JPH0548610B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reduction projection type exposure apparatus that can accurately control the exposure amount by measuring and controlling the amount of exposure light consumed for exposing photoresist.

[Conventional technology]

In reduction projection exposure equipment that requires faithful reproduction of fine patterns, such as the manufacturing process of recent ultra-highly integrated semiconductor devices, the control of the dimension of the transferred pattern (Critrcal Dimension Control: CD control) is performed from the semiconductor substrate. This is an important factor that influences the quality of the semiconductor devices obtained.
This dimension may be said to be dependent on the exposure dose and therefore on the accuracy of the exposure dose control.

Exposure control in conventional reduction projection exposure equipment measures the intensity of the exposure light inside the exposure illumination system located before the exposure mask, integrates this, and adjusts the shutter time to achieve the set exposure. It controls the

[Problem that the invention seeks to solve]

In the case of the above-mentioned conventional method, although the amount of light output from the exposure illumination system is controlled, there are differences in the material of the exposure mask, and in particular the attachment of a member whose transmittance changes over time, such as a pellicle film. When the transmittance changes between the exposure illumination system and the projection optical system, as in the case of an exposure mask, these effects cannot be prevented. A test exposure was carried out, and based on the results, it was necessary to revise the exposure setting, which required an immeasurable amount of time and effort.

The present invention eliminates the problems of the conventional methods described above, makes it possible to obtain stable exposure amount control regardless of conditions such as the material of the exposure mask, the presence or absence of a pellicle film, and dramatically improves work efficiency. improve,
Another object of the present invention is to provide a reduction projection type exposure apparatus that enables efficient operation of the apparatus itself.

[Means for solving problems]

In order to achieve the above object, the reduction projection type exposure apparatus according to the present invention has a light amount sensor and a control section, and the exposure light of the exposure illumination system transmitted through the exposure mask by opening and closing the shutter is transmitted to the reduction projection lens. This is a reduction projection type exposure apparatus that focuses light and exposes a semiconductor substrate covered with photoresist.The light amount sensor is installed between the exposure mask and the reduction projection lens, and detects the peripheral area of the element pattern on the exposure mask. The control unit detects the amount of exposure light that has passed through the light sensor and outputs a detection signal to the control unit.The control unit integrates the output of the light sensor and adjusts the shutter installed in the exposure illumination system to obtain the required amount of exposure. It controls the opening and closing time.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of the present invention. In the figure, 1 is an exposure mask, 2 is a pellicle film attached to both the upper and lower surfaces of the mask 1 to protect the exposure mask 1 from dust, 3 is a slit for controlling the exposure amount, 4 is a light amount sensor, and 5 is in the optical path. The exposure illumination system includes a shutter 5a, 6 is a reduction projection lens, 7 is a masking aperture, 8 is an exposure illumination system, and 9 is a control section.

The exposure amount control in this reduction projection type exposure apparatus is to control the exposure light after passing through the exposure mask 1.
The amount of light is detected by a light amount sensor 4 provided between the exposure mask 1 and the reduction projection lens 6, and the output thereof is integrated by the control section.

At the same time as the shutter 5a provided in the exposure illumination system 5 is opened, the exposure illumination 8 is irradiated onto the exposure mask 1 equipped with the pellicle film 2 through the masking aperture 7, The light is transmitted through the region limited to the element pattern on the exposure mask 1 by the band, and is projected onto the semiconductor substrate 10 via the reduction projection lens 6 . On this exposure mask 1, there is a slit 3 for irradiating exposure light to a light amount sensor 4 for controlling the exposure light amount during the light-shielding zone.
is provided, and through this slit 3, exposure light of the same intensity as projection exposure is made to enter the light amount sensor 4 at the same time. That is, the intensity of the exposure light incident on the light amount sensor 4 is attenuated to some extent by passing through the pellicle film 2, etc., and becomes the same as that for actually exposing the photoresist. The output of the sensor 4 is integrated by a control section 9, and the opening/closing operation of the shutter 5a is controlled by commands from the control section 9.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to realize stable exposure amount control regardless of conditions such as the material of the exposure mask, the presence or absence of a pellicle film, the degree of deterioration, etc. Observing the photoresist pattern produced using a microscope and resetting the exposure conditions eliminates the need for such operations, and has the effect of dramatically improving the efficient operation of the apparatus itself.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention. 1... Exposure mask, 2... Pellicle film, 3...
Exposure amount control slit, 4... Light amount sensor, 5... Exposure illumination system, 6... Reduction projection lens, 7... Masking aperture, 8... Exposure illumination.

Claims (1)

[Scope of Claims] 1. A semiconductor covered with a photoresist, which has a light amount sensor and a control section, and focuses exposure light from an exposure illumination system, which is transmitted through an exposure mask by opening and closing a shutter, using a reduction projection lens. The reduction projection type exposure apparatus exposes a substrate to light, and the light amount sensor is provided between the exposure mask and the reduction projection lens, and measures the amount of exposure light transmitted outside the area of the element pattern on the exposure mask. and outputs a detection signal to the control unit, and the control unit integrates the output of the light amount sensor and adjusts the opening/closing time of the shutter provided in the exposure illumination system so as to obtain the required amount of exposure. What is claimed is: 1. A reduction projection type exposure apparatus characterized in that the apparatus controls: 2. The exposure mask has a light-shielding band outside the area of the element pattern, and a slit is provided in a part of the light-shielding band, and the light amount sensor detects the amount of exposure light transmitted through the slit. A reduction projection type exposure apparatus according to claim 1, characterized in that: