JPH038327A - Ice scrubber - Google Patents

Abstract

PURPOSE:To suppress charging of the surface of a wafer and to reduce adherence of dust on the surface of the wafer by providing an ion shower generator in a processing vessel for injecting fine particle ice, monitoring an ion amount, and controlling the amount in the vessel. CONSTITUTION:Electrostatic capacitor type electrodes 9 are installed in the atmosphere of a processing vessel 7 for generating ultrafine particle ice to spray it to a wafer, etc. One of the electrodes 9 collects charged particles floating in the atmosphere in the vessel 7, and the other is so connected as to become the same potential as that of the wafer 6. A potential difference between the wafer 6 and the atmosphere is measured by a microammeter 10, an output variator 11 receives a microcurrent value to recognize ion amount and polarity, and sends an output signal to an ion shower generator 12 for regulating ion generation amount when positive or negative ion amount exceeds an allowable value. The generator 12 generated ions of the insufficient polarity with an output controlled by its signal. Thus, the charging of the surface of the wafer is suppressed, thereby reducing adherence of dusts on the wafer.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to ice creams used in processing steps such as surface precision cleaning, surface modification resist removal, and etching in the manufacturing process of electronic components such as semiconductors and electronic devices. The present invention relates to a scrubber device.

[Conventional technology]

FIG. 3 is a schematic diagram of a conventional ice scrubber device disclosed in, for example, Japanese Patent Application Laid-Open No. 61-70281. In the figure, a liquid supply source is connected to a spray nozzle (2) attached to an insulated container (1) (3) is connected. A spray nozzle (4) is connected to the lower end of the heat insulating container (1).

A high pressure gas cylinder (5) is connected to the injection nozzle (4) and the spray nozzle (2). (6) is an object to be processed, such as a wafer, which faces the injection nozzle (4) at a certain distance, and is placed in a processing container (7) incorporating the injection nozzle (4).

With the above configuration, the liquid supplied from the liquid supply source (3) is atomized into the atomized container <1) by the spray nozzle (2) due to the gas pressure from the high-pressure gas cylinder (5). At this time, since the heat insulating container (1) is cooled with liquid nitrogen or the like, the mist droplets freeze, and fine ice particles (8) with a diameter of several tens of microns are generated. This fine ice (8) is sprayed from a jet nozzle (4) by gas pressure from a high-pressure gas cylinder (5) onto a wafer (6) placed oppositely, and the surface of this wafer (6) is subjected to cleaning, processing, etc. will be held.

[Problem to be solved by the invention]

Conventional ice scrubber devices have an oval shape as described above, so when the fine ice particles pass through the nozzle at high pressure and high speed in dry gas, the fine ice aerosol becomes electrically charged, and when it is sprayed onto the wafer etc., the wafer is Charge to either positive or negative polarity.

At this time, there is a problem in that the wafer attracts charged dust to the opposite pole in the atmosphere in the processing chamber, and the dust adheres to the wafer, causing surface contamination.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide an ice scrubber device that suppresses charging on the wafer surface and prevents dust from adhering to the wafer or the like.

[Means to solve the problem]

The ice scrubber device according to the present invention is provided with an ion shower generator in a processing container that spouts out fine ice, and also with means for monitoring the amount of ions and controlling the amount of ions in the container.

[For production]

In this invention, by maintaining the same number of ions in the positive and negative electrodes in the processing container that injects ultrafine ice powder, charging of the wafer, etc. is suppressed, and the wafer is prevented from electrically attracting dust in the atmosphere. . Furthermore, since the amount of ions in the atmosphere fluctuates greatly over time, this is continuously monitored and the output of the ion shower generator is controlled in real time to constantly maintain an ion state suitable for Ik.

〔Example〕

FIGS. 1 and 2 show an embodiment of the present invention. In FIG. 1, an electrostatic capacitor type electrode (9) is connected to a processing vessel (7).
It is set in an atmosphere of A micro-ammeter (10) is connected to this electrode (9) by a conductive wire, and an output variable device (11) and an ion shower generator (12) in the processing container are connected to this micro-ammeter (10). has been done.

In addition, the same reference numerals as in FIG. 3 indicate the same parts.

Next, the function and operation of this embodiment will be described.

Generation of fine ice particles and spraying onto wafers, etc. are the same as in the conventional apparatus described above. Here, the processing container (7
) One side of the electrostatic capacitor type electrode (9) installed in the processing container (7) collects charged particles floating in the inner atmosphere of the processing container (7).
Since the other pole is connected to have the same potential as the wafer (6), the potential difference between the wafer (6) and the atmosphere is measured by the microcurrent meter (10). The output variable device (11) receives this minute current value and recognizes the ion amount and polarity, and if the amount of positive or negative ions exceeds a certain tolerance value, the ion shower generator (12) is activated depending on the degree. sends an output signal to adjust the amount of ion generation. The ion generator (12) generates ions of the missing polarity with an output controlled by this signal. Due to this action, the processing container (
By suppressing the potential difference between 7) and the wafer, etc. (6), it is possible to 1) prevent dust from attracting the wafer, etc. due to electrostatic force, and 2) prevent dust in the atmosphere from being charged.

FIG. 2 shows the correlation between the ion concentration in the processing container (7) and the number of dust attached to the wafer.

〔Effect of the invention〕

As described above, according to the present invention, an electrostatic capacitor type ion monitor and an ion shower generator are installed in a processing container that sprays fine ice onto wafers, etc., and the measured values of the ion monitor are used to control the output of the ion shower generator. Feedback provides the effect of reducing dust adhesion to the wafer surface.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of an embodiment of the present invention, Fig. 2 is a characteristic diagram of ion concentration and number of attached dust in this embodiment, and Fig. 3 is a schematic cross-sectional view of a conventional ice scrubber device. . (4)...Injection nozzle, (6)...Workpiece such as wafer, (7)...Processing container, (8)...Fine ice, (9)
・Electrostatic capacitor type electrode, (10)...Micro ammeter, (
11)...Output variable device, (12)...Ion shower generator. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A processing container equipped with an injection nozzle that injects and collides fine ice particles onto the surface of the processing object, an ion shower generator placed within the processing container, and monitoring the amount of ions near the surface of the processing object. and control means for feedback controlling the amount of ions generated by the ion shower generator.