JP2007194454A - Method of development of resist and method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the method of development of resist which permits to wet the whole surface of the photo resist by development solution with high reproductivity while suppressing the using amount of the development solution, and to provide the method of manufacturing a semiconductor device. <P>SOLUTION: The photo resist is developed by a method wherein a wafer having the photo resist with a predetermined pattern exposed thereon is turned while raising the number of rotation from a low-speed rotation to a high-speed rotation, and development solution is dripped from a dripping nozzle with the same length as the diameter of the wafer toward the photo resist on the surface of the turning wafer. In such a method of development of the photo resist, the position of the dripping nozzle is fixed above the wafer so that the center of the dripping nozzle is superposed on the center of the wafer in a plan view while the development solution is not dripped before the wafer arrives at a high-speed rotation (step A), and the development solution is dripped when the wafer has arrived at the high-speed rotation (step B, C). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resist developing method and a semiconductor device manufacturing method.

  In the wafer process step, a resist pattern is formed by a photolithography technique. The resist pattern is used as a mask for etching the base layer and a mask for ion implantation. The resist pattern includes, for example, a resist coating process in which a photoresist is applied onto an underlayer on the wafer surface, an exposure process in which a photomask pattern is transferred to the applied photoresist, and a developer is dropped onto the exposed photoresist. And a developing process for revealing the latent pattern.

  FIG. 2 is a time chart showing a photoresist development sequence according to a conventional example. The development processing along this time chart is performed using a spin coater 10 provided with a dropping nozzle 5 above the chuck stage 1 as shown in FIG. The dripping nozzle 5 is composed of a plurality of nozzles 5a, and these nozzles 5a are formed in a line shape along the diameter of the wafer W (that is, a line segment having both ends on the outer periphery through the center of the wafer W). Is arranged. The length from one end of the dripping nozzle 5 to the other end is substantially equal to the diameter of the wafer W. As shown in FIG. 3B, the position of the dropping nozzle 5 is fixed so that the center of the dropping nozzle 5 and the center of the wafer W overlap in a plan view. The developer 13 is dripped almost simultaneously from all the nozzles 5a.

  As shown in FIG. 2, in the development sequence according to the conventional example, first, the wafer W is stepwise rotated by rotating the chuck stage 1, which sucks and fixes the vicinity of the center of the back surface of the wafer W, about the rotation axis 2. Rotate to around 200 [rpm]. Next, the chuck stage 1 is stopped and the rotation speed (rotation speed) of the wafer W is set to 0 [rpm]. Then, the developer is dropped from all the nozzles 5a toward the wafer W.

  Here, as shown in FIG. 2, in the conventional example, the dropping of the developing solution 13 (that is, liquid accumulation) is performed for 0.3 seconds in a state where the wafer W is stopped. Next, while dropping the developing solution 13, the chuck stage 1 is rotationally driven at a low speed to increase the rotational speed of the wafer W to 30 [rpm]. The low speed rotation of the wafer W while dropping the developer 13 is performed for 1.0 second, whereby the developer 13 dropped on the wafer W spreads in the peripheral direction of the wafer W. The total time under the developing droplet is 1.3 (= 0.3 + 1.0) seconds.

Next, a method (so-called paddle development) that promotes development by repeatedly performing stationary and rotation on the wafer W is performed. Subsequently, the wafer W is rotated at a high speed of 2000 [rpm] to perform a rinsing process, and the developer is removed. Thereafter, the wafer W is rotated at a high speed of 4000 [rpm], spin drying is performed, and the developing process of the photoresist 11 is completed.
In this conventional example, a development sequence using a type of apparatus (that is, a nozzle fixed type spin coater) that drips developer from the tip of the nozzle position is described. There are things other than the nozzle fixing system. For example, Patent Document 1 describes a developing sequence using a device of a type in which a developer is dropped from its tip while moving a nozzle in the horizontal direction (that is, a scanning spin coater 10).
Japanese Patent Laid-Open No. 10-339956

  By the way, in the above conventional example, the developer 13 is simultaneously dropped from the plurality of nozzles 5a toward the wafer W. However, in this method, as shown in FIG. Microbubbles 15 may be generated due to the collision between the developing solutions 13 spreading. In addition, bubbles may be included in the dropped developer from the beginning.

When bubbles or microbubbles 15 are present in the developer 13, a portion that does not get wet with the developer 13 is generated on the surface of the photoresist 11 due to the presence of these bubbles, and the development processing may not proceed at that portion. As a result, for example, as shown in FIG. 4B, a pattern abnormality 17 may occur along the diameter of the wafer W surface.
Therefore, the present invention has been made paying attention to such a problem to be solved, so that the entire surface of the photoresist can be wetted with the developer with high reproducibility while suppressing the amount of the developer used. An object of the present invention is to provide a resist development method and a semiconductor device manufacturing method.

[Invention 1] In order to achieve the above object, the resist development method of Invention 1 rotates a wafer having a photoresist exposed with a predetermined pattern on its surface while increasing the number of rotations from a low speed to a high speed. A method of developing the photoresist by dropping a developer from a plurality of nozzles arranged along the diameter of the wafer toward the photoresist on the rotating wafer surface, The position of the nozzle is fixed above the wafer so that the center of the wafer and the center of the nozzle array overlap in a plan view, and the developer is dropped before the wafer reaches the high speed rotation. Instead, the developer is dropped after the wafer reaches the high speed rotation. Here, “the diameter of the wafer” is a line segment having both ends on the outer periphery through the center of the wafer. The “high-speed rotation” is, for example, a rotation of 900 [rpm] or more and 1100 [rpm] or less, preferably 1000 [rpm].

  According to the resist development method of the first aspect, even if bubbles are included in the dropped developer from the beginning, or microbubbles are generated due to collisions between the developers spreading on the surface of the photoresist, these are rotated at high speed. Therefore, the entire surface of the photoresist can be wetted with the developer with high reproducibility while suppressing the amount of the developer used.

[Invention 2] The resist development method of Invention 2 is characterized in that, in the resist development method of Invention 1, the length from one end to the other end of the array of nozzles is equal to the diameter of the wafer. Here, “equal” does not mean strictly equal, but means that it is equal to a degree in which, for example, a difference of several millimeters to several tens of millimeters is set as an allowable error.
According to the resist development method of the second aspect, not only the centrifugal force but also the developer can be directly supplied from the nozzle to a wide area from the center to the outer periphery of the wafer, so that the entire surface of the photoresist can be made in a shorter time. Can be wetted with developer. Therefore, it is possible to contribute to an improvement in throughput put of development processing.

[Invention 3] A method of manufacturing a semiconductor device according to Invention 3 uses a step of applying a photoresist to the surface of a wafer, a step of exposing a predetermined pattern to the photoresist, and a resist development method of Invention 1 or Invention 2. And developing the photoresist exposed to the predetermined pattern.
With such a configuration, since the resist development methods of Inventions 1 and 2 are applied, the entire surface of the photoresist can be wetted with the developer with high reproducibility while suppressing the amount of the developer used. Thereby, for example, the occurrence of pattern abnormality as shown in FIG. 5 can be prevented, which can contribute to improvement in the yield of the semiconductor device.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a time chart showing a photoresist development sequence according to an embodiment of the present invention. The development processing along this time chart is performed using a nozzle fixed spin coater 10 as in the conventional example.
That is, as shown in FIG. 3A, the spin coater 10 used in the present embodiment includes a dropping nozzle 5 above the chuck stage 1, and the dropping nozzle 5 includes a plurality of nozzles 5a. Yes. These nozzles 5a are arranged in a line along the diameter of the wafer W (that is, a line segment having both ends on the outer periphery through the center of the wafer W). The length from one end of the dropping nozzle 5 to the other end is substantially equal to the diameter of the wafer W, and the error is, for example, about several millimeters to several tens of millimeters. As shown in FIG. 3B, the position of the dropping nozzle 5 is fixed above the wafer W so that the center of the dropping nozzle 5 and the center of the wafer W overlap in plan view. When dripping, the developer 13 is dripped almost simultaneously from all the nozzles 5a.

  As shown in FIG. 1, in the development sequence according to the present embodiment, first, the chuck stage 1 that is sucked and fixed near the center of the back surface of the wafer W is rotated about its rotating shaft 2 to thereby perform the chuck stage 1 and the wafer. Rotate W while gradually increasing the rotational speed from low speed to high speed. This process is step A in FIG. In step A, the developer 13 is not dripped.

  Next, when the rotation speed of the chuck stage 1 and the wafer W reaches around 1000 [rpm], the rotation speed is maintained, for example, for 1.0 second from all the nozzles 5a toward the photoresist 11 on the wafer W surface. Developer 13 is dropped. This process is step B in FIG. Further, while the dropping of the developer 13 is continued for the next 1 second, the rotational speeds of the chuck stage 1 and the wafer W are reduced from 1000 [rpm] to 30 [rpm]. This process is step C in FIG. The dropping flow rate of the developer 13 in steps B and C in FIG. 1 is, for example, 0.8 [liter / min] or more. After Step C, the dropping of the developer 13 is finished, the chuck stage 1 is stopped, and the rotation speed (rotation speed) of the wafer W is set to 0 [rpm].

  The subsequent steps are the same as the conventional development sequence (see FIG. 2). That is, a method (so-called paddle development) is performed on the wafer W wet with the developer 13 by repeatedly performing rest and rotation. Subsequently, the wafer W is rotated at a high speed of 2000 [rpm] to perform a rinsing process, and the developer 13 is removed. Thereafter, the wafer W is rotated at a high speed of 4000 [rpm], spin drying is performed, and the developing process is completed.

  As described above, according to the resist developing method according to the embodiment of the present invention, the developer 13 to be dropped contains bubbles from the beginning, or the developer 13 spreading on the surface of the photoresist 11 collides with each other. Even if the microbubbles 15 are generated, they can be immediately shaken off by high-speed rotation. Accordingly, the entire surface of the photoresist 11 can be wetted with the developer 13 with high reproducibility while suppressing the amount of the developer 13 used.

  In the method for manufacturing a semiconductor device according to the embodiment of the present invention, a photoresist 11 is applied to the surface of the wafer W, and a predetermined pattern is exposed on the photoresist 11. Thereafter, the photoresist 11 having a predetermined pattern exposed is developed by the development sequence shown in FIG. With such a configuration, the entire surface of the photoresist 11 can be wetted with high reproducibility with the developer 13 while suppressing the amount of the developer 13 to be used. For example, a pattern abnormality as shown in FIG. 5 occurs. Can be prevented. Therefore, it can contribute to the improvement of the yield of the semiconductor device.

  In this embodiment, the dropping nozzle 5 corresponds to the “nozzle arrangement” of the present invention.

The time chart which shows the development sequence of the photoresist which concerns on embodiment. The time chart which shows the development sequence of the photoresist which concerns on a prior art example. The figure which shows the structural example of a spin coater, and the position of the nozzle with respect to a wafer. The figure which shows the trouble of a prior art example.

Explanation of symbols

  1 Chuck Stage, 2 Rotating Axis, 5 Dropping Nozzle, 5a Nozzle, 11 Photoresist, 13 Developer, 15 Micro Bubble, W Wafer

Claims (3)

A wafer having a photoresist with a predetermined pattern exposed on the surface is rotated while increasing the number of rotations from a low speed rotation to a high speed rotation, and rotated from a plurality of nozzles arranged along the diameter of the wafer. A method of developing the photoresist by dripping a developer toward the photoresist on the wafer surface,
The position of the nozzle is fixed above the wafer so that the center of the wafer and the center of the array of nozzles overlap in plan view,
A resist developing method, wherein the developer is not dropped before the wafer reaches the high-speed rotation, and the developer is dropped after the wafer reaches the high-speed rotation.   2. The resist developing method according to claim 1, wherein a length from one end to the other end of the nozzle array is equal to a diameter of the wafer. Applying a photoresist to the surface of the wafer;
Exposing the photoresist to a predetermined pattern;
A method for manufacturing a semiconductor device, comprising: developing the photoresist exposed to the predetermined pattern using the resist developing method according to claim 1.

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