JPH04320334A - Purification device - Google Patents

Abstract

PURPOSE:To make it possible to carry out a stabilized cleaning operation by installing a board for making gas flow on the surface in a laminar flow and controlling the thickness of a gas layer flowing between the board and the surface. CONSTITUTION:A quartz board 3 through which ultraviolet rays penetrate is so laid out as to face a wafer so as to form a gas flow layer 15. A plurality of nozzles are welded to the quartz board 3 to supply ozone. Furthermore, there is laid out a nozzle 5 which lets the gas flow in order to measure the thickness of the layer whereas a pressure gauge 6 is installed on the way of a pipeline to the nozzle 5. The pressure of the pressure gauge 6 varies with the size of an outlet cap of the nozzle 5. A pressure range, which is equivalent to a control gap range, is predetermined based on the relation previously established between the cap and the pressure gauge 6. The predetermined pressure range is input into a control circuit. A pulse motor-driven mechanism for vertically moving a stage 2 operates in such a fashion that the gas flow layer 15 is fixed by an output signal of the value of the pressure gauge 6.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to cleaning equipment for cleaning glass and wafers, and oxidizing and removing photoresists used as masks using active oxygen atoms obtained by decomposing ozone, and is used in semiconductor manufacturing, liquid crystal glass manufacturing, and optical glass manufacturing. It is used for cleaning and removing organic matter from processed surfaces in the manufacturing of products, etc.

0002

2. Description of the Related Art A method for removing organic matter using the oxidizing action of ozone has become rapidly popular in recent years as a so-called ashing device. Such a device is described, for example, in US Pat.
As seen in No. 47, photoresist, which is an organic material, after being used as a masking in semiconductor manufacturing,
It is a dry, low-damage process that uses ozone, ultraviolet rays, and heat to convert carbon dioxide and water into evaporation, removing them at atmospheric pressure without using liquid chemicals.

[0003] What is important in this cleaning process is that
The issue is how efficiently the active oxygen atoms generated from the supplied ozone can act on the surface to be treated. In other words, the first point is that ozone is easily decomposed by heat, so ozone must be supplied to the entire surface to be treated in a short period of time, and the second point is that the lifespan of the active oxygen atoms produced when ozone decomposes. Since it is very short, it can be efficiently generated very close to the surface to be treated. As a means of achieving this, reducing the thickness of the layer through which ozone flows and increasing the gas flow rate is an effective means for solving the first problem. At the same time, by narrowing the layer through which this gas flows, as much as possible of ultraviolet rays, which are absorbed by ozone and decompose it to generate active oxygen atoms and destroy the chemical bonds of organic matter, are transmitted onto the surface to be treated. This is an effective means for solving the second problem.

[0004]The most important thing to accurately achieve the above-mentioned effective means is to accurately control the thickness of the layer through which the gas flows in a non-contact manner. In the prior art, sufficient consideration has not been given to a reliable and specific method in this regard.

[0005]

SUMMARY OF THE INVENTION In view of the above points, an object of the present invention is to provide a cleaning device that can perform stable cleaning by accurately controlling the thickness of the layer through which gas flows without contact. .

[0006]

[Means for solving the problem] The thickness of the gas layer flowing on the surface to be treated is constantly measured in a non-contact manner, and the thickness of the gas layer is constantly measured in a non-contact manner, and the gas flow is adjusted to a table on which the object to be treated is placed, or the gas flow is In order to form a layer, plates (for example, the quartz plates) placed opposite to each other are moved up and down and controlled so as to keep the thickness of the layer constant.

[0007]

Operation: Measuring the layer thickness must be done using a non-contact method. This is because dust and scratches caused by contact can damage the product and make it a defective product. For this reason, the thickness of the layer can be measured using methods such as those that utilize changes in the pressure of the outflowing gas or those that utilize the reflection of light. The measured changes in the thickness of the layer through which the gas flows are converted into electrical signals, and the vertical mechanism is operated in conjunction with the signals. The vertical movement maintains the thickness of the layer by raising and lowering a table on which the object to be treated is placed or a plate (for example, the quartz plate) placed oppositely to form a gas flow layer on the surface of the object to be treated. It can be done.

[0008]

[Embodiment] (Embodiment 1) An embodiment will be described below with reference to FIG. A photoresist is applied to the surface of a silicon wafer 1 for semiconductor manufacturing, which is an object to be processed. The wafer 1 is fixed to a rotatable stage 2 by vacuum suction. A quartz plate 3 transparent to ultraviolet light is placed opposite the surface of the wafer to form a gas flow layer 15. A plurality of nozzles 4 for supplying ozone are welded to the quartz plate. Furthermore, a nozzle 5 for flowing gas for measuring the thickness of the layer is further arranged on the quartz plate, and a pressure gauge 6 is arranged in the middle of the piping to the nozzle 5. The gas supply pressure to the pipe is kept constant by a regulator 7.

The pressure in the pressure gauge 6 changes depending on the size of the gap at the outlet of the nozzle 5 (using the principle of an air micrometer). The relationship between the gap and the pressure of the pressure gauge 6 is determined in advance, and a pressure range corresponding to the control gap range is determined and input to a control circuit (not shown). nozzle 4,
The upper side of the quartz plate (opposite side from the wafer) at a position avoiding 5.
High-intensity low-pressure mercury discharge lamps 8 are arranged in a plane.

The area around the low-pressure mercury lamp 8 is covered by a lamp house 9, and the area around the discharge lamp is purged with, for example, nitrogen gas to prevent the generation of ozone. This is to prevent ultraviolet rays from being absorbed at a location far from the wafer surface, reducing the amount of ultraviolet light reaching the wafer surface, and to prevent ozone from scattering into the atmosphere. Ozone gas is supplied to the nozzle 4 from an ozone generator 10. stage 2
The loading and unloading of wafers is carried out by a transfer arm (not shown) that descends and passes through the opening/closing window 12 of the processing chamber 11.

The vertical mechanism 13 of the stage 2 is operated by a cam and a pulse motor, and the pulse motor is connected to the pressure gauge 6.
It operates so that the value of the layer 15 becomes constant according to the output signal of. Note that the ozone gas remaining in the processing chamber 11 is discharged into the duct through the exhaust hole 14 via an ozone processing device (not shown).

(Embodiment 2) Another embodiment of the non-contact control method using reflection of laser light is shown in FIG.
The main points will be explained below. 1 laser beam on 1 silicon wafer
A plurality of elements 17 are arranged to receive the reflected light from the layer 15 through which the reactant gas flows. Using the output signals of the light-receiving element from the upper and lower limits of the control range, the layer thickness is controlled to be kept constant by operating the vertical drive mechanism in conjunction with each other in the same manner as in the method of the first embodiment. It goes without saying that the wavelength of the laser light does not match the wavelength of the light emitted from the low-pressure mercury lamp as the ultraviolet light source.

[0013]

According to the present invention, the thickness of the layer through which the reactive gas flows can be controlled without damaging the object to be treated, so that constant cleaning can be achieved at all times. In addition, changes in the layer due to thermal expansion of the device due to heating and changes over time of the device can be controlled, so that the layer value can be maintained at a constant value regardless of the processing temperature, which greatly improves the reliability of the device operation.

[Brief explanation of the drawing]

FIG. 1 is a mechanical diagram of a cleaning device according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a main part of a cleaning device according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Wafer, 2... Stage, 3... Quartz plate, 4... Reaction gas supply nozzle, 5... Gas supply nozzle for measuring layer thickness, 6...
Pressure gauge, 7...Regulator, 8...Low pressure mercury lamp, 9...Lamp house, 10...Ozone generator, 11...Processing chamber, 12...
Opening/closing window, 13... Vertical mechanism, 14... Exhaust hole, 15... Layer, 1
6... Laser light, 17... Light receiving element.

Claims (4)

[Claims] Claim 1: An apparatus for supplying an oxidizing gas to a surface to oxidize and gasify organic matter on the surface to remove it, including a plate for flowing the gas in a layered manner on the surface, A cleaning device characterized by comprising means for controlling the thickness of a layer through which gas flows between the cleaning device and the surface. Claim 2: The plate for flowing the gas in a layered manner over the surface to be treated is a quartz plate that transmits ultraviolet rays for the purpose of activating the oxidizing gas and simultaneously destroying the chemical bonds of organic matter on the surface. 2. The cleaning device according to claim 1, further comprising a pipe for supplying the oxidizing gas to the quartz plate. 3. A means for supplying gas to the quartz plate and spraying it onto the surface, a means for supplying the gas at a constant pressure to the piping, and measuring the pressure inside the piping and outputting the pressure electrically. 3. The cleaning device according to claim 2, further comprising means for controlling the gas flow rate by moving the quartz plate up and down or the table on which the object to be surface treated is placed up and down in conjunction with the output to control the thickness of the layer through which the gas flows. Device. 4. The quartz plate or the surface of the object to be surface treated is determined by an output signal that optically measures the thickness of a layer that allows oxidizing gas to flow between the quartz plate and the surface of the object using light reflected from the object. 3. The cleaning apparatus according to claim 2, wherein the thickness of the layer through which the oxidizing gas flows is controlled by raising and lowering a table on which the object to be treated is placed.