JP7467264B2 - Substrate processing apparatus, substrate processing method and nozzle - Google Patents

Description

The present disclosure relates to a substrate processing apparatus, a substrate processing method, and a nozzle.

In recent years, as semiconductor devices have become increasingly miniaturized and three-dimensional, there is a demand for improving the processing accuracy of etching when processing semiconductor devices. As one method for improving the processing accuracy of etching, a technology has been developed in which a hard mask for dry etching is formed on a substrate by plating.

Specifically, a plating solution is prepared by mixing liquid A, which contains a metal, with liquid B, which contains a reducing agent, and this plating solution is then heated to a predetermined plating temperature. This temperature-controlled plating solution is supplied to a substrate, thereby forming a hard mask consisting of a plating layer on the substrate. A dry etching process is then performed on the substrate on which the hard mask has been formed, and the parts of the substrate that are not covered by the hard mask are etched. The hard mask is then removed by wet cleaning.

JP 2009-249679 A

This disclosure provides a technology that can supply a plating solution formed by mixing liquid A, which contains metal ions, and liquid B, which contains a reducing agent, to a substrate in a short time after mixing.

One embodiment of the substrate processing apparatus includes an A liquid supply unit that supplies an A liquid containing metal ions, a B liquid supply unit that supplies a B liquid containing a reducing agent, a mixing unit that mixes the A liquid supplied from the A liquid supply unit with the B liquid supplied from the B liquid supply unit to generate a plating solution, and a nozzle block that includes the mixing unit therein and has a discharge unit that discharges the plating solution generated in the mixing unit onto the substrate.

According to the present disclosure, plating solution can be supplied to a substrate in a short time after mixing liquid A and liquid B.

1 is a cross-sectional view of a substrate processing system according to an embodiment of the substrate processing apparatus. 2 is a vertical sectional view showing a configuration example of a processing unit included in the substrate processing system of FIG. 1. 3 is a vertical cross-sectional view showing one configuration example of a nozzle included in the processing unit of FIG. 2, showing the nozzle located at a home position together with peripheral components. FIG. 4A to 4C are diagrams illustrating the operation of the nozzle shown in FIG. 3 . 4A to 4C are diagrams illustrating the operation of the nozzle shown in FIG. 3 . 4A to 4C are diagrams illustrating the operation of the nozzle shown in FIG. 3 . 4A to 4C are diagrams illustrating the operation of the nozzle shown in FIG. 3 . 4A to 4C are diagrams illustrating the operation of the nozzle shown in FIG. 3 . 4A to 4C are diagrams illustrating the operation of the nozzle shown in FIG. 3 . 4A to 4C are diagrams illustrating the operation of the nozzle shown in FIG. 3 .

Below, one embodiment of a substrate processing apparatus (substrate processing system) will be described with reference to the attached drawings.

Figure 1 is a diagram showing a schematic configuration of a substrate processing system according to one embodiment. In the following, to clarify the positional relationships, mutually orthogonal X-axis, Y-axis, and Z-axis are defined, and the positive direction of the Z-axis is defined as the vertical upward direction.

As shown in FIG. 1, the substrate processing system 1 includes a loading/unloading station 2 and a processing station 3. The loading/unloading station 2 and the processing station 3 are provided adjacent to each other.

The loading/unloading station 2 includes a carrier placement section 11 and a transport section 12. On the carrier placement section 11, multiple carriers C are placed, each of which holds multiple substrates, in this embodiment, semiconductor wafers (hereinafter referred to as wafers W), in a horizontal position.

The transfer section 12 is provided adjacent to the carrier placement section 11, and includes a substrate transfer device 13 and a transfer section 14. The substrate transfer device 13 includes a wafer holding mechanism that holds the wafer W. The substrate transfer device 13 is capable of moving horizontally and vertically and rotating about a vertical axis, and transfers the wafer W between the carrier C and the transfer section 14 using the wafer holding mechanism.

The processing station 3 is provided adjacent to the transport section 12. The processing station 3 includes a transport section 15 and a plurality of processing units 16. The plurality of processing units 16 are arranged side by side on both sides of the transport section 15.

The transfer section 15 has a substrate transfer device 17 therein. The substrate transfer device 17 has a wafer holding mechanism that holds the wafer W. The substrate transfer device 17 can move horizontally and vertically and rotate around a vertical axis, and uses the wafer holding mechanism to transfer the wafer W between the delivery section 14 and the processing unit 16.

The processing unit 16 performs a predetermined substrate processing on the wafer W transported by the substrate transport device 17.

The substrate processing system 1 also includes a control device 4. The control device 4 is, for example, a computer, and includes a control unit 18 and a memory unit 19. The memory unit 19 stores programs that control the various processes executed in the substrate processing system 1. The control unit 18 controls the operation of the substrate processing system 1 by reading and executing the programs stored in the memory unit 19.

The program may be recorded on a computer-readable storage medium and installed from that storage medium into the storage unit 19 of the control device 4. Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 in the loading/unloading station 2 removes the wafer W from the carrier C placed on the carrier placement section 11, and places the removed wafer W on the transfer section 14. The wafer W placed on the transfer section 14 is removed from the transfer section 14 by the substrate transfer device 17 in the processing station 3, and is transferred to the processing unit 16.

The wafer W carried into the processing unit 16 is processed by the processing unit 16, and then carried out of the processing unit 16 by the substrate transfer device 17 and placed on the delivery section 14.
Then, the processed wafer W placed on the transfer section 14 is returned to the carrier C on the carrier placement section 11 by the substrate transfer device 13 .

Next, the configuration of one embodiment of the processing unit 16 will be described with reference to FIG. 2. The processing unit 16 is configured as a single-wafer plating processing device.

The processing unit 16 is configured to perform a series of liquid processes, including electroless plating, pre-processing, and post-processing, on the wafer W. The electroless plating process is performed, for example, for the purpose of forming a buried wiring layer on the wafer W, such as a semiconductor wafer, or forming a hard mask for dry etching.

The processing unit 16 includes a chamber 51, a spin chuck 52 disposed within the chamber 51, and a plating solution supply section 61 that supplies plating solution to the wafer W held by the spin chuck 52.

The spin chuck 52 has a turntable 522 that is rotated around a vertical axis via a rotation shaft 521 by a rotation drive unit 524, and a chuck unit 523 provided on the periphery of the turntable 522. The wafer W is clamped to the chuck unit 523 and held horizontally at a slight distance from the upper surface of the turntable 522. As the spin chuck 52, instead of the mechanical chuck type described above, a so-called vacuum chuck type that vacuum-adsorbs the back surface of the wafer W can be used.

The plating solution supply unit 61 has a nozzle 70 that ejects plating solution M onto the wafer W, an A-liquid supply unit 61a that supplies A-liquid as a raw material liquid for plating solution M to the nozzle 70, and a B-liquid supply unit 61b that supplies B-liquid as a raw material liquid for plating solution M to the nozzle 70. As auxiliary components, the plating solution supply unit 61 has a cleaning solution supply unit 61r that supplies a cleaning solution to the nozzle 70, and an N2 gas supply unit 61n that supplies N2 gas (nitrogen gas) to the nozzle 70.

The A liquid supply unit 61a includes an A liquid supply source 611a and an A liquid supply line 613a with flow control devices (which means on-off valves, flow control valves, flow meters, etc.; the same applies below) 612a, which are shown diagrammatically in the figure. The A liquid supply source 611a may be a tank that stores A liquid. A liquid is supplied to the nozzle 70 from the A liquid supply source 611a at a flow rate controlled by the flow control devices 612a provided on the A liquid supply line 613a.

The B liquid supply unit 61b includes a B liquid supply source 611b and a B liquid supply line 613b with flow control devices 612b, which are shown in a schematic manner in the figure. The B liquid supply source 611b may be a tank for storing B liquid. The B liquid supply source 611b supplies B liquid to the nozzle 70 at a flow rate controlled by the flow control devices 612b provided on the B liquid supply line 613b.

Liquid A is formed by mixing metal ions in a complexed form, a complexing agent, a pH adjuster, additives, etc. When preparing Liquid A, it is necessary to precisely control the mixing ratio of the above components. For this reason, Liquid A is prepared in advance in a relatively large tank. Liquid B is a reducing agent. By mixing Liquid B with Liquid A, the reaction between Liquid A and Liquid B gradually progresses and precipitation begins (the plating solution is activated). By heating the mixture of Liquid A and Liquid B to a temperature of, for example, about 60 to 95°C (varies depending on the material), activation progresses further, and the state becomes one in which electroless plating can be performed at a sufficient precipitation speed. In this state, it is preferable to supply plating solution M to the wafer W.

After mixing liquid A and liquid B, precipitation progresses over time, so the mixed liquid (plating liquid M) cannot be stored for a long period of time. For this reason, it is desirable to use the mixed liquid promptly after mixing. As will be explained in detail later, in this embodiment, liquid A and liquid B are mixed inside nozzle 70 immediately before being discharged onto wafer W.

The plating solution M obtained by mixing the A and B solutions is a plating solution for autocatalytic (reducing) electroless plating. The plating solution M contains metal ions such as cobalt (Co) ions, nickel (Ni) ions, and tungsten (W) ions, and reducing agents such as hypophosphorous acid and dimethylamine borane. In autocatalytic (reducing) electroless plating, the metal ions in the plating solution M are reduced by electrons released in the oxidation reaction of the reducing agent in the plating solution M, and are precipitated as metal to form a metal film (plating film). The plating solution M may contain additives, etc.

Metal films (plating layers) produced by plating using plating solution M include, for example, CoB, CoP, CoWP, CoWB, CoWBP, NiWB, NiB, NiWP, and NiWBP. The P in the metal film (plating layer) is derived from a reducing agent containing P (e.g., hypophosphorous acid), and the B in the plating film is derived from a reducing agent containing B (e.g., dimethylamine borane).

The cleaning liquid supply unit 61r includes a cleaning liquid supply source 611r and a cleaning liquid supply line 613r with flow control devices 612r, which are shown in a schematic diagram in the figure. The cleaning liquid supply source 611r may be a tank that stores the cleaning liquid. The cleaning liquid is supplied to the nozzle 70 from the cleaning liquid supply source 611r at a flow rate controlled by the flow control devices 612r provided in the cleaning liquid supply line 613r.

The cleaning liquid is for cleaning the nozzle 70, and examples of the cleaning liquid include a rinse liquid such as DIW, malic acid, hydrochloric acid, SPM (sulfuric acid/hydrogen peroxide), and SC1 (ammonia/hydrogen peroxide). When multiple types of cleaning liquid are used, multiple cleaning liquid supply sources 611r and multiple cleaning liquid supply lines 613r can be provided.

The N2 gas supply unit 61n includes an N2 gas supply source 611n and an N2 gas supply line 613n with flow control devices 612n, which are shown in the figure. The N2 gas supply source 611n may be a factory utility of a semiconductor manufacturing factory. N2 gas is supplied to the nozzle 70 from the N2 gas supply source 611n at a flow rate controlled by the flow control devices 612n provided on the N2 gas supply line 613n. The gas supplied to the nozzle 70 is not limited to N2 gas, and other inert gases may be used.

The nozzle 70 is connected to the nozzle movement mechanism 54. The nozzle movement mechanism 54 has an arm 541 that carries the nozzle 70 at its tip, and a pivoting and lifting mechanism 543 that pivots the arm 541 about a vertical axis and raises and lowers it. The nozzle movement mechanism 54 can move the nozzle 70 between a position above the center of the wafer W held by the spin chuck 52 and a position above the periphery of the wafer W. The nozzle movement mechanism 54 can also move the nozzle 70 to a standby position (home position) that is horizontally outside the cup 57.

The nozzle movement mechanism 54 may be configured to translate the nozzle 70 in a horizontal direction.

The processing unit 16 is further provided with a catalyst liquid supply section (catalyst application section) 55a, a cleaning liquid supply section 55b, and a rinsing liquid supply section 55c, which respectively supply a catalyst liquid K1, a cleaning liquid K2, and a rinsing liquid K3 to the wafer W held on the spin chuck 52.

The catalyst liquid supply unit (catalyst application unit) 55a includes a nozzle 551a that ejects catalyst liquid K1 onto the wafer W held by the spin chuck 52, and a catalyst liquid supply source 552a that supplies catalyst liquid K1 to the nozzle 551a. The catalyst liquid supply source 552a may be a tank that stores catalyst liquid K1. The catalyst liquid K1 is supplied to the nozzle 551a from the catalyst liquid supply source 552a through a supply line 554a in which flow control devices 553a, which are shown diagrammatically in the figure, are interposed.

The cleaning liquid supply unit 55b includes a nozzle 551b that ejects cleaning liquid K2 onto the wafer W held by the spin chuck 52, and a cleaning liquid supply source 552b that supplies cleaning liquid K2 to the nozzle 551b. The cleaning liquid supply source 552b may be a tank that stores cleaning liquid K2. The cleaning liquid K2 is supplied to the nozzle 551b from the cleaning liquid supply source 552b through a supply line 554b in which flow control devices 553b, which are shown diagrammatically in the figure, are interposed.

The rinse liquid supply unit 55c includes a nozzle 551c that ejects rinse liquid K3 onto the wafer W held on the spin chuck 52, and a rinse liquid supply source 552c that supplies rinse liquid K3 to the nozzle 551c. The rinse liquid supply source 552c may be a tank that stores rinse liquid K3. Rinse liquid K3 is supplied to the nozzle 551c from the rinse liquid supply source 552c through a supply line 554c in which flow control devices 553c, which are shown diagrammatically in the figure, are interposed.

The catalytic solution K1 contains metal ions that have catalytic activity against the oxidation reaction of the reducing agent in the plating solution M. In electroless plating, in order for the deposition of metal ions in the plating solution M to begin, it is necessary for the initial film surface (i.e., the surface of the substrate to be plated) to have sufficient catalytic activity against the oxidation reaction of the reducing agent in the plating solution M. Examples of such catalysts include those containing iron group elements (Fe, Co, Ni), platinum group elements (Ru, Rh, Pd, Os, Ir, Pt), Cu, Ag, or Au. The formation of a metal film having catalytic activity occurs through a substitution reaction. In the substitution reaction, the material that constitutes the surface to be plated of the wafer W becomes a reducing agent, and the metal ions (e.g., Pd ions) in the catalytic solution K1 are reduced and precipitated on the surface to be plated of the substrate.

Examples of cleaning solution K2 that can be used include organic acids such as formic acid, malic acid, succinic acid, citric acid, and malonic acid, and hydrofluoric acid (DHF) (aqueous solution of hydrogen fluoride) diluted to a concentration that does not corrode the surface of the substrate to be plated.

As the rinse liquid K3, for example, deionized water (DIW) can be used.

The processing unit 16 has a nozzle moving mechanism 56 that drives the nozzles 551a to 551c. The nozzle moving mechanism 56 has a nozzle arm 561 equipped with a nozzle holding part 562 that carries the nozzles 551a to 551c at its tip, and a rotating and lifting mechanism 563 that rotates the nozzle arm 561 around a vertical axis and raises and lowers it. The nozzle moving mechanism 56 can move the nozzles 551a to 551c between a position above the center of the wafer W held by the spin chuck 52 and a position above the periphery of the wafer W, and can also move them to a standby position (home position) outside the cup 57 described later in a plan view. In the illustrated embodiment, the nozzles 551a to 551c are held by a common arm, but they may be held by separate arms and moved independently. The nozzle moving mechanism 54 may be configured to translate the nozzles 551a to 551c.

A cup 57 is arranged around the spin chuck 52. The cup 57 receives various processing liquids (e.g., plating liquid, cleaning liquid, rinsing liquid, etc.) that have splashed from the wafer W and discharges them outside the chamber 51. The cup 57 has a lifting mechanism 58 that drives the cup 57 in the vertical direction. By changing the height position of the cup 57, the discharge destination of the liquid that has splashed from the wafer W can be changed.

Next, the configuration of the nozzle 70 will be described with reference to Figures 3 to 7.

Figure 3 shows the nozzle 70 in the home position. A dummy dispense port (also called a "drain bath") 80 and a heating device 82 are provided near the nozzle 70 in the home position. The dummy dispense port 80 may have a switching mechanism 81 that switches the discharge destination depending on the type of liquid received from the nozzle 70.

The nozzle 70 has a nozzle block (nozzle body) 71. The nozzle block 71 can be formed, for example, into a generally cubic shape overall. A generally spherical mixing chamber (mixing section) 72 is formed within the nozzle block 71. By making the mixing chamber 72 spherical, the possibility of the nozzle block 71 being damaged by a pressure increase within the mixing chamber 72 can be reduced. Furthermore, by making the mixing chamber 72 spherical, cleaning of the mixing chamber 72 becomes easier. Another advantage of making the mixing chamber 72 spherical is that thermal convection is smooth, making it easier for liquid A and liquid B to mix.

The nozzle block 71 is provided with an A liquid port 71a, a B liquid port 71b, a cleaning liquid port 71r, an N2 gas (nitrogen gas) port 71n, a discharge port (nozzle outlet) 71d, and a discharge port 71e, which are connected to the mixing chamber 72.

The A liquid supply line 613a is connected to the A liquid port 71a. The A liquid supply line 613a is connected to a drain line 711a for draining the liquid from the A liquid supply line 613a. On-off valves 614a and 712a are provided on the A liquid supply line 613a and the drain line 711a, respectively. The on-off valve 614a is one of the flow adjustment devices 612a mentioned above.

The B liquid port 71b is connected to a B liquid supply line 613b. A drain line 711b is connected to the B liquid supply line 613b to drain the liquid from the B liquid supply line 613b. Opening and closing valves 614b and 712b are provided on the B liquid supply line 613b and the drain line 711b, respectively. The opening and closing valve 614b is one of the flow control devices 612b mentioned above.

A cleaning liquid supply line 613r is connected to the cleaning liquid port 71r. A drain line 711r is connected to the cleaning liquid supply line 613r to drain the liquid from the cleaning liquid supply line 613r. Open/close valves 614r, 712r are provided on the cleaning liquid supply line 613r and the drain line 711r, respectively. The open/close valve 614r is one of the flow adjustment devices 612r mentioned above. Examples of cleaning liquids include malic acid, hydrochloric acid, SC1 (ammonia hydrogen peroxide), and DIW (pure water).

As the cleaning liquid, SPM (sulfuric acid/hydrogen peroxide) may be supplied to the mixing chamber 72. In this case, preferably, a cleaning liquid port 71s having a configuration similar to that of the cleaning liquid port 71r is provided in the nozzle block 71, and SPM is supplied at a controlled flow rate through an SPM supply line having flow control devices interposed therein.

The SPM may be supplied to an A liquid tank (not shown) that adjusts the A liquid. The SPM can also be used to clean the A liquid tank. The A liquid supply line 613a and the mixing chamber 72 can also be cleaned by supplying SPM from the A liquid tank (611a) to the A liquid port 71a via the A liquid supply line 613a.

An N2 gas supply line 613n is connected to the N2 gas port 71n. An on-off valve 614n is provided in the N2 gas supply line 613n. The on-off valve 614n is one of the flow control devices 612n described above.

The discharge port 71d, i.e., the discharge portion, is provided to discharge the plating solution M generated in the mixing chamber 72 onto the wafer W. The discharge port 71d is provided at the bottom of the mixing chamber 72.

The discharge port 71e is connected to a discharge line 711e. The discharge line 711e branches into a depressurization line 712e and a drainage line 713e. The depressurization line 712e is provided with a relief valve 714e. The drainage line 713e is provided with an on-off valve 715e.

The on-off valve 715e is opened, for example, when discharging liquid such as cleaning liquid from the mixing chamber 72 during cleaning of the nozzle 70. The relief valve 714e is provided to prevent the nozzle block 71 from being damaged when the pressure in the mixing chamber 72 becomes excessive.

The discharge port 71e is preferably provided at the top of the mixing chamber 72. This allows the gas in the mixing chamber 72 to be discharged reliably regardless of the liquid level in the mixing chamber 72. In addition, this prevents the inner wall surface of the mixing chamber 72 from being left unwashed during cleaning.

By appropriately setting the inner diameter of the discharge port 71e (the inner diameter of the outlet of the discharge port 71e) while taking into consideration the surface tension of the liquid (plating liquid) filling the mixing chamber 72, it is possible to prevent the liquid from dripping from the discharge port 71e even when a predetermined liquid level is present in the mixing chamber 72. However, an opening/closing valve may be provided in the discharge port 71e, or a cap for opening and closing the discharge port 71e may be provided.

When liquid (such as liquid A) is fed into the mixing chamber 72, the internal pressure of the mixing chamber 72 may rise, making it difficult to feed the liquid into the mixing chamber 72. In this case, it is necessary to depressurize the mixing chamber 72. Depressurization can be achieved by opening the on-off valve 715e. Alternatively, if the set pressure of the relief valve 714e is variable, the set pressure when supplying liquid to the mixing chamber 72 (a low value that allows liquid supply) and the set pressure when heating the liquid in the mixing chamber 72 (a high value intended to prevent damage to the nozzle block 71) may be changed.

A circulation pump 90 (e.g., a revitro pump) may be provided to promote the mixing of the liquids (particularly the mixing of liquid A and liquid B) in the mixing chamber 72. In this case, an inlet port 91 and an outlet port 92 are provided in the mixing chamber 72, and the circulation pump 90 is interposed in a circulation line 93 connecting the inlet port 91 and the outlet port 92. The inlet port 91 and the outlet port 92 may be configured in the same manner as the above-mentioned ports 71a, 71b, 71r, etc. It is preferable that the inlet port 91 and the outlet port 92 are provided at positions sufficiently apart from each other so that no dead water area is created in the mixing chamber 72.

The dummy dispense port 80 is located directly below the discharge port 71d of the nozzle 70 located in the home position, and is configured to receive the liquid discharged from the nozzle 70 and discharge it into the factory wastewater system.

The heating device 82 is a lamp, for example an infrared lamp, and is positioned in a position suitable for heating the lower half of the nozzle 70 located at the home position. In the illustrated example, the lower corners of the nozzle block 71, which is formed in a roughly cubic shape, are chamfered to form a surface 74 facing diagonally downward, and the heating device 82 is positioned so that infrared rays are incident on the surface 74 roughly vertically. The heating device 82 irradiates light with a wavelength that can efficiently heat the material of the nozzle block 71 (for example, graphite, Ni, Al).

If the nozzle block 71 is made of a material (e.g., glass) that transmits the heating light from the heating device 82, a material that absorbs the heating light well and generates heat may be attached to the surface of the face 74. Alternatively, a material that absorbs the heating light well and generates heat may be embedded in the area between the face 74 of the nozzle block 71 and the mixing chamber 72. The heating device 82 may directly heat the liquid (i.e., the plating solution) in the mixing chamber 72. In this case, a heating device 82 may be provided that irradiates light with a wavelength that can directly and efficiently heat the plating solution.

The liquid in the nozzle block 71 or the mixing chamber 72 may be heated by a heater, for example, a resistance heater 83. The resistance heater 83 may be provided on the outer surface of the nozzle block 71, or may be embedded in the nozzle block 71. By providing a heating device in the nozzle block 71 in this manner, it becomes easier to maintain the plating liquid at a desired temperature even when the nozzle 70 is away from the home position. A resistance heater may be provided around the discharge port 71d. If the nozzle block 71 has sufficient heat retention, it is not necessary to provide a heater in the nozzle block 71.

In the mixing chamber 72 of the nozzle 70, plating solution M is produced using liquids A and B as raw materials each time a wafer W is processed. Below, with reference to Figures 4 to 10, the procedure of one cycle executed by the nozzle 70 each time a wafer W is processed will be described. Note that in Figures 4 to 5 and 7 to 10, the on-off valves painted black are in a closed state, and the on-off valves not painted black are in an open state. Although the relief valve 714e is not painted black, it is of course always closed under normal circumstances and opens only when the pressure in the mixing chamber 72 exceeds a threshold value. Also, in Figures 4 to 5 and 7 to 10, the thick arrows indicate the fluid flowing at that time.

When the series of steps shown in Figures 4 to 10 are performed, the supply flow rates of the various fluids (liquids and gases) supplied to the mixing chamber 72 are automatically controlled according to the conditions defined in the process recipe by the on-off valves 614a, 614b, 614r, 614n and flow control valves (not shown) included in the flow control devices 612a, 612b, 612r, 612n.

[Bath make-up (plating solution production) process]
First, a predetermined amount of liquid A is supplied into the mixing chamber 72 through the liquid A port 71a (FIG. 4), and then a predetermined amount of liquid B is supplied into the mixing chamber 72 through the liquid B port 71b (FIG. 5). The mixing ratio of liquid A to liquid B is, for example, about 10:1 (not limited to this). Liquid A and liquid B are mixed together only by mutual diffusion, but mixing is also promoted by convection, which will be described later.

When the supply of B liquid is completed, the liquid level Lv of the mixture of A liquid and B liquid in the mixing chamber 72 is, for example, as shown in FIG. 5, lower than the height positions at which the A liquid port 71a, the B liquid port 71b, the cleaning liquid port 71r, the N2 gas port 71n, and the exhaust port 71e open into the mixing chamber 72. In order to achieve such a liquid level Lv, it is preferable that the mixing chamber 72 has an internal volume slightly larger than the amount of plating liquid (e.g., about 100 to 200 ml) used in one processing of one wafer W.

The outlet of the A liquid port 71a into the mixing chamber 72 is located at a position higher than the liquid level Lv described above. Therefore, even if air bubbles are mixed into the A liquid flowing through the A liquid supply line 613a, there is a low possibility that such air bubbles will dissolve in the liquid in the mixing chamber 72, and there is also an advantage in that there is a low possibility that the liquid mixed with air bubbles will be discharged from the discharge port 71d onto the wafer W.

In addition, air bubbles may be mixed into Liquid A when it passes through a filter (not shown) installed in Liquid A supply line 613a, or may be generated when gas dissolved in Liquid A precipitates due to pressure fluctuations (reduced pressure) in Liquid A. Air bubbles can also be generated in other liquids due to the same principle.

In the illustrated example, the outlet of the B liquid port 71b into the mixing chamber 72 opens into the lower region of the mixing chamber 72. Therefore, the B liquid that flows into the lower part of the mixing chamber 72 moves along with the convection current (described later) generated by the heating of the nozzle block 71, promoting the mixing of the A liquid and the B liquid. If a circulation pump 90 is connected to the nozzle 70 or a stirrer is installed in the mixing chamber 72, the outlet of the B liquid port 71b into the mixing chamber 72 may be set at the same height as the outlet of the A liquid supply line 613a. This reduces the possibility of air bubbles caused by the B liquid.

It is also preferable to provide a liquid B port 71b so that liquid B is discharged into the mixing chamber 72 in a generally tangential direction of the sphere (mixing chamber 72) in a plan view (see FIG. 6). In this case, as shown by the arrow in FIG. 6, liquid B flows in a swirling manner along the wall surface of the mixing chamber 72, promoting mixing of liquid B with liquid A. If a circulation pump 90 is provided as described above, it is also preferable to operate the circulation pump 90 to promote mixing. To promote mixing, a stirrer such as a magnetic stirrer (not shown) may be placed in the mixing chamber 72.

In order to promote mixing of liquid A and liquid B in the mixing chamber 72, unevenness (not shown) may be provided on the inner wall of the mixing chamber 72. By providing such unevenness, turbulence is generated in liquid B when liquid B is injected into the mixing chamber 72, promoting mixing. In addition, when the mixed liquid M of liquid A and liquid B undergoes convection due to heat, the flow of the mixed liquid becomes uneven, promoting mixing.

Next, as shown in FIG. 7, the nozzle 70 is heated by the heater 82, and the mixture of A and B liquids, i.e., the plating liquid M, is heated to a predetermined temperature. At this time, if a circulation pump 90 is provided, the circulation pump 90 is operated to equalize the temperature of the plating liquid M in the mixing chamber 72. The temperature of the plating liquid M in the mixing chamber 72 can also be equalized by operating the stirrer. Note that by heating the lower half of the nozzle 70 by the heater 82, convection of the liquid (see arrow CV) occurs in the mixing chamber 72, promoting the mixing of A and B liquids and equalizing the liquid temperature in the mixing chamber 72.

When the temperature of the plating solution M in the mixing chamber 72 rises, the pressure in the mixing chamber 72 rises due to the generation of steam, etc. If the pressure rises excessively, the relief valve 714e opens to prevent damage to the nozzle block 71. The opening/closing valve 715e is closed at all times except during cleaning, which will be described later.

[Plating solution discharge process]
When the temperature of the plating solution M in the mixing chamber 72 is stabilized at a desired temperature, the nozzle 70 is moved directly above the center of the wafer W, and the plating solution M is discharged from the discharge port (nozzle outlet) 71d onto the wafer W. At this time, the on-off valve 614n is preferably opened while the on-off valves 614a, 712a, 715e, 614r, 712r, 614b, and 712b are closed (see FIG. 8). As a result, N2 gas is fed into the mixing chamber 72, and the plating solution M is pushed out from the discharge port 71d by the pressure of the N2 gas.

In addition, since the outlet of the N2 gas port 71n into the mixing chamber 72 is above the liquid level Lv, the plating solution M is not bubbled by the N2 gas.

When the plating solution M has been discharged onto one wafer W, the plating solution M in the mixing chamber 72 will be almost empty. At this time, in order to prevent bubbles from forming in the plating solution M being discharged, a small amount of plating solution M may be left at the bottom of the mixing chamber 72 when the plating solution M has been discharged onto one wafer W.

[Cleaning process]
After the discharge of the plating solution M onto the wafer W is completed, the nozzle 70 is moved to the home position, and the nozzle 70 is cleaned. At the beginning of this cleaning step, N2 gas may be supplied into the mixing chamber 72 (with each valve in the same state as in the plating solution discharge step) to discharge all the liquid in the mixing chamber 72 from the discharge port 71d to the dummy dispense port 80.

As shown in FIG. 9, the on-off valve 614r is opened while the on-off valve 712r is closed, and cleaning liquid is supplied into the mixing chamber 72. The cleaning liquid is supplied until the mixing chamber 72 is completely filled. At this time, the on-off valve 715e may be opened to further supply cleaning liquid into the mixing chamber 72, and the cleaning liquid may be discharged through the discharge line 711e and the drainage line 713e, thereby cleaning the discharge line 711e and the drainage line 713e.

Next, while the on-off valves 712r and 614r are closed, the on-off valve 614n is opened to supply N2 gas to the mixing chamber 72, and all of the cleaning liquid in the mixing chamber 72 is discharged from the mixing chamber 72 to the dummy dispense port 80 (see FIG. 10). The above operation may be repeated multiple times.

The above cleaning may be performed using multiple types of cleaning solutions. For example, cleaning may be performed first using malic acid and then using pure water.

If it is desired to avoid A liquid or plating solution M remaining in the A liquid port 71a and the piping nearby, the mixing chamber 72 may be completely filled with cleaning solution, and then N2 gas may be supplied to the mixing chamber 72 with the on-off valve 614a closed and the on-off valve 712a open, causing the cleaning solution to flow into the A liquid supply line 613a and the drain line 711a to clean these piping. The B liquid port 71b and the piping nearby may also be cleaned in the same manner.

This completes one cycle of operation related to the nozzle 70.

Next, a series of liquid processes related to the plating process performed in the processing unit 16 will be briefly described. The plating process can be performed, for example, for the purpose of forming an embedded wiring layer in a wafer W such as a semiconductor wafer, or for the purpose of forming a hard mask for dry etching. The process described below is automatically performed according to a process recipe under the control of the control device 4.

First, the wafer W is loaded into the processing unit 16 and held on the spin chuck 52.

Next, the wafer W starts to rotate. The nozzle 551b of the cleaning liquid supply unit 55b is positioned directly above the center of the wafer W, and the cleaning liquid K2 is supplied to the wafer W from the nozzle 551b, thereby removing contaminants adhering to the wafer W from the wafer W.

In addition, liquid that is supplied to the rotating wafer W and then scattered outside the wafer W due to centrifugal force is discharged via cup 57. The height of cup 57 is changed according to the type of liquid supplied to the wafer W, and the liquid is discharged to a different location outside cup 57 for each height of cup 57.

Next, while continuing to rotate the wafer W, rinsing liquid K3 is supplied to the wafer W from nozzle 551c of the rinsing liquid supply unit 55c located directly above the center of the wafer W, thereby subjecting the wafer W to a rinsing process that washes away the cleaning liquid K2 and reaction products on the substrate.

Next, while continuing to rotate the wafer W, catalyst solution K1 is supplied from the nozzle 551a of the catalyst solution supply unit 55a located directly above the center of the wafer W, thereby selectively applying a catalyst (metal film having catalytic activity) to the plateable material portions of the wafer W. Substantially no catalyst is applied to the non-platable material portions of the wafer W.

An example of a material that constitutes the non-platable material portion is a material containing _SiO2 as a main component.

The materials that make up the plateable material portion are:
(1) A material containing at least one of an OCHx group and an NHx group (e.g., SiOCH, SiN);
(2) Metallic materials mainly composed of Si-based materials (e.g., Poly-Si, Poly-Si, Si doped with B or P), and (3) Materials mainly composed of catalytic metallic materials (Cu, Pt).
Examples include:

Examples of metals with catalytic activity include iron group elements (Fe, Co, Ni), platinum group elements (Ru, Rh, Pd, Os, Ir, Pt), Cu, Ag, Au, etc. Each of the above metals has a high adsorption to the materials that make up the plateable material parts, but is less adsorbed to the materials that make up the non-platable material parts.

Next, while continuing to rotate the wafer W, rinsing liquid K3 is supplied to the wafer W from nozzle 551c of rinsing liquid supply unit 55c located directly above the center of the wafer W, thereby subjecting the wafer W to a rinsing process for washing away excess catalyst liquid K1 and the like from the substrate. After the rinsing process is completed, nozzle 551c (and nozzles 551a, 551b) are returned to the home position (standby position).

Next, the nozzle 70, which was in the home position, is moved directly above the center of the wafer W. Inside the nozzle 70, the plating solution M has been prepared and the temperature adjusted as described above. While the wafer W continues to rotate, the plating solution M is supplied to the wafer W from the nozzle 70 (see FIG. 8). After the plating solution M is supplied to the wafer W, the rotation of the wafer W may be slowed down or stopped. By continuing this state for a predetermined period of time, the plating metal is selectively deposited only on the plateable material portions to which the catalyst (metal film having catalytic activity) has been applied. When the plating process is completed, the nozzle 70 is returned to the home position.

During the period from the time when the supply of plating solution M from the nozzle 70 to one wafer W ends to the time when the supply of plating solution M from the nozzle 70 to the next wafer W begins, the above-mentioned cleaning of the nozzle 70 and preparation of plating solution M in the nozzle 70 (mixing of solution A and solution B, heating, etc.) are carried out.

After the plating process is completed, the nozzle 551b of the cleaning liquid supply unit 55b, which was in the home position, moves to directly above the center of the wafer W, and while the wafer W is rotating, the nozzle 551b supplies cleaning liquid K2 to the wafer W, thereby removing any abnormal plating film, reaction by-products, etc. adhering to the wafer W from the wafer W.

Next, while continuing to rotate the wafer W, rinsing liquid K3 is supplied to the wafer W from nozzle 551c of rinsing liquid supply unit 55c located directly above the center of the wafer W. This washes away the cleaning liquid K2 and reaction products on the substrate.

Next, the wafer W is rotated at high speed to shake off and dry the substrate. This completes the series of liquid processes related to the plating process. The processed wafer W is then removed from the processing unit 16.

According to the above embodiment, it is possible to eliminate components that occupy a large surface area/volume for preparing the liquid, such as a mixing tank for liquid A and liquid B, and therefore it is possible to make the entire plating processing system extremely compact. In addition, the number of parts is reduced, so the manufacturing cost of the plating processing system can be significantly reduced.

In addition, according to the above embodiment, since plating solution M is prepared in an amount sufficient to supply one wafer W at a time, waste of expensive plating solution can be minimized when the operation of the plating processing system is stopped due to an unexpected equipment trouble or the like. In considering the above effect, it should be noted that in conventional devices in which liquid A and liquid B are mixed in advance and stored in a tank and then supplied from this tank to the nozzle, plating solution must be discarded a long time after mixing. The amount of plating solution M generated at one time in the mixing chamber 72 may be an amount sufficient to supply a small number of wafers W (e.g., 2 to 3 wafers).

In addition, according to the above embodiment, the total surface area of the parts that come into contact with the plating solution is smaller than in conventional devices, making cleaning easy and inexpensive.

When preparing solution A, precise adjustment of each component is required, necessitating tank construction, but there are no such restrictions for solution B, and the mixing precision of solutions A and B does not require the same level of precision as when preparing solution A. For this reason, the performance of the plating solution M prepared in this embodiment is comparable to that prepared using conventional equipment.

The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

The substrates processed by the plating system are not limited to semiconductor wafers, but may be various substrates used in the field of semiconductor device manufacturing, such as glass substrates and ceramic substrates.

The nozzle 70 can be used for mixing and discharging any two or more types of raw material liquids, not limited to plating liquids.

61a (611a, 612a, 613a) A liquid supply section 61b (611b, 612b, 613b) B liquid supply section 71 nozzle block 71d discharge section 72 mixing section

Claims (12)

a liquid A supply unit for supplying a liquid A containing metal ions;
a B liquid supply unit that supplies a B liquid containing a reducing agent;
a mixing section in which the A liquid supplied from the A liquid supply section and the B liquid supplied from the B liquid supply section are mixed to generate a plating solution;
a nozzle block including the mixing section therein and having a discharge section that discharges the plating solution generated in the mixing section onto a substrate;
A substrate holder for holding a substrate;
a nozzle arm that moves the nozzle block between a processing position above the substrate held by the substrate holding part and a standby position retracted from above the substrate;
a heating section for heating the plating solution in the mixing section;
Equipped with
The heating unit is provided to be located near the nozzle block in the standby position. The substrate processing apparatus according to claim 1 , wherein the heating section is provided to heat the nozzle block corresponding to a lower region of the mixing section. The mixing section has a spherical internal space formed in the nozzle block,
3 . The substrate processing apparatus according to claim 1 , wherein the liquid B supply unit is connected to the mixing unit such that the liquid B flows into the mixing unit along a spherical inner wall surface that defines the spherical internal space. The substrate processing apparatus according to claim 3 , wherein the nozzle block has a first supply port for supplying the liquid A to the mixing portion, and a second supply port for supplying the liquid B to the mixing portion. a liquid A supply unit for supplying a liquid A containing metal ions;
a B liquid supply unit that supplies a B liquid containing a reducing agent;
a mixing section in which the A liquid supplied from the A liquid supply section and the B liquid supplied from the B liquid supply section are mixed to generate a plating solution;
a nozzle block including the mixing section therein and having a discharge section that discharges the plating solution generated in the mixing section onto a substrate;
Equipped with
The mixing section has a spherical internal space formed in the nozzle block,
The substrate processing apparatus, wherein the liquid B supply unit is connected to the mixing unit such that the liquid B flows into the mixing unit along a spherical inner wall surface that defines the spherical internal space. The substrate processing apparatus according to claim 5 , wherein the nozzle block has a first supply port for supplying liquid A to the mixing portion, and a second supply port for supplying liquid B to the mixing portion. A substrate holder for holding a substrate;
a nozzle arm that moves the nozzle block between a processing position above the substrate held by the substrate holding part and a standby position retracted from above the substrate;
The substrate processing apparatus of claim 5 , further comprising: The substrate processing apparatus according to claim 5 , further comprising a heating section that heats the plating solution in the mixing section. The substrate processing apparatus according to claim 8 , wherein the heating section is provided to heat the nozzle block corresponding to a lower region of the mixing section. The substrate processing apparatus according to claim 8 , wherein the heating unit is built in the nozzle block. a liquid A supply unit for supplying a liquid A containing metal ions;
a B liquid supply unit that supplies a B liquid containing a reducing agent;
a mixing section in which the A liquid supplied from the A liquid supply section and the B liquid supplied from the B liquid supply section are mixed to generate a plating solution;
a nozzle block including the mixing section therein and having a discharge section that discharges the plating solution generated in the mixing section onto a substrate;
A substrate holder for holding a substrate;
a nozzle arm that moves the nozzle block between a processing position above the substrate held by the substrate holding part and a standby position retracted from above the substrate;
a heating section for heating the plating solution in the mixing section;
Equipped with
a heating unit provided in a vicinity of the nozzle block in the standby position, the heating unit being disposed in the vicinity of the nozzle block in the standby position;
positioning the nozzle block at the standby position by the nozzle arm;
preparing the plating solution by mixing the liquid A and the liquid B in the mixing section of the nozzle block at the standby position, and heating the prepared plating solution to a predetermined temperature by the heating section;
positioning the nozzle block at the processing position by the nozzle arm, and supplying a plating solution from a discharge portion of the nozzle block to the substrate held by the substrate holding portion;
A substrate processing method comprising: a liquid A supply unit for supplying a liquid A containing metal ions;
a B liquid supply unit that supplies a B liquid containing a reducing agent;
a mixing section in which the A liquid supplied from the A liquid supply section and the B liquid supplied from the B liquid supply section are mixed to generate a plating solution;
a nozzle block including the mixing section therein and having a discharge section that discharges the plating solution generated in the mixing section onto a substrate;
Equipped with
The mixing section has a spherical internal space formed in the nozzle block,
a substrate processing method performed by using a substrate processing apparatus , the substrate processing apparatus including: a liquid B supply unit connected to a mixing unit such that the liquid B flows into the mixing unit along a spherical inner wall surface that defines an internal space of the spherical substrate , the method comprising:
a plating solution for plating a substrate by mixing the A liquid and the B liquid in the mixing section and then discharging the plating solution from the discharge section of the nozzle block toward the substrate, thereby plating the substrate.

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