JP2021114569A - Substrate processing method and substrate processing device - Google Patents

Abstract

To provide a technique for etching a multilayer film including a molybdenum film, which can reduce the variation in etching quantity in a lamination direction.SOLUTION: A substrate processing method according to a disclosure hereof comprises the steps of: supplying a first etching liquid; and supplying a second etching liquid. The step of supplying the first etching liquid supplies, to a substrate having a multilayer film including a molybdenum film, the first etching liquid which contains an oxidizer, a catalyst and a moisture conditioner, and in which a content of the moisture conditioner is larger than a total content of the oxidizer and catalyst. The step of supplying the second etching liquid supplies, to the substrate, the second etching liquid having the content of the moisture conditioner larger than that of the first etching liquid after supplying the first etching liquid to the substrate.SELECTED DRAWING: Figure 8

Description

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

Conventionally, as one of the semiconductor manufacturing processes, an etching process for etching a film formed on a substrate such as a semiconductor wafer is known.

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

Japanese Unexamined Patent Publication No. 2008-300618

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

The 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 a laminating agent containing an oxidizing agent, a catalyst, and a moisture adjusting agent, and the first etching solution containing a moisture adjusting agent having a ratio larger than the total ratio of the oxidizing agent and the catalyst is laminated with a molybdenum film. It is supplied to a substrate having a film. In the step of supplying the second etching solution, after supplying the first etching solution to the substrate, the second etching solution having a higher proportion of the moisture adjusting agent than the first etching solution is supplied to the substrate.

According to the present disclosure, in the technique of etching a laminated film containing a molybdenum film, it is possible to reduce variations in the etching amount in the laminated direction.

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

Hereinafter, the substrate processing method according to the present disclosure and the embodiment for implementing the substrate processing apparatus (hereinafter, referred to as “embodiment”) will be described in detail with reference to the drawings. The present disclosure is not limited by this embodiment. In addition, each embodiment can be appropriately combined as long as the processing contents do not contradict each other. Further, in each of the following embodiments, the same parts are designated by the same reference numerals, and duplicate description is omitted.

Further, in each drawing referred to below, in order to make the explanation easy to understand, an orthogonal coordinate system in which the X-axis direction, the Y-axis direction, and the Z-axis direction orthogonal to each other are defined and the Z-axis positive direction is the vertical upward direction is shown. In some cases. Further, the rotation direction centered on the vertical axis may be referred to as the θ direction.

Further, in the embodiments shown below, expressions such as "constant", "orthogonal", "vertical" or "parallel" may be used, but these expressions are strictly "constant", "orthogonal", and "parallel". It does not have to be "vertical" or "parallel". That is, each of the above expressions allows for deviations in manufacturing accuracy, installation accuracy, and the like.

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

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

As described above, the wafer W to be subjected to the substrate treatment has a laminated film in which the molybdenum film 11 and the silicon oxide film 12 are alternately laminated, and the silicon oxide film 12 is a molybdenum film before the etching treatment. It is in a state of being covered by 11. 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, the wafer W is formed with a plurality of grooves 15 for etching the laminated molybdenum film 11 by infiltrating the etching solution.

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

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

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

The processing conditions of the experimental results shown in FIG. 4 are as follows.
Treatment step: 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: normal temperature (23 ° C)
Wafer W immersion time: 240 seconds when the water content is 2.0 wt% or more and less than 3.5 wt%, 120 seconds when the moisture ratio is 3.5 wt% or more and less than 6.0 wt%

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

As shown in FIG. 4, the difference between the etching amount of the top and the etching amount of the bottom became smaller as the water content of the etching solution decreased. From this result, it can be seen that by reducing the water content of the etching solution, the variation in the etching amount in the laminating direction of the molybdenum film 11 can be suppressed.

The results of this experiment are considered, for example, as follows. That is, the etching mechanism of the molybdenum film 11 proceeds as follows. First, as shown in the chemical reaction formula (1), hydrogen ions (H ⁺ ) and nitric acid ions (NO ₃ ⁻ ) are generated _{by ionization of nitric acid (HNO 3) in the etching solution.}

_{^{HNO 3 → H + + NO 3}} - ··· (1)

Subsequently, as shown in reaction formula (2), nitrate ion (NO ₃ ^-) is molybdenum oxide (MoO ₃₎ caused by the reaction with molybdenum.

Mo + 3NO ₃ ⁻ → MoO ₃ + 3NO ₂ ⁻・ ・ ・ (2)

Subsequently, as shown in the chemical reaction formula (3), the phosphoric acid (H ₃ PO ₄ ) in the etching solution functions as a catalyst to ionize _{molybdenum oxide (MoO 3).} Thus, molybdate _(MoO ^{4 2-)} occurs. 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 reaction formula (4), a portion of the molybdate ion _(MoO ^{4 2-),} reacts with hydrogen ions ^{(H +).} This also dissolves (etches) the molybdenum film 11.

MoO4 ^2- + H ⁺ → HMoO ⁴ -... (4)

As described above, the etching of the molybdenum film 11 proceeds by the reaction of _{molybdenum oxide (MoO 3} ) with water (H _{2 O).} Therefore, the etching rate of the molybdenum film 11 increases as the water content in the etching solution increases, and conversely, the etching rate of the molybdenum film 11 decreases as the water content decreases.

As the etching of the molybdenum film 11 progresses, the molybdenum concentration in the etching solution increases. This increase in molybdenum concentration is particularly remarkable in the groove 15.

The etching solution in the groove 15 is replaced with the etching solution existing outside the groove 15. However, when the water 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 having a high molybdenum concentration is generated inside the groove 15, especially near the bottom of the groove 15. It may remain.

As a result, a concentration gradient of molybdenum in the etching solution is generated in the depth direction of the groove 15, and the etching amount of the molybdenum film 11 located near the bottom of the groove 15 is the amount of the molybdenum film 11 located near the opening of the groove 15. It is less than the etching amount. As a result, the etching amount 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 decreases. As a result, the molybdenum concentration in the groove 15 rises slowly, so that the etching solution in the groove 15 can be replaced in time. As a result, it is considered that the variation in the etching amount of the molybdenum film 11 in the stacking direction is smaller than that in the case where the water content of the etching solution is large.

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

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

As the oxidizing agent, in addition to the above-mentioned nitric acid (HNO ₃ ), for example, sulfuric acid (H ₂ SO ₄ ), hydrogen peroxide solution (H ₂ O ₂ ) and the like can be used. The oxidizing agent may also contain two or three of sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ) and hydrogen peroxide solution (H ₂ O _2). For example, the oxidant may be SPM containing _{sulfuric acid (H 2} SO ₄ ) and hydrogen peroxide solution (H ₂ O _2). Thus, the oxidant can be selected from at least one of _{sulfuric acid (H 2} SO ₄ ), nitric acid (HNO ₃ ) and hydrogen peroxide solution (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.

The water conditioner is preferably a substance that does not contain substantially water. As such a water adjusting agent, for example, an organic acid or an organic solvent can be used. The organic acid can be selected from, for example, 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. The organic solvent can be selected from, for example, at least one of glycols such as ethylene glycol, propylene glycol and diethylene glycol, propylene carbonate and IPA (isopropyl alcohol).

The etching solution according to the embodiment contains an oxidizing agent, a catalyst, and a water adjusting agent so that the ratio of the water adjusting agent to the entire etching solution is larger than the total ratio of the oxidizing agent and the catalyst in terms of weight ratio. Will 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 etching amount in the depth direction of the molybdenum film 11 is almost eliminated. Understand. From this result, the water content of the etching solution is preferably 2.2 wt% or less. By increasing the ratio of the water adjusting agent to the entire etching solution to be larger than the total ratio of the oxidizing agent and the catalyst, it is possible to reduce the water content of the etching solution to 2.2 wt% or less.

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

As shown in FIG. 5, the substrate processing apparatus 1 according to the embodiment controls the carrier loading / unloading section 2, the lot forming section 3, the lot loading section 4, the lot transport section 5, and the lot processing section 6. A unit 7 is provided.

The carrier loading / unloading section 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 mounts a plurality of carriers 9 transported from the outside. The carrier 9 is a container for accommodating a plurality of (for example, 25) semiconductor wafers (hereinafter referred to as wafers W) side by side in a horizontal posture. The carrier transport mechanism 21 transports the carrier 9 between the carrier stage 20, the carrier stocks 22, 23, and the carrier mounting table 24.

From the carrier 9 mounted on the carrier mounting table 24, a plurality of wafers W before being processed are carried out to the lot processing unit 6 by the substrate transfer mechanism 30 described later. Further, a plurality of processed wafers W are carried into the carrier 9 mounted on the carrier mounting table 24 from the lot processing unit 6 by the substrate transfer mechanism 30.

The lot forming unit 3 has a substrate transport mechanism 30 and forms a lot. The lot is composed of a plurality of (for example, 50) wafers W that are processed simultaneously by combining the wafers W housed in one or a plurality of 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 mounted on the carrier mounting table 24 and the lot mounting portion 4.

The lot loading unit 4 has a lot transfer table 40, and temporarily places (stands by) a lot transferred between the lot forming unit 3 and the lot processing unit 6 by the lot transport unit 5. The lot transport table 40 includes a carry-in side lot loading table 41 formed by the lot forming unit 3 on which the unprocessed lot is placed, and a carry-out side lot loading table 41 on which the lot processed by the lot processing unit 6 is placed. It has 42 and. A plurality of wafers W for one lot are placed side by side in an upright position on the carry-in side lot loading stand 41 and the carry-out side lot loading stand 42.

The lot transfer unit 5 has a lot transfer mechanism 50, and transfers lots between the lot loading unit 4 and the lot processing unit 6 or inside the lot processing unit 6. The lot transfer mechanism 50 includes a rail 51, a moving body 52, and a substrate holding body 53.

The rail 51 is arranged along the X-axis direction across the lot loading 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 holding body 53 is provided on the moving body 52 and holds a plurality of wafers W arranged in the front-rear position in an upright posture.

The lot processing unit 6 performs etching treatment, cleaning treatment, drying treatment, and the like on a plurality of wafers W for one lot. The lot processing unit 6 is provided with 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 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 for one lot. The substrate holder cleaning treatment apparatus 80 cleans the substrate holder 53. The drying processing apparatus 90 collectively performs a drying process on a plurality of wafers W for one lot. The number of the first etching processing device 60, the second etching processing device 70, the substrate holder cleaning processing device 80, and the drying processing device 90 is not limited to the example of FIG.

The first etching processing apparatus 60 includes a processing tank 61 for the first etching processing (hereinafter, referred to as “first processing tank 61”), a processing tank 62 for rinsing processing, and substrate elevating mechanisms 63 and 64. Be prepared. Further, the second etching processing apparatus 70 includes a processing tank 71 for the second etching processing (hereinafter, referred to as “second processing tank 71”), a processing tank 72 for rinsing processing, and substrate elevating mechanisms 73 and 74. And. The first etching processing apparatus 60 and the second etching processing apparatus 70 have the same configurations, but the etching solutions used are different. This point will be described later.

The treatment tanks 61 and 71 can accommodate one lot of wafer W and store the etching solution. Specifically, etching solutions having different amounts of water are stored in the treatment tanks 61 and 71. Details of the treatment tanks 61 and 71 will be described later.

Treatment liquids (deionized water, etc.) for rinsing treatment are stored in the treatment tanks 62 and 72. The substrate elevating mechanism 63, 64, 73, 74 holds a plurality of wafers W forming a lot in an upright position in a front-rear arrangement.

The first etching processing apparatus 60 and the second etching processing apparatus 70 hold the lot conveyed by the lot transfer unit 5 by the substrate elevating mechanisms 63 and 73, and immerse the lot in the etching solutions of the processing tanks 61 and 71 to perform the etching process. conduct. Further, the first etching processing device 60 and the second etching processing device 70 hold the lots conveyed to the processing tanks 62 and 72 by the lot transfer unit 5 by the substrate elevating mechanisms 64 and 74, and the processing tanks 62 and 72 The rinsing treatment is performed by immersing in a rinsing solution.

The drying processing device 90 includes a processing tank 91 and a substrate elevating mechanism 92. A processing gas for drying processing is supplied to the processing tank 91. A plurality of wafers W for one lot are held side by side in an upright posture in the substrate elevating mechanism 92.

The drying processing apparatus 90 holds the lot transported by the lot transporting unit 5 by the substrate elevating mechanism 92, and performs the drying treatment using the processing gas for the drying treatment supplied into the processing tank 91. The lot that has been dried in the processing tank 91 is conveyed to the lot loading unit 4 by the lot transfer unit 5.

The substrate holding body cleaning processing apparatus 80 performs cleaning processing of the substrate holding body 53 by supplying a processing liquid for cleaning to the substrate holding body 53 of the lot transfer mechanism 50 and further supplying a drying gas.

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

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

Examples of the storage medium 8 readable by a computer 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 treatment tank 61 used for the first etching treatment and the second treatment tank 71 used for the second etching treatment will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram showing the configuration of the first treatment tank 61 according to the embodiment. Further, FIG. 7 is a diagram showing the configuration of the second treatment tank 71 according to the embodiment.

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

The first treatment tank 61 includes an inner tank 100 and an outer tank 110. Further, the first treatment tank 61 includes a circulation unit 120, a first etching solution supply unit 130, and an individual supply unit 140.

The upper part of the inner tank 100 is open, and the first etching solution is stored inside. The lot (plurality of wafers W) is immersed in the inner tank 100.

The outer tank 110 is open above 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 unit 120 includes a circulation path 121, a nozzle 122, a pump 123, a filter 124, and a temperature adjusting unit 125.

The circulation path 121 connects the outer tank 110 and the 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 the nozzle 122 arranged inside the inner tank 100.

The pump 123, the filter 124, and the temperature adjusting unit 125 are provided in the circulation path 121. The pump 123 sends the first etching solution in the outer tank 110 to the circulation path 121. The filter 124 removes impurities from the first etching solution flowing through the circulation path 121. The temperature adjusting unit 125 is, for example, an electronic cold-heat incubator, and adjusts the temperature of the first etching solution flowing through the circulation path 121 to a temperature of room temperature or lower. The pump 123 and the temperature adjusting unit 125 are controlled by the control unit 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 to 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 for heating the first etching solution flowing through the circulation path 121, and the first etching solution flowing through the circulation path 121 is, for example, at room temperature (for example, 20 ° C.) by the temperature adjusting unit 125. It is maintained at ± 10 ° C.). The temperature adjusting unit 125 may be provided with a temperature adjusting unit that adjusts the temperature of the first etching solution flowing through the circulation path 121 to a temperature of room temperature or lower. In this way, in the first treatment tank 61, the first etching treatment is performed using the first etching solution at room temperature or lower.

Molybdenum is a base metal and has a high ionization tendency and is relatively easily oxidized. Therefore, when the heated first etching solution is used, the etching rate of the molybdenum film 11 may become too high, and the variation in the etching amount in the laminating direction of the molybdenum film 11 may become large. Therefore, in the first treatment tank 61, the first etching solution at room temperature or lower is used. The same applies to the second treatment tank 71, which will be described later, and a second etching solution at room temperature or lower is used.

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

The first etching solution supply source 131 supplies the first etching solution in which an oxidizing agent, a catalyst, and a water adjusting agent are mixed in advance. The first supply path 132 is connected to the first etching solution supply source 131, and supplies the first etching solution supplied from the first etching solution 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 outflow 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 unit 134 are electrically connected to the control unit 7 and are controlled by the control unit 7. For example, when the control unit 7 stores the first etching solution in the empty first processing tank 61, the control unit 7 controls the first valve 133 and the first switching unit 134 from the first etching solution supply source 131. A new liquid of the first etching liquid is supplied to the inner tank 100. Further, when the control unit 7 replenishes the first processing tank 61 with the first etching solution, the control unit 7 controls the first valve 133 and the first switching unit 134 from the first etching solution supply source 131. A new liquid of the first etching liquid is supplied to the outer tank 110.

The individual supply unit 140 can individually supply the oxidizing agent, the catalyst, and the water adjusting agent to the first treatment tank 61. The individual supply unit 140 includes an oxidant supply source 141a, a catalyst supply source 141b, and a moisture adjusting agent supply source 141c. Further, the individual supply unit 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 unit 144a to a fourth switching unit 144c, and a second flow rate adjusting unit. 145a to 145c are provided with a fourth flow rate adjusting unit 145c.

The oxidant supply source 141a supplies the oxidant. The oxidizing agent supplied from the oxidizing agent supply source 141a is, for example, nitric acid (HNO ₃ ), sulfuric acid (H ₂ SO ₄ ), hydrogen peroxide solution (H ₂ O ₂ ), or the like. The second supply path 142a is connected to the oxidant supply source 141a, and supplies the oxidant supplied from the oxidant 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 outflow 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 adjusting unit 145a is provided in the second supply path 142a. The second flow rate adjusting unit 145a includes a flow rate adjusting 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.

The catalyst supply source 141b supplies the catalyst. The catalyst supplied from the catalyst 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 outflow 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 adjusting unit 145b is provided in the third supply path 142b. The third flow rate adjusting unit 145b includes a flow rate adjusting valve, a flow meter, and the like, and adjusts the flow rate of the catalyst supplied to the inner tank 100 or the outer tank 110.

The moisture adjusting agent supply source 141c supplies the moisture adjusting agent. The water regulator supplied from the water regulator source 141c is, for example, acetic acid (CH ₃ COOH) or an organic acid. The fourth supply path 142c is connected to the moisture adjusting agent supply source 141c, and supplies the moisture adjusting agent supplied from the moisture adjusting agent 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 outflow destination of the moisture adjusting agent flowing through the fourth supply path 142c between the inner tank 100 and the outer tank 110. The fourth flow rate adjusting unit 145c is provided in the fourth supply path 142c. The fourth flow rate adjusting unit 145c includes a flow rate adjusting valve, a flow meter, and the like, and adjusts the flow rate of the moisture adjusting agent supplied to the inner tank 100 or the outer tank 110.

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

For example, when a new liquid of the first etching solution is stored in the empty first processing tank 61, the control unit 7 sets the second valve 143a to the fourth valve 143c and the second switching unit 144a to the fourth switching unit 144c. Controlled to supply the oxidant, catalyst and moisture conditioner to the inner tank 100. At this time, the control unit 7 controls the second flow rate adjusting unit 145a to the fourth flow rate adjusting unit 145c so as to have a preset water ratio, and adjusts the flow rates of the oxidizing agent, the catalyst, and the water adjusting agent. .. As a result, the oxidizing agent, the catalyst, and the moisture adjusting agent are mixed in the first treatment tank 61 at a preset compounding ratio, and the first etching solution is stored in the first treatment tank 61.

When replenishing the first processing tank 61 with the first etching solution, 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. , Oxidizing agent, catalyst and moisture conditioner are supplied to the outer tank 110.

The water content of the first etching solution in the first treatment tank 61 may fluctuate. For example, the water content of the first etching solution in the first treatment tank 61 may decrease due to volatilization or the like.

Therefore, the control unit 7 controls the third flow rate adjusting unit 145b and the fourth flow rate adjusting unit 145c so that the etching solution having a larger amount of water than the first etching solution is generated, and controls the catalyst and the water content. The flow rate of the adjustment amount may be adjusted. Specifically, the control unit 7 controls the third flow rate adjusting unit 145b and the fourth flow rate adjusting unit 145c to adjust the ratio of the water adjusting agent to the catalyst with respect to the catalyst when producing the first etching solution. Lower than the ratio of the agent. That is, by increasing the ratio of the catalyst and decreasing the ratio of the water adjusting agent, the water content of the replenished etching solution is made larger than the water content of the first etching solution. As a result, fluctuations in the amount of water in the first etching solution in the first treatment tank 61 can be suppressed.

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

Like the first etching solution, the second etching solution contains an oxidizing agent, a catalyst, and a water content adjusting agent, and the oxidizing agent, the catalyst, and the water content are adjusted so that the water content is smaller than that of the first etching solution described above. It is an etching solution containing an 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, the second etching solution has a larger proportion of the catalyst and a smaller proportion of the moisture adjusting agent than the first etching solution.

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

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

The second etching solution supply source 151 supplies a second etching solution in which an oxidizing agent, a catalyst, and a water adjusting agent are mixed in advance. The fifth supply path 152 is connected to the second etching solution supply source 151, and supplies the second etching solution supplied from the second etching solution 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 outflow 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 unit 154 are electrically connected to the control unit 7 and are controlled by the control unit 7.

The individual supply unit 160 individually supplies the oxidizing agent, the catalyst, and the water adjusting agent to the second treatment tank 71. The individual supply unit 160 has the same configuration as the individual supply unit 140. Specifically, the individual supply unit 160 includes an oxidant supply source 161a, a catalyst supply source 161b, and a moisture adjusting agent supply source 161c. Further, the individual supply unit 160 includes a sixth supply path 162a to an eighth supply path 162c, a sixth valve 163a to an eighth valve 163c, a sixth switching unit 164a to an eighth switching unit 164c, and a sixth flow rate adjusting unit. 165a to 8th flow rate adjusting unit 165c are provided.

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

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

As shown in FIG. 8, in the substrate processing apparatus 1, the first etching process using the first etching solution is performed on the plurality of wafers W forming the lot (step S101). In the first etching process, the plurality of wafers W are lowered by using the substrate elevating mechanism 63, so that the plurality of wafers W are immersed in the first etching solution 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 is less likely to have a variation in the etching amount in the stacking direction of the molybdenum film 11 in the first etching process, as compared with the second etching process described later in which the molybdenum film 11 located between the silicon oxide films 12 is etched. This has been confirmed by experiments. Therefore, in the substrate processing apparatus 1, the first etching process is performed using the first etching solution, which has a larger amount of water than the second etching solution, in other words, a smaller amount of catalyst. As a result, the processing time for substrate processing can be shortened.

Subsequently, in the substrate processing apparatus 1, a second etching process using the second etching solution is performed on the plurality of wafers W forming the lot (step S102). In the second etching process, the plurality of wafers W that have completed the first etching process are conveyed from the first processing tank 61 to the second processing tank 71. After that, the plurality of wafers W are lowered by the substrate elevating 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 laminated surfaces (upper and lower surfaces) of the silicon oxide film 12 are exposed by etching the molybdenum film 11 located between the silicon oxide films 12.

In the substrate processing apparatus 1, the second etching solution is performed using the second etching solution, which has a larger amount of catalyst than the first etching solution, in other words, a smaller amount of water. Thereby, the variation in the etching amount in the laminating direction of the molybdenum film 11 can be suppressed.

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

Subsequently, the substrate processing apparatus 1 performs a drying process (step S104). In the drying treatment, the plurality of wafers W that have been rinsed are conveyed to the processing tank 91 for the drying treatment, and the rinsing liquid adhering to the surfaces of the plurality of wafers W is removed by the treatment gas. As a result, the plurality of wafers W are dried.

After that, the plurality of wafers W that have been dried are housed in the carrier 9 placed on the carrier stage 20. As a result, the substrate processing for one lot is completed.

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 the first etching treatment is completed, the individual supply unit 140 (individual supply unit 160) is used to change the ratio of the catalyst and the moisture adjusting agent, so that the material is stored in the treatment tank 61 (treatment tank 71). The etching solution may be changed from the first etching solution to the second etching solution. In this case, it is not necessary to prepare the second etching solution in advance.

[Modification example]
The substrate processing according to the embodiment can also be applied to a single-wafer type processing unit that processes wafers W one by one. FIG. 9 is a diagram showing a configuration example of a processing unit according to a modified example.

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

The chamber 220 houses the substrate holding mechanism 230, the nozzle 240, and the recovery cup 250. An FFU (Fan Filter Unit) 21 is provided on the ceiling of the chamber 220. The FFU221 forms a downflow in the chamber 220.

The substrate holding mechanism 230 includes a holding portion 231, a strut portion 232, and a driving portion 233. The holding portion 231 holds the wafer W horizontally. The strut portion 232 is a member extending in the vertical direction, the base end portion is rotatably supported by the drive portion 233, and the holding portion 231 is horizontally supported at the tip portion. The drive unit 233 rotates the strut unit 232 around the vertical axis. The substrate holding mechanism 230 rotates the holding portion 231 supported by the supporting portion 232 by rotating the supporting portion 232 using the driving unit 233, thereby rotating the wafer W held by the holding portion 231. ..

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

The recovery cup 250 is arranged so as to surround the holding portion 231 and collects the processing liquid scattered from the wafer W by the rotation of the holding portion 231. A drainage port 251 is formed at the bottom of the recovery cup 250, and the treatment liquid collected by the recovery cup 250 is discharged from the drainage port 251 to the outside of the treatment unit 200. Further, at the bottom of the recovery cup 250, an exhaust port 252 for discharging the gas supplied from the FFU 221 to the outside of the processing unit 200 is formed.

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

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

In the processing unit 200, first, the first etching process is performed. In the first etching process, the ninth valve 262 is opened for a predetermined time, so that the first etching solution is supplied to the wafer W which is held by the substrate holding mechanism 230 and rotates.

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

Subsequently, the processing unit 200 performs a rinsing process. In the rinsing process, when the eleventh valve 282 is opened for a predetermined time, the rinsing liquid is supplied to the wafer W which is held by the substrate holding mechanism 230 and rotates. After that, the processing unit 200 performs a drying process. In the drying process, the wafer W is dried by increasing the rotation speed of the wafer W and shaking off the rinse liquid from the wafer W. When the drying process is completed, the substrate process for one wafer W is completed.

As described above, the substrate processing method according to the embodiment includes a step of supplying the first etching solution and a step of supplying the second etching solution. The step of supplying the first etching solution includes a molybdenum film (as an example) of the first etching solution containing an oxidizing agent, a catalyst, and a moisture adjusting agent, and the proportion of the moisture adjusting agent is larger than the total proportion of the oxidizing agent and the catalyst. , A substrate having a laminated film containing a molybdenum film 11) (wafer W as an example) (as an example, a first etching process). In the step of supplying the second etching solution, after supplying the first etching solution to the substrate, the second etching solution having a higher proportion of the moisture adjusting agent than the first etching solution is supplied to the substrate (as an example, the first etching solution is supplied). 2 etching process). Therefore, according to the substrate processing method according to the embodiment, it is possible to reduce the variation in the etching amount in the lamination direction in the technique for etching the laminated film containing the molybdenum film. Further, it is possible to reduce the variation in the etching amount in the stacking direction while shortening the processing time of the substrate processing.

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

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) is a first etching solution supply unit (as an example, a first etching solution supply unit 130). , 260, individual supply unit 140) and a second etching solution supply unit (for example, second etching solution supply units 150, 270, individual supply unit 160). The first etching solution supply unit contains an oxidizing agent, a catalyst, and a moisture adjusting agent, and a first etching solution in which the proportion of the moisture adjusting agent is larger than the total proportion of the oxidizing agent and the catalyst is used as a laminated film containing a molybdenum film. Supply to the substrate to have. The second etching solution supply unit supplies the second etching solution to the substrate in which the proportion of the moisture adjusting agent is larger than that of the first etching solution. Therefore, according to the substrate processing apparatus according to the embodiment, it is possible to reduce the variation in the etching amount in the lamination direction in the technique of etching the laminated film containing the molybdenum film. Further, it is possible to reduce the variation in the etching amount in the stacking direction while shortening the processing time of the substrate processing.

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

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. Indeed, the above embodiments can be embodied in a variety of forms. Further, the above-described embodiment may be omitted, replaced or changed in various forms without departing from the scope of the appended claims and the gist thereof.

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 unit 130: First etching liquid supply unit 140: Individual supply unit 150: Second etching liquid supply unit 160: Individual supply unit W: Wafer

Claims (8)

A first etching solution containing an oxidizing agent, a catalyst, and a moisture adjusting agent, in which the proportion of the moisture adjusting agent is larger than the total proportion of the oxidizing agent and the catalyst, is supplied to a substrate having a laminated film containing a molybdenum film. Process and
A substrate processing method comprising a step of supplying the first etching solution to the substrate and then supplying the second etching solution to the substrate in which the proportion of the moisture adjusting agent is larger than that of 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 solution. The substrate treatment method according to claim 1 or 2, wherein the moisture adjusting agent 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.
The substrate treatment method according to claim 3, wherein the organic solvent is selected from at least one of glycols, propylene carbonate and IPA (isopropyl alcohol). The substrate treatment method according to any one of claims 1 to 4, wherein the catalyst is phosphoric acid or glycols. The substrate processing method according to any one of claims 1 to 5, wherein the temperatures of the first etching solution and the second etching solution are room temperature or lower. A first etching solution containing an oxidizing agent, a catalyst, and a moisture adjusting agent, in which the proportion of the moisture adjusting agent is larger than the total proportion of the oxidizing agent and the catalyst, is supplied to a substrate having a laminated film containing a molybdenum film. The first etching solution supply unit and
A substrate processing apparatus including a second etching solution supply unit that supplies a second etching solution having a higher proportion of the moisture adjusting agent than the first etching solution to the substrate. A first treatment tank in which the first etching solution supplied from the first etching solution supply unit is stored and a plurality of the substrates are immersed in the stored first etching solution.
The substrate according to claim 7, further comprising a second processing tank for storing the second etching solution supplied from the second etching solution supply unit and immersing a plurality of the substrates in the stored second etching solution. Processing equipment.

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