JPS5943752B2 - Manufacturing method of solid state display device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a solid-state display device.

In recent years, devices have been proposed that display images, etc. by arranging a large number of light emitting diodes in rows and columns on a substrate, but the biggest problem in manufacturing such devices is how to arrange a large number of light emitting diodes in an orderly and orderly manner. It is difficult to do so. The present invention has been made in view of the above points, and will be described in detail below in Examples.

FIG. 1 shows the first step, in which row electrodes 2, 2, . . . extending over the length of the substrate 1 are formed at equal intervals on a flat auxiliary substrate 1.

A silicon crystal plate having an oxide film on the surface is suitable as the auxiliary substrate 1, but other ceramic plates can also be used.
FIG. 2 shows the second step, in which a green light emitting diode pellet 4 made of gallium phosphide crystal is prepared.

The pellet has a parallel PN junction surface 5 on both its front and back principal surfaces, and is further provided with dot-shaped back electrodes (i.e., P-side ohmic electrodes) 6, 6, arranged in rows and columns on its back principal surface, and also has It has a window T corresponding to each of the back electrodes 6 on its surface, and includes front electrodes (namely, N-side ohmic electrodes) 8, 8, . . . that are continuous in the column direction of the matrix arrangement. FIG. 3 shows the third step, in which back grooves 9 in the column and row directions are formed from the back main surface of the pellet 4.
, 10 are carved by a dicing method or the like to separate the PN junctions under each of the back electrodes and form separation regions 5', 5 arranged in rows and columns.
'... becomes.

FIG. 4 shows the fourth step, in which the back surfaces of the plurality of pellets 4 are fixed onto the auxiliary substrate 1. At this time, the back electrodes 6 belonging to the same row are arranged to be aligned with the corresponding row electrodes 2 of the auxiliary substrate 1, and the corresponding back electrodes 6 and row electrodes 2 are fixed with solder or conductive adhesive, or If necessary, the other main surfaces on the back side of the pellet and the surface of the auxiliary substrate 1 are firmly fixed with a suitable insulating adhesive. FIG. 5 shows the fifth step, in which the grooves 9, 9, and
. . , a face 11 reaching the groove is provided, and the pellets 4 are separated into each row.

The formation of the above-mentioned facial expression in this process is usually carried out by a dicing method, but since grooves 9, 9, etc. of an appropriate depth have been carved in advance from the back main surface side of the pellet 4, the above-mentioned cutting operation is performed on the pellet. It can be easily done without damaging 4.

FIG. 6 shows the final step, in which the previously described auxiliary substrate 1 on which the pellets 4, 4 are fixed is fixed on an insulating main substrate 15 formed separately, and then each of the row electrodes 2 of the auxiliary substrate and the main substrate are fixed. 15, and between each surface electrode 8 of each pellet and each of the external row terminals 17 provided on the main substrate 15 are connected by thin metal wires 18. be done.

In the above device, when a forward voltage is selectively applied to each of the external row terminals 16 and column terminals 17, green light emission occurs at the PN junction isolation region 5' at the intersection of the selected row and column electrodes, Such light emission is taken out upwardly through the electrode window 7 directly above, and the two pellets 4, 4 display, for example, a two-digit character. At this time, if the emitted light color is green, the green light in the gallium phosphide crystal has an energy wavelength that is about the same as the interband energy of the crystal, so it is relatively easy to attenuate within the crystal, and the above-mentioned When the light is directed toward another electrode window other than directly above, the intracrystal optical path length becomes larger, so attenuation is large, and the amount of light emitted from other electrode windows can be ignored, which is advantageous because the contrast is improved. In the above embodiment, the relationship between rows and columns may be reversed, and it goes without saying that the front electrodes 8 may initially have a shape in which all rows are continuous.

Further, in the above embodiment, the back electrode 6 was formed in a dot shape in the second step, but in the second step, a P-side ohmic electrode film was provided on the entire back main surface, and then the entire surface electrode film was formed in the second step. Separated simultaneously during separation of the PN junction in the 3rd step,
It is also possible to form individual back electrodes.

Further, in the above embodiment, the pellets 4 are separated into each row in the fifth step, but after the auxiliary substrate 1 to which the pellets are fixed is fixed to the main substrate 15 in the fourth step, the pellets are separated into each row. You may do so.

As is clear from the above description, according to the present invention, a pellet is substantially separated into individual light emitting diodes while being fixed on a substrate, and at the time of separation, a predetermined back groove is carved in advance on the back main surface of the pellet. Since surface grooves corresponding to these grooves are provided from the main surface of the pellet, a large number of light emitting diodes can be easily and regularly arranged on the substrate, and display quality can therefore be improved. Furthermore, since the surface electrodes are common to each row (or column), wiring work using thin metal wires is also simplified. Furthermore, the substrate surface to which the pellets are directly fixed is required to have a high degree of flatness, and such substrates tend to be expensive. However, in the present invention, the substrate is divided into an auxiliary substrate and a main substrate, and the pellets are fixed to the auxiliary substrate. Although a high level of flatness is not required, the main board has sufficient thickness to require mechanical strength, and has a sufficient area for connection with the outside. Advantageously, the use of expensive auxiliary substrates can be minimized. Furthermore, according to the present invention, since a plurality of pellets are fixed to the same auxiliary substrate, the positioning between the pellets becomes accurate and the display quality is improved.

[Brief explanation of drawings]

FIGS. 1 to 6 are perspective views showing steps of an embodiment of the present invention. 1...Substrate, 4...Pellet, 5...
...PN junction, 6...back electrode, 8...
...Top electrode.

Claims (1)

[Claims] 1. A step of forming a light emitting diode pellet having a PN junction parallel to both the front and back principal surfaces, in which back grooves in the row and column directions are carved from the back principal surface of the pellet without reaching the front principal surface to form a matrix. a plurality of PN junction isolation regions to be separated; a back electrode existing directly above each of the isolation regions on the back main surface;
a step of forming surface electrodes having windows corresponding to each of the separation regions on the main surface and continuous at least in the column (or row) direction of the matrix arrangement; ) step of preparing an auxiliary substrate having wiring electrodes on its surface extending in the direction of fixing the pellets on the auxiliary substrate, providing a front groove that corresponds to and reaches the back groove in the column (or row) direction from the front main surface of the pellet fixed on the auxiliary substrate; A method for manufacturing a solid-state display device, comprising the steps of: fixing the auxiliary substrate on the main substrate.