JP2003247896A - Thermocouple wafer sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensitive flat temperature sensor in which a thermocouple fitting part does not drop off a substrate. <P>SOLUTION: A rear surface 3 of a substrate 1 is provided with a recessed part 5 and a central through hole 6, which is used as a fitting part 4. A metal holding plate 7 to which a thermocouple hot contact C is welded is so housed in the recessed part as to be flush with the substrate rear surface. The upper surface of the through hole is covered with a lid 9, and the recessed part, the inside of through hole, and the upper surface of lid are filled and coated with a heat-resistant inorganic cement M, with thermocouple wires A and B drawn outside through the lid. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermocouple wafer sensor for measuring the surface temperature of a plate-like body such as a silicon wafer.

[0002]

2. Description of the Related Art As a wafer sensor for measuring a wafer surface temperature in a heat treatment furnace by a thermocouple, a thermocouple temperature measuring contact is located in a concave portion formed on one side of a wafer and a plurality of strands formed in the concave portion. It is known that an element wire is drawn out through a through hole and embedded and fixed with an inorganic cement (JP-A-11-51776, 2000-111418). In general, inorganic cement has a weak bonding force with respect to silicon (wafer), and thus has a drawback that the cement and the hot junction are likely to drop from the recess. For this reason, the recess has a wedge-shaped cross section, or a large number of through holes are provided to fold back the wires (Japanese Patent Laid-Open No. 11-51776). However, in addition to reducing the strength of the wafer itself, processing of the wafer is also difficult. Have difficulty.

[0003]

SUMMARY OF THE INVENTION According to the present invention, a large number of thermocouple hot junctions are scattered on the plate surface of a wafer substrate to enhance the temperature measurement accuracy and sensitivity, and at the same time, the hot junctions and a means for preventing adhered cement from falling off are provided. The present invention provides a temperature-measuring wafer and other flat plate-shaped temperature sensors which are constructed on both front and back sides.

[0004]

A thermocouple wafer sensor according to the present invention is a metal having a recess and a central through hole formed on the back surface side of a substrate such as a silicon wafer as a mounting portion, and a thermocouple hot junction is welded in the recess. The holding plate is housed so that its front surface is the same as the back surface of the substrate, the upper surface of the through hole is covered with a cover plate, and the inside of the recess and the through hole and the upper surface of the cover plate are filled and covered with a heat-resistant inorganic cement, and thermoelectric It is constructed by pulling out a pair of wires to the outside through a cover plate. The thermocouple holding plate and lid plate are fixed and integrated by cement, and are locked to the stepped portion of the recess and the substrate surface, respectively, so the temperature measuring unit cannot move or drop off on the front side or the back side. Absent. A thin platinum plate is suitable for the hot junction holding plate, and a ceramic material such as alumina or silica is suitable for the lid plate. The wire is insulated by cement or the cover plate, but may be drawn out through an insulator.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, 1 is a substrate such as a silicon wafer or glass plate (thickness is about 0.5 mm), 2 is a surface, 3
Is a back surface, and 4 is a thermocouple mounting portion. Reference numeral 5 denotes a recess (diameter 3.0 mm, depth 0.3 mm) provided on the back surface of the substrate. Reference numeral 6 denotes a through hole (diameter 1.2 mm) penetrating the center thereof. The recess 5 and the through hole 6 are formed by, for example, an ultrasonic processing machine. 7 is a thin metal plate such as platinum (thickness 0.2 m
m, diameter 2.5 mm), which is an embedded holding plate,
The diameter is smaller than the diameter of the recess 5 and larger than the diameter of the through hole 6. Further, the bottom surface of the metal thin plate is formed to be flush with the bottom surface of the substrate. Reference numeral 8 denotes an element wire hooking hole provided at the center of the thin metal plate, which is a hot junction by welding (TIG welding) the ends of thermocouple elements A and B such as alumel chromel. This hook hole is convenient for welding the hot junction,
The hot junction may be welded to the surface side of the thin plate without providing the hook hole. Reference numeral 9 is a lid plate having a thickness of 0.2 to 0.3 mm, which is made of a ceramic material and has a diameter larger than that of the through hole 6 and a pair of wire insertion portions 10 formed therein. The shape of the cover plate and the wire insertion part is
The present invention is not limited to the embodiment shown in the figure, but any type such as C type and E type may be used. M is
A heat-resistant cement for fixing, which fills the recesses 5 and the through holes 6 and further covers the cover plate 9, is filled and applied, naturally dried, and then thermoset.

In the sensor of the present invention, the thermocouple contact C is welded to the metal holding plate exposed on the back surface of the substrate and accommodated in the recess, and is formed integrally with the lid plate on the front surface of the substrate. Moreover, since the metal holding plate exposed on the back surface of the substrate functions as a heat transfer thin plate, the sensitivity is good and the substrate surface temperature can be measured faithfully. The sensor of the present invention can be used not only as a circular plate but also as a sensor for a rectangular plate such as a liquid crystal panel.

[Brief description of drawings]

FIG. 1 is a plan view of a hot junction arrangement on a substrate.

FIG. 2 is a cross-sectional view of the hot junction mounting part.

FIG. 3 is a plan view of a cover plate.

FIG. 4 is a plan view of a holding plate.

[Explanation of symbols]

1 substrate 2 surface 3 back side 4 Mounting part 5 recess 6 through holes 7 Hot junction holding plate 8 hook holes 9 Lid plate 10 Wire insertion part A and B strands C thermocouple contact M inorganic cement

Claims (2)

[Claims] 1. A recess and a center through hole are formed on the back side of a substrate, and a metal holding plate having a thermocouple hot junction welded therein is housed in the recess with the back side being the same as the back side of the substrate. And a thermocouple wire is drawn to the outside through the lid plate, and the inside of the recess and the through hole and the upper surface of the lid plate are filled and covered with a heat-resistant inorganic cement. Thermocouple wafer sensor. 2. The wafer sensor according to claim 1, wherein the hot-contact holding plate is a platinum thin plate and the lid plate is a ceramic plate.