JPS606743Y2 - Multi-element infrared detector - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a multi-element type infrared detector, particularly to improving the electrode structure for increasing the number of elements.

Conventional infrared detectors have a configuration in which wiring is done using individual electrodes from the sensing elements arranged approximately in the center of the support plate to the bonding pads provided on the support plate.
In order to improve the resolution of an infrared detector, it is desirable to increase the number of detection elements and reduce the pitch.

In order to increase the number of sensing elements on the same support plate, it is necessary to reduce the size of the sensing elements. Electrode forming methods using etching cannot be adopted.

Therefore, electrode metal is vapor-deposited in a predetermined pattern using a metal mask, but with this metal mask method, pattern accuracy cannot be increased due to the wraparound of the vapor-deposited metal, the thickness of the mask itself, etc. It is difficult to form the following electrode patterns.

Furthermore, if the element size is reduced, the width of the bonding pad and the metal-deposited portion for connection must also be reduced at the same rate.

For this reason, a structure was proposed in which the electrodes on one side of the 5 to 1 screws were collectively used as a common electrode and wired to the bonding pad. The disadvantage was that the integration density was limited.

The present invention solves the above-mentioned drawbacks by dividing a plurality of infrared sensing elements having metal layers for electrodes on both sides of the light-receiving surface into a plurality of blocks, and adding metal layers for electrodes that are not at a common potential of each of the sensing elements. The metal layer for electrodes, which should be connected to the bonding pads in a radial manner on both sides of the light-receiving surface in block units, is connected to the bonding pads in a radial manner. The present invention provides a multi-element infrared detector characterized in that a common electrode has a large area, and a lead wire for external connection is connected to the common electrode.

An embodiment of the infrared detector according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a plan view showing the wiring pattern of a conventional multi-element infrared detector, in which 1 is a support plate, 2 is a light-receiving surface of each element, 3 is a bonding pad, and 4 is a light-receiving surface of a detection element. 2
This is a metal vapor deposition layer for an electrode that connects the edge of the bonding pad 3 with the bonding pad 3.

As can be seen in the figure, both electrodes of the sensing element 2 are wired to individual bonding pads 3 by extensions of the electrodes 4.
In order to improve the resolution of a multi-element infrared detector, it is unsatisfactory to arrange more sensing elements at a minute pitch, but as mentioned above, the size of the sensing elements cannot be reduced to several tens of microns or less. there were.

FIG. 2 is a plan view showing the structure of an infrared detector in which the electrodes on one side of the five elements are collectively used as a common electrode, and the same reference numerals are used for the same parts as in the previous figure.

Reference numeral 5 denotes a common electrode for grounding which combines the electrodes on one side, and this electrode is directly continuous to one bonding pad.

By adopting this structure, it was possible to increase the integration density slightly compared to the structure shown in FIG.

However, if the size of the sensing element is reduced, the widths of the bonding pad 3 and the electrode metal vapor deposition layer 4 must also be reduced accordingly.

However, since the compound semiconductors generally used in infrared detectors are eroded by the electrode etching solution, processes similar to those for silicon devices cannot be adopted, and even with this structure there is a limit to increasing the integration density.

FIG. 3 is a plan view showing the structure of an embodiment of the infrared detector according to the present invention, and the same reference numerals are used for the same parts as in the previous figure.

In this embodiment, infrared sensing elements having electrode metal layers 4 on both sides of the light-receiving surface 2 are arranged in a line, with five elements forming one block. It extends radially and is connected to the bonding pad 3.

On the other hand, metal layers for electrodes having a common potential are integrated for each block to form a common electrode 6 having a large area.

However, this common electrode 6 does not extend to the bonding pad as in the conventional case, but the lead wire is bonded directly to the common electrode 6 by thermocompression.

As can be seen in the figure, according to the present invention, the bonding pad for the common electrode is not required, and the number of bonding pads can be reduced by that amount, making it possible to increase the width or pitch of the bonding pads by this amount. However, if the width of the bonding pad is set to the conventional size, the number of sensing elements will be increased on the same substrate.

In other words, the integration density can be increased.

As can be easily understood from the above explanation, a plurality of, for example, 5 to 5
The number of bonding pads can be reduced by integrating the electrodes on one side of the m-element into a common electrode and thermocompressing the lead wire directly to the common electrode. Although it is possible to increase the width, if a bonding pad with a conventional width is used, it is possible to increase the number of detection elements, making it possible to provide a high-resolution multi-element infrared detector. Become.

[Brief explanation of the drawing]

1 and 2 are plan views showing the structure of a conventional multi-element infrared detector, and FIG. 3 is a plan view showing the structure of an embodiment of the multi-element infrared detector according to the present invention. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Light-receiving surface of detection element, 3... Bonding pad, 4...
Metal vapor deposition layer for electrode, 5.6...Common electrode.

Claims (1)

[Scope of utility model registration request] A plurality of infrared sensing elements having metal layers for electrodes on both sides of the light-receiving surface are divided into a plurality of blocks, and metal layers for electrodes that are not at a common potential of each of the sensing elements are arranged radially on both sides of the light-receiving surface in blocks. The metal layer for the electrode, which is to be extended and connected to the bonding pad and has a common potential, is integrated in each block inside the arrangement of the bonding pads to form a large-area common electrode, and the common electrode is used for external connection. A multi-element infrared detector characterized by connected lead wires.