JPH07161628A - Peripheral exposure device - Google Patents

Abstract

PURPOSE:To efficiently improve illuminance and increase the exposure area keeping the exposure quantity by relatively moving projection edges and the substrate along the previously fixed moving direction and relatively moving the projection edges in the direction that orthogonally intersects with the moving direction. CONSTITUTION:A projection edge 6b1 and a projection edge 6b2 are moved while starting the edge detection using a photosensor. The edge of a wafer W is detected by turning on and off the photosensor, and the projection edge 6b1 and the projection edge 6b2 are arranged at peripheral exposure positions at prescribed distances previously calculated from the edges. Under such conditions, beams from a lamp 1 reach the projection edge 6b1 and the projection edge 6b2 through fiber 61 and fiber 62 by opening a shutter 5. The beams are applied from the desired position to the edges on the wafer W and exposure is performed circumferentially in response to the rotation of a rotating stage 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to ICs, LSIs, LCs.
D, in the manufacturing process of other electronic elements, etc., when forming a fine pattern, of the resist applied on the surface of the substrate such as a glass substrate, a semiconductor substrate, a derivative metal, or an insulator, unnecessary resist around the substrate is developed. The present invention relates to a peripheral exposure apparatus used when performing pre-exposure separately from an exposure step for forming a pattern in order to remove it in the step.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices such as ICs and LSIs, a resist is applied to the surface of a silicon substrate or the like to form a fine pattern, and exposure and development are performed to form a resist pattern. Processing such as ion implantation, etching and lithography is performed using the pattern as a mask to obtain a desired fine pattern.

The resist is usually applied by spin coating. In this method, the resist is applied to the entire surface of the wafer by centrifugal force by rotating the wafer while pouring the resist on the center position of the wafer surface. However, the resist applied by this spin coating method may protrude from the peripheral portion of the wafer and may even reach the back surface of the wafer.

After the resist is applied, the substrate is carried out while its peripheral portion is gripped. At this time, the unnecessary resist wrapping around the wafer peripheral portion and the back side thereof as described above may peel off at the gripped portion. This occurs when the wall of a container such as a substrate cassette is rubbed or during the development process of the substrate. If such unnecessary resist is peeled off and becomes dust and adheres to the pattern forming portion of the wafer, a correct pattern cannot be formed and the product yield is extremely reduced. This is a serious problem, especially at present when the function and miniaturization of integrated circuits are progressing.

Therefore, as a technique for removing the unnecessary resist in the peripheral portion of the substrate, a method of injecting a solvent from the back surface of the peripheral portion of the substrate to dissolve and remove the unnecessary resist by a solvent injection method has been put into practical use. . However, with this method, the resist in the protruding portion can be removed, but the resist in the peripheral portion of the substrate surface is not removed. Even if the solvent is sprayed onto the substrate surface to remove the resist on the periphery of the substrate surface, it is not only a problem that the solvent is splashed, but it is also necessary as a mask layer in the subsequent etching and ion implantation processes. It is not possible to remove only the unnecessary resist sharply and with good controllability at the boundary with the resist portion corresponding to the different pattern forming portion.

Therefore, recently, in addition to the exposure step for forming a pattern, a peripheral exposure method in which a separate exposure is performed is used in order to remove unnecessary resist in the peripheral portion of the substrate in a developing step. In this peripheral exposure method, the peripheral portion of the substrate coated with the resist is irradiated with the light guided by the light guide fiber, and the substrate and the light guide fiber are relatively moved along the surface direction of the substrate. The peripheral portion of the substrate is circumferentially exposed by moving or rotating.

An example of such a conventional peripheral exposure apparatus is shown in FIG. In this peripheral exposure apparatus, first, a light source lamp 11 such as an ultra-high pressure mercury lamp, an elliptical focusing mirror 12, and a flat reflecting mirror 1 are provided.
3, the shutter 16, and the light guide fiber 16 constitute a light irradiation mechanism. Further, it has a drive system including a rotary stage 17 on which a wafer W transferred from a wafer cassette (not shown) from the transfer mechanism 14 is placed and vacuum-sucked, and a control mechanism 18 for controlling this.

In the above structure, the shutter 15 is opened at the same time when the rotary stage 17 to which the wafer W is sucked and fixed starts to rotate, and the light emitted from the light source lamp 11 is reflected by the elliptical focusing mirror 12 and the plane reflection. The light is reflected by the mirror 13, passes through the mirror 15, and is incident on the incident end of the light guide fiber 16. The exposure light emitted from the emission end of the light guide fiber 16 irradiates the peripheral portion of the wafer W, and the peripheral exposure is performed according to the rotation of the rotary stage 17. When the exposure is completed, the rotation of the rotary stage 17 is stopped by the signal from the controller, and the shutter 1
5 is closed, and the peripheral exposure operation is completed.

[0009]

However, in the above-mentioned spin coating method, it is difficult to uniformly apply the resist to the entire surface of the substrate, and the film thickness in the vicinity of the peripheral portion becomes thicker than that in the central portion. Therefore, when the conventional peripheral exposure apparatus as described above is used to expose a portion having a large film thickness, the exposure amount must be increased. Since this exposure amount is the product of illuminance and time, in order to obtain the exposure amount required to expose a portion with a large film thickness and remove it in the developing process, increase the illuminance or the exposure time. There is only a way to lengthen. However, when the exposure time is lengthened, the throughput is lowered and the efficiency of the entire process is deteriorated. Therefore, it is required to shorten the exposure time as much as possible, and the exposure amount is increased by lengthening the exposure time. I couldn't do that.

Therefore, it is possible to increase the output of the light source in order to increase the illuminance. However, in a light source used in an exposure apparatus, for example, even if the output is doubled, double illuminance is not obtained, and in order to obtain nearly double illuminance, the output of the light source is double or larger. I have to make one. In this case, if the light source 1 becomes large, not only the elliptical focusing mirror 12 and the reflecting mirror 13 become large, but also the optical path length from the light source 11 to the incident end of the guide fiber 16 becomes long, and the size of the entire apparatus becomes very large. . Also,
There is also the problem of temperature rise and exhaust, and the method of increasing the output of the light source to increase the illuminance is extremely inefficient overall.

Further, when it is desired to widen the exposure range such as when the width of the unnecessary resist around the substrate is wide, in the prior art, the irradiation area is widened by increasing the effective diameter of the incident end of the light guide fiber 16. . However, as shown in the illuminance distributions of FIGS. 5A and 5B, the light quantity distribution at the optical fiber entrance end has a peak near the center and decreases toward the periphery, and the illuminance is not uniform within the effective range. From the viewpoint of efficiency, it is desirable that the effective light flux that can be actually used is smaller than the effective diameter of the fiber.
It is desirable that p _{1 be} the following formula. 2R ≧ 2p ₁ (1) formula

Therefore, if the effective diameter 2p ₁ at the entrance end is simply increased to 2p ₂ , the average illuminance in the exposure range will decrease, and exposure will be performed with the low illuminance as a reference in order to obtain the required exposure amount. The exposure time becomes long and the throughput decreases. As described above, in the conventional peripheral exposure apparatus, it has not been possible to efficiently increase the illuminance of the exposure light or widen the exposure range while maintaining the illuminance.

The present invention can solve the above problems and increase the exposure amount by efficiently increasing the illuminance, and at the same time, expand the exposure region while maintaining the same exposure amount as the conventional one. It is an object to obtain a peripheral exposure apparatus which can be obtained.

[0014]

In order to achieve the above object, in the peripheral exposure apparatus according to the invention as defined in claim 1, a plurality of light sources and light from each of the light sources are respectively applied to an irradiation area on a photosensitive substrate. A plurality of light guide means for guiding, a moving mechanism for relatively moving the respective emission ends of these light guide means and the substrate along a predetermined movement direction, and a direction in which the respective emission ends are orthogonal to the movement direction. And a moving means for relatively moving the same.

Further, in the peripheral exposure apparatus according to the invention described in claim 2, in the peripheral exposure apparatus described in claim 1,
Each of the exit ends of the light guide means is provided so as to irradiate light onto the substrate in an obliquely incident state.

Further, in the peripheral exposure apparatus according to a third aspect of the present invention, in the peripheral exposure apparatus according to the first or second aspect, the light irradiation to the substrate by each of the light guide means is a predetermined angle. Further, there is further provided a rotating means for changing the angle of each of the emission ends with respect to the substrate so that the light is obliquely incident.

[0017]

The present invention comprises a plurality of illumination optical systems each including a light source and light guide means for guiding the light from the light source to the irradiation area on the photosensitive substrate, and each exit end of the light guide means and the substrate are predetermined. The peripheral exposure apparatus includes a moving mechanism that relatively moves along the moving direction, and a moving unit that relatively moves each of the exit ends in a direction orthogonal to the moving direction.

Here, the operation of the present invention will be described by taking as an example the case of a peripheral exposure apparatus having two illumination optical systems, that is, two light sources and two light guide means respectively corresponding to these light sources. First, by scanning the exposure light from the two illumination optical systems on the periphery of the substrate in the same exposure direction, the irradiation in the same area is doubled at the same exposure speed as in the case where one illumination optical system is used conventionally. The illuminance, that is, the double exposure amount can be obtained. Here, the space of the device, which is increased by providing two illumination optical systems, hardly poses a problem compared with the enormous upsizing of the device that occurs when the output of the light source is increased to obtain twice the illuminance.

Further, according to the present invention, by irradiating the respective emission ends of the respective light guide means with respect to the substrate in a state of oblique incidence, it is possible to perform irradiation with higher uniformity in the exposure region. That is, as shown in FIG. 2, if the two illumination optical systems have the illuminance distributions shown in FIGS. 2 (a) and 2 (b) respectively, the exposure area by each light guide means is set as shown in FIG. 2 (c). By shifting in the direction orthogonal to the exposure direction so as to partially overlap, the low illuminance area around each exposure area overlaps and becomes closer to the peak illuminance, and the exposure area with almost uniform and high illuminance (indicated by the dotted line in the figure). Is widely available. Therefore, according to the present invention, peripheral exposure can be performed in a short time with highly uniform and strong illuminance, and the productivity of products can be improved.

If the diaphragm BL is installed near the exit end of the light guide means, it is possible to use only the exposure light having high illuminance and uniform. In this case, sharper optimum exposure can be performed at the boundary between the unnecessary resist and the necessary resist.

When a large exposure area is required,
Accordingly, the exposure areas may be appropriately overlapped or shifted in the direction orthogonal to the exposure direction. For example, in the case where there are two illumination optical systems, if the exposure area is operated without being overlapped and the substrate is operated, the effective diameter of the conventional technology cannot be expanded in the widest exposure area (it remains p ₁ ). A double exposure area is obtained at the same exposure speed.

In the present invention, it is also possible to change the exposure width by changing the oblique incident angle of each emission end of each light guide means with respect to the substrate by the rotating means. For example, as shown in FIG. 3, when the same area on the substrate is exposed by two guide light fibers from the left and right directions, the exposure width L is the effective diameter l _y of the exit end y of the light guide fiber Y, and the substrate W. Let θ be the angle formed by the light guide fiber Y and the normal to
Can be expressed by the following formula. _{L = l y / cosθ ... (} 2) Equation therefore it is possible to change the θ by changing the angle with respect to the substrate in the exit end of the light guide fiber at turning means.

Although the operation of the present invention has been described above by taking the case of two illumination optical systems as an example, the present invention is similarly effective even when there are two or more illumination optical systems. In the peripheral exposure apparatus according to the present invention, by providing a plurality of illumination optical systems, it is possible to increase the exposure amount without increasing the exposure time and enlarging the size of the apparatus, and without lowering the exposure amount. The exposure width can be widened to allow more efficient peripheral exposure than ever before.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A peripheral exposure apparatus having two illumination optical systems will be described below with reference to FIG. 1 as an embodiment of the present invention.
Here, the case where the wafer W is used as the substrate is shown. The wafer W coated with the resist to be processed is transferred from the wafer cassette (not shown) by the transfer mechanism 4, placed on the rotating stage 7, and vacuum-adsorbed. The rotary stage 7 is rotationally driven and controlled by a drive control mechanism 8 equipped with a motor. Further, the drive control mechanism 8 is controlled in conjunction with the movement control mechanism 9 so that exposure can be performed at an arbitrary position and width.

Of the two illumination optical systems, the first illumination optical system is a lamp 1 as a light source, an elliptical focusing mirror 2 for condensing and reflecting the light from the lamp 1, and an elliptic focusing mirror 2. The reflecting mirror 3 that reflects the light reflected from the horizontal direction, the shutter 5 that is arranged so that it can enter and exit the exit optical path of the reflecting mirror 3, and the incident end 6a ₁ at the converging position of the elliptical converging mirror 2.
There is provided, the exit end 6b ₁ is made of a light guide fiber 6 _1, which is movably disposed on the periphery of the wafer W.
The second illumination optical system has the same configuration as the first illumination optical system, and has a light source lamp (not shown), an elliptical focusing mirror, a reflecting mirror, a shutter, and an incident end at a focusing position by the elliptic focusing mirror. Of the light guide fiber 6 ₂ is disposed so that the emitting end 6 b ₂ is movably arranged on the periphery of the wafer W.

The movement control mechanism 9 has a photosensor (not shown) for edge detection which is provided so as to be movable integrally with the ejection end 6b ₁ and the ejection end 6b _2, and a signal from this edge detection photosensor is provided. The positions of both ejection ends are controlled according to.
The exit end 6b ₁ and the exit end 6b ₂ are held by the arm 10 of the movement control mechanism 9 so as to irradiate the same region on the substrate with oblique incidence, and the arm 10 is controlled by a plurality of motors provided in the movement control mechanism 9 to move the X-axis. It is configured to be freely movable in the -Y direction (perpendicular to the paper surface).

The drive control mechanism 8 and the movement control mechanism 9 previously store the width and length of the resist-free portion of the object to be processed as data, and the movement control mechanism 9 detects the fiber length according to the data read from this memory. 6 ₁ and fiber 6
The movement of each of the _two ejection ends 6b ₁ and 6b ₂ is controlled.

In such a structure, first, the wafer W is
After being placed on the rotary stage 7 and vacuum-adsorbed, the rotary stage 7 is rotated by the drive control mechanism 8 in advance, where on the wafer W the fiber emitting end is to be arranged is calculated, and the exposure amount is determined in advance. . The ejection end 6b ₁ and the ejection end 6b ₂ are moved while starting the edge detection by the above-mentioned photosensor, the edge of the wafer W is detected by turning the photosensor on and off, and the ejection end 6b ₁ and the ejection end 6b ₂ are edged. It is arranged at the peripheral exposure position of a predetermined distance previously calculated from.

In this state, by opening the shutter 5, the light of the lamp 1 reaches the exit end 6b ₁ and the exit end 6b ₂ via the fiber 6 _{1 and the} fiber 6 ₂ , and the edge of the wafer W is changed from a desired point. Illuminated over the rotating stage 7
The exposure is carried out in a circular fashion according to the rotation of the. When the exposure is completed, the rotary stage 7 is driven by a signal from the controller.
Is stopped, the shutter 5 is closed and the peripheral exposure operation is completed. Here, since the same area is exposed by the two illumination optical systems, the exposure amount is twice the normal amount, and the peripheral exposure is completed in a relatively short time.

When the exposure width is wide, the fiber 6
_The angle θ between the exit ends of ₁ and the fiber 6 ₂ with respect to the wafer may be changed by the arm 10 of the movement control mechanism 9 to widen the exposure width. Alternatively, each exposure area by the emission end 6b ₁ and the emission end 6b ₂ may be shifted and irradiated in a direction orthogonal to the exposure direction. At this time, the illuminance distribution at each exit end of the fiber 6 ₁ and the fiber 6 ₂ is measured by the one-dimensional or two-dimensional sensor S in advance just before the exposure, and the data is shown in FIG. It is possible to create such a state of exposure light having a uniform and strong illuminance.
Further, by providing diaphragms near both exit ends and using only the exposure light portion in the optimum state, optimum exposure can be performed in which the boundary between the unnecessary resist and the necessary resist becomes sharper.

In the above embodiment, the illumination optical system is 2
Although the peripheral exposure apparatus provided with three illumination optical systems has been described, the present invention is not limited to this, and the same effect can be obtained even when three or more illumination optical systems are provided. The exposure amount is efficiently increased by the number of the provided illumination optical systems, and the exposure time is shortened.

Further, in the above embodiment, the case where the spot shape of the exposure light irradiated from the exit end of each fiber is rectangular is explained, but not limited to rectangular, various shapes such as circular and elliptical can be used. Needless to say. However, it is necessary to measure the illuminance distribution at the exit end in advance when determining the exposure amount.

[0033]

According to the present invention, as described above,
The exposure amount can be efficiently increased and the exposure can be performed in an arbitrary width without increasing the size of the device including the problems such as exhaust and heating. Therefore, the peripheral exposure time can be shortened and the product productivity can be improved. There is an effect of getting.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a peripheral exposure apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation in the case where the exposure areas formed by two light guide fibers are overlapped with each other.

FIG. 3 is an explanatory diagram showing an operation when the exposure width is changed.

FIG. 4 is a schematic configuration diagram of a peripheral exposure apparatus according to a conventional technique.

FIG. 5 is an explanatory diagram showing an intensity distribution of a light source used in a normal peripheral exposure apparatus.

[Explanation of symbols]

1, 11: Light source lamp 2, 12: Elliptical condensing mirror 3, 13: Reflecting mirror 4, 14: Conveying mechanism 5, 15: Shutter 6 ₁ , 6 ₂ , 16: Light guide fiber 7, 17: Rotating stage 8, 18: Drive control mechanism 9: Movement control mechanism W: Wafer (substrate)

Claims (3)

[Claims] 1. A plurality of light sources, a plurality of light guide means for guiding light from each of the light sources to an irradiation area on a photosensitive substrate, and respective emission ends of the light guide means and the substrate are predetermined. An edge exposure apparatus comprising: a moving mechanism that relatively moves along a moving direction; and a moving unit that relatively moves each of the exit ends in a direction orthogonal to the moving direction. 2. The peripheral exposure apparatus according to claim 1, wherein each of the emission ends of the light guide means is provided so as to irradiate the substrate with light obliquely. 3. A rotation means for changing the angle of each emission end with respect to the substrate so that the light irradiation to the substrate by each of the light guide means is obliquely incident at a predetermined angle. The peripheral exposure apparatus according to claim 1 or 2, wherein: