JPS60230058A - Silicon wafer for column of chromatograph instrument - Google Patents

Abstract

PURPOSE:To simplify measurement and to reduce the size of an instrument by forming a recess having the base of a thin film-like pressure-receiving membrane on a silicon wafer surface by etching and providing a pressure receiving membrane for measuring static pressure in the recess. CONSTITUTION:A capillary column 6, a flow passage groove 2 of a carrier gas and a flow passage groove of a gas for a detector are formed on the specular surface of a silicon wafer 1. An inlet hole 3 for the carrier gas and an injection hole 4 for a sample gas are provided to penetrate the wafer 1 and further a detector 9 is communicated with the outlet of the column groove 6. The recess 5 attached with the pressure receiving membrane having, for example, 2mm.X2mm. pressure receiving area and 10-20mum thickness is provided to the groove 2 and is so constituted as to communicate in a T shape with the groove 2. The recess is thus directly formed on the surface of the wafer 1 and the pressure receiving membrane is provided and therefore the measurement of the gaseous pressure in the flow passage of the capillary column is made easy and the reduction in the size is made easy.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a silicon wafer for a portaple or pocket type gas chromatograph device, particularly for gas flow in a capillary column, a carrier gas flow path, a sample gas flow path, etc. A portable cavity with grooves used in the gas flow path, through-holes communicating with the gas flow path such as a carrier gas introduction hole, a sample gas introduction hole and a discharge hole, and a detected gas discharge hole, and a detector are provided on the surface thereof. The present invention relates to silicon wafers for free gas chromatography devices.

(B) Prior art On the surface of a silicon wafer, there are grooves for gas flow paths such as a capillary column, a carrier gas flow path and a sample gas flow path, a carrier gas introduction hole, a sample gas introduction hole and a discharge hole, and a discharge of detected gas. A portable capillary gas chromatograph 7 device is already known, which is provided with a through hole communicating with a groove for a gas flow path such as a hole, a thermal conductivity detector, etc., and is coated with Pyrex glass.

By the way, in gas chromatography analysis, if the carrier gas flow rate is unstable, the retention time of each component becomes unstable, which reduces the accuracy of identification, and also causes changes in peak area, causing errors in quantitative analysis. Because of these inconveniences, gas chromatograph apparatuses require a mechanism to keep the flow rate of carrier gas constant.

And this kind of thing is no exception in portaple gas chromatograph equipment, and even in conventional equipment, there is a hole near the carrier gas introduction hole of the silicon wafer.
A pressure regulator and pressure gauge are provided. Moreover, this pressure gauge is usually a Bourdon tube with a diameter of 5 cm (1), which is about the same size as a silicon wafer! Because of this, it was bulky, and it was difficult to make it into a portaple or pocket type because of the need to attach other accessories in addition to the main body. However, when installing a commercially available semiconductor pressure sensor or strain-age type pressure sensor, the mounting hardware and the pressure sensor itself are not necessarily small in size, so there are difficulties in making it not only a pocket type but also a portable type. Ta.

(C) Purpose of the Invention The present invention provides a silicon wafer for a column of a Scchromatograph 7 apparatus, which is a capillary that can be easily made into a portapulle or pocket type, in which a concave pressure-receiving film for static pressure measurement is provided on the silicon wafer. .

(D) Structure of the Invention The present invention is characterized in that at least four parts -a having a bottom surface of a thin pressure-receiving film are formed on a silicon wafer surface, and between Un h #
There is a silicon way 1 for a gas chromatograph device, which is characterized by a carrier gas flow path groove.

silicon wafers are used. In addition, as a thin film-like pressure-receiving film, Guyar 7 Ram for semiconductor pressure sensors is used, but a part of a silicon wafer may be formed into a thin film-like shape, and other thin-film-like pressure-sensitive films can also be used. You can also use It is preferable that the communication groove from the recessed portion having the pressure-receiving membrane is connected to the carrier gas flow groove in a T-shape. The size of the four parts is sufficiently thick compared to the carrier gas flow groove (
It is preferable to form such a structure because the pressure-sensitive area can be kept large.

Furthermore, by keeping it large in this way, slight pressure fluctuations are eliminated, making it easier to stabilize the carrier gas flow rate.

Although such a concave portion having a thin film-like bottom portion may be formed by any means, it is preferable to use etching treatment. For example, by etching a thin film of p-type silicon semiconductor bonded to n-type silicon semiconductor with a mixture of ethylenediamine, pyrocatechol, and water known as FDP, four parts with a thin film of desired thickness on the bottom can be etched. is obtained. As the etching agent, an anisotropic etching agent is used in order to precisely form the contour of the groove. Examples of anisotropic etching agents include a mixture of ethylenecyamine, pyrocatechol and water known as EDP, aqueous sodium hydroxide, and aqueous alkaline solutions such as aqueous potassium hydroxide, especially hot aqueous alkaline solutions. It is considered preferable.

However, in addition to these, HMA etchants, ie mixtures of hydrofluoric acid, nitric acid and acetic acid, can be used.

When anisotropic etching is applied to the mirror surface of an n-type silicon wafer, the mirror surface of the n-type silicon wafer is etched into an f-shape with a surface index of (10σl°, for example, a square, 5.); Since the 1ii+ surface is etched into a diamond shape, it is preferable to use the surface with a surface index of +1001.

(E) This is a schematic plan view of the wafer IH111+-Taiki III Mereliri, and FIG. 2 is a partial cross-sectional view of the recessed portion thereof.

The present invention will be described below with reference to these figures; however, the present invention is not limited by these explanations.

On the mirror surface of the silicon wafer 1, for example (1001 surface, 1
1400 to 500μ! A capillary column 6, a carrier gas channel groove 2, and a detector gas channel groove 8 are formed by grooves having a depth of 10 to 20 μm. At the end of the carrier gas flow groove 2, a carrier gas inlet hole 3 having the same width as these flow grooves is provided so as to pass through the wafer 1. It communicates with a carrier gas a (both not shown) through it. Between the cavity-free column groove 6 and the carrier gas flow groove 2, a sample gas injection hole 4 is provided penetrating the wafer 1 and has the same width as the flow groove width.Sample gas injection hole 3 may be in communication with a sample gas source (both not shown), for example, via a metering tube.

The outlet of the capillary column groove 6 communicates with the gas flow groove of the detector. The carrier gas channel groove 2 is provided with a recess 5 having a substantially square shape and having a pressure receiving area of 2iiX2xa+ and a pressure receiving membrane having a thickness of 10 to 20 .mu.m attached thereto. This recess communicates with the carrier gas flow groove 2 through the communication groove 7 in a 1'-shaped configuration.

The capillary column groove 6 is carved in a meandering shape, a spiral shape, or any other suitable shape depending on the position where the detector 9 is provided.

In this example, since the detector 9 is provided outside the spiral ring of the capillary column 6,
The flow of f″7% is formed so that every other one flows in the same direction.

Further, in this example, a thermal conductivity detector is used as the detector 9. A groove 11 in which a thermistor or platinum film resistor is placed is provided perpendicularly to the gas flow groove 8 from the capillary column. In order to provide electrode terminals on the back side of the silicon wafer 1, electrode terminal insertion holes 10 are provided at both ends of the groove in which the thermistor or platinum film resistor is placed.

The thermal conductivity of the gas leaving the capillary capillary is measured by a detector 9', and the gas flows out from a discharge hole 12 formed through the silicon wafer.

In this example, the silicon wafer 1 used is 400
It has a thickness of ~500 tlx, and the four parts 5 are submerged in this, the pressure receiving area is 2my x 2am, and the thickness is 10~20μ.
A pressure receiving film 13 of p is formed. In this case, Jl of this dimension
The silicon wafer is hydroxylated in an aqueous alkaline solution, such as a mixture of ethylenediamine/pyrocatechol and water, known as ED1), aqueous potassium hydroxide solution, aqueous potassium hydroxide solution, etc. The four parts 5 and the pressure-receiving film 13 can be formed by performing an anisotropic etching process using a heated alkaline aqueous solution.

For example, a Pyrex glass plate is placed on the surface of the silicon wafer on which the column grooves and the like are provided! Glued hermetically and formed for gas chromatograph use.

The carrier gas inlet hole 3 of the silicon wafer covered with this lath plate is communicated with a pressure WI4 regulating device and a carrier gas source via this, and the sample gas is communicated through the injection hole 4 with a gas metering tube and a sample injection device. let Further, the pressure-receiving membrane 13 and the electrode terminals of the detector 9 are connected to a meter to perform gas chromatography analysis.

Carrier gas is introduced through the carrier gas inlet hole, and the carrier gas pressure is adjusted by a pressure regulator to adjust the carrier gas flow rate to a constant amount. A known amount of sample gas is added to this flow through the sample gas injection hole. 4 and sends it to the capillary column together with the carrier gas.The component gases in the sample are chromatographically separated in the capillary column and flow out from the column 6, but this outflow gas is detected by the detector 9 to detect the sample gas. Perform analysis.

(F) Effects of the Invention The present invention makes it possible to extremely easily measure the gas pressure in the cavity-free column flow path by forming the four parts directly on the silicone surface and providing a pressure-receiving membrane thereon. As a result, there is no need to attach complicated conduits, etc., making it easier to downsize the device.

In this way, the conventionally large, high-precision capillary gas chromatograph device can be made smaller, allowing it to be used in gathering places, subways, oil heating rooms, etc. without having to collect samples and take them back to the analysis laboratory. This makes it easier to analyze gas in a closed place, and prevents accidents caused by oxygen deficiency.

In this way, the present invention provides a pocket-sized, convenient to use and transport, and high-performance ッs analyzer, so that high-precision analysis can be performed at any time. big.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view for explaining one embodiment of the silicon wafer for columns of the capillary gas chromatograph apparatus of the present invention, and FIG. 2 is an explanation of the four parts of the silicon wafer to which the glass plate is bonded. FIG. 1 is a silicon wafer, 2 is a carrier gas channel groove, 3 is a carrier gas inlet, 4 is a sample gas injection hole, 5 is a recess, 6 is a cavity free column groove, 7 is a communication groove, 8 is a detector 9 , 10 is a measurement electrode terminal insertion hole, 11 is a gas flow groove;
is between the thermistor or platinum film resistor for measuring thermal conductivity! 12 is a gas discharge hole, 13 is a pressure-receiving membrane, and 14 is a glass plate. Representative Patent Attorney Masahiko Takeda! Patent Attorney Masaru Takiguchi Patent Attorney Hiroshi Naka Kaze - Ochi 1 Zugaku - 2 Ochi

Claims (1)

[Claims] A gas chromatograph apparatus characterized in that four parts each having a bottom surface of a pressure-receiving film, at least a part of which is a grooved film, are formed on the surface of a silicon wafer, and the recessed parts communicate with a carrier gas channel groove. Silicon wafer for columns.