The present invention relates to a method and an apparatus for manufacturing a semiconductor device.
In a conventional semiconductor device manufacturing process, a fine circuit pattern is formed by a photolithography technique using a photoresist. Further, in order to further miniaturize the circuit pattern, a SWT (Side Wall Transfer) process, a DP (Double Patterning) process and the like have been examined.
As for a miniaturization technique in photolithography, there is known a technique in which a pattern of an initially formed photoresist is transferred to a hard mask to use the hard mask and a resist mask. However, in order to transfer the pattern to the hard mask, the hard mask needs to be formed and etched. This leads to an increase of the number of processes.
Therefore, there is known a technique for performing a lithography process twice in which a first photoresist pattern is formed and is subject to freeze (insolubilization process), and a second photoresist pattern is formed (coating, exposure and development of the photoresist), and then performing etching while using, as a mask, the double photoresist patterns obtained (see, e.g., Japanese Patent Application Publication No. 2008-306143).
In a conventional semiconductor manufacturing process, in order to form a fine hole at a desired location on a substrate, three steps are carried out. In a first step, a V-LINE is formed by first exposure. In a second step, an H-LINE perpendicular to the V-LINE is formed by second exposure. An orthogonal pattern obtained by the first and the second step is transferred to a hard mask. In a third step, a desired pattern for forming holes at desired locations is formed. By transferring this pattern to the hard mask, fine arbitrary holes are formed on the substrate.
The three steps are required because the resist pattern forming the desired pattern at the locations of fine arbitrary holes cannot be used in the second step.
In view of the above, the present invention provides a method and an apparatus for manufacturing a semiconductor device, capable of improving productivity by omitting an initial step of transferring a pattern to a hard mask.
In accordance with an aspect of the present invention, there is provided a semiconductor device manufacturing method including forming a mask layer on an etching target layer formed on a substrate and etching the etching target layer while using the mask layer as a mask.
The method includes: forming a first photoresist layer on the substrate; forming a first photoresist pattern of holes arranged at a first pitch on the first photoresist layer; insolubilizing the first photoresist pattern; forming a second photoresist layer on the first photoresist pattern; and forming a second photoresist pattern having a second pitch wider than the first pitch on the second photoresist layer, thereby forming the mask layer.
In accordance with another aspect of the present invention, there is provided a semiconductor device manufacturing method including forming a mask layer on an etching target layer formed on a substrate and etching the etching target layer while using the mask layer as a mask.
The method includes: forming a first photoresist pattern by forming, exposing and developing a first photoresist layer on the substrate; insolubilizing the first photoresist pattern; forming a second photoresist pattern that intersects with the first photoresist pattern by forming, exposing and developing a second photoresist layer on top of the first photoresist layer; insolubilizing the second photoresist pattern; and forming a third photoresist pattern by forming, exposing and developing a third photoresist layer on top of the first and second photoresist patterns, thereby forming the mask layer.
In accordance with still another aspect of the present invention, there is provided a semiconductor device manufacturing method including: transferring a first parallel pattern to a photoresist coated on a substrate; transferring second parallel pattern perpendicular to the first parallel pattern to the photoresist; and transferring a pattern corresponding to holes of a third predetermined arbitrary pattern to the photoresist.
In accordance with still another aspect of the present invention, there is provided a semiconductor device manufacturing method including: transferring a first parallel pattern to a photoresist coated on a substrate; transferring a second parallel pattern parallel to the first parallel pattern to the photoresist; and transferring a pattern corresponding to holes of a third predetermined arbitrary pattern to the photoresist.
In accordance with the present invention, it is possible to provide a method and an apparatus for manufacturing a semiconductor device, capable of improving productivity by omitting an initial step of transferring a pattern to a hard mask.
The present invention can also provide a method and an apparatus for manufacturing a semiconductor device, capable of forming a fine pattern effectively by decreasing the number of processes and improving productivity compared to a prior art.
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings which form a part hereof.
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By performing the above processes, a mask having a pattern in which contact holes arranged at a narrow pitch and arbitrary-shaped holes arranged at a wider pitch than that of the contact holes are mixed can be formed. The lower bottom anti-reflection coating film 103, the hard mask 102 and the insulating film (e.g., TEOS film) 101 are etched by using this mask. Accordingly, holes are formed in the insulating film 101.
As described above, in the present embodiment, without transferring a pattern onto the hard mask first and forming the mask of the photoresist on the hard mask, the contact holes densely arranged at a line width of about 40 nm to 50 nm and a pitch of about 80 nm to 100 nm (half pitch of about 40 nm to 50 nm) and a two-dimensional pattern formed at a pitch of about 160 nm to 200 nm wider than that of the contact holes can be transferred at one time by using a mask formed of three-layer photoresist patterns. Therefore, a fine pattern can be effectively formed by decreasing the number of processes and the productivity can be improved compared to the prior art.
The first photoresist pattern 104 has a line-and-space shape having a pitch of about 80 nm to 100 nm, and the second photoresist pattern 106 has a line-and-space shape perpendicular to the first photoresist pattern and having the same pitch as that of the first photoresist pattern.
Thus, contact holes densely arranged at a pitch of about 80 nm to 100 nm can be formed without precise alignment. Thereafter, only predetermined contact holes among the densely arranged contact holes remain by a third photoresist pattern having a pitch of about 160 nm to 200 nm which is wider than those of the first and the second photoresist pattern. Accordingly, contact holes of a predetermined shape can be formed by simply exposing two patterns having a minimum pitch and the pattern having a wider pitch three times in total without using minimum resolution for all patterns.
In other words, in order to form the contact holes densely arranged at the pitch of about 80 nm to 100 nm, the pattern needs to be divided multiple times. When the second resist pattern formed of holes arranged between the holes arranged in the first photoresist pattern is exposed for example, the precise alignment is required and there is high possibility in which the positions of the holes are misaligned.
Meanwhile, when the holes are formed by intersecting line-and-space-shaped patterns at right angles as in the present embodiment, contact holes arranged at a dense pitch can be formed without precise alignment. By increasing the pitch of the third photoresist pattern compared to that of the first and the second photoresist patterns as in the present embodiment, the present invention can achieve the technique capable of selectively forming contact holes of the first and the second photoresist patterns, the contact holes overlapping with holes of the third photoresist pattern by overlapping these patterns without precise alignment.
In the present embodiment, the first and the second photoresist pattern 104 and 106 have the line-and-space shape having the same pitch and perpendicular to each other. However, the pitch may be different, and the patterns may not be perpendicular to each other. Moreover, in a process for forming a densely aligned hole pattern, a densely aligned hole-shaped pattern can be used. In that case, a photoresist pattern formed of densely arranged holes is formed by a single exposure and development process instead of intersecting line-and-space-shaped patterns as in the present embodiment. Then, an arbitrary hole pattern can be formed by the same sequences as the present embodiment.
Hereinafter, the embodiment of a semiconductor device manufacturing apparatus for performing the above-described semiconductor device manufacturing method will be described.
A wafer cassette CR where a plurality of semiconductor wafers W to be processed by the resist coating/developing system 1000 is horizontally accommodated is loaded into the cassette station 111 from another system. Further, a wafer cassette CR where a plurality of semiconductor wafers W processed by the resist coating/developing system 1000 is accommodated is unloaded from the cassette station 111 and loaded into another system. Further, the cassette station 111 transfers the semiconductor wafers W between the wafer cassette CR and the processing station 112.
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In the cassette station 111, a wafer transfer unit 121 is positioned between the cassette mounting table 120 and the processing station 112. The wafer transfer unit 121 has wafer transfer picks 121a capable of moving in the cassette arrangement direction (X direction) and the arrangement direction of the semiconductor wafers W in the wafer cassette CR (Z direction). The wafer transfer picks 121a can rotate in the θ direction shown in
In the processing station 112, a first and a second processing unit group G1 and G2 are provided at a front side of the system in that order from the cassette station 111 side. Further, a third to a fifth processing unit group G3 to G5 are provided at a rear side of the system in that order from the cassette station 111 side. A first main transfer unit A1 is disposed between the third processing unit group G3 and the fourth processing unit group G4, and a second main transfer unit A2 is disposed between the fourth processing unit group G4 and the fifth processing unit group G5. A sixth processing unit group G6 is provided at a bottom surface side of the first main transfer unit A1, and a seventh processing unit group G7 is provided at a bottom surface side of the second main transfer unit A2.
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In the fourth processing unit group G4, a high-precision temperature control unit (CPL-G4), four pre-bake units (PAB) for performing heat treatment on a semiconductor wafer W after resist coating, and five post-bake units (POST) for performing heat treatment on a semiconductor wafer W after development are laminated at ten stages from the bottom.
In the fifth processing unit group G5, four high-precision temperature control units (CPL-G5), and six post exposure bake units (PEE) for performing heat treatment on a semiconductor wafer W before development and after exposure are laminated at ten stages from the bottom.
The high-temperature heat treatment unit (BAKE), the pre-bake unit (PAB), the post-bake unit (POST), and the post-exposure bake unit (PEB) which are provided at the third to the fifth processing unit group G3 to G5 have the same structure, for example, to form a heat treatment unit.
The laminated number and the arrangement of the third to the fifth processing unit group G3 to G5 may be set arbitrarily without being limited to the illustrated ones.
In the sixth processing unit group G6, two adhesion units (AD) and two heating units (HP) for heating a semiconductor wafer W are laminated at four stages from the bottom.
In the seventh processing unit group G7, a film thickness measuring unit (FTI) for measuring a resist film thickness and a peripheral exposure unit (WEE) for selectively exposing an edge portion of a semiconductor wafer W are laminated at two stages from the bottom.
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The second main transfer unit A2 is provided with a second main wafer transfer unit 117, which can selectively access each unit of the second, the fourth, the fifth and the seventh processing unit groups G2, G4, G5 and G7.
In the first and the second main wafer transfer device 116 and 117, three arms for supporting the semiconductor wafer W are laminated in a vertical direction. Further, the semiconductor wafer W supported by the arms can be transferred in any of the X direction, Y direction, Z direction and e direction.
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The first to the seventh processing unit groups G1 to G7 can be detached for maintenance, and a panel provided at the rear surface side of the processing station 112 can be detached or opened/closed. As shown in
The interface station 113 includes a first interface station 113a of the processing station 112 side and a second interface station 113b of the exposure device 114 side. In the first interface station 113a, a first wafer transfer body 162 is provided so as to face the opening of the fifth processing unit group G5. In the second interface station 113b, a second wafer transfer body 163 capable of moving in the X direction is provided.
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In the same manner, the second wafer transfer body 163 has wafer transfer forks 163a capable of moving in the X and Y direction, rotating in the 9 direction and moving back and forth on the X-Y plane. The forks 163a can selectively access each unit in the ninth processing unit group G9 and an IN stage 114a and an OUT stage 114b of the exposure device 114, and thus can transfer the semiconductor wafers W therebetween.
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The following is description on the processes for forming the first to the third resist patterns by using the resist coating/developing system 1000 configured as described above.
First, unprocessed semiconductor wafers W are unloaded from the wafer cassette CR one at a time by the wafer transfer unit 121 and then transferred to the transition unit (TRS-G3) of the processing unit group G3 of the processing station 112.
Next, the temperature control unit TCP performs a temperature control process on the semiconductor wafer W. Thereafter, the bottom anti-reflection coating film is formed by the coating unit (BARC) in the first processing unit group G1; the heat treatment is performed by the heating unit (HP); and the bake process is performed by the high-temperature heat treatment unit (BAKE). The adhesion process may be performed by the adhesion unit (AD) before the bottom anti-reflection coating film is formed on the semiconductor wafer W by the coating unit (BARC).
Then, the temperature of the semiconductor wafer W is controlled by the high precision temperature control unit (CPL-G4). Next, the semiconductor wafer W is transferred to the resist coating unit (COT) of the first processing unit group G1, and the coating of the photoresist is carried out.
Next, the prebake unit (PAB) in the fourth processing unit group G4 performs a pre-bake process on the semiconductor wafer W, and the peripheral exposure process is performed by the peripheral exposure device (WEE). Thereafter, the temperature control is performed by the high precision temperature control unit (CPL-G9) or the like. Then, the semiconductor wafer W is transferred into the exposure device 114 by the second wafer transfer body 163.
The semiconductor wafer W subjected to the exposure process by the exposure device 114 is loaded into the transition unit (TRS-G9) by the second wafer transfer body 163. Next, the temperature control process is performed on the semiconductor wafer W. The temperature control process includes a post exposure bake process performed by the post exposure bake unit (PEB) in the fifth processing unit group G5, a development process performed by the development unit (DEV) in the second processing unit group G2, a post bake process performed by the post bake unit (POST), or the like.
By performing the above-described sequences, the first photoresist pattern is patterned. Next, the semiconductor wafer W is transferred to the chemical freezing unit (CHF) in the second processing unit group G2 so as to be subjected to an insolubilization process.
Thereafter, a second photoresist pattern is formed by repeating the sequences from the photoresist coating process performed by the resist coating unit (COT) to the insolubilization process performed by the chemical freezing unit (CHF). Further, the third photoresist pattern is formed by repeating the sequences from the photoresist coating process performed by the resist coating unit (COT) to the temperature control process such as the post bake process performed by the post bake unit (POST) or the like. The etching is performed while using as a mask the first to the third photoresist patterns.
While the invention has been shown and described with respect to the embodiments, the present invention can be variously modified without being limited to the above-described embodiments.
The present invention can be used in a semiconductor device manufacturing field or the like. Thus, the present invention has an industrial applicability.
Number | Date | Country | Kind |
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2010-035295 | Feb 2010 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2011/000887 | 2/17/2011 | WO | 00 | 10/24/2012 |