JPS62174939A - Electrostatic attraction device - Google Patents

Abstract

PURPOSE:To detect the existance of a specimen using a simple structure by a method wherein an electrode is used both as an electrode for electrostatic attraction and as an electrode for detecting specimens. CONSTITUTION:In electrostatic attraction of a specimen, switches 4a, b are switched over to an attraction voltage impressing DC power supply and a control part 5 side while electrodes 2a, 2b are impressed with specified voltage to provide a specimen 1 and electrodes 2a, 2b with electrostatic attraction for attracting and holding the specimen 1. The switches 4a, 4b are changed over to an electric capacity detector 6 side to check the existance of specimen 1. When the specimen 1 exists, the capacity checked by the electric capacity detector 6 is increased compared with the case when the specimen 1 does not exist making it feasible to discriminate the existance of specimen 1 by means of a discriminator 7.

Description

Detailed Description of the Invention [Field of the Invention] The present invention relates to an electrostatic adsorption device, and particularly an electrostatic adsorption device that detects the presence or absence of a sample on an adsorption surface by a change in electric capacity fil between electrostatic adsorption electrodes. Regarding.

[Prior Art] In recent years, as integrated circuit devices have become more highly integrated and have higher performance, dry integrated circuit device manufacturing processes, that is, processing steps in vacuum, have come to play an important role. Conventionally, samples have to be held and transported mechanically in a vacuum because vacuum suction that utilizes the pressure difference with the atmosphere is not possible. However, mechanical holding has the drawback that the entire sample cannot be held uniformly in the holder, and there is a risk of damaging the sample.Recently, attention has been focused on adsorption using electrostatic force, which can operate even in a vacuum. Ta.

Furthermore, knowing the position of the sample has become essential in advancing the automation of vacuum equipment. Conventionally, the presence or absence of a sample on the sample holder has been confirmed by placing the sample on the holder and turning on the switch based on the weight of the sample to detect the presence or absence of the sample. Special processing is required.

Furthermore, since the electrode portion is reduced, there is a problem that the adsorption force is also reduced.

[Object of the Invention] The object of the present invention has been made in view of the problems of the prior art described above, and it is possible to automate the function of detecting the presence or absence of a sample without performing special machining on the electrostatic adsorption device. The purpose is to increase the reliability of vacuum processing equipment.

[Summary of the Invention] The present invention is an electrostatic adsorption device that applies a voltage to one or more pairs of electrodes insulated by an insulator and holds a sample by electrostatic adsorption force. It is characterized by being used as a detection unit for detection.

Embodiment j FIG. 1 shows the configuration of an electrostatic adsorption device according to an embodiment of the present invention. In the figure, 1 is a sample, for example a wafer, 2a
, 2b is an electrode for electrostatic adsorption, 3 is an insulator, 4a and 4b are switches, 5 is a DC power supply for applying adsorption voltage and a control section,
6 is a capacitance detection section, and 7 is a discrimination section.

In the above configuration, switch 4 is used when electrostatically adsorbing the sample.
a, 4b as DC power supply and control for applying adsorption voltage
5 side and apply a predetermined voltage to the electrode 2a.

2b. As a result, sample 1 and electrode 2il! .

Electrostatic attraction is generated on 2b, and sample 1 is attracted and held. On the other hand, to detect the presence or absence of test y311, switch 4a
, 4b to the capacitance detection unit 6 side.

When sample 1 is present, the capacitance seen from capacitance detection section 6 increases compared to when sample 1 is not present. For example, electric [2a, 2
Assuming that the area of b is △, the distance from the wires 442a and 2b to sample 2'41 is d, the dielectric constant of insulator 3 is ε, and sample 11 is an electrical conductor, the increased capacitance is 1/2.・ε
Δ/d. This change in capacitance is detected by the capacitance (1) detection unit 6, and the determination unit 7 determines the presence or absence of the sample.

To detect changes in electrical junction, for example, an oscillation circuit that starts or stops oscillation due to a change in electric (electrostatic) capacitance,
Alternatively, it is possible to use an oscillation circuit whose frequency changes according to changes in each city. Although this embodiment shows an example in which the present invention is applied to an electrostatic adsorption device having 1 ta·j electrodes, the present invention can be applied in exactly the same way even to a case having a plurality of electrodes.

[Effects of the Invention] As explained above, according to the present invention, since the electrode for electrostatic adsorption is also used as the electrode for sample detection, the sample can be detected without the need for a special device in the sample holder. , and the structure can be simplified. Moreover, the reliability of an automated vacuum processing apparatus using such an electrostatic chuck device can be improved.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an electrostatic adsorption device according to an embodiment of the present invention. 1: sample, 2a, 2b: electrode for electrostatic attraction, 3: insulator, 4a, 4b: switch, 5: DC power supply and control unit for applying attraction voltage, 6: capacitance detection unit, 7:
Discrimination part.

Claims (1)

[Scope of Claims] An insulator having a surface on which a conductive object is placed, one or more pairs of electrodes facing the object with the insulator interposed therebetween, and applying a voltage to the electrodes. a power source that detects a conductive object; a capacitance detection unit that detects a change in capacitance between the pair of electrodes; and a determination unit that determines the presence or absence of a conductive object on the mounting surface based on the detection output of the capacitance detection unit. An electrostatic adsorption device comprising: