JPS63184329A - Irradiated body holder for electron beam exposure system - Google Patents

Abstract

PURPOSE:To remove the waiting time, when a temperature balances, approximately and to improve accuracy of finishing when a mask is mounted to a cassette and further set up to a stage by using the cassette and the stage consisting of a conductive ceramic material. CONSTITUTION:A cassette 2 and a stage 3 are manufactured by employing a conductive ceramic material. Thermal expansion coefficients are made remarkably smaller than a metal because of the ceramic material, and the time until the ceramic material is fitted as the stage and the cassette and stabilized can be shortened. Since the ceramic material has conductivity, not merely a ceramic material, electron beams are not deflected owing to charging by the driving of electron beams. Precise electric discharge machining is enabled because of conductivity, thus acquiring the accuracy of finishing equal to the metal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electron beam exposure apparatus for manufacturing semiconductor devices.

[Conventional technology]

Conventionally, in an electron beam exposure apparatus used in production, a mask 1 is first placed in a cassette 2, as shown in FIG.
Further, the cassette 2 is mounted on the stage 3 and held, and the stage 3 is moved minutely in the X and Y directions to bring a predetermined position on the mask 1 to the irradiation point of the electron beam.

This position adjustment is performed using the mirror 4 (X) installed on the side of the stage 3.
, 4(Y) was irradiated with a laser beam and measurements were made from the interference. As mentioned above, the reason why there are two stages, the cassette 2 and the stage 3, is because the mask 1 has a moderate shape.

[Problem that the invention seeks to solve]

Recently, the accuracy of the circuit pattern of the mask is required to be less than 1 μm in line width, so the holding accuracy of the mask is extremely strict. Furthermore, it is especially required for production that the time from when the mask is attached to when a stable state is reached is short. However, conventionally, the mask is a glass plate, and the cassette and stage are made of metal, have a high coefficient of thermal expansion, and are made of different materials. Therefore, if cassettes are mounted on a stage with different temperatures, the cassettes will expand and contract after being fixed, causing changes in their relative positions until their temperatures are balanced. Furthermore, when the cassette expands and contracts, the mask attached thereon also shifts in position relative to the cassette.

Temperature adjustment is performed to minimize relative positional distortion due to this temperature difference, but in order to fully expose a highly accurate circuit pattern with a line width of 1 micron or less, the temperature must be adjusted after the cassette is mounted on the stage. A waiting time for equilibration is required, and slight temperature changes occur during exposure due to the energy of the electron beam, so metal stages and cassettes have disadvantages in exposure accuracy and temperature equilibrium waiting time. Note that the same applies when the electron beam is directly irradiated onto the wafer instead of the mask.

In order to eliminate this drawback, it has been proposed at the research level to make the stage from a ceramic material with a relatively small coefficient of thermal expansion. However, it has the drawbacks that it is difficult to process and is expensive, and because it is a non-monumental object, if the electron beam hits the area even once, it will be charged with electric charge, which will deflect the electron beam and prevent normal exposure. Ta.

[Means for Solving the Problems] The irradiator holding device of the present invention includes a cassette that holds the irradiator and a stage that holds the irradiator and is capable of minute movement. at least one of the conductive ceramic materials is made of a conductive ceramic material.

[Effect]

In the present invention, a cassette, using a conductive ceramic material,
Create a stage. Since it is a ceramic material, its coefficient of thermal expansion is significantly lower than that of metal, and the time required for it to stabilize after being installed as a stage or cassette can be shortened. Furthermore, since it is not just a ceramic material but is electrically conductive, there is no deflection of the electron beam due to charging caused by electron beam implantation. Also, because it is conductive, precise electrical discharge machining is possible, and the machining accuracy is comparable to that of metal.

〔Example〕

The following ceramic materials are used for the holding device of the present invention.

Here, the volume resistivity is the resistance value of a 1 cm square cube. It is a ceramic material with a thermal expansion coefficient of aluminum 23X.
10-'I stainless steel 16.4 x 10-' is one order of magnitude lower.

The cassette and stage of the present invention do not need to be particularly different in shape from conventional metal ones, and can be realized in the form shown in FIG. In FIG. 1, cassette 2. The mask 1 is forced upward from below with a spring, and is fixed with a presser shown at 5.5'. Presser 5
5' has nothing to do with the position on the plane in the xY direction, so it does not necessarily have to be a ceramic material. In addition, cassette,
It is best if both stages are made of conductive ceramic material, but the same effect can be produced even if only one of them is used.

Furthermore, it goes without saying that the object to be held in the present invention is not limited to a mask, but may also be a wafer.

〔Effect of the invention〕

As explained above, by using the cassette and stage made of the conductive ceramic material of the present invention in an electron beam exposure apparatus, a mask is attached to the cassette,
Furthermore, when mounted on a stage, there is almost no waiting time for the temperature to equilibrate, and the relative position of a circuit pattern with a line width of 1 μm or less can be adjusted and maintained with an accuracy of about 0.1 μm. Since the cassette and stage are made of conductive ceramic material, the processing accuracy can be on the same level as metal ones.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an irradiator holding device of an electron beam exposure apparatus. 1...Wafer, 2...Cassette, 3...
Stage, 4 (X), 4 (Y)...mirror, 5.5'...presser.

Claims (1)

[Claims] An electron beam exposure apparatus comprising a cassette that holds an irradiation object and a stage that holds the cassette and is capable of minute movement, and at least one of the cassette and the stage is made of a conductive ceramic material. Body retention device.