JPH01174918A - Pyroelectric type infrared detection element - Google Patents

Abstract

PURPOSE:To obtain an element having high mechanical strength and excellent in vibration resistance and acoustic resistance, by a method wherein a pyroelectric element plate weak in mechanical strength is held between a semiconductor substrate and an infrared ray incident window plate, both of which are relatively excellent in strength, from both sides and all of them are laminated by the shrink-curable adhesive interposed therebetween. CONSTITUTION:A pyroelectric element plate 1 is provided on a vapor deposition substrate processed into a frame shape and an infrared ray detecting electrode 6 is provided to the element plate 1 on the light detecting side thereof and a platinum electrode 2 having the function of a signal taking-out separation electrode is provided to the other surface of said element plate 1. Further, an infrared ray incident window plate 10 is provided on the side of the electrode 6 and a semiconductor substrate 4 is provided on the side of the electrode 2 and a plurality of signals are read in time sequence. The element plate 1 is enhanced in its mechanical strength by laminating the substrate 4 and the window plate 10 to both surfaces of said element plate 1. The signal reading electrode 8 of the substrate 4 is electrically connected to the electrode 2 by a signal lead-out electrode 7. The periphery of the junction point of the element plate 1 and the electrode 8 is filled with a shrink-curable adhesive 9 and the bonding strength of both of them is enhanced as well as the electrical connection thereof is also strengthened by curing.

Description

[Detailed Description of the Invention] Industrial Application Fields The present invention is particularly applicable to infrared rays used in temperature measurement, earth resource observation, weather observation, pollution monitoring, disaster prevention, crime prevention monitoring, operation management of transportation facilities, heat management processes in factories, etc. This invention relates to an array of pyroelectric infrared detection elements used for measurement.

BACKGROUND OF THE INVENTION Pyroelectric infrared imaging plates are being developed as thermal infrared detection elements that measure infrared rays emitted from an object according to its temperature to obtain an infrared image of the object.

For example, InfraRed Physics Volume 22 2
Page 59 (Infrared Physics Vo.
1, 22, P-269, 1982) is known.

A conventional pyroelectric infrared imaging plate will be explained below with reference to FIG. The semiconductor substrate 14 is a COD or a shift register, and has an injiram protrusion 13 formed as a signal readout electrode, and is electrically and mechanically paired with an injiram protrusion 13' formed on the separation electrode 2 of the pyroelectric element plate 11. A separation electrode 12 is connected to the pyroelectric element plate 11 corresponding to one
A common electrode/infrared absorbing layer 16 is formed on the opposite side where the common electrode and infrared absorbing layer 16 is formed, and when infrared rays are incident, heat is absorbed and the element temperature rises slightly. Due to this temperature change, the pyroelectric effect causes
Surface charge is generated depending on the degree of temperature rise, and the signal is converted to CO
D or a shift register can be used to read out the data sequentially in time. In this way, an infrared image signal of the object can be obtained.

Problems to be Solved by the Invention In such a conventional pyroelectric infrared imaging plate, electrical and mechanical connections are made only by one-to-one indium protrusions 13 and 13' by thermocompression bonding, so mechanical There are problems with weak bonding strength and poor mechanical strength such as vibration resistance and shock resistance.

Further, the flatness of the semiconductor substrate 14 and the pyroelectric element plate 11 is usually ±2 to 3 μm, and in one-to-one bonding, there is a gap of several μm in some parts, resulting in unconnected portions.

In this case, it is impossible to connect all the one-to-one joints even if they are sandwiched from both sides with a flat plate jig and compressed and bonded. Injiram protrusion 13.13
The height of ' is about 2 μm on one side only, and the deformation rate is 50%.
As a result, it is possible to approach the gap by approximately 2 μm on both sides, but it is impossible to completely compensate for the gap of ±3 μm by simply compressing the entire surface uniformly.

The present invention solves the above-mentioned problems, and aims to provide a pyroelectric infrared detection element that has high mechanical strength and excellent vibration resistance and sound resistance.

Means for Solving the Problems In order to achieve the above object, in the present invention, a pyroelectric element plate having a weak mechanical strength is connected to a semiconductor substrate having a relatively high strength and an infrared incident window plate from both sides. The semiconductor substrate and the pyroelectric element plate are sandwiched together and a shrink-hardening adhesive is interposed between the semiconductor substrate and the pyroelectric element plate.

Effects According to the above structure, the mechanical strength is increased by bonding the semiconductor substrate, which has relatively excellent mechanical strength, and the infrared incidence window plate to both sides of the pyroelectric element plate. For bonding to the pyroelectric element plate, the periphery of multiple bonding points is filled with a shrink-hardening adhesive, which attracts both plates when cured, significantly increasing the adhesive strength, as well as improving the signal strength of the semiconductor substrate. Each electrical connection between the readout electrode and the separate electrode of the pyroelectric element plate is strengthened by the contractile force of the adhesive layer.

EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an arrayed pyroelectric infrared detection element according to the present invention. 1 is a pyroelectric element thin film, which is a lead titanate (PTO)-based sputter-deposited (ool) alignment film.

Reference numeral 2 denotes a platinum electrode of a (100) alignment film whose crystal lattice constant is the same as that of the pyroelectric element thin film 1, and serves as a separation electrode for signal extraction.

An electrode extraction electrode 7 is deposited on top of this, and the other end is deposited up to the lower top of a frame-shaped deposition substrate 6. The vapor deposition substrate 5 was made of magnesium oxide single crystal, and the electrode extraction electrode 7 was made of an aluminum vapor deposition film. This extraction electrode 7
As shown in FIG. 2, the width of each element was 15 μm with respect to the dimension of 100 μm square. FIG. 2 is a top plan view of the pyroelectric element film on the frame-shaped vapor deposition substrate of FIG.
0 shows the state before being glued. Also, Figure 1 shows the
This corresponds to the AA' cross-sectional view in the figure, and shows a state in which the window plate 10 and the semiconductor substrate 4 are stacked and completed.

The window plate 10 was made of germanium, and the semiconductor substrate 4 was a charge transfer type device.

The magnesium oxide single crystal of the vapor deposition substrate 5 has a thickness of 60 μm, and is arranged in a 128×128 two-dimensional array of 26 parts corresponding to a 76 μm square sensitive area with a 100 μm square pitch.
It is etched into a concave shape with a depth of μm, and a platinum electrode 2 as a back electrode is sputter-deposited only on the sensitive part of this part or only on a part slightly wider than the sensitive part. Then, PTO is sputter-deposited as a pyroelectric element thin film 1 over the entire surface. Furthermore, nichrome is deposited on the entire surface as an infrared receiving electrode θ. Next, the vapor deposition substrate 6 was
Only the square part, ie, the position corresponding to the sensitive part of the array arrangement, is completely removed from the back surface. Next, as shown in FIG. 2, an aluminum vapor-deposited film, which is the signal extraction electrode 7, is vapor-deposited over the platinum electrode 2 exposed by etching, and a signal is transmitted from the upper part of the frame-shaped magnesium oxide single crystal vapor-deposited substrate 6. Make it possible to take out.

In order to electrically bond the signal extraction electrode 7 of this aluminum vapor-deposited film to the signal readout part 8 of the semiconductor substrate 4, indium 3 was vapor-deposited on both to a thickness of 2 μm, and 1
Heat and press at 70'C. At this time, mechanical adhesion is reinforced using shrinkage hardening adhesive 9.

In FIG. 1, the adhesive 9 is applied only on the right side due to the presence of the aluminum vapor deposition film 7, but as shown in FIG. The adhesive 9 is filled not only on the right side but also on the left side and the upper part.

On the other hand, on the light receiving side, glue the germanium window plate 1o with adhesive 9'.
and the upper part of the magnesium oxide vapor-deposited substrate 6 on which nichrome was vapor-deposited are bonded. This window plate 10 can be provided with a function as an infrared filter, if necessary.

The adhesive 9.9' is attached to the signal readout electrode 8 of the semiconductor substrate 4,
Platinum electrode 2, signal extraction electrode 7 do not get wet, indium 3
A material that does not adhere to the material was used, such as a mixture of shrink-curing acrylic resin and epoxy resin. This adhesive shrinks in volume when cured, and the adhesive force between the semiconductor substrate and the pyroelectric element plate is greater than the shrinkage force.

Additionally, air vent holes were formed at arbitrary locations on both sides, making vacuum sealing possible.

As described above, a pyroelectric infrared detection element with high mechanical strength and high vibration resistance was completed.

Effects of the Invention As described above, the present invention makes the light-receiving side of the sensitive part of the substrate concave, and after depositing the electrode and pyroelectric film, completely removes the sensitive part on the back surface of the substrate, and the infrared incident side is provided with a window plate. By bonding the semiconductor substrate on the backside signal extraction electrode side using shrink-curing adhesive, the mechanical strength is greatly increased without impairing the sensitivity characteristics, and the vibration resistance is four times that of the conventional one. Acoustic properties could be improved 100 times, and the defect rate of electrical joints could be reduced from 1% to 1/1 degree.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the structure of a pyroelectric infrared detection element according to the present invention, Fig. 2 is a plan view of the same element during manufacture, and Fig. 3 shows the structure of a conventional pyroelectric infrared detection element. FIG. DESCRIPTION OF SYMBOLS 1... Pyroelectric element thin film, 2... Platinum electrode, 3... Indium, 4... Semiconductor substrate, 6... Evaporation substrate, 6
...Infrared receiving electrode, 7...Signal extraction electrode, 8...
- Signal readout electrode of semiconductor substrate, 9.9'...adhesive, 1o...window plate. Name of agent: Patent attorney Toshio Nakao and one other person
lt! if Figure 2

Claims (7)

[Claims] (1) a substrate in which a recess is formed at least in a portion of an effective light-receiving surface; a pyroelectric thin film formed on the substrate; a first electrode provided on the light-receiving side of the pyroelectric thin film; a second electrode separated and arranged in an array on the other surface of the pyroelectric thin film; an infrared incidence window plate disposed on the first electrode surface side;
a semiconductor substrate disposed on the second electrode surface side from which a plurality of signals are read out in time sequence, the signal readout section of the semiconductor substrate and the second electrode are electrically connected, and at least the pyroelectric A pyroelectric infrared detection element characterized in that a mold thin film and a semiconductor substrate are bonded together with a shrink-hardening adhesive. (2) The pyroelectric device according to claim 1, wherein each of the first electrode and the second electrode in the effective light-receiving surface portion is spaced apart from the infrared incidence window plate and the semiconductor substrate. type infrared detection element. (3) The pyroelectric infrared detection element according to claim 1, wherein the substrate is a single crystal substrate, and the pyroelectric thin film is a vapor-deposited alignment film. (4) A patent claim characterized in that the substrate is a magnesium oxide single crystal, the pyroelectric thin film is a lead titanate-based (001) oriented film, and the second electrode is a platinum vapor-deposited film and is a (100) oriented film. The pyroelectric infrared detection element according to the range 1 above. (5) The pyroelectric infrared detection element according to claim 1, wherein the infrared incidence window plate is an infrared filter. (6) The adhesive is applied to the signal readout electrode of the semiconductor substrate, the second
The pyroelectric infrared detection element according to claim 1, characterized in that the adhesive does not get wet with the electrode and is unevenly distributed around the electrode. (7) The pyroelectric red resin according to claim 1, wherein the adhesive shrinks in volume upon curing, and the adhesive force between the semiconductor substrate and the pyroelectric element plate is greater than the shrinkage force. Outside detection element.