Substrate processing method, substrate processing device and computer storage medium

Abstract

The invention provides a substrate processing method, a substrate processing apparatus, and a computer storage medium capable of obtaining a good pattern containing a metal resist. The substrate processing method includes a step of developing a substrate on which a coating film containing a metal resist is formed and which has been subjected to an exposure treatment and a heat treatment after the exposure treatment, the developing step including a step of exposing the substrate to an acid atmosphere while heating the substrate. The acid atmosphere is at least one of a gas containing a weak acid and a mist.

Description

Technical Field

[0001] The invention relates to a substrate processing method, a substrate processing device and a computer storage medium. Background Art

[0002] Patent Document 1 discloses a method for developing a substrate, the method comprising supplying a developer containing an organic solvent to the substrate on which a metal-containing coating film has been exposed in a predetermined pattern.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-96081 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] The technology of the present invention produces a good pattern of a metal-containing resist.

[0008] Technical solutions to technical problems

[0009] One embodiment of the present invention is a substrate processing method, which includes the step of developing a substrate formed with a film containing a metal resist and subjected to exposure treatment and heat treatment after the exposure treatment, the developing step including the step of exposing the substrate to an acid atmosphere while heating it, the acid atmosphere being an atmosphere containing at least either a gas or a mist of a weak acid.

[0010] Effects of the Invention

[0011] According to the present invention, a good pattern of a metal-containing resist can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a plan view schematically showing the general structure of a wafer processing system as a substrate processing apparatus according to this embodiment.

[0013] Figure 2 It is a front view schematically showing the general structure of a wafer processing system as a substrate processing apparatus according to this embodiment.

[0014] Figure 3 It is a longitudinal sectional view schematically showing the general structure of the developing unit.

[0015] Figure 4 It is a bottom view schematically showing the general structure of the upper chamber.

[0016] Figure 5This is a flowchart showing the main steps of Example 1 of the processing flow.

[0017] Figure 6 Yes Figure 3 An explanatory diagram of the operation of the developing unit is provided.

[0018] Figure 7 This is a diagram showing the results of developing a metal-containing resist for forming a pillar pattern.

[0019] Figure 8 This is a diagram showing the results of developing a metal-containing resist for forming a pillar pattern.

[0020] Figure 9 This is a diagram showing the results of developing a metal-containing resist for forming a pillar pattern.

[0021] Figure 10 It is a diagram showing the results of developing for forming a line and space pattern of a metal-containing resist.

[0022] Figure 11 It is a diagram showing the results of developing for forming a line and space pattern of a metal-containing resist.

[0023] Figure 12 It is a diagram showing the results of developing for forming a line and space pattern of a metal-containing resist.

[0024] Figure 13 It is a diagram showing the etching results using a line and space pattern containing a metal resist as a mask.

[0025] Description of Reference Numerals

[0026] 1Wafer processing system

[0027] 100 Control Department

[0028] 200 developing unit

[0029] 311 sprinkler head

[0030] 350 hot plate

[0031] H Storage Media

[0032] W chip. DETAILED DESCRIPTION

[0033] In photolithography, a process used in the manufacturing of semiconductor devices, a series of processes is performed to form a desired resist pattern on a substrate such as a semiconductor wafer (hereinafter referred to as a "wafer"). This series of processes includes, for example, a resist coating process in which a resist liquid is supplied to the substrate to form a resist film (hereinafter referred to as a resist film); an exposure process in which the resist film is exposed to light in a predetermined pattern; a post-exposure bake (PEB) process in which the substrate is heated after exposure to promote chemical reactions within the exposed resist film; and a development process in which the exposed substrate is developed to form a resist pattern.

[0034] In the above-mentioned development process, for example, a developer is supplied to the substrate to form a liquid film of the developer on the substrate surface to develop the substrate. In addition, in this case, a cleaning solution such as pure water is sometimes supplied to the substrate afterwards to clean the substrate by rotating it at high speed.

[0035] However, recent advances in exposure technology have led to further miniaturization of semiconductor devices, specifically, resist patterns. Problems arise when developer or cleaning fluid remains on the substrate during the development process in a tiny resist pattern. For example, residual developer or cleaning fluid between patterns can cause so-called pattern collapse due to the surface tension of the residual developer or cleaning fluid.

[0036] Furthermore, chemically amplified resists have been commonly used as resists in the past, but in recent years, non-chemically amplified metal-containing resists have also been used. These metal-containing resists are expected to be more suitable for forming micro-patterns. However, even when metal-containing resists are used, developing a substrate with a processing solution such as a developer to form a micro-resist pattern can cause pattern collapse, which is a defect known as pattern collapse.

[0037] Therefore, the technology of the present invention suppresses the occurrence of defects such as pattern collapse and obtains a good pattern of a metal-containing resist.

[0038] Hereinafter, the substrate processing method and substrate processing apparatus of this embodiment will be described with reference to the accompanying drawings. In addition, in this specification and the accompanying drawings, elements having substantially the same functional configuration are denoted by the same reference numerals and repeated descriptions are omitted.

[0039] <Wafer processing system>

[0040] First, the configuration of a wafer processing system as a substrate processing apparatus according to this embodiment will be described. Figure 1 、 Figure 2They are a top view and a front view schematically showing the general structure of the wafer processing system 1. In this embodiment, the wafer processing system 1 is described as an example of a photolithography processing system that performs resist film formation and development on a wafer W.

[0041] like Figure 1 As shown, the wafer processing system 1 includes: a box station 2, which can carry in and out a box C containing a plurality of wafers W; and a processing station 3, which includes a plurality of various processing devices for performing predetermined processing on the wafers W. Moreover, the wafer processing system 1 has a structure in which the box station 2, the processing station 3 and the interface station 4 are connected as one body. The interface station 4 transfers the wafers W between the processing station 3 and an exposure device (not shown) adjacent to the interface station on the opposite side of the processing station 3. In addition, as Figure 1 As shown, two processing stations 3 are provided between the cassette station 2 and the interface station 4, but one or three or more processing stations may be provided.

[0042] The cassette station 2 is provided with a cassette mounting table 21, a wafer conveyor 22, and a wafer conveyor 23. A plurality of cassette mounting plates 24 are arranged in the X direction on the cassette mounting table 21. The cassette station 2 uses the wafer conveyor 22 or the wafer conveyor 23 to transport wafers between the cassette C mounted on the cassette mounting table 21 and the processing station 3. Therefore, the wafer conveyor 22 and the wafer conveyor 23 each include a drive mechanism for movement in various directions, such as the horizontal direction (X and Y directions), the vertical direction (Z direction), and around the vertical axis (θ direction), as required. They may also include a drive mechanism for movement in all directions.

[0043] At least one of the wafer conveyor 22 and the wafer conveyor 23 can deliver wafers W to the cassette C and can also deliver wafers to the processing station 3. The delivery of wafers W to the processing station 3, for example, involves delivering wafers to a third block G3 that includes a delivery device accessible to a wafer conveyor 33 within the processing station 3, as described later. The third block G3 may also include a plurality of delivery devices (not shown) arranged in a vertical direction.

[0044] Furthermore, an inspection device (not shown) for inspecting the wafer W may be provided at a position accessible to either the wafer conveyance device 22 or the wafer conveyance device 23 .

[0045] The processing station 3 is provided with a plurality of blocks, for example, the first, second and fourth blocks G1, G2 and G4. Figure 2 As shown, a plurality of layers 31 including first and second blocks G1 and G2 are stacked in the vertical direction. For example, on the front side of the processing station 3 ( Figure 1 The first block G1 is provided on the negative side of the X direction of the processing station 3. Figure 1The second block G2 is provided on the positive X direction side of the processing station 3. Figure 1 A fourth block G4 is provided at the connection portion (on the positive Y direction) or to another adjacent processing station 3. The fourth block G4 may also include multiple transfer devices arranged in a vertical direction. Furthermore, the aforementioned third block G3 may also be provided within a processing station 3.

[0046] The first block G1 includes a plurality of processing devices, such as a patterning film forming device and a developing device (not shown). The patterning film forming device may include, for example, a resist film forming device and an anti-reflective film forming device.

[0047] For example, a plurality of processing devices are arranged horizontally in the first block G1 . The number, arrangement, and type of the processing devices in the first block G1 can be arbitrarily selected.

[0048] In these patterning film-forming apparatuses and development processing apparatuses, predetermined processes are performed, for example, by supplying a predetermined processing liquid or a predetermined gas onto the wafer W. Thus, in the patterning film-forming apparatus, a resist film is formed as a mask for forming a pattern of the underlying film, and an antireflection film is formed for efficiently performing light irradiation processing, such as exposure processing. Meanwhile, in the development processing apparatus, a portion of the exposed resist film is removed to form the concave and convex shapes serving as the aforementioned mask.

[0049] For example, in the second block G2, heat treatment devices (not shown) are arranged in the vertical and horizontal directions to perform heat treatments such as heating and cooling of the wafer W. In addition, although not shown, in the second block G2, hydrophobic treatment devices for performing hydrophobic treatment to improve the fixation (fixability) between the resist liquid and the wafer W, and peripheral exposure devices for exposing the outer periphery of the wafer W are arranged in the vertical (Z) and horizontal directions. The number and arrangement of these heat treatment devices, hydrophobic treatment devices, and peripheral exposure devices can also be arbitrarily selected.

[0050] like Figure 1 As shown in FIG. 1 , a region sandwiched between the first block G1 and the second block G2 in a plan view forms a wafer conveying region 32. In the wafer conveying region 32, a wafer conveying device 33 is disposed, for example.

[0051] The wafer conveyor 33 has a conveying arm that can move in the Y direction, the front-back direction, the θ direction, and the Z direction. The wafer conveyor 33 can move within the wafer conveying area 32 and convey the wafer W to the predetermined devices in the surrounding first block G1, second block G2, third block G3, and fourth block G4. Figure 1As shown, when there are multiple processing stations 3, the chip conveying device 33 set in the processing station 3 located on the side of the interface station 4 can not only convey the chip W to the specified devices in the first, second and fourth blocks G1, G2, and G4, but also convey the chip W to the specified device in the fifth block G5 described later.

[0052] For example, multiple wafer conveyor devices 33 are arranged vertically. One wafer conveyor device 33 can convey a wafer W to a predetermined device at the height of the upper layers 31 of the multiple layers 31 stacked vertically. Other wafer conveyor devices 33 can convey wafers W to predetermined devices at the height of the layers 31 below these layers 31. Multiple wafer conveyor areas 32 are provided to enable such conveyance of wafers W. Furthermore, the number of wafer conveyor devices 33 and the number of layers 31 corresponding to one wafer conveyor device 33 can be arbitrarily selected, such as by providing a wafer conveyor device 33 for each layer 31.

[0053] In addition, a shuttle device (not shown) may be provided in the wafer transfer area 32 or the first block G1 or the second block G2. The shuttle device linearly transfers wafers W between a space adjacent to one side of the processing station 3 and another space adjacent to the opposite side.

[0054] The interface station 4 is provided with a fifth block G5 including a plurality of transfer devices, a wafer conveyor 41, and a wafer conveyor 42. The interface station 4 uses the wafer conveyor 41 or the wafer conveyor 42 to transport wafers W between the fifth block G5, where the wafer conveyor 33 transfers wafers W, and the exposure machine. Therefore, the wafer conveyor 41 and the wafer conveyor 42 each include a drive mechanism for movement in various directions, such as the X direction, the Y direction, the Z direction, and around the vertical axis (θ direction), as needed, and may also include a drive mechanism for movement in all directions. At least one of the wafer conveyor 41 and the wafer conveyor 42 is capable of supporting the wafer W and transporting it between the transfer device and the exposure machine within the fifth block G5.

[0055] A cleaning device for cleaning the surface of the wafer W and the aforementioned edge exposure device may be provided in the interface station 4 at a position accessible to either the wafer conveying device 41 or the wafer conveying device 42 .

[0056] The inspection device can be set in the box station 2 as described above, but can also be set in the processing station 3 and the interface station 4 at a position that can be reached by any of the wafer conveying devices 33, 41, and 42 set inside each (processing station 3 and interface station 4).

[0057] like Figure 1As shown, the wafer processing system 1 described above is provided with at least one control unit 100. The control unit 100 processes computer-executable commands that cause the wafer processing system 1 to perform the various steps described herein. The control unit 100 is capable of controlling various components of the wafer processing system 1 to execute the various steps described herein. In one embodiment, part or all of the control unit 100 may be included in the wafer processing system 1. The control unit 100 may also include a processing unit, a storage unit, and a communication interface. The control unit 100 may be implemented, for example, by a computer. The processing unit may be configured to perform various control operations by reading a program from the storage unit that provides logic or routines for performing various control operations and executing the read program. This program may be pre-stored in the storage unit or retrieved from a medium when needed. The retrieved program is stored in the storage unit and read from the storage unit and executed by the processing unit. The medium may be any computer-readable storage medium or a communication line connected to the communication interface. The storage medium may be volatile or non-volatile. The processing unit may be a CPU (Central Processing Unit) or one or more circuits. The storage unit may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface may also communicate with the wafer processing system 1 via a communication line such as a LAN (Local Area Network).

[0058] Furthermore, the wafer processing system of the present invention is not limited to the configuration described above. For example, in the above-described embodiment, the wafer processing system is directly connected to the exposure apparatus, and wafers W are transferred between the interface station 4 and the exposure apparatus. However, the wafer processing system may not be directly connected to the exposure apparatus. In this case, for example, after wafer W is transferred from the cassette station 2 to the processing station 3 and subjected to necessary processing, it is transferred back to the cassette station 2 to be transported outside the system.

[0059] Furthermore, unnecessary devices among the devices listed as processing devices may not be provided in the wafer processing system, or processing in the devices may not be performed.

[0060] <Types of Resists>

[0061] In the wafer processing system 1 of the present invention, the resist film formed on the wafer W by the resist film forming apparatus is a metal-containing resist film.

[0062] The metal contained in the metal-containing resist is arbitrary, and is, for example, tin. The metal-containing resist used in the wafer processing system 1 is a negative type.

[0063] <Developing Unit 200>

[0064] Next, the developing unit 200 will be described. Figure 3 It is a longitudinal sectional view schematically showing the general structure of the developing unit 200 . Figure 4 It is a bottom view schematically showing the general structure of an upper chamber 301 described later.

[0065] Figure 3 The developing unit 200 is provided with a chamber 300, which covers a processing space K on a heat plate 350 described later and accommodates wafers W during heat treatment. The chamber 300 includes an upper chamber 301 located at the upper side and a lower chamber 302 located at the lower side and integrated with the upper chamber 301. The lower chamber 302 can hermetically seal the interior.

[0066] The upper chamber 301 is configured to be movable upward and downward by a lifting mechanism (not shown). The lifting mechanism includes a driving source (not shown) such as a motor that generates a driving force for lifting the upper chamber 301. The lifting mechanism is controlled by the control unit 100.

[0067] The upper chamber 301 is formed, for example, in a generally cylindrical shape with an open bottom surface. The upper chamber 301 has a top 310. A processing space K is formed below the top 310 and is positioned to face a wafer W on a hot plate 350, described later. A showerhead 311, serving as a gas outlet, is also provided on the top 310.

[0068] The shower head 311 discharges a process gas containing a weak acid gas into the chamber 300. Specifically, the process gas containing a weak acid gas is discharged from the top 310 toward the hot plate 350. The weak acid gas is, for example, a gas of a carboxylic acid which is a weak acid. In addition, the gas of the carboxylic acid which is a weak acid can be, for example, the vapor of acetic acid. In the present invention, "weak acid" has an acid strength such that the development of the metal-containing resist does not progress at room temperature (20°C to 30°C), and specifically refers to an acid having an acid dissociation constant (acidity coefficient, pka) of 4 or more (for example, about 5). In addition, the process gas containing a weak acid gas can also contain a gas of an organic solvent. The process gas containing a weak acid gas contains, for example, a vapor of a mixed solution of a carboxylic acid which is a weak acid and an organic solvent, and a carrier gas. In addition, the process gas containing a weak acid gas can also contain a vapor from a carboxylic acid monomer which is a weak acid and a carrier gas. The carboxylic acid which is a weak acid is specifically, for example, acetic acid. The organic solvent is, for example, propylene glycol methyl ether acetate (PGMEA), and the carrier gas is, for example, an inert gas such as nitrogen or argon (Ar).

[0069] In this embodiment, the shower head 311 also discharges an inert gas such as nitrogen gas or Ar gas into the chamber 300. That is, the shower head 311 also functions as another gas discharge unit that discharges an inert gas into the chamber 300.

[0070] In addition, the shower head 311 has a plurality of discharge holes 312 and a gas distribution space 313 .

[0071] The discharge holes 312 are respectively formed on the lower surface of the shower head 311. For example, Figure 4 As shown, the discharge holes 312 are substantially evenly arranged in the center of the lower surface of the shower head 311 .

[0072] The gas distribution space 313 distributes the gas introduced into the shower head 311 and supplies it to each ejection hole 312. Figure 3 As shown, the shower head 311 is connected to the supply mechanisms 330 and 340 via a supply pipe 314 .

[0073] The supply mechanism 330 supplies a processing gas containing a weak acid gas to the shower head 311 (specifically, the gas distribution space 313). In addition, the supply mechanism 330 includes, for example, a container 331 for storing a mixed solution of a carboxylic acid as a weak acid and an organic solvent as a raw material of the weak acid gas, and a supply pipe 332 for supplying a carrier gas to the container 331. In order to promote the vaporization of the above-mentioned mixed solution, a heater (not shown) for heating the above-mentioned mixed solution may also be provided in the container 331. In addition, the carrier gas may also be used for bubbling the above-mentioned mixed solution in the container 331 to vaporize the above-mentioned mixed solution. A supply device group 333 including an on-off valve, a flow regulating valve, etc. for controlling the circulation of the carrier gas is provided in the supply pipe 332.

[0074] The supply mechanism 330 also includes an inlet pipe 334 for introducing the process gas containing the weak acid gas from the container 331 into the supply pipe 314. The inlet pipe 334 is provided with a supply device group 335 including an on-off valve, a flow rate regulating valve, and the like for controlling the flow of the process gas containing the weak acid gas.

[0075] The supply equipment groups 333 and 335 are controlled by the control unit 100 .

[0076] Supply mechanism 340 includes an introduction pipe 341 for introducing inert gas stored in a storage source (not shown) into supply pipe 314. Introduction pipe 341 is provided with a supply equipment group 342 including an on-off valve and a flow regulating valve for controlling the flow of inert gas.

[0077] The supply equipment group 342 is controlled by the control unit 100 .

[0078] In addition, a peripheral exhaust portion 320 is provided at the top 310 of the upper chamber 301. The peripheral exhaust portion 320 exhausts the processing space K from above the peripheral portion of the wafer W on the hot plate 350 in the top 310. The peripheral exhaust portion 320 has an exhaust port 321. Figure 4 As shown, the exhaust port 321 opens downward from the lower surface of the top 310 in a manner surrounding the outer periphery of the shower head 311. The exhaust port 321 may also be formed by arranging multiple exhaust holes along the outer periphery of the shower head 311. The peripheral exhaust portion 320 exhausts the processing space K through the exhaust port 321. The peripheral exhaust portion 320 constitutes the exhaust portion for exhausting the interior of the chamber 300, that is, the processing space K.

[0079] The exhaust port 321 is provided, for example, between a position where the peripheral end of the exhaust port 321 overlaps with the peripheral end of the wafer W on the heat plate 350 and a position 10 mm inside the position in a plan view.

[0080] Figure 3 The peripheral exhaust section 320 includes a peripheral exhaust path extending from an exhaust port 321. The peripheral exhaust path is connected to an exhaust device 323, such as a vacuum pump, via an exhaust pipe 322. An exhaust device group 324, including a valve and other components for adjusting the exhaust volume, is provided on the exhaust pipe 322. Exhaust device 323 and exhaust device group 324 are controlled by the control unit 100.

[0081] Alternatively, a central exhaust portion may be provided for exhausting the processing space K from above the central portion of the wafer W on the hot plate 350. In this case, exhaust may be performed from the central exhaust portion at a predetermined timing during the heat treatment process. The exhaust path of the central exhaust portion may, for example, be provided from the upper surface of the top portion 310 to the lower surface of the shower head 311 in a manner that passes through the central area of ​​the shower head 311. One or more exhaust ports of the central exhaust portion may also be provided on the lower surface of the shower head 311.

[0082] The lower chamber 302 is provided, for example, so as to surround the periphery of the heat plate 350 (specifically, the sides and the bottom of the heat plate 350 ).

[0083] The hot plate 350 is used to heat the wafer W. Furthermore, the hot plate 350 is configured to support the wafer W. The hot plate 350 has a disk shape with a thickness. A heater 351 is built into the hot plate 350, for example. The heater 351 is, for example, a resistance heater. The temperature of the hot plate 350 is adjusted, for example, by the control unit 100 controlling the heater 351. As a result, the wafer W placed on the hot plate 350 is heated to a predetermined temperature.

[0084] Furthermore, the hot plate 350 is provided with, for example, a plurality of adsorption holes (not shown) for adsorbing the wafer W onto the hot plate 350 .

[0085] The heat plate 350 may be configured to heat the wafer W so that the temperature thereof varies in the radial direction of the wafer W.

[0086] Furthermore, within the lower chamber 302, below the hot plate 350, there are provided, for example, three lift pins 360 that support the wafer W from below and raise and lower it. The lift pins 360 are raised and lowered by a lift mechanism 361. The lift mechanism 361 includes a drive source (not shown) such as a motor that generates a driving force for raising and lowering the lift pins 360. The lift mechanism 361 is controlled by the control unit 100. A through hole 352 is formed in the center of the hot plate 350, through which the lift pins 360 pass. The lift pins 360 can pass through the through hole 352 and extend from the upper surface of the hot plate 350.

[0087] The heat plate 350 is supported by, for example, the bottom wall of the lower chamber 302. Specifically, the heat plate 350 is supported by, for example, the bottom wall of the lower chamber 302 via the support portion 370.

[0088] In addition, when using Figure 1 and Figure 2 In the example described, the developing apparatus is installed in the first block G1 in the wafer processing system 1. In contrast, the developing unit 200 is installed in the second block G2 where a heat treatment apparatus including a hot plate is located, similar to the developing unit 200.

[0089] <Processing Flow Example 1>

[0090] Next, an example of a processing flow executed by the wafer processing system 1 will be described. Figure 5 This is a flowchart showing the main steps of Example 1 of the processing flow. Figure 6 1 and 2 are explanatory diagrams showing the operation of the developing unit 200 .

[0091] (Step S1)

[0092] First, a wafer W is introduced into the wafer processing system 1 .

[0093] Specifically, a cassette C containing a plurality of wafers W is brought into the cassette station 2 of the wafer processing system 1 and placed on the cassette placement plate 24. Subsequently, the wafers W in the cassette C are sequentially removed by the wafer conveyor 22 or the wafer conveyor 23 and conveyed to the delivery device in the third block G3.

[0094] (Step S2)

[0095] Next, the wafer W is subjected to an anti-reflection film forming process to form an anti-reflection film on the wafer W.

[0096] Specifically, the wafer W transferred to the transfer device in the third block G3 is supported by the wafer transfer device 33 and transferred to the anti-reflection film forming device provided in the first block G1, where an anti-reflection film is formed to cover the surface of the wafer W as a base film for the metal-containing resist. This step S2 may be omitted.

[0097] (Step S3)

[0098] Next, a resist coating process is performed on the wafer W to form a metal-containing resist film on the wafer W.

[0099] Specifically, the wafer W is supported by the wafer transfer device 33 and transferred to the resist film forming device set in the first block G1, so that a negative metal-containing resist film is formed to cover the anti-reflection film as a base film on the wafer W.

[0100] (Step S4)

[0101] Next, the wafer W is subjected to a PAB process.

[0102] Specifically, the wafer W is supported by the wafer conveyor 33 and conveyed to the heat treatment device for PAB treatment in the second block G2, where the PAB treatment is performed. Thereafter, the wafer W is conveyed to the transfer device in the fifth block G5. Figure 1 、 Figure 2 When there are multiple processing stations 3 , the wafer W is temporarily placed in the delivery device of the fourth block G4 before being transferred to the delivery device of the fifth block G5 , and then transferred between it and multiple wafer transfer devices 33 .

[0103] (Step S5)

[0104] Next, the wafer W is subjected to an exposure process.

[0105] Specifically, wafers W delivered to the interface in the fifth block G5 are transferred to the exposure device using wafer conveyor 41 and wafer conveyor 42, where they are exposed using a predetermined pattern. After exposure, wafers W are transferred to the interface in the fifth block G5 by wafer conveyor 41 and wafer conveyor 42.

[0106] (Step S6)

[0107] Next, the wafer W is subjected to a PEB process.

[0108] Specifically, the wafer W transferred to the transfer device of the fifth block G5 after the exposure process is transferred to the heat treatment device for PEB process by the wafer transfer device 33, and the PEB process is performed.

[0109] (Step S7)

[0110] Next, the wafer W is developed (step S7 ).

[0111] Specifically, the following steps S7a to S7d are performed.

[0112] (Step S7a)

[0113] First, a wafer W is placed into the chamber 300 .

[0114] Specifically, first, after the wafer W is moved into the developing unit 200 by the wafer conveyor 33, the lift pins 360 are raised and the transfer arm of the wafer conveyor 33 is withdrawn, and the wafer W is supported by the lift pins 360. Then, the upper chamber 301 is lowered, and the processing space K is divided by the upper chamber 301 and the lower chamber 302. At this time, Figure 6 As shown in FIG. 3 (A), the wafer W is, for example, still supported by the lift pins 360 and spaced apart from the hot plate 350. Subsequently, the lift pins 360 supporting the wafer W are lowered, and the wafer W is transferred and placed on the hot plate 350. Furthermore, the wafer W is suctioned to the hot plate 350 via suction holes (not shown).

[0115] (Step S7b)

[0116] Next, while the wafer W is heated, the wafer W is exposed to an acid atmosphere, which is an atmosphere containing a weak acid and an organic solvent gas.

[0117] Specifically, if Figure 6 As shown in (B), the process gas containing a weak acid and an organic solvent is discharged from the shower head 311 toward the wafer W, and the exhaust is performed using the peripheral exhaust portion 320. As a result, the wafer W is heated and exposed to the acid atmosphere of the weak acid gas in the processing space K. Specifically, the wafer W is heated and exposed to the acid atmosphere of the weak acid gas at a predetermined pressure above atmospheric pressure. When the negative metal-containing resist film on the wafer W is exposed to the above-mentioned acid atmosphere, the unexposed portion reacts with the weak acid gas and is degraded. In addition, by heating the wafer W, the unexposed portion of the negative metal-containing resist film on the wafer W that has been degraded by the reaction with the weak acid gas sublimates, forming a pattern of the metal-containing resist. For example, when the weak acid gas is acetic acid gas and the metal-containing resist film contains tin as a metal, tin acetate sublimates.

[0118] In addition, “atmospheric pressure” is, for example, 670 Torr to 760 Torr.

[0119] The temperature of the wafer W in step S7b is, for example, the same as that in the PEB process, specifically, 100° C. to 200° C. This step S7b is completed, for example, when a predetermined time has passed since the start of supply of the process gas.

[0120] (Step S7c)

[0121] On the other hand, in this step, the atmosphere around the wafer W is replaced from an acid atmosphere to an inert gas atmosphere.

[0122] Specifically, for example, Figure 6 As shown in (C), while the wafer W is not transported out of the chamber 300 and the peripheral exhaust unit 320 continues to exhaust, an inert gas is supplied from the showerhead 311. This changes the acidic atmosphere within the chamber 300 to an inert gas atmosphere. This step S7c is completed by, for example, stopping the inert gas supply after a predetermined time has passed since the initiation of the inert gas supply.

[0123] (Step S7d)

[0124] Thereafter, the wafer W is carried out from the chamber 300 .

[0125] Specifically, for example, the wafer W is discharged from the chamber 300 and carried out to the outside of the developing unit 200 in the reverse order of step S7 a .

[0126] Furthermore, the processing conditions of development can be adjusted according to the size of the pattern.

[0127] (Step S8)

[0128] After development, the wafer W is subjected to a POST process.

[0129] Specifically, the wafer W is transported to the thermal treatment unit 40 for POST processing by the wafer transport device 33, and the POST processing is performed. This step S8 may be omitted.

[0130] (Step S9)

[0131] Then, the wafer W is carried out from the wafer processing system 1 .

[0132] Specifically, the wafer W is transported by the wafer transport device 33 to the transfer device in the third block G3 and then transported by the wafer transport device 22 or 23 of the cassette station 2 to a cassette C on a predetermined cassette mounting plate 24. Thus, a series of photolithography steps are completed.

[0133] <Main effects of treatment flow example 1>

[0134] As described above, in this example, the step of developing the wafer W having the metal-containing resist film formed thereon involves exposing the wafer W, which has been subjected to PEB treatment, to an acidic atmosphere of a weak acid gas (specifically, a weak acid and an organic solvent gas) while heating it. Specifically, in this example, the portions of the metal-containing resist film to be removed by development are removed using acetic acid gas and heat, rather than using a developer or cleaning solution, to form a metal-containing resist pattern. Therefore, pattern collapse caused by the surface tension of the treatment solution is prevented. Therefore, according to this example, pattern collapse of the metal-containing resist can be suppressed, resulting in a good metal-containing resist pattern.

[0135] In addition, in this example, since the processing gas containing a weak acid is used, damage to components of the developing unit 200 such as the inner wall of the chamber 300 due to the processing gas can be suppressed compared to the case of using a processing gas containing a strong acid.

[0136] Furthermore, in this example, the weak acid in the acid atmosphere has a strength such that development of the metal-containing resist does not progress at room temperature. Therefore, after the development step of step S7 in Example 1 of the aforementioned process flow, development progresses while the temperature of the wafer W is at room temperature, and metal-containing components (specifically, tin acetate, etc.) that are reaction products during development are less likely to be produced. Consequently, after the development step of step S7 in Example 1 of the aforementioned process flow, contamination of the surrounding area of ​​the developed wafer W (e.g., other wafers W located above within the wafer processing system 1 or within the cassette C) by the metal-containing components can be suppressed.

[0137] Furthermore, one reason why weak acids are considered to have such strength that development of metal-containing resists does not progress at room temperature is that development involves an acid-base reaction in which the acid cleaves bonds. Weak acids are considered to have weak development due to the acid-base reaction, and development does not progress easily without heat application.

[0138] Furthermore, after the above-described processing flow, the wafer W is etched using the pattern of the metal-containing resist as a mask. However, before this etching, the periphery of the developed wafer W can be prevented from being contaminated by the metal-containing component.

[0139] <Factors when the developing gas contains vapor (gas) of acetic acid and an organic solvent>

[0140] (1. Elements of auto-ignition point)

[0141] Development using a mixed gas of acetic acid and an organic solvent cannot be carried out safely if the temperature of the processing space K, that is, the processing temperature, exceeds the auto-ignition temperature of acetic acid or the organic solvent. In addition, the auto-ignition temperature of an organic solvent is generally lower than the auto-ignition temperature of acetic acid (485°C). For example, the auto-ignition temperature of PGMEA is 272°C. Therefore, the processing temperature when developing using a mixed gas of acetic acid and an organic solvent is limited to the auto-ignition temperature of the organic solvent. Therefore, when the processing temperature when developing using a mixed gas of acetic acid and an organic solvent is preferred in terms of development performance, an organic solvent with a high auto-ignition temperature close to that of acetic acid is preferred as the organic solvent.

[0142] (2. Factors affecting ease of vaporization)

[0143] When a mixed solution of acetic acid and an organic solvent is vaporized using a vaporizer to generate a mixed gas of acetic acid and an organic solvent as a developer gas, if the acetic acid and the organic solvent have different vaporization facilitations, the concentration of the mixed solution in the vaporizer varies, resulting in a change in the concentration of acetic acid gas in the generated developer gas. This makes it difficult to maintain a constant concentration of acetic acid gas in the developer gas supplied to the processing space K. Therefore, it is preferable that the vaporization facilitations of acetic acid and the organic solvent be similar. Parameters related to the vaporization facilitation of a liquid include boiling point and vapor pressure. The higher the boiling point, the more difficult it is to vaporize the liquid, while the lower the boiling point, the easier it is to vaporize the liquid. Furthermore, the higher the vapor pressure, the easier it is to vaporize the liquid, while the lower the vapor pressure, the more difficult it is to vaporize the liquid. Furthermore, in the case of a mixed fluid, the vaporization facilitation is proportional to the mole fraction, which is determined by the molecular weight. In other words, molecular weight is also a parameter related to the vaporization facilitation.

[0144] In view of the above two factors, when the mixture of acetic acid and an organic solvent is generated, it is preferable to use an organic solvent that satisfies at least one of the following (A) and (B).

[0145] (A) The autoignition temperature is the same as that of PGMEA, which is commonly used in substrate processing, or is closer to that of acetic acid.

[0146] (B) It is preferable to use an organic solvent having at least any one of a boiling point at the same treatment pressure, a vapor pressure at the same treatment temperature, and a molecular weight which is the same as that of PGMEA or closer to that of acetic acid than that of PGMEA.

[0147] There are many types of such organic solvents. As a few examples, in addition to PGMEA, propylene glycol monomethyl ether (PGME), methyl isobutyl carbinol (MIBC), methyl isobutyl ketone (MIBK), butyl acetate (nBA), and γ-butyrolactone can also be used. Furthermore, organic solvents that meet the above requirements are also organic solvents such as sulfoxides, sulfones, lactams, polyols, dialkyl glycol ethers, alkylene glycol monoalkyl ethers, alkylene glycol esters, alkylene glycol monoalkyl ether acetates, ketones, alkyl lactates, other ethers, esters, aliphatic hydrocarbons, aromatic hydrocarbons, and terpenes.

[0148] Development Results

[0149] Figures 7 to 9 are diagrams showing the results of developing a pillar pattern for forming a metal-containing resist, Figure 7 It shows the relationship between CD (Critical Dimension), i.e., the diameter of the pillar and the rate of defect generation. Figure 8 The relationship between exposure and CD is exposure sensitivity. Figure 9 Indicates the relationship between CD and LCDU (Local CD Uniformity). In addition, Figure 7 The defects in the ratio are caused by pattern collapse. Figure 9 The LCDU is the deviation (2σ) of the column diameter.

[0150] Figures 7 to 9 The following table shows the results of wet development, dry development, and development according to Example 1 of the above-described process flow (hereinafter referred to as weak acid development). In wet development, a conventional developer was used, and the development time was 27 seconds. In dry development, hydrogen bromide was used under a reduced pressure atmosphere (approximately 500 mTorr), and the development time was 40 seconds. In weak acid development, the development time (specifically, the time during which the weak acid gas was supplied) was 120 seconds. Furthermore, in dry development, an additional PEB treatment was performed after the PEB treatment and before development. In contrast, no additional PEB treatment was performed in wet or weak acid development.

[0151] like Figure 7 As shown, the defect generation ratio in weak acid development is lower than that in wet development and is the same as that in dry development.

[0152] like Figure 8 As shown, in weak acid development, the exposure sensitivity is the same as that in dry development.

[0153] like Figure 9 As shown, in the weak acid development, LCDU, which is an indicator of surface roughness, is lower than those in the wet development and dry development.

[0154] Figures 10 to 12 are diagrams showing the results of developing a line and space pattern of a metal-containing resist, Figure 10 Indicates the relationship between CD, i.e. the width of the line, and the ratio of defects. Figure 11 The relationship between exposure and CD is exposure sensitivity. Figure 12 Indicates the relationship between CD and uLWR (unbiased Line Edge Roughness). In addition, Figure 10 The defect in the middle is caused by pattern collapse and the upper part of the pattern is missing.

[0155] Figures 10 to 12 The following table shows the results of wet development, dry development, and development according to Example 1 of the above-described process flow (hereinafter referred to as weak acid development). The wet and dry development methods used here are the same as those used for the hole pattern. Unlike the hole pattern, the weak acid development used here was performed for 120 seconds (specifically, the time for supplying the weak acid gas).

[0156] like Figures 10 to 12 As shown, the development result for forming the line and space pattern is the same as the development result for forming the pillar pattern.

[0157] These results show that a hole pattern and a line and space pattern of a metal-containing resist having small surface roughness and few defects can be formed with appropriate exposure sensitivity by weak acid development.

[0158] In addition, in the case of hole pattern, as one of the reasons why weak acid development needs longer time than line and space pattern, it is considered as follows. That is, when the metal-containing resist of unexposed portion is depolymerized by the reaction (specifically acid and alkali) with the gas of weak acid, a by-product (gas) is generated. This by-product reacts with the gas of weak acid, and therefore hinders the reaction of the metal-containing resist of unexposed portion with the gas of weak acid, i.e. development. The hole pattern has more unexposed portion than line and space pattern, so the generation amount of the above-mentioned by-product is also more. Therefore, the reaction of the metal-containing resist of unexposed portion with the gas of weak acid, i.e. development, is significantly hindered by the by-product. This is considered to be one of the reasons why weak acid development needs long time in the case of hole pattern.

[0159] Furthermore, the inventors of the present invention have confirmed that a pattern having a rectangular shape in cross-sectional observation can be obtained in weak acid development without performing an additional PEB treatment.

[0160] <Etching using a metal-containing resist pattern as a mask>

[0161] Figure 13This graph shows the results of etching using a line and space pattern containing a metal resist as a mask, and shows the rate of defect generation (specifically, bridge defects) when wet development, dry development, and weak acid development are performed. Figures 10 to 12 The results are the same.

[0162] like Figure 13 As shown, in the weak acid development, the generation ratio of defects in etching after development is lower than that in the wet development and is the same as that in the dry development.

[0163] <Processing Flow Example 2>

[0164] In this example, the development step in step S7 differs from that in Example 1 of the process flow. In Example 1, the step of exposing the substrate to an acidic atmosphere while heating in step S7b and the step of replacing the substrate with an inert gas atmosphere in step S7c were each performed once. In this example, however, the step of exposing the substrate to an acidic atmosphere while heating in step S7b was performed multiple times, sandwiching the step of replacing the substrate with an inert gas atmosphere in step S7c within the development step.

[0165] Thus, by replacing step S7c, the byproducts located above and near the unexposed portion in the previous step S7b are removed, thereby preventing the byproducts from hindering development in the subsequent step S7b, and enabling appropriate development. Consequently, development can proceed sufficiently with a shorter development time.

[0166] This example is particularly preferable when development for forming a hole pattern is performed.

[0167] <Processing Flow Example 3>

[0168] In this example, the development step of step S7 is different from that of Example 1 of the process flow. In this example, in the development step, wet development, i.e., development with a developer solution, is performed in the developing unit 200 before steps S7a to S7d, so that a portion of the metal-containing resist film to be removed by development remains.

[0169] When a developer is used, development proceeds faster than when a weak acid gas is used. Therefore, according to this example, the time required for development can be shortened.

[0170] <Modification>

[0171] Depending on the processing flow performed by the wafer processing system 1, the components of the wafer processing system 1 may be omitted as appropriate. Specifically, when the wafer processing system 1 performs only a portion of the processing flow example described above, the components of the wafer processing system 1 that are not used in the processing flow may be omitted.

[0172] In the above examples, the acid atmosphere contains both a weak acid component (specifically, a weak acid gas) and an organic solvent component (specifically, an organic solvent gas). However, the acid atmosphere may contain no organic solvent component as long as it contains the weak acid component.

[0173] In the above examples, the acid atmosphere contains weak acid gas as the weak acid component, but may contain weak acid mist instead of the weak acid gas.

[0174] Alternatively, the acid atmosphere may contain both weak acid gas and mist as weak acid components.

[0175] However, the acid atmosphere preferably contains not weak acid mist but weak acid gas as the weak acid component, because the development result can be more uniform across the surface of the wafer W.

[0176] The acid atmosphere may contain organic solvent mist instead of organic solvent gas as the organic solvent component.

[0177] Alternatively, the acid atmosphere may contain both gas and mist of an organic solvent as the organic solvent component.

[0178] However, the acid atmosphere preferably contains not organic solvent mist but organic solvent gas as the organic solvent component, because the uniformity of the development result within the surface of the wafer W is higher.

[0179] In order to prevent weak acid gas from spreading to the back side of the wafer W, the developing unit 200 may be provided with a structure for forming a flow of inert gas along the back side of the wafer W toward the peripheral edge.

[0180] After weak acid development and before etching using the pattern obtained by the weak acid development as a mask, the wafer W may be subjected to plasma treatment. This plasma treatment is performed, for example, by the etching apparatus that performs the above-mentioned etching.

[0181] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope of the invention and its purpose. For example, the constituent elements of the above embodiments may be combined in any manner. According to such arbitrary combination, the functions and effects of the individual constituent elements involved in the combination can naturally be obtained, and other functions and effects clearly defined by the description of this specification can be obtained.

[0182] Furthermore, the effects described in this specification are merely illustrative or exemplary and are not limiting. That is, the technology of the present invention may also produce other effects that are apparent from the description of this specification in addition to or in place of the above-mentioned effects.

[0183] In addition, the following configuration examples also belong to the technical scope of the present invention.

[0184] (1) A substrate processing method, wherein:

[0185] The method comprises the steps of developing a substrate on which a film containing a metal resist is formed and which has been subjected to an exposure treatment and a heat treatment after the exposure treatment.

[0186] The developing step includes exposing the substrate to an acid atmosphere while heating the substrate. The acid atmosphere is an atmosphere containing at least one of a weak acid gas and a mist.

[0187] (2) The substrate processing method according to (1) above, wherein:

[0188] The weak acid has such strength that development of the metal-containing resist does not proceed at room temperature.

[0189] (3) The substrate processing method according to (1) or (2) above, wherein:

[0190] In the development step, the step of exposing while heating is performed a plurality of times with a step of replacing the atmosphere around the substrate from the acid atmosphere to an inert gas atmosphere interposed therebetween.

[0191] (4) A substrate processing device for processing a substrate, comprising:

[0192] a developing unit for developing the substrate; and

[0193] Control Department,

[0194] The developing unit includes:

[0195] a chamber for receiving substrates;

[0196] a hot plate for heating the substrate in the chamber; and

[0197] a gas discharge portion for discharging at least one of a weak acid gas and a mist into the chamber;

[0198] The control unit controls the substrate processing apparatus to execute a step of developing the substrate on which a film containing a metal resist is formed and which has been subjected to an exposure process and a heat treatment after the exposure process.

[0199] The developing step includes exposing the substrate subjected to the heat treatment after the exposure step to an acid atmosphere while heating the substrate. The acid atmosphere is an atmosphere containing at least one of a gas and a mist of the weak acid.

[0200] (5) The substrate processing apparatus according to (4) above, wherein:

[0201] The weak acid has such strength that development of the metal-containing resist does not proceed at room temperature.

[0202] (6) The substrate processing apparatus according to (4) or (5) above, wherein:

[0203] The developing unit further includes another gas discharge portion for discharging an inert gas into the chamber.

[0204] In the development step, the step of exposing while heating is performed a plurality of times with a step of replacing the atmosphere around the substrate from the acid atmosphere to an inert gas atmosphere interposed therebetween.

[0205] (7) A computer storage medium, wherein:

[0206] A readable program is stored, and the program is executed on a computer of a control unit that controls a substrate processing apparatus so as to cause the substrate processing apparatus to execute a substrate processing method.

[0207] The substrate processing method includes the steps of developing a substrate on which a film containing a metal resist is formed and which has been subjected to an exposure process and a heat treatment after the exposure process.

[0208] The developing step includes exposing the substrate to an acid atmosphere while heating the substrate. The acid atmosphere is an atmosphere containing at least one of a weak acid gas and a mist.

Claims

1. A substrate processing method, characterized in that: The method comprises the steps of developing a substrate on which a film containing a metal resist is formed and which has been subjected to an exposure process and a heat treatment after the exposure process. The developing step includes exposing the substrate to an acid atmosphere while heating the substrate. The acid atmosphere is an atmosphere of at least one of a gas and a mist containing a weak acid.

2. The substrate processing method according to claim 1, wherein: The weak acid has such strength that development of the metal-containing resist does not proceed at room temperature.

3. The substrate processing method according to claim 1 or 2, characterized in that: In the developing step, the step of exposing while heating is performed a plurality of times with a step of replacing the atmosphere around the substrate from the acid atmosphere to an inert gas atmosphere interposed therebetween.

4. A substrate processing device for processing a substrate, characterized in that: include: a developing unit for developing the substrate; and Control Department, The developing unit comprises: a chamber for receiving substrates; a hot plate that heats the substrate within the chamber; and a gas discharge unit that discharges at least one of weak acid gas and mist into the chamber, The control unit controls the substrate processing apparatus to execute a step of developing the substrate on which a film containing a metal resist is formed and which has been subjected to an exposure process and a heat treatment after the exposure process. The developing step includes exposing the substrate subjected to the heat treatment after the exposure process to an acid atmosphere while heating the substrate. The acid atmosphere is an atmosphere containing at least one of a gas and a mist of the weak acid.

5. The substrate processing device according to claim 4, wherein: The weak acid has such strength that development of the metal-containing resist does not proceed at room temperature.

6. The substrate processing device according to claim 4 or 5, characterized in that: The developing unit further includes another gas discharge portion for discharging an inert gas into the chamber. In the developing step, the step of exposing while heating is performed a plurality of times with a step of replacing the atmosphere around the substrate from the acid atmosphere to an inert gas atmosphere interposed therebetween.

7. A computer storage medium, characterized in that: A readable program is stored, and the program is executed on a computer of a control unit that controls a substrate processing apparatus so as to cause the substrate processing apparatus to execute a substrate processing method. The substrate processing method includes the steps of developing a substrate having a film containing a metal resist formed thereon and subjected to an exposure process and a heat treatment after the exposure process. The developing step includes exposing the substrate to an acid atmosphere while heating the substrate. The acid atmosphere is an atmosphere of at least one of a gas and a mist containing a weak acid.

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