0063] The processing liquid in the DIW supply device 82 is DIW. The processing liquid (cleaning liquid) in the pre-cleaning device 83 is, for example, nitric acid (HNO ３The processing liquid (cleaning liquid) of the post-cleaning unit 84 is, for example, a nitric acid-based chemical liquid, which is more concentrated than the nitric acid-based chemical liquid of the pre-cleaning unit 83. After the series of liquid processes is completed, the drying unit 85 supplies gas to the lot mounting unit 4 to dry the wafers W and the rectifying plate 60. After the drying process, the lot mounting unit 4 is transferred to the waiting area 50, and the wafers W and the rectifying plate 60 are transferred to the carrier C. The number of units of each unit 81 to 85 is not limited to the example shown in FIG. 1.

[0064] The control device 7 controls the operation of each part of the substrate processing system 100 (such as the carrier loading / unloading part 2, the lot formation part 3, the lot placement part 4, the lot transport part 5, and the lot processing part 6). The control device 7 outputs control signals based on signals from switches, various sensors, and the like, to control the operation of each part of the substrate processing system 100. The control device 7 includes a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), input / output ports, and various other circuits. The control device 7 controls the operation of each part of the substrate processing system 100 by, for example, reading and executing a program stored in a storage part 7a included therein.

[0065] As described above, before etching in the etching apparatus 81, the wafer W is processed in the DIW supply apparatus 82 and the pre-cleaning apparatus 83. Even during processing in these apparatuses, the flow rectifying plate 60 is disposed close to the wafer W, as in the etching apparatus 81, to reduce the speed of the processing liquid flowing along the surface of the wafer W. This prevents the precious metal layer M from being detached from the wafer W before etching due to the liquid pressure of the processing liquid in each apparatus. For example, a processing liquid having some solubility in the precious metal layer M may be used in the pre-cleaning apparatus 83. In this case, the processing liquid may penetrate into the minute gaps between the precious metal layer M and the Si layer W0, slightly dissolving the precious metal layer M and reducing the adhesion between the precious metal layer M and the Si layer W0. In such cases, it is particularly effective to reduce the flow speed of the processing liquid using the flow rectifying plate 60, as described above.

[0066] In the substrate processing system 100 of the present disclosure, the rectifying plate 60 is carried into the apparatus from a carrier C, but this is not limiting. For example, a plurality of rectifying plates 60 may be pre-arranged in positions within the substrate processing system 100 accessible by the substrate transport mechanism 56. That is, a mounting section for the rectifying plate 60 may be provided within the substrate processing system 100, and the rectifying plate 60 may be transferred between the mounting section and the lot mounting section 4 in the waiting area 50 by the substrate transport mechanism 56. Furthermore, the rectifying plate 60 is not limited to being shared by the apparatuses 81 to 84 as in the example shown above, and may be provided for each of the apparatuses 81 to 84 together with the lifting mechanism 72 and support section 71 shown in FIG. 16 .

[0067] (Evaluation Test) A test was conducted to verify the relationship between the width H1 of the gap 61 on the front side of the wafer W and the width H2 of the gap 64 on the back side of the wafer W, as described in FIG. 4 , which is effective in suppressing the liquid flow on the front side of the wafer W. In this test, the supply of the etching liquid L1 was started simultaneously from one side of the gaps 61 and 64 to the other side, and it was observed whether there was a difference in the leading edge position of the liquid flow toward the other side between the gaps 61 and 64. The ratio of H1 to H2 was changed by changing the position of the flow rectifier 60 between adjacent wafers W, and the leading edge position of the liquid flow was observed for each ratio. The specific settings of the ratio of H1 to H2 were H2:H1 = 1:0.5, 1:0.8, 1:1.0, and 1:1.3. The flow rectifier 60 used was made entirely of fluororesin, and the contact angle of the surface of the flow rectifier 60 with respect to the etching liquid L1 was 90° or more.

[0068] As a result of this evaluation test, when H2:H1 = 1:0.5 and 1:0.8, the tip position of the liquid flow in gap 61 was closer to one side of each gap 61, 64 (the etching liquid supply side) than the tip position of the liquid flow in gap 64, which was a preferable result. When H2:H1 = 1:1.0 and 1:1.3, no difference in tip position was observed, as was the case when H2:H1 = 1:0.5 and 1:0.8. From this evaluation test, it was found that, as already mentioned, it is preferable to make H1 < H2 in order to suppress the liquid flow along the surface of the wafer W. It was also shown that it is more preferable to make H1 / H2 = 0.8 or less.

[0069] L1 Etching solution M Noble metal layer W Substrate 11 Reservoir 41 Substrate holder 43 Driving mechanism 60, 60A Rectifying plate

Claims

1. A liquid processing apparatus comprising: a substrate holding unit that holds a substrate having a surface on which a precious metal layer that acts as a catalyst for etching the substrate when the substrate is immersed in an etching solution is formed; a storage tank that stores a processing solution for processing the substrate; a movement mechanism that moves the substrate holding unit and the storage tank relatively to each other to move the substrate held by the substrate holding unit inside and outside the storage tank; and a liquid flow regulation member that faces a regulation area in the storage tank to regulate the flow of the processing solution in a regulation area that includes the area on the surface of the substrate where the precious metal layer is formed and the outer periphery of the formation area.

2. A liquid processing apparatus according to claim 1, wherein said liquid flow regulating member has a plurality of openings on the surface of said substrate, each opening having a through-hole that faces said substrate.

3. A liquid processing apparatus according to claim 2, further comprising a flow mechanism for causing the processing liquid in the storage tank to flow, and the liquid flow regulating member regulates the flow of the processing liquid toward the regulating area due to the flow.

4. A liquid processing apparatus as described in claim 3, wherein the movement mechanism moves the liquid flow regulating member, facing the regulating area, together with the substrate into the storage tank in which the processing liquid is stored, and the liquid flow regulating member regulates the flow of the processing liquid relative to the regulating area due to the relative movement.

5. The liquid processing apparatus according to claim 2, wherein the contact angle of the processing liquid on the surface of the liquid flow regulating member facing the regulating area is 90° or more.

6. A liquid treatment apparatus according to claim 5, wherein the surface of said liquid flow regulating member facing said regulating area is made of fluororesin.

7. A liquid processing apparatus according to claim 1, wherein the surface of said liquid flow regulating member does not contain metal.

8. The liquid processing apparatus according to claim 2, wherein a plurality of recesses or protrusions are provided on the surface of said liquid flow regulating member that faces the surface of said substrate.

9. A liquid processing apparatus as described in claim 1, wherein the substrate holding section holds a plurality of substrates so that they form rows spaced apart and overlap each other when viewed in the direction of the rows, and the liquid flow control member is a plate-like member provided for each substrate and arranged alternately with the substrates in the direction of the rows of substrates, facing the substrates.

10. A liquid processing apparatus according to claim 9, wherein the liquid flow regulating member located between the rear surface of the one substrate and the front surface of the other substrate is located closer to the front surface of the other substrate than the rear surface of the one substrate.

11. A liquid processing apparatus according to claim 9, wherein the liquid flow regulating member is held by the substrate holder.

12. The liquid processing apparatus according to claim 1, wherein the side surfaces of said noble metal layer are exposed.

13. The liquid treatment apparatus according to claim 1, wherein said noble metal layer is made of gold, silver, platinum or ruthenium.

14. The liquid processing apparatus according to claim 1, wherein the processing liquid is the etching liquid or a cleaning liquid for cleaning the substrate as a pre-processing before the etching.

15. A liquid processing method comprising the steps of: holding a substrate, on a substrate holding section, the substrate having a precious metal layer formed on its surface which acts as a catalyst for etching the substrate when the substrate is immersed in an etching liquid; storing a processing liquid for processing the substrate in a storage tank; moving the substrate holding section and the storage tank relatively using a movement mechanism to move the substrate held by the substrate holding section inside and outside the storage tank; and regulating the flow of the processing liquid in a regulated region within the storage tank using a liquid flow regulating member facing the regulated region including the formation region of the precious metal layer on the surface of the substrate and the outer periphery of the formation region.

16. A liquid processing apparatus comprising: a substrate holding section for holding a substrate having a precious metal layer formed on its surface which serves as a catalyst for etching the substrate when the substrate is immersed in an etching solution; a storage tank for storing a processing solution for processing the substrate; and a movement mechanism for relatively moving the substrate holding section and the storage tank to move the substrate held by the substrate holding section inside and outside the storage tank, wherein the liquid flow control member faces the regulation area in the storage tank to control the flow of the processing solution in a regulation area including the area where the precious metal layer is formed on the surface of the substrate and the outer periphery of the formation area.

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