JP6663773B2 - Processed object processing method and processed object processing apparatus - Google Patents

Description

  An embodiment of the present invention relates to a method for processing a processed object and a processing apparatus for the processed object.

In manufacturing a semiconductor device, a so-called STI (Shallow Trench Isolation) step may be performed.
In the STI process, for example, a groove (trench) is formed in the substrate by RIE (Reactive Ion Etching), an insulator such as silicon oxide is buried in the groove by CVD (Chemical Vapor Deposition), and the groove is formed by CMP (Chemical Mechanical Polishing). The surface of the substrate is flattened.
In some cases, holes are formed in the substrate by RIE, an insulator such as silicon oxide is embedded in the holes by CVD, and the surface of the substrate is planarized by CMP.

In recent years, in order to achieve high integration, the opening dimension of an opening such as a groove or a hole tends to be small. For this reason, it is difficult to embed an insulator in the opening.
Therefore, a technique has been proposed in which a roundness is formed around the periphery of the opening of the groove by RIE (for example, see Patent Document 1).
However, if the periphery of the opening is rounded by RIE, the sidewall of the opening may be damaged.
In addition, if the etching is performed in a state where the hard mask serving as the etching mask does not cover at least a part of the surface of the substrate main surface in order to form a round shape at the periphery of the opening of the groove, the exposed substrate main surface is not etched. On the surface of the surface, damage such as surface alteration or surface roughness is given to the surface of the main surface of the substrate, or the main surface of the substrate is etched, so that the thickness (height dimension) of the substrate decreases. Resulting in. Thus, there is a possibility that desired electrical characteristics of the semiconductor device cannot be obtained.

JP 2003-218093 A

  The problem to be solved by the present invention is to provide a processing method and a processing apparatus for a processed object, which can easily embed an insulator in the opening and can suppress occurrence of damage. It is to be.

The processing method of a processed object according to the embodiment includes a substrate including silicon and having an opening, and provided on the substrate, including at least one of silicon oxide and silicon nitride, and provided above the opening. And a resist mask provided on the hard mask and having a pattern provided above the opening.
The processing method of the processing object is to supply a processing liquid to the processing object, to gradually decrease the thickness of the hard mask in the vicinity of the hole toward the center of the hole, and to apply a plasma to the processing object. Supplying the generated radicals to form roundness around the periphery of the opening.

  According to the embodiments of the present invention, there are provided a processing method and a processing apparatus of a processed object which can easily embed an insulator in the opening and can suppress occurrence of damage. You.

FIG. 2 is a schematic cross-sectional view illustrating a processing object 200. FIG. 2 is a schematic enlarged view of a portion A in FIG. 1. FIGS. 2A and 2B are schematic process cross-sectional views illustrating a method for processing a processed object according to the first embodiment. FIG. 3A is a schematic enlarged view of a portion B in FIG. FIG. 3B is a schematic enlarged view of a portion C in FIG. (A), (b) is a schematic cross-sectional view for illustrating peeling of the resist mask 102. (A), (b) is a schematic cross-sectional view for illustrating the relationship between the concentration of hydrogen fluoride in hydrofluoric acid and the size of a region into which hydrofluoric acid enters. FIG. 4 is a schematic cross-sectional view illustrating a relationship between the concentration of hydrogen fluoride in buffered hydrofluoric acid and the size of a region into which buffered hydrofluoric acid enters. FIG. 9 is a layout diagram illustrating a processing device 1 according to a second embodiment. FIG. 3 is a schematic cross-sectional view illustrating a wet processing unit 4. FIG. 3 is a schematic cross-sectional view illustrating a dry processing unit 5.

  Hereinafter, embodiments will be described with reference to the drawings. In each of the drawings, similar components are denoted by the same reference numerals, and detailed description will be omitted as appropriate.

(First embodiment)
FIG. 1 is a schematic cross-sectional view illustrating a processing object 200.
FIG. 2 is a schematic enlarged view of a portion A in FIG.
As shown in FIG. 1, a substrate 200, a hard mask 101, and a resist mask 102 are provided on a processing object 200.
The substrate 100 can be, for example, a plate-like body containing silicon (Si). The substrate 100 can be, for example, a semiconductor wafer or the like. The substrate 100 has an opening 100a. The opening 100a can be, for example, a groove or a hole. The opening 100a is provided inside the substrate 100. The opening 100a does not penetrate the substrate 100.
The hard mask 101 is provided on the substrate 100. The hard mask 101 can be, for example, a film made of silicon oxide (SiO ₂ ) or silicon nitride (SiN). The hard mask 101 has a hole 101b. The hole 101b is provided above the opening 100a (in a direction opposite to the bottom of the opening 100a). The hole 101b penetrates the hard mask 101.
The resist mask 102 is provided on the hard mask 101. The resist mask 102 has a pattern 102a for forming the opening 100a and the hole 101b. The pattern 102a is provided above the opening 100a.
That is, the pattern 102a of the resist mask 102 is an opening formed in the film-shaped resist, and when viewed from above the substrate 100, the pattern 102a, the opening 100a, and the hole 101b overlap.

The opening 100a and the hole 101b can be formed, for example, as follows.
First, a hard mask 101 is formed on a substrate 100.
The hard mask 101 can be formed by, for example, a CVD method or a thermal oxidation method.

Next, a resist mask 102 having a pattern 102a is formed on the hard mask 101.
The resist mask 102 having the pattern 102a can be formed by, for example, a photolithography method or the like.

Next, holes 101b are formed in the hard mask 101 using the resist mask 102 as an etching mask, and an opening 100a is formed in the substrate 100.
The opening 100a and the hole 101b can be formed by, for example, anisotropic etching such as RIE.

  Note that a known technique can be applied to the formation of the hard mask 101, the formation of the resist mask 102, and the formation of the opening 100a and the hole 101b, and a detailed description thereof will be omitted.

Here, when the opening 100a and the hole 101b are formed by anisotropic etching such as RIE, damage such as a crystal defect occurs on the side wall of the opening 100a, or the side wall of the opening 100a is opened.
Further, as shown in FIGS. 1 and 2, a protrusion 101 a protruding into the hole 101 b is formed on the hard mask 101.
This is because the hard mask 101 is etched so that the selectivity of the substrate 100 is higher than that of the hard mask 101 so that the hard mask 101 becomes a mask when the substrate 100 is etched, so that the hard mask 101 remains. In addition, the reason that the etching of the exposed surface of the hard mask 101 (the opening of the hole 101b) does not proceed uniformly and remains in a tapered shape is that the pattern 102a of the resist mask 102 serving as the etching mask of the hard mask 101 This is because the hard mask 101 below the scum is not etched.
If the side wall of the opening 100a is damaged, if the side wall of the opening 100a is exposed, or if the protrusion 101a is formed, it becomes difficult to embed an insulator in the inside of the opening 100a.

  In this case, if the protrusion 101a is removed by anisotropic etching such as RIE, the sidewall of the opening 100a may be further damaged, or the sidewall of the opening 100a may be further depressed.

In addition, when the resist mask 102 and the hard mask 101 are partially removed when the protruding portion 101a is removed by anisotropic etching such as RIE, the surface of the substrate 100 may be damaged, or the surface of the substrate 100 may be damaged. May be broken.
Therefore, it may be difficult to embed an insulator in the opening 100a, or the performance of the semiconductor device may be reduced.

On the other hand, when the protruding portion 101a is removed by isotropic etching such as CDE (Chemical Dry Etching), the damage on the side wall of the opening 100a is removed, and the state of the side wall of the opening 100a is improved. It can be carried out.
However, if the protruding portion 101a is simply removed by isotropic etching such as CDE, a round shape cannot be formed around the opening 100a.
This is because, in order to remove the protrusion 101a, the hard mask 101 must be selectively removed from the substrate 100 and the resist mask 102, and the opening 100a is formed round while the protrusion 101a is removed. Thus, the hard mask 101 and the substrate 100 need to be etched at the same time. However, it is difficult to perform isotropic etching of a specific portion while maintaining the etching selectivity of the resist mask 102, the substrate 100, and the hard mask 101.
Therefore, there is room for improvement in facilitating the embedding of an insulator into the opening 100a.

Therefore, in the processing method of the processed material according to the present embodiment, the following wet processing and dry processing are performed on the opening 100a and the hole 101b.
FIGS. 3A and 3B are schematic process cross-sectional views for illustrating the processing method of the processed object according to the first embodiment.
FIG. 4A is a schematic enlarged view of a portion B in FIG.
FIG. 4B is a schematic enlarged view of a portion C in FIG. 3B.

First, as shown in FIG. 3A, a wet process is performed on the opening 100a and the hole 101b. In the wet processing, the processing liquid 300 is supplied to the processing object 200, and the thickness of the hard mask 101 is gradually reduced near the hole 101b toward the center of the hole 101b.
The treatment liquid may be, for example, hydrofluoric acid (also referred to as hydrofluoric acid), which is an aqueous solution of hydrogen fluoride (HF), or buffered hydrofluoric acid (BHF).

  The wet processing can be, for example, an immersion processing in which the processing object 200 is immersed in the processing liquid, a spin processing of supplying the processing liquid to the processing object 200 in a state where the processing object 200 is rotated, or the like. In this case, it is preferable to use the immersion treatment in consideration of suppressing the air resistance due to the rotation during the spin treatment and the peeling of the resist mask 102 caused by the physical impact due to the occasional supply of the treatment liquid. In the case where the immersion processing is performed, a batch processing in which a plurality of processed objects 200 are simultaneously immersed in the processing liquid may be performed.

  By performing the wet processing, the protruding portion 101a is removed as shown in FIGS. 3A and 4A. Further, the inner wall of the hole 101b can be located outside the side wall of the opening 100a. Further, it is possible to remove damage on the side wall of the opening 100a, improve the state of the side wall of the opening 100a, and the like.

  Here, the hard mask 101 is formed over the substrate 100 using a film formation method. On the other hand, the resist mask 102 is formed on the hard mask 101 by using a coating method. In this case, the adhesive force between the resist mask 102 and the hard mask 101 is weaker than the adhesive force between the hard mask 101 and the substrate 100. Therefore, the processing liquid easily enters between the resist mask 102 and the hard mask 101, so that the resist mask 102 is more easily removed toward the inside of the hole 101b and toward the resist mask 102. As a result, the inner wall surface of the hole 101b is inclined. The inner wall surface of the hole 101b is inclined in a direction away from the center of the hole 101b toward the resist mask 102 side. That is, in the vicinity of the hole 101b, the thickness of the hard mask 101 gradually decreases toward the center of the hole 101b.

In this case, if the region into which the processing liquid enters between the resist mask 102 and the hard mask 101 becomes large, the resist mask 102 may be separated from the hard mask 101.
5A and 5B are schematic cross-sectional views illustrating the removal of the resist mask 102. FIG.
As shown in FIG. 5A, a plurality of openings 100a may be provided side by side. Therefore, when the region into which the processing liquid enters between the resist mask 102 and the hard mask 101 becomes large, the bonding area between the resist mask 102 and the hard mask 101 becomes small, and the bonding force may be too small. is there.

  If the bonding force between the resist mask 102 and the hard mask 101 becomes too small, the resist mask 102 may be peeled from the hard mask 101 as shown in FIG.

When the resist mask 102 is peeled off, the hard mask 101 cannot be protected during a dry process described later.
Further, since the peeled resist mask 102 becomes particles, there is a possibility that the product yield may be significantly reduced.

Therefore, in the processing method of the processing object according to the present embodiment, the size of the region into which the processing liquid enters is controlled.
According to the knowledge obtained by the present inventor, when the concentration of hydrogen fluoride in the treatment liquid is within an appropriate range, peeling of the resist mask 102 can be suppressed.
FIGS. 6A and 6B are schematic cross-sectional views illustrating the relationship between the concentration of hydrogen fluoride in hydrofluoric acid and the size of a region into which hydrofluoric acid enters.
FIG. 6A shows a case where the concentration of hydrogen fluoride in hydrofluoric acid is 0.5 wt%.
FIG. 6B shows a case where the concentration of hydrogen fluoride in hydrofluoric acid is 3 wt%.

  As can be seen from FIG. 6A, if the concentration of hydrogen fluoride in hydrofluoric acid is set to 0.5 wt% or less, the size of the region where hydrofluoric acid enters between the resist mask 102 and the hard mask 101 is reduced. Can be appropriate. Therefore, the resist mask 102 is hardly peeled off.

  On the other hand, as can be seen from FIG. 6B, if the concentration of hydrogen fluoride in hydrofluoric acid exceeds 0.5 wt%, the size of the region into which hydrofluoric acid enters becomes too large. Therefore, peeling of the resist mask 102 easily occurs.

  When the concentration of hydrogen fluoride in hydrofluoric acid is 3 wt% or less, the hard mask 101 can be selectively removed from the substrate 100 and the resist mask 102. That is, the removal of the substrate 100 and the resist mask 102 can be suppressed, and the removal of the hard mask 101 can be promoted.

FIG. 7 is a schematic cross-sectional view illustrating the relationship between the concentration of hydrogen fluoride in buffered hydrofluoric acid and the size of a region into which buffered hydrofluoric acid enters.
FIG. 7 shows the case where the concentration of hydrogen fluoride in buffered hydrofluoric acid is 1 wt%.

  As can be seen from FIG. 7, when the concentration of hydrogen fluoride in the buffered hydrofluoric acid is 1 wt% or less, the size of the region into which the buffered hydrofluoric acid enters can be made appropriate. Therefore, the resist mask 102 is hardly peeled off.

Further, buffered hydrofluoric acid is difficult to penetrate between the hard mask 101 and the resist mask 102 due to the high viscosity of the solution, and even when the concentration of buffered hydrofluoric acid is about 3 wt%, erosion is less likely than in hydrofluoric acid . Therefore, the resist removal rate can be reduced, and the removal rate of the hard mask 101 can be easily controlled.

  When the concentration of hydrogen fluoride in buffered hydrofluoric acid is 1 wt% or less, the hard mask 101 can be selectively removed from the substrate 100 and the resist mask 102. That is, the removal of the substrate 100 and the resist mask 102 can be suppressed, and the removal of the hard mask 101 can be promoted.

Next, as shown in FIG. 3B and FIG. 4B, a roundness 100b is formed around the periphery of the opening of the opening 100a.
In this case, dry processing is performed on the opening 100a and the hole 101b. Note that after the above-described wet processing is performed, the processed object 200 is in a wet state, and thus a drying step is performed before performing the dry processing. The drying step can be performed by a known technique such as blowing with an inert gas such as N2 or spin drying. In the dry process, for example, radicals are supplied to the opening 100a and the hole 101b.
That is, in the dry process, radicals generated by using plasma are supplied to the processing object 200, so that the periphery of the opening of the opening 100a is rounded.
The radical can be, for example, a fluorine radical.
Fluorine radicals can be generated, for example, by exciting and activating a gas containing fluorine atoms using plasma. In this case, ions and the like are generated together with the fluorine radicals, but it is preferable that the ions and the like do not reach the processing object 200. For example, when a remote plasma method such as CDE is used, fluorine radicals mainly reach the processing object 200.
By preventing ions or the like from reaching the processing object 200, it is possible to prevent the side wall of the opening 100a from being damaged or the side wall of the opening 100a from being opened.
At this time, as shown in FIG. 3B, fluorine radicals are supplied in a state where the hard mask 101 is present on the surface of the main surface 100b of the substrate 100 where the opening 100 is not rounded.

The gas containing a fluorine atom can be, for example, CHF ₃ , CF ₄ , C ₄ F ₈ or the like.

Here, simply supplying fluorine radicals to the opening 100a and the hole 101b cannot form the roundness 100b on the periphery of the opening of the opening 100a.
According to the knowledge obtained by the present inventor, in the vicinity of the hole 101b, the thickness of the hard mask 101 is set to gradually decrease toward the center of the hole 101b, and the substrate 100 (for example, If the selection ratio of the hard mask 101 (for example, silicon oxide) to silicon (silicon) is 0.5 or more and 2 or less, the roundness 100b can be formed.
In this case, by controlling the selection ratio, the size of the roundness 100b can be changed. For example, if the selection ratio is 1, the size of the roundness 100b can be maximized.
If the size of the roundness 100b can be increased, it becomes easy to embed an insulator inside the opening 100a.

The selection ratio can be changed by controlling the ratio of the gas containing a fluorine atom to the additional gas, the temperature of the processing object 200, and the like in the plasma processing.
For example, when the selectivity is about 1, oxygen can be used as the additive gas so that the concentration of oxygen is 70 vol% or more. Further, the temperature of the processing object 200 can be set to 120 ° C. or higher.

In this case, depending on the selectivity and the temperature of the processing object 200, the etching rate of the hard mask 101 with respect to the resist mask 102 may be reduced in some cases. If the etching rate of the resist mask 102 can be reduced, the removal of the resist mask 102 and the etching of the hard mask 101 can be suppressed.
If the hard mask 101 can be suppressed from being etched, it is possible to suppress the plasma from damaging the surface of the substrate 100.

  Further, depending on the selectivity and the temperature of the processing object 200, the etching rate of the hard mask 101 with respect to the resist mask 102 may not be reduced in some cases. In such a case, a plasma treatment in which the concentration of a gas containing fluorine atoms is increased before or during the above-described dry treatment may be performed. When the plasma treatment is performed with an increased concentration of a gas containing fluorine atoms, the surface of the resist mask 102 is fluorinated. For example, the concentration of the gas containing a fluorine atom can be 70 vol% or more of the processing gas. If the surface of the resist mask 102 is fluorinated, it becomes difficult to remove the resist mask 102 even by performing the above-described dry treatment.

If the etching rate for the resist mask 102 cannot be reduced, the thickness of the hard mask 101 may be increased. That is, the thickness of the hard mask 101 may be such that the hard mask 101 remains during the above-described dry processing. In this case, since the resist mask 102 is removed during the above-mentioned dry processing, the ashing step can be omitted or shortened.
The following effects are also obtained in the present embodiment described above.
When the opening 100a is formed by RIE, ions may enter the surface of the opening 100a to cause ion damage or crystal defects. However, in the dry processing of the present embodiment, the fluorine radicals reach the surface of the opening 100a, so that the damaged surface area of the opening 100 can be removed. Further, at the bottom of the opening 100a, the corner at the bottom has a lower etching rate than at the bottom of the bottom, so that the corner at the bottom can be rounded. Thus, in the subsequent step of embedding the insulator in the opening 100a, the insulator can be easily embedded in the opening 100a.
In addition, in the dry processing of the present embodiment, since the periphery of the opening of the opening 100a can be rounded while the surface of the main surface 100b of the substrate 100 is covered with the hard mask 101, the surface of the main surface 100b The roundness can be formed around the periphery of the opening of the opening 100a without causing damage such as roughness and surface modification. Further, since fluorine radicals do not reach the surface of the main surface 100b covered with the hard mask 101, the surface of the main surface 100b is not etched. Accordingly, the periphery of the opening can be rounded without changing the thickness (height dimension) of the substrate. As described above, desired electric characteristics as a semiconductor device can be obtained.

(Second embodiment)
FIG. 8 is a layout diagram illustrating the processing apparatus 1 according to the second embodiment.
As shown in FIG. 8, the processing apparatus 1 includes a storage unit 2, a transport unit 3, a wet processing unit 4, a dry processing unit 5, and a control unit 6.
Further, a drying device (not shown) can be provided in the wet processing section 4, the dry processing section 5, or a transport path between both. The drying device has a function of drying the processed material 200 that has been subjected to the wet processing in the wet processing unit 4, for example, a nozzle that blows an inert gas such as N 2 gas, a rotating table that rotates the processed material 200, and a rotation table. Has a mechanism.

  The storage section 2 stores the processed material 200. The storage unit 2 can be a carrier or the like that can store a plurality of processed products 200 in a stacked (multi-stage) shape. The storage unit 2 can be, for example, a FOUP (Front-Opening Unified Pod) or a SMIF (Standard Mechanical Interface). The FOUP is a front-opening carrier for transporting and storing a processed product 200 used in a mini-environment type semiconductor factory. SMIF is a bottom open carrier.

  The storage unit 2 includes a storage unit 2 a for storing the processed material 200 (the processed material 200 before processing) conveyed to the wet processing unit 4, and the processed material 200 (the processed processed material 200) conveyed from the dry processing unit 5. ) Can be provided.

The transport unit 3 transports the processed material 200 between the storage unit 2a and the wet processing unit 4, between the wet processing unit 4 and the dry processing unit 5, and between the dry processing unit 5 and the storage unit 2b.
The transport unit 3 includes a holding unit 3a, an arm unit 3b, and a driving unit 3c.
The support part 3a supports the processing object 200. The support section 3a may be provided with holding means such as a mechanical chuck, a vacuum chuck, and an electrostatic chuck for holding the processing object 200, for example. The holding means is not always necessary, and may be provided as necessary.

The arm 3b has an articulated structure, and is capable of performing a bending operation and a turning operation. A support 3a is attached to one end of the arm 3b. The arm 3b can turn the attached support 3a.
The other end of the arm 3b is attached to the drive 3c.
The drive unit 3c has a control motor such as a servomotor, and causes the arm unit 3b to perform a bending operation and a turning operation. Further, the driving unit 3c causes the support unit 3a attached to the arm unit 3b to perform a turning operation.
The transport unit 3 can be, for example, a horizontal articulated robot.
However, the configuration of the transport unit 3 is not limited to the illustrated one, and any configuration may be used as long as at least the workpiece 200 can be transported.

The wet processing unit 4 processes the processing object 200 using the processing liquid. The wet processing unit 4 supplies a processing liquid to the opening 100a and the hole 101b of the processing object 200.
FIG. 9 is a schematic cross-sectional view illustrating the wet processing unit 4.
The wet processing unit 4 illustrated in FIG. 9 immerses the processing object 200 in the processing liquid 300.
As described above, the wet processing unit 4 may supply the processing liquid 300 to the processing object 200 in a state where the processing object 200 is rotated. However, in consideration of suppressing the removal of the resist mask 102, it is preferable that the wet processing unit 4 immerses the processing object 200 in the processing liquid 300.

As shown in FIG. 9, the wet processing section 4 is provided with a processing container 40, a processing tank 41, a processing liquid storage section 42, a supply section 43, and a discharge section 44.
The processing container 40 has an airtight structure that does not allow particles to enter. The processing container 40 is provided with a loading / unloading port (not shown), so that the processing object 200 can be loaded and unloaded through the loading / unloading port (not shown).

The processing tank 41 is provided inside the processing container 40. The upper end of the processing tank 41 is open so that the processing object 200 can be loaded and pulled up by a lifting device (not shown).
The inside of the processing tank 41 is filled with the processing liquid 300.
The treatment liquid 300 can be, for example, hydrofluoric acid having a hydrogen fluoride concentration of 0.5 wt% or less, or buffered hydrofluoric acid having a hydrogen fluoride concentration of 1 wt% or less.
Since the concentration of hydrogen fluoride is the same as that described above, detailed description is omitted.

The processing liquid storage section 42 stores the processing liquid 300 before use.
The supply unit 43 supplies the processing liquid 300 before use stored in the processing liquid storage unit 42 into the processing tank 41.
The supply unit 43 may include, for example, a pump 43a, an on-off valve 43b, and a pipe 43c.

The discharge unit 44 discharges the used processing liquid 300 inside the processing tank 41 to the outside of the processing container 40.
The discharge unit 44 may be provided with, for example, an on-off valve 44a and a pipe 44b.

The dry processing unit 5 processes the processed object 200 using radicals generated using plasma. The dry processing unit 5 supplies radicals to the opening 100a and the hole 101b of the processed product 200.
FIG. 10 is a schematic cross-sectional view illustrating the dry processing unit 5.
The dry processing unit 5 illustrated in FIG. 10 is a CDE device that is a remote plasma device.
However, the dry processing unit 5 is not limited to the CDE apparatus, and it is sufficient that the radicals mainly reach the processing object 200. For example, the dry processing unit 5 may be a down-flow type plasma processing apparatus.

As shown in FIG. 10, the dry processing section 5 is provided with a processing container 50, a plasma generation section 51, a decompression section 52, a gas supply section 53, and a transport pipe 54.
The processing container 50 has an airtight structure capable of maintaining an atmosphere reduced in pressure from the atmospheric pressure. The processing container 50 is provided with a carry-in / carry-out port (not shown), so that the processing object 200 can be carried in / out via the carry-in / out port (not shown).

A mounting section 50a having a built-in electrostatic chuck (not shown) is provided inside the processing container 50. Further, a heating device 55 for controlling the temperature of the processing object 200 and the like can be provided on the mounting portion 50a.
A current plate 50b is provided inside the processing container 50 and above the mounting portion 50a. The rectifying plate 50b rectifies the flow of the gas containing radicals introduced from the transport pipe 54 so that the amount of radicals above the processing object 200 becomes uniform. A region between the rectifying plate 50b and the upper surface (mounting surface) of the mounting portion 50a becomes a processing space 50c in which the dry processing is performed on the processing object 200.

The plasma generator 51 includes a discharge tube 51a, an introduction waveguide 51b, and a microwave generator 51c.
The discharge tube 51 a has a region for generating plasma inside, and is provided at a position separated from the processing container 50. The discharge tube 51a has a tubular shape, and is formed of a material that has a high transmittance to microwaves M and is difficult to be etched. For example, the discharge tube 51a can be formed from a dielectric such as alumina or quartz.

The introduction waveguide 51b has a tubular shape. The microwave M emitted from the microwave generation unit 51c propagates in the space inside the introduction waveguide 51b.
A microwave generator 51c is connected to one end of the introduction waveguide 51b. The other end of the introduction waveguide 51b is connected to the discharge tube 51a via the shield 51b1. Further, an annular slot 51b2 is provided at a connection portion between the introduction waveguide 51b and the shielding portion 51b1. The microwave M that has propagated inside the introduction waveguide 51b is introduced into the discharge tube 51a via the slot 51b2.

The microwave generation unit 51c generates a microwave M having a predetermined frequency (for example, 2.45 GHz) and radiates the microwave M toward the introduction waveguide 51b.
The decompression unit 52 can be, for example, a turbo molecular pump or the like. The decompression unit 52 is connected to the processing container 50 via a pressure control unit (Auto Pressure Controller: APC) 52a.

The gas supply unit 53 is connected to an end of the discharge tube 51a on the opposite side to the transport tube 54 via a mass flow controller (MFC) 53a.
The gas supply unit 53 supplies the gas G to the inside of the discharge tube 51a. The supply amount of the gas G supplied into the discharge tube 51a is controlled by the flow control unit 53a. The gas G can be, for example, a mixed gas of a gas containing a fluorine atom and oxygen. In this case, the oxygen concentration is set to 70 vol% or more. The gas containing a fluorine atom can be, for example, CHF ₃ , CF ₄ , C ₄ F ₈ or the like.

  One end of the transport tube 54 is connected to an end of the discharge tube 51a opposite to the gas supply unit 53 side. The other end of the transport pipe 54 is connected to the processing container 50.

The control unit 6 controls the operation of each element provided in the processing device 1.
For example, the control unit 6 controls a lifting device (not shown) provided in the storage unit 2 to change the storage position of the processing object 200 in the vertical direction.
For example, the control unit 6 controls the operation of each element provided in the transport unit 3 to transport and deliver the processed object 200.
For example, the control unit 6 controls the operation of each element provided in the wet processing unit 4 to perform the above-described wet processing on the processing object 200. That is, the control unit 6 controls the operation of each element provided in the wet processing unit 4 to immerse the processing object 200 in the processing liquid 300 and pull up the processing object 200 from the processing liquid 300.

For example, the control unit 6 controls the operation of each element provided in the dry processing unit 5 to perform the above-described dry processing on the processed object 200.
The dry processing unit 5 performs the above-described dry processing on the processed product 200 as described below, for example.

First, the processing object 200 is placed on the placement unit 50a by a transport device (not shown).
Next, the inside of the processing container 50 is reduced to a predetermined pressure by the decompression unit 52.
Next, a gas G of a predetermined flow rate in which oxygen and fluorine are mixed at a predetermined mixing ratio is supplied into the discharge tube 51a from the gas supply unit 53 via the flow control unit 53a. On the other hand, a microwave M having a predetermined power is radiated from the microwave generation unit 51c into the introduction waveguide 51b. The radiated microwave M propagates through the introduction waveguide 51b and is radiated toward the discharge tube 51a via the slot 51b2.

  The microwave M radiated toward the discharge tube 51a propagates on the surface of the discharge tube 51a and is radiated into the discharge tube 51a. The plasma P is generated by the energy of the microwave M radiated into the discharge tube 51a in this manner. When the electron density in the generated plasma P becomes higher than the density (cut-off density) at which the microwave M supplied through the discharge tube 51a can be shielded, the microwave M is discharged from the inner wall surface of the discharge tube 51a. The light is reflected before entering a space (skin depth) toward the space within 51a. Therefore, a standing wave of the microwave M is formed between the reflection surface of the microwave M and the lower surface of the slot 51b2. As a result, the reflection surface of the microwave M becomes a plasma excitation surface, and the plasma P is stably excited and generated on the plasma excitation surface. In the plasma P excited and generated on the plasma excitation surface, the gas G is excited and activated to generate plasma products such as radicals and ions.

  The gas containing the generated plasma product is transported into the processing container 50 via the transport pipe 54. At this time, ions having a short life cannot reach the processing container 50, and only radicals having a long life reach the processing container 50. The gas containing radicals introduced into the processing container 50 is rectified by the rectifying plate 50b, reaches the surface of the processing object 200, and is subjected to the above-described dry processing.

When forming the roundness 100b on the periphery of the opening of the opening 100a, the dry processing unit 5 sets the selection ratio of the hard mask 101 to the substrate 100 to be 0.5 or more and 2 or less.
The selection ratio can be changed by controlling the ratio of the gas containing a fluorine atom to the additional gas, the temperature of the processing object 200, and the like in the plasma processing.
For example, when the selectivity is about 1, oxygen can be used as the additive gas and the flow rate control unit 53a can be controlled so that the oxygen concentration becomes 70 vol% or more. Further, the heating device 55 can be controlled so that the temperature of the processing object 200 becomes 120 ° C. or higher.

The embodiment has been described above. However, the invention is not limited to these descriptions.
Regarding the above-described embodiments, those in which those skilled in the art appropriately add, delete, or change the design of components, or add, omit, or change the conditions of the process, also have the features of the present invention. As long as they are included in the scope of the present invention.
For example, the shapes, dimensions, materials, arrangements, numbers, and the like of the components included in the wet processing unit 4 and the dry processing unit 5 are not limited to those illustrated, but can be appropriately changed. Further, each element included in each of the above-described embodiments can be combined as far as possible, and a combination of these elements is included in the scope of the present invention as long as it includes the features of the present invention.

Reference Signs List 1 processing apparatus, 2 storage section, 3 transfer section, 4 wet processing section, 5 dry processing section, 6 control section, 40 processing vessel, 41 processing tank, 42 processing liquid storage section, 50 processing vessel, 51 plasma generation section, 52 Decompression unit, 53 gas supply unit, 54 transport tube, 100 substrate, 100a opening, 101 hard mask, 101b hole, 102 resist mask, 102a pattern, 200 processed product, 300 processing liquid, G gas, M microwave

Claims (12)

A substrate including silicon and having an opening;
A hard mask provided on the substrate, including at least one of silicon oxide and silicon nitride, and having a hole provided above the opening,
A resist mask provided on the hard mask and having a pattern provided above the opening;
A method for processing a processed material comprising:
Supplying a processing liquid to the processing object, in the vicinity of the hole, gradually reducing the thickness of the hard mask toward the center of the hole;
Supplying a radical generated by using plasma to the processing object, and forming a rounded edge of the opening of the opening;
A method for treating a processed material comprising:   2. The method according to claim 1, wherein the treatment liquid is hydrofluoric acid having a hydrogen fluoride concentration of 0.5 wt% or less.   2. The method according to claim 1, wherein the treatment liquid is buffered hydrofluoric acid. The method for treating a treated product according to claim 3, wherein the concentration of hydrogen fluoride in the buffered hydrofluoric acid is 1 wt% or less. The process according to any one of claims 1 to 4 , wherein in the step of forming roundness at the periphery of the opening of the opening, a selection ratio of the hard mask to the substrate is set to 0.5 or more and 2 or less. How to handle things. The method for treating a treated product according to any one of claims 1 to 5 , wherein the radical is a fluorine radical. A substrate including silicon and having an opening;
A hard mask provided on the substrate, including at least one of silicon oxide and silicon nitride, and having a hole provided above the opening,
A resist mask provided on the hard mask and having a pattern provided above the opening;
A processing apparatus for processing a workpiece, comprising:
Supplying a processing liquid to the processing object, in the vicinity of the hole, a wet processing unit that gradually reduces the thickness of the hard mask toward the center of the hole,
A dry processing unit that supplies a radical generated by using plasma to the processing object, and forms roundness around a periphery of the opening,
A processing device for processing objects provided with: The processing apparatus according to claim 7 , wherein the processing liquid is hydrofluoric acid having a hydrogen fluoride concentration of 0.5 wt% or less. The apparatus for processing a processed product according to claim 7 , wherein the processing liquid is buffered hydrofluoric acid. The processing device for a processed product according to claim 9, wherein the concentration of hydrogen fluoride in the buffered hydrofluoric acid is 1 wt% or less. 11. The dry processing unit according to claim 7 , wherein, when forming roundness around a periphery of the opening of the opening, a selection ratio of the hard mask to the substrate is 0.5 or more and 2 or less. An apparatus for processing a processed product according to any one of the above. The processing apparatus of a processed product according to claim 7 , wherein the radical is a fluorine radical.

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