JPS6156942A - Gas detector for semiconductor - Google Patents

Abstract

PURPOSE:To make gas detection safe, by providing a column, which concentrates and separates gas for semiconductors, providing the first exciting chamber, in which ultraviolet rays are applied to the gas for semiconductors and a chemical species that can be measured is obtained, and efficiently exciting and detecting the chemical species by a detecting part. CONSTITUTION:A sample of atmosphere 26 is made to pass the column 20 of a gaschromatograph (GC), and only a gas for semiconductors is adsorbed and separated. The temperature of the GC column 20 is increased by a temperature controller 19 and desorption is performed. The gas is sent to the first exciting chamber by nitrogen argon and the like. The gas passes through a quartz spiral pipe 10 and receives ultraviolet rays from an ultraviolet-ray lamp ( I ) 9. The gas is transformed into a chemical species, which can be detected, by a photoluminescence method. The detectable gas is sent to a quartz measuring cell 8. The gas is excited by an ultraviolet lamp (II) 2 again. Thus the clean, safe gas detection, which can be handled simply, can be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a gas detector used in a semiconductor manufacturing process.

[Prior art] Conventional technologies include (1) flame photodeposition method (FPD method) using a hydrogen-nitrogen flame, (2) ionizing gas by irradiating it with ultraviolet rays, and calculating the gas concentration from the ion current generated at that time. photoionization method (PjD method) to measure, (3) chemiluminescence method that utilizes reaction with ozone, (4) infrared spectrophotometry to examine absorption of infrared rays, (5) reaction between gas and mercury oxide, and Chemical reaction/atomic absorption spectrometry to indirectly determine the concentration from mercury vapor, (6) Ii! There are the test paper photoelectric surface method to determine u, and (7) the electrochemical method (diaphragm galvanic cell method and constant potential electrolysis method) that utilizes the oxidation reaction of gas on the electrode surface. These detectors have insufficient sensitivity (4, 6, 7) and poor gas selectivity ('2.' 5.6
．． 7) Since flame, which is generally unstable, is used, zero drift is unavoidable, and explosive hydrogen flame is used (1). Vacuum pumps and ozone generators are used. There are problems as an automatic analyzer, such as (3), which requires mercury oxide, and (5), which uses highly toxic mercury oxide.

[Objective] The object of the present invention is to provide a gas detector for semiconductors that has high sensitivity and high selectivity, does not use dangerous flames or reagents, and does not require any accessory parts other than an ultraviolet lamp. It is to be.

[Configuration] The present invention comprises a column for concentrating and separating a semiconductor gas from an atmospheric sample, a first excitation chamber for irradiating the semiconductor gas with ultraviolet rays to make it a measurable chemical species, and a first excitation chamber for converting the semiconductor gas into a measurable chemical species. It consists of a non-dispersive detection section to efficiently excite and detect the chemical species that have become.

[Example] To explain an example of the present invention based on the drawings, the main parts of the semiconductor gas detector of the present invention are a column that concentrates and separates semiconductor gas, and a column that can be measured by irradiating the gas with ultraviolet rays. It consists of a first excitation chamber for producing chemical species, and a non-dispersed detection section for efficiently exciting and detecting the measurable chemical species. In addition, this detection part is equipped with an ultraviolet lamp (II) (deuterium lamp, xenon lamp, mercury lamp, zinc hollow cathode lamp, etc. can be used),
optical filter (I) (200
(transmits light of around 360 nm), a quartz measurement cell, a reflecting mirror, an optical filter (II) (transmits light of around 360 nm), and a 4B photomultiplier tube. The first excitation chamber consists of an ultraviolet lamp (1) (mercury lamp, xenon lamp, etc.) and a quartz spiral tube. Note that when a mercury lamp is used in the first excitation chamber, it is necessary to purge with nitrogen or the like to prevent ultraviolet rays from being absorbed by oxygen. This also serves to air cool the lamp. The first excitation chamber is made of aluminum with good light reflection so that ultraviolet rays can be effectively irradiated. By using this first excitation chamber, measurable chemical species can be efficiently generated, thereby increasing sensitivity. Furthermore, since the gas flow rate can be increased compared to the case without the first excitation chamber, gas control becomes easier and connection with a gas chromatograph becomes possible. Furthermore, measurement time can also be shortened. On the other hand, high sensitivity can be achieved by making the detection section non-dispersive by using optical filters on both the excitation side and the photometry side. A reflecting mirror is used to effectively use the excitation light.

In the semiconductor gas detector having the above configuration, the semiconductor gas (which is desorbed by heating with arsine, phosphine, and sele) is sent to the first excitation chamber with nitrogen, argon, or helium gas. As it passes through the tube, it is exposed to ultraviolet light from an ultraviolet lamp (I) and is converted into a chemical species that can be detected by photoluminescence.The detectable gas is sent to a quartz measurement cell. It is excited again by the ultraviolet lamp (II).

Of the light emitted when returning from the excited state to the ground state, only the light of a specific wavelength that passes through the optical filter (T[) is converted into current by a photomultiplier tube, amplified by an amplifier, and then sent to an indicator. Display concentration.

'a degree is determined from the intensity ratio with the signal obtained when using a standard gas. Gas released from the measurement cell is removed by an absorber to prevent it from leaking to the outside.

[Effects] As explained above, since the present invention is an optical analysis method, it does not require dangerous flames, reagents, ozone generators, etc., and is a clean, safe, and easy-to-handle method for automatically producing gas for semiconductors. It can be used as an analyzer.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the detection principle of the present invention.

Claims (1)

[Claims] (1) A column for concentrating and separating semiconductor gases, a first excitation chamber for irradiating the gas with ultraviolet rays to make measurable chemical species, and for efficiently exciting and detecting the measurable chemical species. A semiconductor gas detector consisting of a non-distributed detection section.