JP4187770B2 - Development method and development apparatus - Google Patents

Description

  The present invention relates to a developing method and a developing apparatus, and more particularly to a developing method and a developing apparatus that perform a developing process by supplying a developing solution to a resist film on a substrate such as a semiconductor.

  As the degree of integration of a semiconductor integrated circuit device (LSI) improves, the design rule is reduced, and accordingly, a resist development method used in a lithography process in LSI manufacturing is required to have a higher accuracy. In general, a resist development method has been improved so far in order to form a finer pattern with high accuracy. For example, a commonly used rotary developing device has a developer discharge nozzle that holds a substrate horizontally on a chuck capable of vacuum suction, rotates the substrate, and supplies the developer uniformly downward toward the substrate surface facing upward. I have.

During the development process, the developer discharge nozzle moves from the standby position when the development is not performed to above the semiconductor substrate, and then supplies the developer toward the resist film coated on the semiconductor substrate. The supplied developer is spread over the entire surface of the substrate by centrifugal force based on the rotation of the substrate. Thereafter, the resist is developed by allowing the substrate to stand still for a certain period of time while the developer is held on the substrate by the surface tension of the developer itself.
JP 2001-57334 A

  However, since the conventional developing method as described above employs a method of supplying the developer while rotating the semiconductor substrate, the supply amount of the developer to the central portion of the semiconductor substrate that is slower than the peripheral portion. Since the amount of development increases and the development amount differs, the uniformity of the circuit pattern dimension formed on the chip near the center of the substrate and the circuit pattern dimension formed on the periphery of the substrate is likely to be lost.

  Therefore, in order to increase the accuracy of development pattern dimension uniformity between the central portion of the semiconductor substrate and the peripheral portion of the substrate, recently, a rod-shaped developer discharge nozzle having a size close to the diameter of the substrate while the substrate is stationary. , And an apparatus for supplying a developing solution to a resist film on a substrate while scanning the nozzle in a horizontal direction from one end of the substrate while the substrate is stationary. Also in this apparatus, after supplying the developing solution, the resist is developed by allowing the substrate to stand still for a certain period of time while the developing solution is held on the substrate by the surface tension.

In this case, a difference in pattern size between the central portion of the substrate and the peripheral portion of the substrate can be suppressed to some extent, but a new problem arises in that a difference occurs in the supply time of the developing solution to the substrate surface. That is, the development pattern dimension of one substrate end where the developer is applied in the initial stage when the discharge nozzle starts scanning, that is, the supply of the developer, and the development pattern dimension of the other substrate end near the end of nozzle scanning A difference occurs in the size, and the uniformity of the dimensions decreases.
This is because the resist in the developer supply start area is developed more than the resist in the supply end area by the time the nozzle scans the entire surface of the substrate. Such variations in pattern dimensions due to the difference in scanning time are becoming more prominent when the size of the semiconductor substrate is 150 mm or more or the design rule is 0.25 μm or less. One.

  The reduction in dimensional uniformity as described above is a major issue for reliably reducing the yield in LSI processing that requires fine pattern dimensions, and therefore it is strongly required to form a fine resist pattern with high accuracy. .

  Accordingly, an object of the present invention is to provide a developing method and a developing apparatus capable of accurately forming a fine resist pattern over the entire surface of a semiconductor substrate using a developing apparatus having a rod-shaped developer discharge nozzle. is there.

  In the developing method of the present invention for solving the above-described problem, a developer discharging means capable of discharging the developer toward the substrate having the exposed photosensitive resin film is directed from one end of the substrate to the other end. When the developer is discharged while moving, the moving speed is increased from one end of the substrate toward the other end.

  Alternatively, the developer is moved toward the substrate while moving the developer discharge means installed at a distance from the substrate having the exposed photosensitive resin film from one end to the other end of the substrate. When discharging the liquid, the distance is decreased from one end of the substrate toward the other end.

  Further, when the developer is discharged while moving the developer discharge means capable of discharging the developer toward the substrate having the exposed photosensitive resin film from one end to the other end of the substrate. The discharge rate of the developer is increased from one end of the substrate to the other end to increase the discharge amount.

  Further, the developer is discharged while moving the developer discharge means capable of discharging the developer toward the substrate having the exposed photosensitive resin film from the one end to the other end of the substrate, Thereafter, the developer is discharged while moving the developer discharge means in the reverse direction from the other end of the substrate toward the one end. That is, the developer discharge means is reciprocated.

  According to the above-described method of the present invention, the development time difference between one end portion and the other end portion of the substrate can be reduced as will be described later, so that uniform development can be performed and development pattern size variation can be reduced. Can be prevented.

  The developing device of the present invention has a developer discharge means capable of discharging the developer toward the substrate while moving from one end to the other end of the substrate having the exposed photosensitive resin film, The developer discharge means is configured so that the moving speed can be increased from one end of the substrate toward the other end.

  Alternatively, a developer capable of discharging the developer toward the substrate while moving from one end of the substrate toward the other end with a distance from the substrate having the exposed photosensitive resin film. It has a discharge means, and this developer discharge means is configured such that the distance can be reduced from one end of the substrate to the other end.

  Furthermore, it has a developer discharge means capable of discharging the developer toward the substrate while moving from one end portion to the other end portion of the substrate having the exposed photosensitive resin film. Is configured such that the discharge rate of the developer can be increased as the distance from one end to the other end of the substrate increases, thereby increasing the discharge amount.

  Further, it has a developer discharge means capable of discharging the developer toward the exposed substrate having the photosensitive resin film, and moves the developer discharge means from one end of the substrate toward the other end. The developer can be discharged while the developer can be discharged while moving in the opposite direction from the other end of the substrate toward the one end.

  According to the above-described apparatus of the present invention, the development time difference between one end and the other end of the substrate can be reduced as will be described later, so that uniform development can be performed and development pattern size variation can be reduced. Can be prevented.

  As described above, according to the resist developing method and developing apparatus of the present invention, a fine resist pattern can be formed with high accuracy, and the development uniformity within the substrate surface, that is, the pattern dimension uniformity can be improved. it can. In particular, in the case of a semiconductor substrate, the effect can be exerted when the diameter is 200 mm or more and the design rule is 0.18 μm or less.

  FIG. 1 is a diagram showing an outline of main parts and operations of a developing device used when carrying out the developing method of the present invention. A disk-shaped semiconductor substrate 100 is installed and fixed in a horizontal posture on a vacuum chuck inside a developing cup (not shown), and a movable rod-shaped developer is discharged at a position about 10 cm away from the substrate 100 in the horizontal direction. A nozzle 1 is arranged. The developer discharge nozzle 1 can be opposed to the semiconductor substrate 1 from the upper side by moving, and a plurality of developer discharge holes are provided on the facing surface so that the developer can be discharged downward. And has a length at least equal to or greater than the width or diameter of the substrate 1 and moves in a direction parallel to the surface of the substrate 1 from one end to the other end of the substrate 1. It is possible. Further, in FIG. 1, a position Ps indicates a movement start position of the developer discharge nozzle 1, a position P1 indicates a start end at which the application of the developer from the developer discharge nozzle 1 to the substrate 100 is started, and a position P2 indicates the substrate. Reference numeral 100 denotes an end position at which the application of the developer from the developer discharge nozzle 1 to the substrate 100 is ended, and position Pe indicates a movement end position of the developer discharge nozzle 1. An arrow 2 indicates the moving direction of the discharge nozzle 1.

  FIG. 2 is a diagram for explaining a resist developing method according to the first embodiment of the present invention. In the present embodiment, the scanning speed of the developer discharge nozzle 1 is not constant as in the prior art, but the developer discharge amount while the developer discharge nozzle 1 is moving above the substrate 100. The scanning speed of the developer discharge nozzle 1 is variably controlled while keeping the discharge height constant. In FIG. 2, the scanning speed is constant VL between Ps and P1, but when the discharge nozzle 1 moves between P1 and P2 while discharging the developer on the semiconductor substrate 100, the speed is Is accelerated from VL to VH at a constant acceleration. Then, VH is constant between P2 and Pe.

  When the above method is used, the first developer is applied on the substrate 100 in the vicinity of the position P1 of the coating start end portion of the substrate 100. However, since the moving speed of the nozzle 1 is accelerated, the nozzle 1 It can reach the application end position P2 near the other end of the substrate 100 in a short time, and the time difference between the times when the developer application starts at P1 and P2 can be reduced. Accordingly, the development times are substantially the same at the positions P1 and P2, and a resist pattern having a uniform dimension can be formed over the entire surface of the substrate 100.

  For example, when the substrate 100 has a diameter of 200 mm, acceleration is performed so that VL is 50 mm / second at the position P1 and VH is 75 mm / second at the position P2. An example of the result of applying this condition is shown in FIG. The evaluation pattern uses isolated lines and dense lines, and compares the in-plane dimension variation 3σ between the conventional developing method and the developing method of the present embodiment. It can be seen that with the developing method of the present invention, the in-plane dimension variation 3σ of the isolated line can be suppressed to 40% of the conventional developing method.

  In addition, as shown in FIG. 8, there has been a large difference in the variation of the in-plane dimensions of the isolated pattern and the dense pattern in the related art, but it can be suppressed to the same level. A development method that does not depend on pattern density can be provided. In the case of an isolated pattern, when a positive resist is used, the amount of developer consumed to dissolve the resist around the pattern increases during the development process, so the development speed fluctuates depending on the size of the surrounding empty space, and compared with dense pattern development. Therefore, the dimensional variation is considered to be large.

  FIG. 3 is a diagram showing a developing method according to the second embodiment of the present invention. In this method, the height of the developer discharge nozzle 1 is variably controlled while the developer is discharged and moved onto the semiconductor substrate 100. In FIG. 3, the height of the nozzle 1 is gradually lowered so that the height from the substrate 100 is HH when the nozzle 1 is at the position P1, and the height is HL when the nozzle 1 is at the position P2. In this way, the discharge of the developer onto the substrate 100 starts the earliest in the vicinity of the developer application start position P1 on the substrate 100, but the developer falls to the surface of the substrate 100 because the position of the nozzle 1 is high. It takes time until the liquid contacts the resist and development begins. On the other hand, in the vicinity of the developer application end position P2, it takes time for the nozzle 1 to reach the P2 position from the P1 position. However, since the position of the nozzle 1 is low, the liquid falls in a short time after reaching the resist and the resist. You can come into contact and start developing.

  As described above, the development time difference between the both ends of the substrate 100 is reduced by reducing the discharge height of the developer discharge nozzle 1 as needed from the initial position where the supply of the developer to the substrate 100 to the end position is completed. Can be shortened, and the pattern dimensional difference can be reduced. For example, when the substrate 100 has a diameter of 200 mm, the HH is 1.5 mm at the position P1, and the HL is 1.0 mm at the position P2. Then, even when this method is used, it is possible to suppress the variation 3σ in the in-plane dimension of the isolated pattern by 40% of the conventional developing method. In addition, it is possible to suppress the dimensional variation in the substrate surface between the isolated pattern and the dense pattern to the same extent.

  FIG. 4 is a diagram showing a developing method according to the third embodiment of the present invention. In this method, when the developer discharge nozzle 1 discharges the developer while moving above the substrate 100 while keeping the moving speed and its height constant, the developer discharge speed is set at the position P1. Is gradually increased so as to become WH when in the position of WL, P2.

  In this method, development is started earliest in the vicinity of the developer application start position P1 on the substrate 100. However, in this part, the developer discharge speed is as low as WL, that is, development applied locally to this part. Since the amount of the liquid is reduced, the liquid is consumed to dissolve the excess resist, and thus the development speed is decreased.

  On the other hand, in the vicinity of the developer application end position P2, it takes time until the moving nozzle 1 arrives and the development is started. However, since the discharge speed of the developer is as high as WH, the local area around P2 is eventually reached. The amount of the developing solution is large, and the developing speed is sufficiently fast even if the solution is consumed to dissolve the resist. The application of the developer is completed at the position P2, but since the amount of the developer is larger at the position P2 than at the position P1, the developer flows toward the point P1 with time and finally reaches the entire surface of the substrate 100. The coating amount is made uniform throughout.

  Therefore, the development speed difference between the P1 position and the P2 position is reduced as described above, and the resist pattern dimension difference is reduced. For example, when the substrate 100 has a diameter of 200 mm, it is preferable that the WL is 1.5 liters / minute at the position P1, and the WH is 2.0 liters / minute at the position P2. Even when this method is used, the same effects as those of the other embodiments can be obtained.

  5, 6 and 7 are diagrams showing a developing method according to the fourth embodiment of the present invention. In the first to third embodiments, the nozzle 1 is moved only once in the direction from the position P1 at one end of the substrate 100 toward the position P2 at the other end, and the developer is discharged during that time. However, in the present embodiment, the developer discharge nozzle 1 is reciprocated under the same conditions as in the first to third embodiments.

  For example, in FIG. 5, the developer is discharged and applied while increasing the scanning speed of the nozzle 1 from VL to VH from the position P1 at one end of the substrate 100 to the position P2 at the other end. The developer is discharged and applied while increasing from the speed VL to VH toward P1. That is, the developer discharge start point is exchanged from P1 to P2, the end point is exchanged from P2 to P1, and the developer is supplied again. Accordingly, the application state of the developer to the substrate 100 is symmetric, so that the development time is naturally substantially the same for the P1 part and the P2 part, and the development uniformity is improved compared to the first embodiment, and the development pattern dimensions are improved. Variability decreases.

As shown in FIGS. 6 and 7, the same effect can be obtained even when the nozzle 1 is reciprocated while discharging the developer by changing the amount of the discharged developer and the height of the nozzle 1 with respect to the substrate 100.
Further, the nozzle 1 may be reciprocated while discharging the developer onto the surface of the substrate 100 with the nozzle scanning speed, the nozzle height, and the discharge liquid amount being constant as in the prior art. In this case, at the stage of scanning in the direction from P1 to P2, the development of the P1 portion starts first, but at the stage of scanning in the direction from P2 to P1, the P2 portion first has a new developer with a resist. As a result, the difference in development time at both ends of the substrate 100 is shortened as compared with the conventional case, so that the pattern dimension difference is reduced.

  Although the embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and various modifications based on the technical idea of the present invention are possible. For example, the numbers given in the above-described embodiments are merely examples, and different numbers may be used.

  INDUSTRIAL APPLICABILITY The present invention can accurately form a fine resist pattern over the entire surface of a semiconductor substrate, and is useful for a developing method and a developing apparatus that perform a developing process by supplying a developing solution to a resist film on a substrate such as a semiconductor. It is.

The figure explaining the outline of the principal part and operation | movement of the image development apparatus based on this invention The figure which shows the image development method by the 1st Embodiment of this invention. The figure which shows the image development method by the 2nd Embodiment of this invention. The figure which shows the image development method by the 3rd Embodiment of this invention. The figure which shows an example of the image development method by the 4th Embodiment of this invention. The figure which shows the other example of the image development method by the 4th Embodiment of this invention. The figure which shows the further another example of the image development method by the 4th Embodiment of this invention. Comparison of pattern dimensional variations between the present invention and the prior art

Explanation of symbols

1 Developer discharge nozzle 2 Scan direction 100 Substrate

Claims (3)

The developer is discharged while moving a developer discharge means capable of discharging the developer toward the substrate having the exposed photosensitive resin film from one end of the substrate toward the other end. A developing method for developing a resin film to form a pattern, wherein the developing rate is increased by increasing the discharge speed of the developer from one end of the substrate toward the other end. . The developing method according to claim 1, wherein the substrate is a semiconductor substrate, and the developer discharge means includes a rod-shaped developer discharge nozzle, and the length thereof is equal to or greater than the diameter of the substrate. The developer discharge means that can discharge the developer toward the substrate while moving from one end of the substrate having the exposed photosensitive resin film toward the other end, and the developer discharge means, A developing device configured to increase a discharge rate of a developer as the distance from one end portion to the other end portion of the substrate increases.

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