JP7345401B2 - Substrate processing method and substrate processing apparatus - Google Patents

Description

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

2. Description of the Related Art Conventionally, an etching process for etching a film formed on a substrate such as a semiconductor wafer has been known as one of the semiconductor manufacturing processes.

Patent Document 1 discloses a technique for etching a laminated film including a molybdenum film using an etching solution containing phosphoric acid, nitrate, organic acid, and water.

Japanese Patent Application Publication No. 2008-300618

The present disclosure provides a technique for etching a laminated film including a molybdenum film, which can reduce variations in etching amount in the lamination direction.

A substrate processing method according to one aspect of the present disclosure includes a step of supplying a first etching solution and a step of supplying a second etching solution. The step of supplying the first etching solution includes applying the first etching solution containing an oxidizing agent, a catalyst, and a moisture regulating agent, in which the proportion of the moisture regulating agent is larger than the total proportion of the oxidizing agent and the catalyst, to a lamination layer containing a molybdenum film. Supply the substrate with the film. In the step of supplying the second etching solution, after supplying the first etching solution to the substrate, the second etching solution containing a higher proportion of a moisture conditioner than the first etching solution is supplied to the substrate.

According to the present disclosure, in a technique for etching a laminated film including a molybdenum film, variations in the amount of etching in the lamination direction can be reduced.

FIG. 1 is an explanatory diagram of substrate processing according to the embodiment. FIG. 2 is an explanatory diagram of substrate processing according to the embodiment. FIG. 3 is an explanatory diagram of substrate processing according to the embodiment. FIG. 4 is a graph showing changes in the amount of etching at each position of the molybdenum film when the water percentage of the etching solution is changed. FIG. 5 is a diagram showing the configuration of the substrate processing apparatus according to the embodiment. FIG. 6 is a diagram showing the configuration of the first processing tank according to the embodiment. FIG. 7 is a diagram showing the configuration of the second processing tank according to the embodiment. FIG. 8 is a flowchart showing the procedure of processing executed by the substrate processing apparatus according to the embodiment. FIG. 9 is a diagram illustrating a configuration example of a processing unit according to a modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments (hereinafter referred to as "embodiments") for implementing a substrate processing method and a substrate processing apparatus according to the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to this embodiment. Moreover, each embodiment can be combined as appropriate within the range that does not conflict with the processing contents. Further, in each of the embodiments below, the same parts are given the same reference numerals, and redundant explanations will be omitted.

In addition, in order to make the explanation easier to understand, each of the drawings referred to below shows an orthogonal coordinate system in which the X-axis direction, Y-axis direction, and Z-axis direction that are orthogonal to each other are defined, and the positive Z-axis direction is the vertically upward direction. There are cases. Further, the direction of rotation about the vertical axis is sometimes referred to as the θ direction.

In addition, in the embodiments described below, expressions such as "constant", "orthogonal", "perpendicular", or "parallel" may be used, but these expressions strictly do not mean "constant", "orthogonal", "parallel", etc. They do not need to be "perpendicular" or "parallel". That is, each of the above expressions allows deviations in manufacturing accuracy, installation accuracy, etc.

<About substrate processing>
First, the contents of substrate processing according to the embodiment will be explained with reference to FIGS. 1 to 3. 1 to 3 are explanatory diagrams of substrate processing according to the embodiment.

As shown in FIG. 1, the substrate processing according to the embodiment includes, for example, etching a semiconductor wafer (hereinafter referred to as wafer W) in which a molybdenum film 11 and a silicon oxide film 12 are formed on a polysilicon film 10. . The silicon oxide films 12 are formed in multiple layers on the polysilicon film 10 at intervals, and the molybdenum film 11 is formed to cover these silicon oxide films 12.

In this way, the wafer W to be subjected to substrate processing has a laminated film in which molybdenum films 11 and silicon oxide films 12 are alternately laminated. 11. Note that the wafer W may be a laminated film including at least the molybdenum film 11, and the structure of the laminated film is not particularly limited to the example shown in FIG.

Further, a plurality of grooves 15 are formed in the wafer W, through which an etching solution enters and etches the stacked molybdenum films 11.

In the substrate processing according to the embodiment, the end face of the silicon oxide film 12 facing the groove 15 is exposed by etching the molybdenum film 11, as shown in FIG. Thereafter, the molybdenum film 11 is further etched to expose the upper and lower surfaces of the ends of the silicon oxide film 12, as shown in FIG.

The higher the aspect ratio of the grooves 15, and the thinner (fine) the thickness of each layer in the laminated film, the greater the variation in the amount of etching in the lamination direction of the molybdenum film 11 (the depth direction of the grooves 15). . Specifically, the bottom, which is closer to the bottom of the groove 15, is less likely to be etched than the top, which is closer to the opening of the groove 15.

On the other hand, the inventors of the present invention have found that by reducing the proportion of water in the etching solution, variations in the amount of etching in the stacking direction of the molybdenum film 11 can be suppressed. FIG. 4 is a graph showing changes in the amount of etching at each position (top, middle, bottom) of the molybdenum film 11 when the water content of the etching solution is changed.

The processing conditions for the experimental results shown in FIG. 4 are as follows.
Treatment process: immersion in etching solution (etching treatment), then immersion in DIW (deionized water) (rinsing treatment), then drying treatment using dry gas Etching solution: phosphoric acid (H ₃ PO ₄ ), Mixture of nitric acid (HNO ₃ ) and acetic acid (CH ₃ COOH) Etching solution temperature: Room temperature (23°C)
Immersion time of wafer W: 240 seconds when the moisture content is 2.0 wt% or more and less than 3.5 wt%, 120 seconds when it is 3.5 wt% or more and less than 6.0 wt%

In the graph shown in FIG. 4, the circular plot indicates the result for the molybdenum film 11 (top) located near the opening of the groove 15 among the plurality of laminated molybdenum films 11. Moreover, the plot shown by the rectangle shows the result for the molybdenum film 11 (bottom) located near the bottom of the groove 15 among the plurality of laminated molybdenum films 11. Further, the plot indicated by a triangle indicates the result for the molybdenum film 11 (middle) located at the center in the depth direction among the plurality of stacked molybdenum films 11.

As shown in FIG. 4, the difference between the top etching amount and the bottom etching amount became smaller as the water percentage of the etching solution decreased. This result shows that by reducing the water content of the etching solution, variations in the amount of etching in the stacking direction of the molybdenum film 11 can be suppressed.

The experimental results can be considered, for example, as follows. That is, the etching mechanism of the molybdenum film 11 proceeds as follows. First, as shown in chemical reaction formula (1), nitric acid (HNO ₃ ) in the etching solution is ionized to generate hydrogen ions (H ⁺ ) and nitrate ions (NO ₃ ⁻ ).

HNO ₃ →H ⁺ +NO ₃ ^-... (1)

Subsequently, as shown in chemical reaction formula (2), nitrate ions (NO ₃ ⁻ ) react with molybdenum to generate molybdenum oxide (MoO ₃ ).

Mo+3NO ₃ ^- →MoO ₃ +3NO ₂ ^-... (2)

Subsequently, as shown in chemical reaction formula (3), phosphoric acid (H ₃ PO ₄ ) in the etching solution functions as a catalyst to ionize molybdenum oxide (MoO ₃ ). This produces molybdate ions (MoO ₄ ²⁻ ). In other words, the molybdenum film 11 is dissolved (etched).

MoO ₃ +H ₃ PO ₄ +H ₂ O→MoO ₄ ^2- +H ₃ PO ₄ +2H ⁺ ... (3)

Further, as shown in chemical reaction formula (4), a portion of molybdate ions (MoO ₄ ²⁻ ) reacts with hydrogen ions (H ⁺ ). This also dissolves (etches) the molybdenum film 11.

MoO4 ^2- +H ⁺ →HMoO ^4-... (4)

In this way, the etching of the molybdenum film 11 progresses as molybdenum oxide (MoO ₃ ) reacts with water (H ₂ O). Therefore, the higher the water content in the etching solution, the faster the etching rate of the molybdenum film 11 becomes. Conversely, the lower the water content is, the slower the etching speed of the molybdenum film 11 becomes.

As the etching of the molybdenum film 11 progresses, the molybdenum concentration in the etching solution increases. This increase in molybdenum concentration is particularly noticeable within the grooves 15.

The etching liquid in the groove 15 is replaced with the etching liquid present outside the groove 15. However, when the moisture content in the etching solution is high, that is, when the etching rate of the molybdenum film 11 is high, the etching solution cannot be replaced in time, and the etching solution with a high molybdenum concentration is deposited inside the groove 15, especially near the bottom of the groove 15. There is a risk that it may remain.

As a result, a concentration gradient of molybdenum in the etching solution occurs in the depth direction of the groove 15, and the amount of etching of the molybdenum film 11 located near the bottom of the groove 15 is different from that of the molybdenum film 11 located near the opening of the groove 15. The amount is smaller than the amount of etching. As a result, the amount of etching of the molybdenum film 11 varies in the stacking direction.

On the other hand, when the water content of the etching solution is reduced, the etching rate of the molybdenum film 11 is reduced. As a result, the increase in molybdenum concentration within the groove 15 becomes gradual, so that the etching solution within the groove 15 can be replaced in time. As a result, it is thought that the variation in the amount of etching of the molybdenum film 11 in the stacking direction is reduced compared to the case where the amount of water in the etching solution is large.

Therefore, based on the results shown in FIG. 4, in the substrate processing according to the embodiment, it was decided to etch the molybdenum film 11 using an etching solution with a low water content.

The etching solution according to the embodiment is a chemical solution containing an oxidizing agent, a catalyst, and a moisture regulator.

As the oxidizing agent, in addition to the above-mentioned nitric acid (HNO ₃ ), for example, sulfuric acid (H ₂ SO ₄ ), hydrogen peroxide (H ₂ O ₂ ), etc. can be used. Further, the oxidizing agent may include two or three of sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ), and hydrogen peroxide (H ₂ O ₂ ). For example, the oxidizing agent may be SPM containing sulfuric acid (H ₂ SO ₄ ) and hydrogen peroxide (H ₂ O ₂ ). Thus, the oxidizing agent may be selected from at least one of sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ) and hydrogen peroxide (H ₂ O ₂ ).

As the catalyst, in addition to the above-mentioned phosphoric acid (H ₃ PO ₄ ), for example, glycols such as ethylene glycol, propylene glycol, and diethylene glycol can be used.

Preferably, the moisture conditioner is a substance that is substantially free of moisture. As such a moisture regulator, for example, an organic acid or an organic solvent can be used. The organic acid may be selected from at least one of, for example, acetic acid, methanesulfonic acid, paratoluenesulfonic acid, phthalic acid, succinic acid, maleic acid, malonic acid, oxalic acid, propionic acid and orthoperiodic acid. Further, the organic solvent may be selected from at least one of glycols such as ethylene glycol, propylene glycol and diethylene glycol, propylene carbonate, and IPA (isopropyl alcohol).

In the etching solution according to the embodiment, the oxidizing agent, the catalyst, and the moisture regulating agent are mixed so that the proportion of the moisture regulating agent to the entire etching solution is larger than the total proportion of the oxidizing agent and the catalyst. be done.

Specifically, as is clear from the experimental results shown in FIG. 4, when the water content of the etching solution is 2.2 wt% or less, the variation in the amount of etching in the depth direction of the molybdenum film 11 is almost eliminated. Recognize. From this result, it is preferable that the water content of the etching solution is 2.2 wt% or less. By making the proportion of the moisture regulator to the entire etching liquid larger than the total proportion of the oxidizing agent and the catalyst, it is possible to make the water proportion of the etching liquid 2.2 wt % or less.

[Substrate processing equipment configuration]
Next, the configuration of a substrate processing apparatus that performs the above-described substrate processing will be described with reference to FIG. 5. FIG. 5 is a diagram showing the configuration of the substrate processing apparatus according to the embodiment.

As shown in FIG. 5, the substrate processing apparatus 1 according to the embodiment includes a carrier loading/unloading section 2, a lot forming section 3, a lot mounting section 4, a lot transport section 5, a lot processing section 6, and a control section 2. 7.

The carrier loading/unloading unit 2 includes a carrier stage 20 , a carrier transport mechanism 21 , carrier stocks 22 and 23 , and a carrier mounting table 24 .

The carrier stage 20 places a plurality of carriers 9 transported from the outside. The carrier 9 is a container that accommodates a plurality of (for example, 25) semiconductor wafers (hereinafter referred to as wafers W) arranged vertically in a horizontal position. The carrier transport mechanism 21 transports the carrier 9 between the carrier stage 20, carrier stocks 22, 23, and carrier mounting table 24.

From the carrier 9 placed on the carrier mounting table 24, a plurality of wafers W before being processed are carried out to the lot processing section 6 by a substrate transport mechanism 30, which will be described later. Further, a plurality of processed wafers W are carried from the lot processing section 6 by the substrate transport mechanism 30 onto the carrier 9 placed on the carrier mounting table 24 .

The lot forming section 3 has a substrate transport mechanism 30 and forms lots. A lot is composed of a plurality of wafers W (for example, 50 wafers) that are processed simultaneously by combining wafers W accommodated in one or more carriers 9. A plurality of wafers W forming one lot are arranged at regular intervals with their plate surfaces facing each other.

The substrate transport mechanism 30 transports a plurality of wafers W between the carrier 9 placed on the carrier mounting table 24 and the lot mounting section 4 .

The lot placement section 4 has a lot conveyance table 40, and temporarily places (standby) the lot that is conveyed between the lot forming section 3 and the lot processing section 6 by the lot conveyance section 5. The lot conveyance table 40 includes an inlet lot loading table 41 on which a lot formed in the lot forming section 3 before being processed is placed, and an unloading lot loading table 41 on which a lot processed in the lot processing section 6 is placed. 42. A plurality of wafers W for one lot are placed on the loading-side lot mounting table 41 and the carrying-out side lot mounting table 42 in an upright position.

The lot transport section 5 includes a lot transport mechanism 50 and transports lots between the lot placement section 4 and the lot processing section 6 or inside the lot processing section 6 . The lot transport mechanism 50 includes a rail 51, a moving body 52, and a substrate holder 53.

The rail 51 is arranged along the X-axis direction across the lot placement section 4 and the lot processing section 6. The moving body 52 is configured to be movable along the rail 51 while holding a plurality of wafers W. The substrate holder 53 is provided on the movable body 52 and holds a plurality of wafers W lined up one after the other in an upright position.

The lot processing unit 6 performs etching processing, cleaning processing, drying processing, etc. on a plurality of wafers W for one lot. In the lot processing section 6 , a first etching processing device 60 , a second etching processing device 70 , a substrate holder cleaning processing device 80 , and a drying processing device 90 are provided side by side along the rail 51 .

The first etching processing apparatus 60 and the second etching processing apparatus 70 collectively perform etching processing on a plurality of wafers W corresponding to one lot. The substrate holder cleaning processing device 80 performs a cleaning process on the substrate holder 53. The drying processing apparatus 90 performs drying processing on a plurality of wafers W for one lot at once. The numbers of the first etching processing apparatus 60, the second etching processing apparatus 70, the substrate holder cleaning processing apparatus 80, and the drying processing apparatus 90 are not limited to the example shown in FIG.

The first etching processing apparatus 60 includes a processing tank 61 for first etching processing (hereinafter referred to as "first processing tank 61"), a processing tank 62 for rinsing processing, and substrate lifting mechanisms 63 and 64. Be prepared. The second etching processing apparatus 70 also includes a processing tank 71 for second etching processing (hereinafter referred to as "second processing tank 71"), a processing tank 72 for rinsing processing, and substrate lifting mechanisms 73 and 74. Equipped with. The first etching processing apparatus 60 and the second etching processing apparatus 70 have the same configuration, but use different etching solutions. This point will be discussed later.

The processing tanks 61 and 71 can accommodate one lot of wafers W, and store an etching solution. Specifically, the processing tanks 61 and 71 store etching solutions having different amounts of water. Details of the processing tanks 61 and 71 will be described later.

The treatment tanks 62 and 72 store a treatment liquid for rinsing (deionized water, etc.). The substrate elevating mechanisms 63, 64, 73, and 74 hold a plurality of wafers W forming a lot in an upright position and arranged one behind the other.

The first etching processing apparatus 60 and the second etching processing apparatus 70 hold the lots transported by the lot transporting section 5 using substrate lifting mechanisms 63 and 73, and perform etching processing by immersing them in etching liquid in processing tanks 61 and 71. conduct. In addition, the first etching processing apparatus 60 and the second etching processing apparatus 70 hold the lots transferred to the processing tanks 62 and 72 by the lot transfer unit 5 using substrate lifting mechanisms 64 and 74, and The rinsing process is performed by immersing it in a rinsing liquid.

The drying processing apparatus 90 includes a processing tank 91 and a substrate lifting mechanism 92. A processing gas for drying processing is supplied to the processing tank 91 . The substrate elevating mechanism 92 holds a plurality of wafers W for one lot in an upright position, lined up one after the other.

The drying processing apparatus 90 holds the lot transported by the lot transporting section 5 with a substrate lifting mechanism 92, and performs a drying process using a processing gas for drying processing supplied into a processing tank 91. The lot that has been dried in the processing tank 91 is transported to the lot mounting section 4 by the lot transport section 5.

The substrate holder cleaning processing apparatus 80 performs a cleaning process on the substrate holder 53 by supplying a cleaning processing liquid to the substrate holder 53 of the lot transport mechanism 50 and further supplying dry gas.

The control section 7 controls the operation of each section of the substrate processing apparatus 1 (carrier loading/unloading section 2, lot forming section 3, lot mounting section 4, lot transport section 5, lot processing section 6, etc.). The control section 7 controls the operation of each section of the substrate processing apparatus 1 based on signals from switches, various sensors, and the like.

The control unit 7 includes a microcomputer and various circuits having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input/output port, etc., and a program stored in a storage unit (not shown). The operation of the substrate processing apparatus 1 is controlled by reading and executing the . The control unit 7 has a computer-readable storage medium 8 . The storage medium 8 stores the above programs that control various processes executed in the substrate processing apparatus 1. The program may have been stored in the computer-readable storage medium 8, or may have been installed in the storage medium 8 of the control unit 7 from another storage medium.

Examples of the computer-readable storage medium 8 include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), and a memory card.

[Processing tank configuration]
Next, the configurations of the first processing tank 61 used in the first etching process and the second processing tank 71 used in the second etching process will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram showing the configuration of the first processing tank 61 according to the embodiment. Moreover, FIG. 7 is a diagram showing the configuration of the second processing tank 71 according to the embodiment.

As shown in FIG. 6, the first processing tank 61 performs a first etching process to etch the molybdenum film 11 formed on the wafer W by immersing one lot of wafers W in a first etching solution. .

The first processing tank 61 includes an inner tank 100 and an outer tank 110. Further, the first processing tank 61 includes a circulation section 120, a first etching liquid supply section 130, and an individual supply section 140.

The inner tank 100 is open at the top and stores the first etching solution therein. A lot (a plurality of wafers W) is immersed in such an inner tank 100.

The outer tank 110 is open at the top and is arranged around the upper part of the inner tank 100. The first etching solution overflowing from the inner tank 100 flows into the outer tank 110 .

The circulation unit 120 circulates the first etching solution between the inner tank 100 and the outer tank 110. The circulation section 120 includes a circulation path 121, a nozzle 122, a pump 123, a filter 124, and a temperature adjustment section 125.

Circulation path 121 connects outer tank 110 and inner tank 100. One end of the circulation path 121 is connected to the outer tank 110 , and the other end of the circulation path 121 is connected to a nozzle 122 arranged inside the inner tank 100 .

Pump 123, filter 124, and temperature adjustment section 125 are provided in circulation path 121. Pump 123 sends out the first etching solution in outer tank 110 to circulation path 121 . The filter 124 removes impurities from the first etching solution flowing through the circulation path 121. The temperature adjustment unit 125 is, for example, an electronic thermostat, and adjusts the temperature of the first etching solution flowing through the circulation path 121 to a temperature below room temperature. Pump 123 and temperature adjustment section 125 are controlled by control section 7.

The circulation unit 120 sends the first etching solution from the outer tank 110 into the inner tank 100 via the circulation path 121. The first etching solution sent into the inner tank 100 overflows from the inner tank 100 and flows out into the outer tank 110 again. In this way, the first etching solution circulates between the inner tank 100 and the outer tank 110.

The circulation unit 120 is not provided with a heater that heats the first etching liquid flowing through the circulation path 121, and the first etching liquid flowing through the circulation path 121 is controlled to be at normal temperature (for example, 20°C) by the temperature adjustment unit 125. ±10°C). Note that the temperature adjustment section 125 may be provided with a temperature adjustment section that adjusts the temperature of the first etching solution flowing through the circulation path 121 to a temperature equal to or lower than room temperature. In this manner, the first etching process is performed in the first processing tank 61 using the first etching solution at room temperature or lower.

Molybdenum falls under the category of base metals, has a high tendency to ionize, and is relatively easily oxidized. Therefore, when the heated first etching solution is used, the etching rate of the molybdenum film 11 becomes too fast, and there is a possibility that the variation in the etching amount of the molybdenum film 11 in the stacking direction becomes large. Therefore, in the first processing tank 61, a first etching solution at room temperature or lower is used. The same applies to the second processing tank 71, which will be described later, and a second etching solution at room temperature or lower is used.

The first etching liquid supply unit 130 supplies a new first etching liquid to the first processing tank 61 . The first etching liquid supply section 130 includes a first etching liquid supply source 131, a first supply path 132, a first valve 133, and a first switching section 134.

The first etchant supply source 131 supplies a first etchant in which an oxidizing agent, a catalyst, and a moisture control agent are mixed in advance. The first supply path 132 is connected to the first etching liquid supply source 131 and supplies the first etching liquid supplied from the first etching liquid supply source 131 to the inner tank 100 or the outer tank 110. The first valve 133 is provided in the first supply path 132 and opens and closes the first supply path 132. The first switching unit 134 is provided in the first supply path 132 and switches the destination of the first etching solution flowing through the first supply path 132 between the inner tank 100 and the outer tank 110.

The first valve 133 and the first switching section 134 are electrically connected to the control section 7 and are controlled by the control section 7. For example, when storing the first etching liquid in the empty first processing tank 61, the control unit 7 controls the first valve 133 and the first switching unit 134 to supply the first etching liquid from the first etching liquid supply source 131. A new first etching solution is supplied to the inner tank 100. Further, when replenishing the first etching liquid to the first processing tank 61, the control unit 7 controls the first valve 133 and the first switching unit 134 to supply the first etching liquid from the first etching liquid supply source 131. A new first etching solution is supplied to the outer tank 110.

The individual supply unit 140 can individually supply the oxidizing agent, the catalyst, and the moisture conditioner to the first treatment tank 61. The individual supply section 140 includes an oxidizing agent supply source 141a, a catalyst supply source 141b, and a moisture conditioner supply source 141c. Further, the individual supply section 140 includes a second supply path 142a to a fourth supply path 142c, a second valve 143a to a fourth valve 143c, a second switching section 144a to a fourth switching section 144c, and a second flow rate adjustment section. 145a to a fourth flow rate adjustment section 145c.

The oxidizing agent supply source 141a supplies an oxidizing agent. Examples of the oxidizing agent supplied from the oxidizing agent supply source 141a include nitric acid (HNO ₃ ), sulfuric acid (H ₂ SO ₄ ), and hydrogen peroxide (H ₂ O ₂ ). The second supply path 142a is connected to the oxidizing agent supply source 141a, and supplies the oxidizing agent supplied from the oxidizing agent supply source 141a to the inner tank 100 or the outer tank 110. The second valve 143a is provided in the second supply path 142a, and opens and closes the second supply path 142a. The second switching unit 144a is provided in the second supply path 142a and switches the destination of the oxidizing agent flowing through the second supply path 142a between the inner tank 100 and the outer tank 110. The second flow rate adjustment section 145a is provided in the second supply path 142a. The second flow rate adjustment section 145a includes a flow rate adjustment valve, a flow meter, and the like, and adjusts the flow rate of the oxidizing agent supplied to the inner tank 100 or the outer tank 110.

Catalyst supply source 141b supplies a catalyst. The catalyst supplied from the catalyst supply source 141b is, for example, phosphoric acid (H ₃ PO ₄ ) or glycols. The third supply path 142b is connected to the catalyst supply source 141b, and supplies the catalyst supplied from the catalyst supply source 141b to the inner tank 100 or the outer tank 110. The third valve 143b is provided in the third supply path 142b, and opens and closes the third supply path 142b. The third switching unit 144b is provided in the third supply path 142b and switches the destination of the catalyst flowing through the third supply path 142b between the inner tank 100 and the outer tank 110. The third flow rate adjustment section 145b is provided in the third supply path 142b. The third flow rate adjustment section 145b includes a flow rate adjustment valve, a flow meter, etc., and adjusts the flow rate of the catalyst supplied to the inner tank 100 or the outer tank 110.

The moisture conditioner supply source 141c supplies a moisture conditioner. The moisture regulator supplied from the moisture regulator supply source 141c is, for example, acetic acid (CH ₃ COOH) or an organic acid. The fourth supply path 142c is connected to the moisture conditioner supply source 141c, and supplies the moisture conditioner supplied from the moisture conditioner supply source 141c to the inner tank 100 or the outer tank 110. The fourth valve 143c is provided in the fourth supply path 142c, and opens and closes the fourth supply path 142c. The fourth switching unit 144c is provided in the fourth supply path 142c, and switches the destination of the moisture conditioner flowing through the fourth supply path 142c between the inner tank 100 and the outer tank 110. The fourth flow rate adjustment section 145c is provided in the fourth supply path 142c. The fourth flow rate adjustment section 145c is configured to include a flow rate adjustment valve, a flow meter, etc., and adjusts the flow rate of the moisture regulating agent supplied to the inner tank 100 or the outer tank 110.

The second valve 143a to the fourth valve 143c, the second switching section 144a to the fourth switching section 144c, and the second flow rate adjustment section 145a to the fourth flow rate adjustment section 145c are electrically connected to the control section 7 and control Opening/closing is controlled by section 7.

For example, when storing a new first etching solution in the empty first processing tank 61, the control unit 7 controls the second valve 143a to the fourth valve 143c and the second switching unit 144a to the fourth switching unit 144c. The oxidizer, catalyst, and moisture regulator are supplied to the inner tank 100 in a controlled manner. At this time, the control unit 7 controls the second flow rate adjustment unit 145a to the fourth flow rate adjustment unit 145c to adjust the flow rates of the oxidizer, catalyst, and moisture adjustment agent so that the moisture ratio is set in advance. . As a result, the oxidizing agent, the catalyst, and the moisture regulator are mixed in the first processing tank 61 at a preset mixing ratio, and the first etching liquid is stored in the first processing tank 61 .

Further, when replenishing the first etching solution to the first processing tank 61, the control unit 7 controls the second valve 143a to the fourth valve 143c and the second switching unit 144a to the fourth switching unit 144c. , an oxidizing agent, a catalyst, and a moisture regulator are supplied to the outer tank 110.

The moisture content of the first etching liquid in the first processing tank 61 may vary. For example, the amount of water in the first etching solution in the first processing tank 61 may decrease due to volatilization or the like.

Therefore, the control section 7 controls the third flow rate adjustment section 145b and the fourth flow rate adjustment section 145c so that the distribution is such that an etching solution having a higher moisture content than the first etching solution is generated, so that the catalyst and the moisture content are The flow rate of the adjustment amount may be adjusted. Specifically, the control unit 7 controls the third flow rate adjustment unit 145b and the fourth flow rate adjustment unit 145c to adjust the ratio of the moisture adjusting agent to the catalyst to adjust the moisture content of the catalyst when generating the first etching liquid. lower than the drug ratio. That is, by increasing the proportion of the catalyst and decreasing the proportion of the moisture regulator, the moisture content of the replenishing etching solution is made larger than the moisture content of the first etching solution. Thereby, fluctuations in the water content of the first etching solution in the first processing tank 61 can be suppressed.

Next, the configuration of the second processing tank 71 will be explained. The second processing tank 71 performs a second etching process to etch the molybdenum film 11 formed on the wafer W by immersing one lot of wafers W in the second etching solution.

The second etching solution contains an oxidizing agent, a catalyst, and a moisture regulating agent like the first etching solution, and contains an oxidizing agent, a catalyst, and a moisture regulating agent so that the moisture content is lower than that of the first etching solution. This is an etching solution containing a chemical agent. That is, the second etching process is set so that the etching rate of the molybdenum film 11 is slower than that of the first etching process. Specifically, compared to the first etching solution, the second etching solution has a higher proportion of the catalyst and a lower proportion of the moisture conditioner.

As shown in FIG. 7, the second processing tank 71 includes an inner tank 100, an outer tank 110, and a circulation section 120 similar to the first processing tank 61.

Further, the second processing tank 71 includes a second etching liquid supply section 150. A new second etching solution is supplied to the second processing tank 71 . The second etching liquid supply section 150 includes a second etching liquid supply source 151 , a fifth supply path 152 , a fifth valve 153 , and a fifth switching section 154 .

The second etching liquid supply source 151 supplies a second etching liquid in which an oxidizing agent, a catalyst, and a moisture control agent are mixed in advance. The fifth supply path 152 is connected to the second etching liquid supply source 151 and supplies the second etching liquid supplied from the second etching liquid supply source 151 to the inner tank 100 or the outer tank 110. The fifth valve 153 is provided in the fifth supply path 152 and opens and closes the fifth supply path 152. The fifth switching unit 154 is provided in the fifth supply path 152 and switches the destination of the second etching solution flowing through the fifth supply path 152 between the inner tank 100 and the outer tank 110.

The fifth valve 153 and the fifth switching section 154 are electrically connected to and controlled by the control section 7 .

The individual supply unit 160 individually supplies the oxidizing agent, the catalyst, and the moisture conditioner to the second treatment tank 71 . Individual supply section 160 has a similar configuration to individual supply section 140. Specifically, the individual supply unit 160 includes an oxidizing agent supply source 161a, a catalyst supply source 161b, and a moisture conditioner supply source 161c. The individual supply section 160 also includes a sixth supply path 162a to an eighth supply path 162c, a sixth valve 163a to an eighth valve 163c, a sixth switching section 164a to an eighth switching section 164c, and a sixth flow rate adjustment section. 165a to eighth flow rate adjustment section 165c.

The sixth valve 163a to the eighth valve 163c, the sixth switching section 164a to the eighth switching section 164c, and the sixth flow rate adjustment section 165a to the eighth flow rate adjustment section 165c are electrically connected to the control section 7 and control Opening/closing is controlled by section 7.

[Specific operation of substrate processing equipment]
Next, specific operations of the substrate processing apparatus 1 according to the embodiment will be described with reference to FIG. 8. FIG. 8 is a flowchart showing the procedure of processing executed by the substrate processing apparatus 1 according to the embodiment. The processing procedure shown in FIG. 8 is executed under the control of the control unit 7.

As shown in FIG. 8, in the substrate processing apparatus 1, a first etching process using a first etching liquid is performed on a plurality of wafers W forming a lot (step S101). In the first etching process, the plurality of wafers W are lowered using the substrate lifting mechanism 63, so that the plurality of wafers W are immersed in the first etching liquid stored in the inner tank 100 of the first processing tank 61.

The first etching process is performed until the laminated film formed on the wafer W changes from the initial state shown in FIG. 1 to the end face exposed state shown in FIG. That is, in the first etching process, the molybdenum film 11 is etched until the end face of the silicon oxide film 12 facing the groove 15 is exposed from the molybdenum film 11.

The inventor of the present application has found that, compared to a second etching process described later in which the molybdenum film 11 located between the silicon oxide films 12 is etched, in the first etching process, variations in the amount of etching in the stacking direction of the molybdenum film 11 are less likely to occur. This has been confirmed through experiments. Therefore, in the substrate processing apparatus 1, it was decided to perform the first etching process using a first etching liquid that has a higher water content, or in other words, a lower amount of catalyst, than the second etching liquid. Thereby, the processing time for substrate processing can be shortened.

Subsequently, in the substrate processing apparatus 1, a second etching process using a second etching liquid is performed on a plurality of wafers W forming a lot (step S102). In the second etching process, the plurality of wafers W that have undergone the first etching process are transferred from the first processing tank 61 to the second processing tank 71. Thereafter, the plurality of wafers W are lowered by the substrate lifting mechanism 73 and immersed in the second etching solution stored in the inner tank 100 of the second processing tank 71.

The second etching process is performed until the laminated film formed on the wafer W changes from the end face exposed state shown in FIG. 2 to the laminated surface exposed state shown in FIG. That is, in the second etching process, the molybdenum film 11 located between the silicon oxide films 12 is etched to expose the laminated surfaces (upper and lower surfaces) of the silicon oxide film 12.

In the substrate processing apparatus 1, the second etching solution is performed using a second etching solution that contains a larger amount of catalyst, or in other words, a smaller amount of water than the first etching solution. Thereby, variations in the amount of etching in the stacking direction of the molybdenum film 11 can be suppressed.

Subsequently, a rinsing process is performed in the substrate processing apparatus 1 (step S103). In the rinsing process, the plurality of wafers W that have undergone the second etching process are transported to a processing tank 72 for rinsing processing, and are immersed in a rinsing liquid (deionized water or the like) stored in the processing tank 72. As a result, the second etching liquid is washed away from the plurality of wafers W.

Subsequently, a drying process is performed in the substrate processing apparatus 1 (step S104). In the drying process, the plurality of wafers W that have undergone the rinsing process are transported to the processing bath 91 for drying processing, and the rinsing liquid adhering to the surfaces of the plurality of wafers W is removed by the processing gas. As a result, the plurality of wafers W are dried.

Thereafter, the plurality of wafers W that have undergone the drying process are accommodated in the carrier 9 placed on the carrier stage 20. This completes the substrate processing for one lot.

Note that the substrate processing apparatus 1 can also perform the first etching process and the second etching process using only one processing tank (for example, one of the first processing tank 61 and the second processing tank 71). In this case, after finishing the first etching process, by changing the ratio of the catalyst and the water conditioner using the individual supply unit 140 (individual supply unit 160), the catalyst and the moisture conditioner are stored in the treatment tank 61 (processing tank 71). What is necessary is to change the etching solution from the first etching solution to the second etching solution. In this case, there is no need to prepare the second etching solution in advance.

[Modified example]
The substrate processing according to the embodiment is also applicable to a single-wafer processing unit that processes wafers W one by one. FIG. 9 is a diagram illustrating a configuration example of a processing unit according to a modification.

As shown in FIG. 9, the processing unit 200 according to the modification includes a chamber 220, a substrate holding mechanism 230, a nozzle 240, and a collection cup 250.

Chamber 220 accommodates substrate holding mechanism 230, nozzle 240, and collection cup 250. An FFU (Fan Filter Unit) 21 is provided on the ceiling of the chamber 220 . FFU 221 forms a downflow within chamber 220 .

The substrate holding mechanism 230 includes a holding section 231, a support section 232, and a driving section 233. The holding section 231 holds the wafer W horizontally. The support portion 232 is a member extending in the vertical direction, has a base end rotatably supported by a drive portion 233, and a distal end portion that supports the holding portion 231 horizontally. The drive section 233 rotates the support column 232 around a vertical axis. This substrate holding mechanism 230 rotates the holding part 231 supported by the supporting part 232 by rotating the supporting part 232 using the driving part 233, thereby rotating the wafer W held by the holding part 231. .

The nozzle 240 is arranged above the wafer W held by the holding part 231, and supplies various processing liquids to the wafer W.

The collection cup 250 is arranged to surround the holding part 231 and collects the processing liquid scattered from the wafer W by the rotation of the holding part 231. A drain port 251 is formed at the bottom of the recovery cup 250, and the processing liquid collected by the recovery cup 250 is discharged from the drain port 251 to the outside of the processing unit 200. Furthermore, an exhaust port 252 is formed at the bottom of the recovery cup 250 to exhaust the gas supplied from the FFU 221 to the outside of the processing unit 200 .

The processing unit 200 further includes a first etching liquid supply section 260, a second etching liquid supply section 270, and a rinsing liquid supply section 280.

The first etching liquid supply unit 260 includes a first etching liquid supply source 261 and a ninth valve 262, and supplies the first etching liquid supplied from the first etching liquid supply source 261 to the nozzle 240. The second etching liquid supply unit 270 includes a second etching liquid supply source 271 and a tenth valve 272, and supplies the second etching liquid supplied from the second etching liquid supply source 271 to the nozzle 240. The rinsing liquid supply unit 280 includes a rinsing liquid supply source 281 and an eleventh valve 282, and supplies the rinsing liquid (deionized water or the like) supplied from the rinsing liquid supply source 281 to the nozzle 240.

In this processing unit 200, first, a first etching process is performed. In the first etching process, the ninth valve 262 is opened for a predetermined period of time, so that the first etching liquid is supplied to the rotating wafer W held by the substrate holding mechanism 230.

Subsequently, in the processing unit 200, a second etching process is performed. In the second etching process, the tenth valve 272 is opened for a predetermined period of time, so that the second etching liquid is supplied to the wafer W that is held by the substrate holding mechanism 230 and rotates. Note that, as described above, the temperatures of the first etching solution and the second etching solution are room temperature or lower.

Subsequently, the processing unit 200 performs a rinsing process. In the rinsing process, the eleventh valve 282 is opened for a predetermined period of time, so that a rinsing liquid is supplied to the wafer W that is being rotated while being held by the substrate holding mechanism 230. After that, a drying process is performed in the processing unit 200. In the drying process, the wafer W is dried by increasing the rotational speed of the wafer W and shaking off the rinsing liquid from the wafer W. When the drying process is completed, the substrate processing for one wafer W is completed.

As described above, the substrate processing method according to the embodiment includes a step of supplying a first etching solution and a step of supplying a second etching solution. The step of supplying the first etching solution includes applying the first etching solution to the molybdenum film (for example, , a molybdenum film 11) (for example, a wafer W) (for example, a first etching process). The step of supplying the second etching solution includes supplying the first etching solution to the substrate, and then supplying the second etching solution containing a higher percentage of moisture control agent than the first etching solution (for example, the first etching solution is supplied to the substrate). 2 etching process). Therefore, according to the substrate processing method according to the embodiment, in a technique for etching a stacked film including a molybdenum film, variations in the amount of etching in the stacking direction can be reduced. Furthermore, it is possible to reduce the variation in etching amount in the stacking direction while shortening the processing time for substrate processing.

The temperatures of the first etching solution and the second etching solution may be room temperature or lower. Thereby, it is possible to prevent the etching rate of the molybdenum film from becoming too high and the variation in the amount of etching in the stacking direction of the molybdenum film from increasing.

Further, the substrate processing apparatus according to the embodiment (for example, the first etching processing apparatus 60, the second etching processing apparatus 70, and the processing unit 200) has a first etching liquid supply section (for example, the first etching liquid supply section 130). , 260, individual supply section 140) and a second etching solution supply section (for example, second etching solution supply sections 150, 270, and individual supply section 160). The first etching solution supply section supplies the first etching solution containing an oxidizing agent, a catalyst, and a moisture regulator, in which the proportion of the moisture regulating agent is larger than the total proportion of the oxidizing agent and the catalyst, to the laminated film containing the molybdenum film. supply to the substrate. The second etching liquid supply unit supplies a second etching liquid containing a higher proportion of a moisture conditioner than the first etching liquid to the substrate. Therefore, according to the substrate processing apparatus according to the embodiment, in the technique of etching a stacked film including a molybdenum film, variations in the amount of etching in the stacking direction can be reduced. Furthermore, it is possible to reduce the variation in etching amount in the stacking direction while shortening the processing time for substrate processing.

The substrate processing apparatus may include a first processing tank (for example, the first processing tank 61) and a second processing tank (for example, the second processing tank 71). The first processing tank stores the first etching liquid supplied from the first etching liquid supply section, and immerses the plurality of substrates in the stored first etching liquid. The second processing tank stores the second etching liquid supplied from the second etching liquid supply section, and immerses the plurality of substrates in the stored second etching liquid. Thereby, for example, the first etching process and the second etching process can be performed on a plurality of substrates without performing liquid exchange.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. Indeed, the embodiments described above may be implemented in various forms. Moreover, the above-described embodiments may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the appended claims.

1: Substrate processing device 7: Control unit 8: Storage medium 10: Polysilicon film 11: Molybdenum film 12: Silicon oxide film 15: Groove 60: First etching processing device 61: First processing tank 70: Second etching processing device 71 : Second processing tank 100 : Inner tank 110 : Outer tank 120 : Circulation part 130 : First etching liquid supply part 140 : Individual supply part 150 : Second etching liquid supply part 160 : Individual supply part W : Wafer

Claims (8)

Supplying a first etching solution containing an oxidizing agent, a catalyst, and a moisture regulator, in which the proportion of the moisture regulator is greater than the total proportion of the oxidizing agent and the catalyst, to a substrate having a laminated film containing a molybdenum film. process and
A substrate processing method, comprising: supplying the first etching solution to the substrate, and then supplying the substrate with a second etching solution containing a higher proportion of the moisture conditioner than the first etching solution. The substrate processing method according to claim 1, wherein the oxidizing agent is selected from at least one of sulfuric acid, nitric acid, and hydrogen peroxide. 3. The substrate processing method according to claim 1, wherein the moisture conditioner is an organic acid or an organic solvent. The organic acid is selected from at least one of acetic acid, methanesulfonic acid, paratoluenesulfonic acid, phthalic acid, succinic acid, maleic acid, malonic acid, oxalic acid, propionic acid and orthoperiodic acid,
4. The substrate processing method according to claim 3, wherein the organic solvent is selected from at least one of glycols, propylene carbonate, and IPA (isopropyl alcohol). 5. The substrate processing method according to claim 1, wherein the catalyst is phosphoric acid or glycols. 6. The substrate processing method according to claim 1, wherein the temperatures of the first etching solution and the second etching solution are room temperature or lower. Supplying a first etching solution containing an oxidizing agent, a catalyst, and a moisture regulator, in which the proportion of the moisture regulator is greater than the total proportion of the oxidizing agent and the catalyst, to a substrate having a laminated film containing a molybdenum film. a first etching liquid supply section;
and a second etching liquid supply section that supplies a second etching liquid in which the proportion of the moisture conditioner is higher than that of the first etching liquid to the substrate. a first processing tank that stores the first etching solution supplied from the first etching solution supply section and immerses the plurality of substrates in the stored first etching solution;
The substrate according to claim 7, further comprising: a second processing tank that stores the second etching solution supplied from the second etching solution supply unit and immerses the plurality of substrates in the stored second etching solution. Processing equipment.

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