JPH11214294A - Peripheral aligner and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform peripheral exposure from an outer circumference of a peripheral part of a substrate to the inside of a step, by moving a light irradiation position by an irradiation means from an outer circumference of a substrate to the inside of the step by moving a radiation means and a θ part relatively. SOLUTION: At first, a single axle stage 6 is driven, an outer shape of a wafer 1 is detected by a step detection sensor 2 and a position thereof is obtained. Then, the single axle stage 6 is driven to a central direction and a step is detected and a position thereof is obtained. A setting value for positioning how far an imaging lens 4 is to a central side from an outer shape is obtained from the two values. Revolution by a θ part 7 and a position of the imaging lens 4 by the single axle stage 6 are controlled, so that light falls on from an outer circumference to an inside of the step based on the setting value. Light from a light source 3 is cast on the wafer 1 through the imaging lens 4 by way of a fiber 5. Here, a position of the single axle stage 6 is changed at a revolution position of θ. As a result, unnecessary resist on a wafer is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for forming a fine pattern in an IC, LSI, or other electronic device, which is applied to a peripheral portion of a substrate such as a silicon wafer or a substrate such as a dielectric, metal or insulator. The present invention relates to a wafer peripheral exposure device for removing a resist in a developing step.

[0002]

2. Description of the Related Art Conventionally, in a technique for forming a circuit pattern on a semiconductor wafer, when a photosensitive resist film is formed on a wafer, a spin coating method (rotation coating method) is generally used.

In the spin coating method, the wafer is rotated while pouring the resist to a central position on the surface of the wafer, and the resist is applied to the surface of the wafer by centrifugal force. In this spin coating method, the resist may protrude from the peripheral portion of the wafer, and may reach the back surface of the wafer.

FIG. 3A is a view showing a state in which a resist is applied to the surface of a wafer, and FIG. 3B is an enlarged sectional view of the periphery of the wafer in FIG. 3A. In the figure, reference numeral 9 denotes a wafer, reference numeral 10 denotes a resist, and reference numeral 11 denotes a resist wrapping around the back surface of the wafer. The resist 11 which has reached the back surface is not irradiated in the exposure step for forming a pattern, and remains after development in the case of a positive resist. The resist 11 wrapped around to the back side is caught between the wafer chucks when it is attracted to the wafer chuck for correcting the wafer at the time of exposure, so that not only the wafer cannot be corrected to a sufficient flatness but also a vacuum error or the like. It also causes.

Further, the resist from the front surface and the edge of the peripheral portion of the wafer to the rear surface of the wafer causes the following problem. The wafer coated with the resist goes through various processing steps and is transported by various methods. At this time, the peripheral portion of the wafer is mechanically grasped and held, or the peripheral portion of the wafer slides on the wall of a storage container such as a wafer carrier. At this time, unnecessary resist is removed from the peripheral portion of the wafer to generate particles, thereby lowering the yield.

Therefore, in order to remove unnecessary resist in the peripheral portion of the wafer separately from the exposure step for pattern formation, peripheral exposure is performed (Japanese Patent Laid-Open No. 62-1423).
No. 21).

FIG. 4 is a schematic explanatory view of a main part of the wafer peripheral exposure apparatus. Reference numeral 3 denotes a light source, 4 denotes an imaging lens, 5 denotes a fiber, and 6c denotes a θ stage which rotates while holding the wafer 9. In this figure, it is considered that an unnecessary resist around the wafer is removed by exposure by positioning the head of the imaging lens 4 around the wafer and rotating the wafer while applying light.

[0008]

In the above conventional example, the resist at the peripheral portion is removed by peripheral exposure within a range of several mm from the outer periphery of the wafer. However, in recent years, wafers having steps such as SOI wafers have been used. This SOI wafer is a Si On Insulator W
This is an abbreviation of "afer" and is a semiconductor wafer necessary for further high-speed operation and low power consumption of semiconductor devices. Although there are various methods for manufacturing the wafer, the wafer is made by a technique of bonding the wafers to each other, so that the wafer has a step. In such a wafer having a step such as an SOI wafer (hereinafter referred to as a stepped wafer), it is necessary to remove the resist from the step to the inside without determining the width for removing the resist by the distance from the outer periphery of the wafer. .

FIG. 5 shows a state where a wafer is contained in a carrier. FIG. 6 shows details of the portion A in FIG. 5 when the wafer is lifted up and down by a hand (not shown) when loading and unloading the wafer from the carrier. In FIG. 6, 20 is Si, 21 is SiO ₂ , 22 is Si,
Indicates a resist, and 23 indicates a carrier. 20 shows a stepped wafer such as an SOI wafer including 20 to 22. Normally, when the wafer is floated by a hand, there is a gap in the vertical direction of the carrier, and the wafer is loaded and unloaded in a direction perpendicular to the plane of FIG. However, the wafer may rub against the carrier in the vertical direction when the wafer is loaded or unloaded due to a processing error of the carrier or thermal deformation received in the processing step. FIG.
When the carrier is rubbed upward, the tapered portion of the carrier rubs against the resist, the resist is removed, and particles are generated.

Accordingly, it is an object of the present invention to provide a peripheral exposure apparatus and method capable of preventing a resist in a peripheral portion of a substrate from becoming particles even when a stepped substrate is used.

[0011]

In order to achieve the above object, according to the present invention, when exposing a peripheral portion of a stepped substrate,
The resist is removed to the inside from the step.
That is, the peripheral exposure apparatus of the present invention includes: an irradiating unit that irradiates light to a peripheral portion of a substrate;
Part, and a stage for relatively moving the irradiation unit and the θ part, wherein when the substrate is a stepped substrate having a step in the peripheral portion, the stepped portion is located inside the step from the outer periphery of the substrate. And control means for controlling the operation of the irradiation means, the θ section and the stage so that the peripheral portion up to the exposure is exposed. Further, in the peripheral exposure method of the present invention, while holding and rotating the stepped substrate at the θ portion, the peripheral portion of the substrate is irradiated with light by the irradiating means, and the irradiating means and the θ portion are relatively moved. By moving the irradiation means to move the light irradiation position from the outer periphery of the substrate to the inside of the step, peripheral exposure is performed from the outer periphery of the peripheral portion of the substrate to the inside of the step.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An edge exposure apparatus according to an embodiment of the present invention includes a light source for edge exposure, a fiber connecting the light source and an imaging lens, a unit for driving the imaging lens uniaxially, The apparatus has a θ drive unit for sucking and rotating the wafer, and is set to perform peripheral exposure to the inside of the step of the wafer having a step, thereby removing unnecessary resist. Further, in addition to the above configuration, a sensor for detecting a step on the wafer is provided, and the distance from the outer periphery of the detected step is set as a set value, so that peripheral exposure can be performed to the inside of the set value.

With the above configuration, it is possible to provide a peripheral exposure apparatus that removes an unnecessary resist by peripheral exposure to the inside of a step in peripheral exposure of a wafer having a step. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014]

Embodiment 1 FIG. 1 shows the configuration of a peripheral exposure apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a stepped wafer, 2 denotes a step detection sensor, 3 denotes a light source, 4 denotes an imaging lens,
Reference numeral 5 denotes a fiber for connecting the light source 3 to the imaging lens 4, reference numeral 6 denotes a stage for driving the members 2 to 5 simultaneously by one motor (not shown) in one axis (left and right directions in the drawing), and reference numeral 7 denotes a θ unit for rotating the stepped wafer. And 8 denote suction units for sucking the wafer.

First, a stepped wafer 1 which has been coated with a resist in advance by spin coating is loaded on a suction unit 8 by a transfer hand (not shown). At this time, the stepped wafer 1 on which the orientation flat and centering of the wafer have been completed is loaded. The orientation flat and the center position may be determined before placing on the suction unit 8, or the center position may be determined by arranging a step detecting sensor having a wide detection area as shown in FIG. The description will be made assuming that the center position setting and the orientation flat are measured in advance. In order to hold the stepped wafer 1, a suction force such as a vacuum force is generated in the suction unit 8.

Next, a step detecting sensor is operated to detect how far the step of the stepped wafer 1 is inside from the outer shape of the wafer. First, the one-axis stage 6 is driven, the outer shape of the wafer is detected by the step detecting sensor 2, and its position is obtained. Here, the step detecting sensor 2 uses a reflection type sensor. Next, a one-axis stage 6 moves toward the center.
Is driven to detect the step and obtain the position. From the two values, a set value for determining how far the center of the imaging lens 4 is positioned from the outer shape is obtained. This set value is a position at which the imaging lens 4 is positioned so that light shines inside the step. This position is set to an optimum value from the shape of the hand and the shape of the carrier. At the time of peripheral exposure, the rotation by the θ unit 7 and the position of the imaging lens 4 by the uniaxial stage 6 are controlled by a control means (not shown) so that light is applied from the outer periphery to the inside of the stepped portion based on the set value. And light source 3
Is irradiated on the wafer through the imaging lens 4 via the fiber 5. Here, the position of the one-axis stage 6 is changed according to the rotational position of θ. This is because the distance between the center and the outer shape changes at the position of the orientation flat. Thus, unnecessary resist on the wafer can be removed.

FIG. 7 is a cross-sectional view when the resist is removed to the inside from the step. With a wafer from which unnecessary resist has been removed to the inside of this step, resist particles will not be generated even if the wafer slides on the tapered portion of the carrier when unloading from and loading into the carrier. In addition, the generation of particles can be prevented even when the wafer peripheral part is mechanically held when the wafer is transported by various processing steps and various methods.

[0018]

Embodiment 2 Embodiment 2 of the present invention will be described with reference to FIG. In FIG. 2, the same reference numerals are given to parts common or corresponding to FIG. In the peripheral exposure apparatus shown in FIG. 2, while the apparatus shown in FIG. 1 fixes the θ section 7 side and drives the light source 3, the step detecting sensor 2, the light source 3, the imaging lens 4 and the fiber 5 are fixed. The θ section 7 and the suction section 8 are configured on the uniaxial stage 6b so that they can be driven in one direction.

In this embodiment, as in the first embodiment,
The stepped wafer 1 that has been coated with a resist in advance by spin coating is loaded onto the suction unit 8 by a transfer hand (not shown). At this time, the stepped wafer 1 on which the orientation flat and centering of the wafer have been completed is loaded. In order to hold the stepped wafer 1, a suction force such as a vacuum force is generated in the suction unit 8.

Next, the step detecting sensor 2 is operated in order to detect how far the step of the stepped wafer 1 is inside the outer shape of the wafer. Since the step detecting sensor 2 is fixed, the uniaxial stage 6b on which the stepped wafer 1 is mounted is driven, and the outer shape of the wafer is first detected by the step detecting sensor 2 to determine its position. Next, the one-axis stage 6b is driven toward the center to detect a step, and the position of the step is obtained. The set value of the one-axis stage 6b is obtained from the two values. This set value is a position at which the imaging lens 4 is positioned so that light shines inside the step. When performing peripheral exposure, the θ unit 7 and the uniaxial stage 6
b is controlled by a control unit (not shown), and the light from the light source 3 is irradiated onto the wafer through the imaging lens 4 via the fiber 5. Here, the position of one axis is changed by the rotational position of θ. The reason is the same as the reason described in the first embodiment. Thus, unnecessary resist on the wafer can be removed.

[0021]

Modification of Embodiment In the above embodiment, a reflection type sensor is used as the step detecting sensor 2, but another sensor may be used. Alternatively, the stepped detection sensor 2 may be used to distinguish a stepped wafer from a normal wafer. That is, a wafer for which a step is not detected by the step position detection operation is determined to be a normal wafer,
The peripheral exposure may be performed by a predetermined distance from the outer shape of the wafer. In the above-described embodiment, the step portion is detected, and the set value of the peripheral exposure is determined based on the detected step portion. However, if the position of the step portion is known from the outer shape in advance, the setting value is input so that the setting is input. You may do it.

[0022]

According to the above-described structure, when the peripheral exposure is performed on the stepped substrate, the peripheral exposure is performed inside the step, so that the substrate slides on the tapered portion of the carrier when the carrier is carried out and is carried into the carrier. No garbage is generated. In addition, when the substrate is transported by various processing steps and various methods, the generation of particles can be prevented even when the peripheral part of the substrate is mechanically held.

[Brief description of the drawings]

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

FIG. 2 is an explanatory view of a peripheral exposure apparatus according to another embodiment of the present invention.

FIG. 3 is an explanatory view of a wafer coated with a resist.

FIG. 4 is a schematic explanatory view of a conventional peripheral exposure apparatus.

FIG. 5 is an explanatory diagram of a wafer stored in a carrier.

FIG. 6 is a detailed view of a portion A in FIG. 5 and an explanatory view of a wafer and a carrier at the time of loading and unloading.

FIG. 7 is a diagram illustrating a carrier after peripheral exposure of a stepped wafer.

[Explanation of symbols]

1: stepped wafer, 2: step detection sensor, 3: light source,
4: imaging lens, 5: fiber, 6: 1 axis stage (light source side), 6b: 1 axis stage (θ axis side), 6c: θ
Stage (conventional example), 7: θ portion, 8: suction portion, 9: wafer, 10: resist, 11: back surface resist, 20: S
i, 21: SiO ₂ , 22: Si, 23: carrier.

Claims (6)

[Claims] 1. An edge exposure apparatus having an irradiation unit for irradiating light to a peripheral portion of a substrate, a θ unit for holding and rotating the substrate, and a stage for relatively moving the irradiation unit and the θ unit. In the above, when the substrate is a stepped substrate having a step in the peripheral portion, control is performed to control the operation of the irradiation unit, the θ unit, and the stage such that the peripheral portion from the outer periphery of the substrate to the inside of the step is exposed. A peripheral exposure apparatus comprising: 2. The apparatus according to claim 1, further comprising a sensor for detecting a step of the substrate, wherein the control means determines a moving amount of the stage based on a detection output of the sensor.
A peripheral exposure apparatus as described in the above. 3. The peripheral exposure apparatus according to claim 1, wherein the stepped substrate is an SIO wafer. 4. While irradiating the peripheral portion of the substrate with light by an irradiating means while rotating the stepped substrate at the θ portion while rotating the substrate at the θ portion, moving the irradiating means and the θ portion relative to each other to perform the irradiation. A peripheral exposure method comprising: moving a light irradiation position by a means from an outer periphery of a substrate to an inside of a step; thereby exposing the periphery from an outer periphery of a peripheral portion of the substrate to an inside of the step. 5. The peripheral exposure method according to claim 4, wherein a step on the substrate is detected using a sensor, and the stage is moved based on a detection output. 6. The peripheral exposure method according to claim 4, wherein the stepped substrate is an SIO wafer.