JPS5913926A - Pyroelectric element - Google Patents

Abstract

PURPOSE:To make easy a bonding of an external element and an external circuit and to increase a yield by connecting a photodetecting electrode to a connection electrode formed on an insulating layer of a supporting base and applying the bonding from this connection electrode. CONSTITUTION:An Si plate is used as the supporting base 15, the insulating layer 25 such as oxidized film, nitride film is made on the surface and an Al electrode 29 is formed by vapor deposition. An element which is consisting of attaching an NiCz vapor-deposited photodetecting electrode 12, an Al vapor-deposited reflection electrode 13, an Al vapor-deposited connection electrode 14 to a polarized PbTiO3 ceramic is adhered thereon with adhesives 16, 27. The electrode 14 and the Al electrode 29 on the layer 25 are connected with a conductive adhesive 28. The other semicondutor tip and a package pad can be connected from the electrode 29 by the bonding. Since a supporting frame 15 is made of the same Si as the other semiconductor tip, the bonding condition, etc. are nearly equal, the yield of the bonding is improved and the reliability is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a pyroelectric element that utilizes the pyroelectric effect of a pyroelectric material.

Conventional structure and its problems Two-base pyroelectric materials are materials that can detect thermal changes caused by incident infrared energy by converting them into changes in electric charge.
Single crystals such as aO3, SBN, TGS, PbT103.
Organic materials such as PZT (D ceramic, PvF2, etc.) are often used. Since this is a thermal sensor, it is susceptible to the effects of element shape dimensions, support structure, etc. For this reason, various conventional sensor structures have been used. Figure 1 is an example of this. In the figure, the pyroelectric material 11
A light-receiving electrode 12. A reflective electrode 13 is formed on the other surface, and the reflective electrode 13 side is adhered to the support base 15 with a conductive adhesive 16. A connection electrode 14 is provided on a part of the light-receiving electrode 12, and is connected to other components (not shown) via a thin wire 17.

To make the sensor more sensitive, it should be suspended in the air to reduce heat loss through conduction. For this purpose, a material with low thermal conductivity is used for the element support 15,
The support base 16 may be hollowed out as shown in FIG. In particular, if it is hollow, heat escape will be reduced, and linear array
This method is particularly suitable for a configuration such as a sensor in which thermal diffusion is a serious problem.

In order to connect the element made in this way to another element, conventionally a connection electrode is placed on a part of the light-receiving surface of the element as shown in FIG.
4, and the electrode 14 and other parts are connected by bonding or the like with a thin wire 17. In this case, the bonding conditions for the element material are different from those of other semiconductor chips or packages, and it is troublesome to determine the bonding conditions for each.

The conditions also differ depending on the type of pyroelectric material 11.

In addition, if each element of the linear array is completely separated by dicing, etc. in order to thermally isolate it in the lateral direction, each element will become considerably smaller, and the connecting electrodes on it will also become smaller. . As a result, bonding conditions become more severe, resulting in not only poor connections but also damage to the elements. Therefore, the yield of bonding becomes poor, and the yield of a sensor when manufacturing multiple elements such as a linear array becomes extremely poor.

OBJECTS OF THE INVENTION The present invention provides a pyroelectric element that can be manufactured with high yield while eliminating the above-mentioned drawbacks.

Structure of the Invention In the present invention, the electrode on the front side is also connected to the second electrode of the insulator on the support base.

DESCRIPTION OF EMBODIMENTS The cross-sectional structure of a pyroelectric element according to the present invention is shown in FIG. The element has an absorbing electrode 12 and a connecting electrode 14 on the light-receiving surface of a pyroelectric material 11.
．． The configuration is the same as that shown in FIG. 1 with a reflective electrode 13 on the back surface. This element is attached to a hollow support 16 with an electrically insulating layer 25 using an insulating adhesive 27. Adhesion is made using a conductive adhesive 16.

The conductive adhesive 16 is connected to the lower side of the support base 15 through the inside of the hollow support base 16, and the back electrode 13 of the element can be connected to the lower side of the support base 15 without a lead. On the light receiving side, the connection electrode 14 and the electrode 29 formed on the insulating layer 25 of the support are electrically connected using a conductive adhesive 28. In the case of forming a linear array, it is sufficient to cut a part of the support base 15 together with the elements by dicing or the like, so it is easy to separate the conductive adhesive 28.degree. 5 page electrodes 29. The element constructed in this manner can be connected to other components through the electrode 29 by bonding.

Next, specific examples will be shown. A Si plate is used as the support base 15, and an insulating layer 25 such as an oxide film or a nitride film is formed on the surface thereof.
Etch a hole and cut it with dicing to create a support frame. An Al electrode 29 is formed on the insulating layer 25 by vapor deposition. On top of this is a polarized PbTiO3 ceramic with N1Cv evaporated light receiving electrode 12. Al vapor deposited reflective electrode 13
．． The element with the Al vapor-deposited connection electrode 14 attached is glued with adhesive 16.2.
Put it on at 7. Thereafter, the light-receiving surface connection electrode 14 and the A[electrode 29 on the Si support insulating layer 26 are connected with a conductive adhesive 28. In order to form this into a linear array, the pyroelectric element may be cut into strips by dicing so as to make notches in the Si support 15. The situation is shown in Figure 3. 36
is a dicing line for cutting and separating the elements 31;
The Si of the support frame 15 is also slightly cut to provide lateral thermal isolation and electrical isolation. The 6-page pitch of the dicing line 35 is easily 100 μm, and it is possible to cut the dicing line 35 at a pitch of about 20 μm.It can be connected to other semiconductor chips or a path cage pad by bonding from the electrode 29 on the support frame 15. By doing this, since the support frame 15 is also made of Si, which is the same as other semiconductor chips, the bonding conditions etc. are almost the same, the yield of bonding is improved, and the reliability is improved. This connection method provides good results not only for bonding but also for other means such as film carriers. Note that the support frame 15 can be made of either metal or an insulator as long as it is insulated.

Effects of the Invention As described above, the present invention provides a connection in which a pyroelectric material with electrodes formed on both sides is mounted on a support having an insulating layer on its surface, and a light-receiving electrode of the pyroelectric material is formed on the insulating layer of the support. A pyroelectric element that is bonded to an electrode and bonded from this connecting electrode, making bonding with external elements and external circuits extremely easy, greatly improving yield and obtaining a highly reliable pyroelectric element. be able to. In particular, when the linear array structure is made into 7 pages, the yield rate is remarkable, making it particularly suitable as an infrared linear array element.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an example of a conventional pyroelectric element, Fig. 2 is a sectional view of an embodiment of a pyroelectric element according to the present invention, and Fig. 3 is a sectional view showing an example of a pyroelectric element according to the present invention in an IJ near array structure. FIG. 11... Pyroelectric material, 12... Light receiving electrode, 13... Reflecting electrode, 14... Connection electrode, 15.24... Support stand, 16, 28...
... Conductive adhesive, 25 ... Insulating layer, 27
...Insulating adhesive, 1. Thin wire, 2
9... Connection electrode, 31... Element, 35
・・・・・・Dicing line. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (3)

[Claims] (1) A pyroelectric material with electrodes formed on both sides is mounted on a hollow support having an insulating layer on its surface, and the first electrode on the surface side of the pyroelectric material is connected to the insulating layer of the support. A pyroelectric element, characterized in that the second electrode on the back side of the pyroelectric material is connected to the support base. (2) A pyroelectric element according to claim 1, in which a pyroelectric material is cut into strips. (3) The pyroelectric element according to claim 1, wherein the support base is made of silicon and the insulating layer is made of silicon oxide or nitride.