JP2016034009A - Substrate processing apparatus and substrate processing method - Google Patents

Abstract

A substrate processing apparatus and a substrate processing method for processing a substrate using plasma are provided.
The present invention relates to a substrate processing apparatus and a substrate processing method. According to an embodiment of the present invention, there is provided a substrate processing method in which an interlayer insulating layer and a sacrificial layer are alternately stacked on polysilicon, and a hole is formed in the interlayer insulating layer and the sacrificial layer. Supplying a first process gas excited to a plasma state to the substrate to form a protective layer on the side and bottom surfaces of the hole and the top surface of the substrate; and the substrate was excited to a plasma state. Supplying a second process gas to remove the protective layer formed on the side surface of the hole; and supplying a third process gas excited to a plasma state to the substrate to expose the side surface of the hole. Removing the sacrificial layer formed, and supplying a fourth process gas excited to a plasma state to the substrate to remove the protective layer on the top surface of the substrate and the bottom surface of the hole. .
[Selection] Figure 2

Description

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

  Electronic products are required to process high-capacity data while their volumes are becoming smaller. Accordingly, it is necessary to improve the integration degree of semiconductor memory devices used in such electronic products. As one of methods for improving the integration degree of a semiconductor memory device, a memory device having a vertical transistor structure instead of an existing planar transistor structure has been proposed.

  Such a stacked memory includes a step of alternately laminating an interlayer insulating layer and a sacrificial layer on polysilicon, a step of forming a hole in the interlayer insulating layer and the sacrificial layer, and a step of removing the sacrificial layer through the hole. Of these, the step of removing the sacrificial layer is performed by a wet etching method, which is low in efficiency and requires high costs.

US Patent Application Publication No. 2011/0286275

  An object of the present invention is to provide a substrate processing apparatus and a substrate processing method for processing a substrate using plasma.

  Another object of the present invention is to provide a substrate processing apparatus and a substrate processing method capable of removing a sacrificial layer in a dry process on a substrate provided for manufacturing a stacked memory device.

  According to an aspect of the present invention, providing a substrate in which an interlayer insulating layer and a sacrificial layer are alternately stacked on polysilicon, and a hole is formed in the interlayer insulating layer and the sacrificial layer; Supplying a first process gas excited in a plasma state to the substrate to form a protective layer on the side and bottom surfaces of the hole and the upper surface of the substrate; and a second process excited in the plasma state on the substrate. Supplying a gas to remove the protective layer formed on the side surface of the hole; and supplying a third process gas excited to a plasma state to the substrate to expose the side surface of the hole. Removing the sacrificial layer; and supplying a fourth process gas excited to a plasma state to the substrate to remove the protective layer on the upper surface of the substrate and the bottom surface of the hole. Is provided.

  The interlayer insulating layer is an oxide, and the sacrificial layer is a nitride.

  In addition, oxygen gas is provided as the first process gas, and the protective layer is a silicon dioxide layer.

  Further, hydrogen gas is provided as the second process gas, and the protective layer reacts with the second process gas and is decomposed into silane.

  The third process gas includes nitrogen trifluoride gas and oxygen gas.

  The third process gas further includes nitrogen gas.

  The fourth process gas is hydrogen gas.

  The fourth process gas is a state in which nitrogen gas, hydrogen gas, and nitrogen trifluoride gas are mixed.

  The method may further include heating the substrate to a set temperature after supplying the fourth process gas and reacting with the protective layer.

  The substrate is provided for manufacturing a stacked memory device.

  According to another aspect of the present invention, a chamber, a susceptor positioned in the chamber, and a first process gas, a second process gas, a third process gas, and a fourth process gas are sequentially disposed on the chamber. There is provided a substrate processing apparatus including a process gas supply unit for supplying the first process gas and a plasma excitation unit for exciting the first to fourth process gases into a plasma state.

  In addition, oxygen gas is provided as the first process gas.

  Further, hydrogen gas is provided as the second process gas.

  The third process gas includes nitrogen trifluoride gas and oxygen gas.

  The third process gas further includes nitrogen gas.

  The fourth process gas is hydrogen gas.

  The fourth process gas is a state in which nitrogen gas, hydrogen gas, and nitrogen trifluoride gas are mixed.

  According to an embodiment of the present invention, it is possible to provide a substrate processing apparatus and a substrate processing method for efficiently processing a substrate using plasma.

  In addition, according to an embodiment of the present invention, it is possible to provide a substrate processing apparatus and a substrate processing method capable of removing a sacrificial layer by a dry process on a substrate provided for manufacturing a stacked memory device.

It is a top view which shows the substrate processing apparatus by one Embodiment of this invention. It is drawing which shows the plasma module provided to the process module of FIG. It is drawing which shows the board | substrate processed with a process module. 5 is a diagram illustrating a process of removing a sacrificial layer from a substrate by a substrate processing apparatus according to an embodiment of the present invention. 5 is a diagram illustrating a process of removing a sacrificial layer from a substrate by a substrate processing apparatus according to an embodiment of the present invention. 5 is a diagram illustrating a process of removing a sacrificial layer from a substrate by a substrate processing apparatus according to an embodiment of the present invention. 5 is a diagram illustrating a process of removing a sacrificial layer from a substrate by a substrate processing apparatus according to an embodiment of the present invention. 6 is a diagram illustrating a process of removing a protective layer according to another embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The embodiments of the present invention can be modified in various forms, and the scope of the present invention should not be construed as being limited to the following embodiments. This embodiment is provided to more fully explain the present invention to those skilled in the art. Accordingly, the shape of the elements in the drawings is exaggerated to emphasize a clearer description.

  FIG. 1 is a plan view showing a substrate processing apparatus according to an embodiment of the present invention.

  Referring to FIG. 1, the substrate processing apparatus 1 includes an equipment front end module (EFEM) 20 and a process processing unit 30. The equipment front end module 20 and the process processing unit 30 are arranged in one direction. Hereinafter, a direction in which the equipment front end module 20 and the process processing unit 30 are arranged is a first direction X, and when viewed from above, a direction perpendicular to the first direction X is a second direction Y.

  The equipment front end module 20 has a load port 10 and a transfer frame 21. The load port 10 is disposed in front of the equipment front end module 20 in the first direction 11. The load port 10 has a plurality of support portions 6. Each support portion 6 is arranged in a row in the second direction Y, and a carrier 4 (for example, a cassette, a FOUP, etc.) in which a substrate W provided in a process and a substrate W that has been processed is stored is positioned. . The carrier 4 stores a substrate W provided for the process and a substrate W that has been subjected to the process. The transfer frame 21 is disposed between the load port 10 and the process chamber 30. The transfer frame 21 includes a first transfer robot 25 that is disposed inside the transfer frame 21 and transfers the substrate W between the load port 10 and the process processing unit 30. The first transfer robot 25 moves along the transfer rail 27 provided in the second direction Y, and transfers the substrate W between the carrier 4 and the process chamber 30.

  The process chamber 30 includes a load lock chamber 40, a transfer chamber 50, and a process module 60.

  The load lock chamber 40 is disposed adjacent to the transfer frame 21. As an example, the load lock chamber 40 is disposed between the transfer chamber 50 and the equipment front end module 20. The load lock chamber 40 provides a space for waiting before the substrate W to be provided for the process is transferred to the process module 60 or before the processed substrate W is transferred to the equipment front end module 20. .

  The transfer chamber 50 is disposed adjacent to the load lock chamber 40. The transfer chamber 50 has a polygonal body when viewed from above. Referring to FIG. 1, the transfer chamber 50 has a pentagonal body when viewed from above. A load lock chamber 40 and a plurality of process modules 60 are arranged outside the main body along the periphery of the main body. A passage (not shown) through which the substrate W enters and exits is formed on each side wall of the main body, and the passage connects the transfer chamber 50 and the load lock chamber 40 or the process module 60. Each passage is provided with a door (not shown) that opens and closes the passage to seal the inside. A second transfer robot 53 that transfers the substrate W between the load lock chamber 40 and the process module 60 is disposed in the internal space of the transfer chamber 50. The second transfer robot 53 transfers the unprocessed substrate W waiting in the load lock chamber 40 to the process module 60, or transfers the substrate W after the process is completed to the load lock chamber 40. Then, the substrate W is transferred between the process modules 60 in order to sequentially provide the substrates W to the plurality of process modules 60. As shown in FIG. 1, when the transfer chamber 50 has a pentagonal main body, the load lock chamber 40 is disposed on the side wall adjacent to the equipment front end module 20, and the process module 60 is continuously disposed on the remaining side wall. Is done. The transfer chamber 50 may be provided in various forms according to a required process module as well as the above-described shape.

  The process module 60 is disposed along the periphery of the transfer chamber 50. A plurality of process modules 60 may be provided. In each process module 60, the process for the substrate W is performed. The process module 60 transfers the substrate W from the second transfer robot 53 to perform a process process, and provides the substrate W after the process process to the second transfer robot 53. The process processing performed in each process module 60 may be different from each other. The process performed by the process module 60 is one of the processes for producing a semiconductor device or a display panel using the substrate W. One or more of the process modules 60 includes a process module (200a in FIG. 2) for processing the substrate W using plasma.

  FIG. 2 is a view illustrating a plasma module provided in the process module of FIG.

  Referring to FIG. 3, the plasma module 200 a includes a chamber 2100, a susceptor 2200, a shower head 2300, and a plasma excitation unit 2400.

  The chamber 2100 provides a space in which process processing is performed. The chamber 2100 has a body 2110 and a sealing cover 2120. The body 2110 has an open upper surface and forms a space inside. An opening (not shown) through which the substrate W enters and exits is formed on the side wall of the body 2110, and the opening is opened and closed by an opening / closing member such as a slit door (not shown). The opening / closing member closes the opening while the substrate W processing is performed in the chamber 2100, and opens the opening when the substrate W is carried into the chamber 2100 and carried out of the chamber 2100. A hand portion of a robot (not shown) enters and exits the chamber 2100 with the opening opened.

  An exhaust hole 2111 is formed in the lower wall of the body 2110. The exhaust hole 2111 is connected to the exhaust line 2112. The internal pressure of the chamber 2100 is adjusted through the exhaust line 2112, and the reaction part product generated in the process is discharged to the outside of the chamber 2100.

  The sealing cover 2120 is coupled to the upper wall of the body 2110 and covers the open upper surface of the body 2110 to seal the inside of the body 2110. The upper end of the hermetic cover 2120 is connected to the plasma excitation unit 2400. A diffusion space 2121 is formed in the hermetic cover 2120. The closer the diffusion space 2121 is to the shower head 2300, the wider the width. For example, the diffusion space 2121 has a reverse funnel shape.

  The susceptor 2200 is located inside the chamber 2100. A substrate W is placed on the upper surface of the susceptor. Inside the susceptor 2200, a cooling channel (not shown) through which a cooling fluid circulates is formed. The cooling fluid circulates according to the cooling flow path and cools the substrate W. Electric power is applied to the susceptor 2200 from a bias power source 2210 in order to adjust the degree of plasma processing of the substrate W. The power applied by the bias power source 2210 may be a radio frequency (RF) power source. The susceptor 2200 can form a sheath by power supplied from the bias power source 2210, and can form high-density plasma in the region to improve process capability.

  A heating member 2220 is provided inside the susceptor 2200. According to an example, the heating member 2220 may be provided on a hot wire. The heating member 2220 heats the substrate W to a preset temperature.

  The shower head 2300 is coupled to the upper wall of the body 2110. The shower head 2300 may be arranged in a disc shape and aligned with the upper surface of the susceptor 2200. The shower head 2300 may be provided with an aluminum material whose surface is oxidized. A distribution hole 2310 is formed in the shower head 2300. The distribution holes 2310 are formed at constant intervals on a concentric circumference for uniform radical supply. The plasma diffused from the diffusion space 2121 flows into the distribution hole 2310. At this time, charged particles such as electrons or ions are confined in the shower head 2300, and neutral particles such as oxygen radicals that are not charged are supplied to the substrate W through the distribution holes 2310. Also, the shower head can be grounded to form a passage through which electrons or ions are moved.

  The plasma excitation unit 2400 generates plasma and supplies it to the chamber 2100. The plasma excitation unit 2400 is provided on the upper portion of the chamber 2100. The plasma excitation unit 2400 includes an oscillator 2410, a waveguide 2420, a dielectric tube 2430, and a process gas supply unit 2440.

  The oscillator 2410 generates an electromagnetic wave. The waveguide 2420 connects the oscillator 2410 and the dielectric tube 2430, and provides a path through which electromagnetic waves generated by the oscillator 2410 are transmitted to the inside of the dielectric tube 2430. The process gas supply unit 2440 supplies process gas to the upper part of the chamber 2100. As the process gas, the first process gas to the fourth process gas may be supplied according to the progress of the process. The process gas contains oxygen and nitrogen. Further, the process gas includes a fluorine-based gas. The process gas supplied into the dielectric tube 2430 is excited into a plasma state by an electromagnetic wave. The plasma flows into the diffusion space 2121 through the dielectric tube 2430.

  The case where the plasma excitation unit described above uses an electromagnetic wave has been described as an example. However, in other embodiments, the plasma excitation unit may be provided with an inductively coupled plasma excitation unit and a capacitively coupled plasma excitation unit.

  FIG. 3 is a view showing a substrate processed by the process module.

  Referring to FIG. 3, a plurality of layers are formed on the substrate W. First, an impurity region 3110 is formed by implanting impurities into the upper portion of the polysilicon 3100. Subsequently, interlayer insulating layers 3210 and sacrificial layers 3220 are alternately stacked on the impurity regions 3110. Here, the sacrificial layer 3220 has an etching selectivity with respect to the interlayer insulating layer 3210. For example, the interlayer insulating layer 3210 may be an oxide, and the sacrificial layer 3220 may be a nitride. The substrate W having such a structure in which the interlayer insulating layers 3210 and the sacrificial layers 3220 are alternately stacked is used for manufacturing a stacked memory device.

  Further, holes H are formed in the interlayer insulating layer 3210 and the sacrificial layer 3220. The hole H may be formed using photolithography and etching techniques.

  In order to manufacture a stacked memory device, the sacrificial layer 3220 positioned between the interlayer insulating layer 3210 must be removed. Thereafter, a storage medium and a conductive layer are formed in the space where the hole H and the sacrificial layer 3220 are removed.

  4 to 7 are views illustrating a process of removing a sacrificial layer from a substrate by a substrate processing apparatus according to an embodiment of the present invention.

  The sacrificial layer 3220 can be removed through a dry etching method.

  Referring to FIG. 4, a protective layer 3300 is formed on the upper surface and the hole of the substrate. The protective layer 3300 is formed from a silicon dioxide layer. In order to form the protective layer 3300, the process gas supply unit 2440 supplies the first process gas into the chamber 2100. Oxygen gas may be provided as the first process gas. The first process gas is excited to a plasma state and then supplied to the upper portion of the substrate W. The first process gas acts on the uppermost interlayer insulating layer 3210 to form a silicon dioxide layer on the upper surface of the uppermost interlayer insulating layer 3210. In addition, the first process gas is supplied through the hole H to form a silicon dioxide layer on the interlayer insulating layer 3210 and the sacrificial layer 3220 that form the sidewall of the hole H. A silicon dioxide layer is also formed on the bottom surface of the hole H by the first process gas.

  The protective layer 3300 is formed to have a different thickness for each region. Specifically, the first process gas is moved downward when a space is formed in the lower part. That is, the first process gas is supplied to the hole H and then reacts with the interlayer insulating layer 3210 and the sacrificial layer 3220 forming the side wall of the hole H while flowing downward. On the other hand, when the first process gas reacts with the uppermost interlayer insulating layer 3210 and the bottom surface of the hole H, it is in a stopped state or in a state of flowing at a slow speed. The reaction in which the silicon dioxide layer is formed is greatly affected by the contact time with the first process gas or the possibility of movement of the first process gas. Therefore, the silicon dioxide layer formed on the upper surface of the substrate W and the bottom surface of the hole H is formed thicker than the silicon dioxide layer formed on the side wall of the hole H.

  Referring to FIG. 5, the protective layer 3300 formed on the sidewall of the hole is removed.

  If the protective layer 3300 is formed, the process gas supply unit 2440 supplies the second process gas into the chamber 2100. Hydrogen gas may be provided as the second process gas. The second process gas is supplied to the upper portion of the substrate W and reacts sequentially with the silicon dioxide layer as shown in the following chemical formulas 1 to 3.

  Then, silane which is a final reaction product is discharged from the chamber 2100 to the outside in a gas phase. At this time, a part of the silicon dioxide layer formed on the upper surface of the substrate W and the bottom surface of the hole H remains while etching the entire silicon dioxide layer formed on the side wall of the hole H during the process time by the second process gas. Adjusted as follows.

  Referring to FIG. 6, the sacrificial layer is selectively dry etched.

  If the protective layer 3300 formed on the sidewall of the hole is removed, the process gas supply unit 2440 supplies the third process gas into the chamber 2100. The third process gas includes nitrogen trifluoride gas and oxygen gas. Since the sacrificial layer 3220 has an etching selectivity with respect to the interlayer insulating layer 3210, the third process gas is excited into a plasma state and then selectively reacted with the sacrificial layer 3220 as shown in Formula 4 below.

  The material generated by the third process gas etching the sacrificial layer 3220 is discharged out of the chamber 2100 into the gas phase.

  The polysilicon 3100 and the impurity region 3110 do not have an etching selectivity with respect to the sacrificial layer 3220 with respect to the third process gas. Therefore, the protective layer 3300 formed on the bottom surface of the hole H blocks the polysilicon 3100 and the impurity region 3110 located therebelow from coming into contact with the third process gas.

  Further, the third process gas further includes nitrogen gas. Nitrogen gas can adjust the etch selectivity in the above reaction process.

  Referring to FIG. 7, after the selective etching of the sacrificial layer, the protective layer is removed.

  The process gas supply unit 2440 supplies the fourth process gas into the chamber 2100. Hydrogen gas is provided as the fourth process gas. The fourth process gas is supplied to the upper portion of the substrate W, and reacts sequentially with the protective layer 3300 remaining on the substrate W as shown in Chemical Formulas 1 to 3. If the silicon dioxide layer is etched on the upper surface of the substrate W and the bottom surface of the hole H, the removal process of the sacrificial layer 3220 positioned between the interlayer insulating layer 3210 is completed.

  FIG. 8 is a view illustrating a process of removing a protective layer according to another embodiment.

  Referring to FIG. 8, the protective layer is removed through a changing process to the by-product layer 3400. The process gas supply unit 2440 supplies nitrogen gas, hydrogen gas, and nitrogen trifluoride gas to the chamber 2100 as the fourth process gas. The upper fourth process gas reacts with the silicon dioxide layer on the upper surface of the substrate W and the bottom surface of the hole H to become ammonium hexafluorosilicate and water. Ammonium hexafluorosilicate forms a by-product layer 3400 on the top surface of the substrate and the bottom surface of the holes. The by-product layer 3400 can be removed by heating the substrate W to a set temperature or higher. At this time, the heating temperature of the substrate W is 100 ° C. or higher. The substrate W can be heated by a heating member 2220 provided to the susceptor 2200 to remove ammonium hexafluorosilicate. As another example, the substrate W may be heat-treated in another chamber after being unloaded from the plasma module 200a.

  The foregoing detailed description is merely illustrative of the invention. Also, the foregoing is intended to illustrate and describe the preferred embodiment of the present invention, and the present invention can be used in a variety of other combinations, modifications and environments. That is, changes or modifications can be made within the scope of the inventive concept disclosed in the present specification, the scope equivalent to the above-described disclosure, and / or the skill or knowledge of the industry. The above-described embodiments are for explaining the best state for embodying the technical idea of the present invention, and various modifications required in specific application fields and applications of the present invention are possible. Accordingly, the above detailed description of the invention is not intended to limit the invention to the disclosed embodiments. Also, the appended claims should be construed to include other implementations.

DESCRIPTION OF SYMBOLS 10 ... Load port 20 ... Equipment front end module 21 ... Transfer frame 25 ... First transfer robot 27 ... Transfer rail 40 ... Load lock chamber 50 ... Transfer chamber 60- ..Process module 200a ... plasma module 2100 ... chamber 2110 ... body 2200 ... susceptor 2400 ... plasma excitation part 3100 ... polysilicon 3110 ... impurity region 3210 ... interlayer insulation Layer 3220 ... Sacrificial layer

Claims (17)

Providing a substrate in which an interlayer insulating layer and a sacrificial layer are alternately stacked on top of polysilicon, and a hole is formed in the interlayer insulating layer and the sacrificial layer;
Supplying a first process gas excited in a plasma state to the substrate to form a protective layer on the side and bottom surfaces of the hole and the top surface of the substrate;
Supplying a second process gas excited in a plasma state to the substrate to remove the protective layer formed on the side surface of the hole;
Supplying a third process gas excited in a plasma state to the substrate to remove the sacrificial layer exposed on the side surface of the hole;
Supplying a fourth process gas excited in a plasma state to the substrate to remove the protective layer on the upper surface of the substrate and the bottom surface of the hole.   The substrate processing method according to claim 1, wherein the interlayer insulating layer is an oxide, and the sacrificial layer is a nitride.   The substrate processing method according to claim 2, wherein oxygen gas is provided as the first process gas, and the protective layer is a silicon dioxide layer.   The substrate processing method according to claim 2, wherein hydrogen gas is provided as the second process gas, and the protective layer is decomposed into silane by reacting with the second process gas.   The substrate processing method according to claim 2, wherein the third process gas includes nitrogen trifluoride gas and oxygen gas.   The substrate processing method according to claim 5, wherein the third process gas further includes a nitrogen gas.   The substrate processing method according to claim 2, wherein the fourth process gas is hydrogen gas.   The substrate processing method according to claim 2, wherein the fourth process gas is a mixed state of nitrogen gas, hydrogen gas, and nitrogen trifluoride gas.   The substrate processing method according to claim 8, further comprising heating the substrate to a set temperature after supplying the fourth process gas to react with the protective layer.   The substrate processing method of claim 1, wherein the substrate is provided for manufacturing a stacked memory device. A chamber;
A susceptor located inside the chamber;
A process gas supply unit for sequentially supplying a first process gas, a second process gas, a third process gas, and a fourth process gas to an upper portion of the chamber;
A substrate processing apparatus comprising: a plasma excitation unit that excites the first process gas to the fourth process gas into a plasma state.   The substrate processing apparatus according to claim 11, wherein oxygen gas is provided as the first process gas.   The substrate processing apparatus according to claim 11, wherein hydrogen gas is provided as the second process gas.   The substrate processing apparatus according to claim 11, wherein the third process gas includes nitrogen trifluoride gas and oxygen gas.   The substrate processing apparatus according to claim 14, wherein the third process gas further includes a nitrogen gas.   The substrate processing apparatus according to claim 11, wherein the fourth process gas is hydrogen gas.   The substrate processing apparatus according to claim 11, wherein the fourth process gas is a mixed state of nitrogen gas, hydrogen gas, and nitrogen trifluoride gas.