JPS6034085A - Manufacture of element for infrared radiation thermometer - Google Patents

Abstract

PURPOSE:To improve workability and yield by bonding and manufacturing a piezoelectric substrate, a dummy board and an abrasive jig in succession by using two kinds of heat softening resins having different softening points and mounting an element to a package. CONSTITUTION:A large number of crossed finger type electrodes are formed on a piezoelectric substrate 14. A heat softening resin is applied on a dummy glass plate 12 to form a first heat softening resin layer 13, and the substrate 14 is bonded on the layer 13 so that the surface if directed downward. The glass plate 12 is bonded with an abrasive jig 10 by using a second heat softening resin layer 11 composed of a heat softening resin having a lower softening point. The back 15 of the substrate 14 is abraded up to predetermined plate thickness. Only the layer 11 is heated and softened to separate the jig 10 and the glass plate 12. The substrate 14 is cut and separated to element size as the substrate 14 and the glass plate 12 are left as they are bonded, thus manufacturing elements. The element is mounted to a package, and the layer 13 is heated and softened and the glass plate 12 is removed. Accordingly, the element can be formed without being cracked with excellent workability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an infrared radiation temperature quoting element, and particularly to a method for manufacturing a highly reliable and high performance element.

Conventional Structures and Problems There has recently been a trend towards higher reliability and higher performance of infrared radiation heating assemblies, and as a result, there has been an increasing demand for elements for F thermometers and their development.

A well-known thermometer of this type is one consisting of an oscillator using a surface acoustic wave delay line element.

The structure of the above element will be explained below with reference to the drawings. FIG. 1 shows a perspective view of the above element. In FIG. 1, 1.
2 shows interdigital electrodes for transmitting and receiving surface acoustic waves. Reference numeral 3 indicates a piezoelectric substrate, 4 indicates an infrared light receiving section on the piezoelectric substrate 3, and 5 indicates a support base for thermally insulating the piezoelectric substrate 3.

Next, I will briefly explain the principle of operation as a thermometer.

When infrared radiation enters the infrared light receiving section 4, the piezoelectric substrate 3
The temperature changes slightly. This change occurs from electrode 1 to electrode 2.
This causes a change in the propagation time of the surface acoustic wave propagating to 1°.Therefore, by detecting this slightly changing propagation time, changes in the humidity of the piezoelectric substrate 3 can be detected, and the piezoelectric substrate 3 can operate as an infrared radiation thermometer. do. Therefore, in order to increase the temperature change of the piezoelectric substrate 3, the thickness of the piezoelectric substrate 3 is approximately 50 to 100 μm.

A conventional device manufacturing method will be explained below. First, a large number of interdigital electrodes are formed on the surface of a piezoelectric substrate (2 inches Φ), and a large number of elements are formed on the same substrate. next,
A thermosoftening resin is applied onto the substrate, and a polishing jig is pressure-bonded thereon.

Next, the back surface of the substrate is polished to a predetermined thickness (50 to 100 μm/) using abrasive grains of an appropriate particle size.

Next, the substrate heated to a predetermined thickness is removed from the polishing jig, and the substrate is again bonded to a glass plate for cutting and separation using a thermosoftening resin, and the device size is adjusted using a dicer, e.g. Cut and separate to 5 mm. Next, after cleaning the above element, the first
As shown in the figure, the device was mounted, connected using an ultrasonic bonder, and the device was crushed.

In the above conventional manufacturing method, the piezoelectric substrate that has been polished to a predetermined thickness must be re-adhered to the glass plate for cutting and separation after polishing, which requires very careful attention. However, the workability was poor, and many cracks occurred in the ff: conductive substrate due to heat treatment, resulting in a very poor yield.

Furthermore, the efficiency was extremely low because the thin plate-like elements that had been polished, cut, and separated had to be cleaned. Furthermore, since the flaky elements are cleaned and assembled using a bottle set, for example, the elements are often cracked and the yield is extremely low.

Purpose of the Invention The present invention eliminates the above-mentioned conventional problems, and provides a method with good workability.
The object of this invention is to provide a method for manufacturing the above-mentioned device with improved yield.

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for manufacturing a surface acoustic wave element used in an infrared radiation thermometer, in which a large number of interdigital electrodes are formed on the surface of an IC piezoelectric substrate. A dummy plate with a uniform and smooth surface is bonded with a first thermosoftening resin, the dummy plate is bonded to a polishing jig with a second thermosoftening resin, and the substrate is polished to a predetermined thickness ( For example 50-10
0 μm), then heat-soften only the second heat-softening resin, remove the piezoelectric substrate with the dummy plate from the polishing jig, and polish the piezoelectric substrate with the dummy plate to an element nice (for example, 3 After adhering the above-mentioned element to the package with an adhesive such as epoxy resin, the first heat-softening resin is heated and softened and the dummy plate is removed. can be manufactured.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be explained below based on the drawings. In FIG. 2, 10 is a polishing jig, 11 is a thermo-softening resin layer, 12 is a smooth dummy glass plate with a uniform thickness, for example, 0.5 mm, and 13 is a thermo-softening resin 1111. layer,
14 is a LiNBO3 substrate (2 inch Φ, 450 μIn thickness, Y-plane) as a piezoelectric substrate, 15 is a piezoelectric substrate 14
Showing the back side. At a3 in FIG. 2, first the piezoelectric substrate 14
In the case of Ii, a large number of interdigital electrodes are formed on the same substrate (in the form of a 2-inch Φ wafer) using normal photolithography technology so that the propagation direction of the surface wave is aligned with the Z-axis direction. Form an element. Next, the dummy glass plate 12 is heated, and a thermosoftening resin such as clear wax (softening point 130 to 150°C) is thinly coated to form a first thermosoftening resin layer 13. The placed wafer-shaped piezoelectric substrate 14 is bonded with its surface facing downward. After adhesion, heat treatment is performed while applying pressure so that the thermoplastic resin layer 13 becomes uniformly thin.

Next, the polishing jig 10 is contacted with a second thermosoftening resin layer 11 made of a thermosoftening resin having a lower softening point, such as Elec-1-ron wax (softening point: 60 to 80° C.). Thereafter, the back surface 15 of the wafer-shaped piezoelectric substrate 14 is polished to a desired thickness. After that, gradually heat up the lily,
Only the adhesive layer 11 was softened to separate the polishing crusher 10 and the glass plate 12, and the piezoelectric substrate 14 was cut and separated into element sizes while the piezoelectric substrate 14 and the dummy glass plate 12 were adhered to form elements. Thereafter, the device with the dummy glass plate is mounted on a package, for example, TO-5, using an adhesive, such as an epoxy resin.Then, the thermoplastic resin layer 13 is heated and softened, and the dummy glass plate 12 is removed.
The resin layer 13 on the surface of the device was cleaned to prepare a device.

After sequentially bonding the piezoelectric substrate, dummy glass plate, and polishing jig using two types of thermoplastic resins with different softening temperatures, the piezoelectric substrate is polished, cut, and separated, and the device is assembled. Since the device was mounted on a package, it was possible to manufacture the device with good workability and a high yield without breaking the device.

However, since the dummy glass plates 1 and 2 in the order of plate thickness 05 are glued to the element with a plate thickness of 50 to 100μ, the above element can be handled as having a plate thickness of 0.55 to 0.6M, The workability of package mounting has been greatly improved. Additionally, since the surface of the element can be cleaned while it is mounted on the package, it has become possible to manufacture the element with good workability and high yield.

In the above embodiment, the piezoelectric substrate is -CLtN
Although an I103 crystal plate is used, a piezoelectric IIT+ film such as zinc oxide may be used on a non-pressure M substrate such as glass or zaphire. Further, the substrate may be a crystal plate such as 1-i-"a03. Also, PCM.

A piezoelectric porcelain plate such as P7 may also be used.

Moreover, although a delay line type element is taken as an example of the surface acoustic wave element in FIG. 1, a resonator type element may be used.

More than the effects of the invention, the element of the invention t! In the I manufacturing method, a piezoelectric substrate, a dummy plate, and a polishing jig are sequentially bonded together using two types of heat-softening resins with different softening points. After mounting the element with the dummy plate on a package, Since the plates are removed and made into 11 pieces, the device can be manufactured with good workability and high yield, and its practical effects are very large.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a surface acoustic wave element for an infrared radiation thermometer, and FIG. 2 is a sectional view for explaining one embodiment of the present invention. 1.2... Interdigital electrode, 3... Piezoelectric substrate, 1o
... Polishing jig, 11.13 ... Thermosoftening resin, 12
...Dummy glass plate, 14...Piezoelectric substrate, 15.
...Representative for the back side of the board Yoshihiro Morimoto Figure 1

Claims (1)

[Claims] 1. When manufacturing a surface acoustic wave element used in an infrared radiation temperature meter, a piezoelectric substrate on which a large number of interdigital electrodes are formed has a uniform thickness and a surface. A smooth dummy board is glued with a first thermosoftening resin, the dummy board is attached to a polishing jig with a second thermosoftening resin, the board is polished to a predetermined thickness, and then Then, only the second heat-softening resin is heated and softened, the piezoelectric substrate with the dummy plate is removed from the polishing jig, the piezoelectric substrate with the dummy plate is cut and separated into element sizes, and the element is bonded to the package. A method of manufacturing an element for an infrared radiation thermometer, which comprises bonding with an agent such as epoxy resin, and then heating and softening the first thermoplastic resin to remove the dummy plate. 2. The infrared ray according to claim 1, wherein the piezoelectric substrate is made of a single crystal Y-plane of lithium dibutyrate, and the propagation direction of the surface acoustic wave is the Z-axis direction. A method for manufacturing an element for a radiation thermometer.