JPS60195951A - Light erasable type semiconductor memory device - Google Patents

Abstract

PURPOSE:To omit transparent glass bonding step and to reduce the thickness of an entire package by opening a plurality of through holes passing externally of a cap at the cap, solidifying a melting agent coated on the holes to form light transmitting windows. CONSTITUTION:Circular holes (spot facing holes) 10 of suitable depth are opened upward from the inner surface of a ceiling plate 9 which forms a cap 8 of a box shape, and a plurality of circular through holes 11 communicated with the exterior of the cap 8 are opened integrally with the top of the holes. This effectively block the through holes with a melting agent, and the thickness of the light transmission unit is readily reduced. The agent is coated in the holes 11. A semiconductor memory is hermetically sealed by the cap 8. In this case, when a bake furnace set at 400-450 deg.C is passed, the agent is heated and melted together with sealing material, cooled, solidified in the holes 11 to form a transparent window 16 capable of emitting ultraviolet rays.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a semiconductor memory device, and more particularly to a cap for a photo-erasable semiconductor memory device. [Background] The present invention relates to a cap for a photo-erasable semiconductor memory device. writable read-only memory)
It is necessary to erase the contents stored in the semiconductor memory by irradiating it with light.

An example of the conventional storage device is shown in FIGS. 1 and 2.

Conventionally, as shown in FIGS. 1 and 2, a through hole 2 is formed in the center of a cap 1, and a transparent glass plate 3 is bonded to the cap 1 within the through hole, thereby forming a transparent glass plate. 3, the contents stored in the semiconductor memory were erased by irradiation with ultraviolet rays. In these figures, reference numeral 4 denotes a semiconductor pellet, which is an EFROM chip formed from, for example, a silicon single crystal substrate and in which a large number of circuit elements are formed using well-known techniques.

Further, 5 is a plate (substrate) for mounting the semiconductor element 4, and is made of, for example, a ceramic substrate. Furthermore,
6 is a connector wire composed of, for example, an AJ thin wire;
By bonding one end of this connector wire 6 to a pad (not shown) of the semiconductor element 4 and bonding the other end of the wire 6 to a lead 7, the internal wiring within the semiconductor element 4 can be connected to the lead. 7, it is drawn out to the outside. However, in this case, the bondability between the cap 1 and the transparent glass 3 is not a problem, and a process for bonding the transparent glass is required, which causes cost delays, and the overall thickness of the package is also affected by the presence of the transparent glass. The disadvantage was that it had to be thick.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photo-erasable semiconductor device that avoids the bonding problem between a cap and transparent glass and does not require special attachment of transparent glass.

The above and other objects and novel characteristics of the present invention are as follows:
It will become clear from the description of this specification 8A and the attached drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, in the present invention, a small 'X through hole is formed in the cap, a flux is applied to the through hole, and when the cap is sealed, the flux is heated and melted and vitrified to form an ultraviolet irradiation window. It is something.

〔Example〕

Embodiments of the present invention will be described based on FIGS. 3 to 5.

Fig. 3 is a sectional view of a cap to which the present invention is applied, Fig. 4 is a plan view thereof, Fig. 3 shows a cross section taken along line I-I in Fig. 4, and Fig. 5 is a sectional view of a cap to which the present invention is applied. 1 is a cross-sectional view of a semiconductor memory device made of

In the present invention, as shown in FIG. 3, a box-shaped cap 8 is provided.
A circular hole (spot-bored hole) 10 of an appropriate depth is bored upward from the inner surface of the ceiling plate 9 constituting the ceiling plate 9, and a circular hole (spot-bored hole) 10 is formed in a row above the crest hole.
A plurality of small circular through holes 11 communicating with the outside of the cap 8 are bored. This allows the flux to reliably close the through hole, and also makes it easier to reduce the thickness of the light transmitting portion.

A flux is applied to this through hole 11 . Examples of fluxes include materials that can form the light irradiation window of P1 photo-erasable semiconductor devices by firing in a heating furnace, and specific examples include powdered glass materials and materials used in ceramic products. Glaze (′
! @Medicine>, AJzos bath liquid or colloid, and the like.

Examples of glass materials include silicates and borosilicate glasses; kasu is very similar in composition to glass; both are mixtures of various silicates as solids, and glazes are silicate mixtures or borosilicate glasses. Consists of a mixture with borates.

In this manner, a glass material, glaze, or the like is adhered to the through hole 11, and the cap 8 performs hermetic sealing (hermetic sealing) in the semiconductor memory device.

That is, as shown in the fifth factor, after mounting the semiconductor element 13 on the base (substrate) 12 and electrically connecting the semiconductor element 13 and the leads 14 using the connector wire 15 based on the well-known technique, the above-mentioned A sealing material is applied to the cap 8 and the cap 8 is passed through a baking oven to hermetically seal the semiconductor element 13 using a well-known technique. At this time, when passing through a baking oven set at, for example, 400 to 450°C, the above-mentioned flux is melted together with the sealing material, and the through-hole 11 is cooled and solidified.
A transparent window portion 16 that can be irradiated with ultraviolet rays can be formed in the semiconductor element 13 constituting the semiconductor device according to the present invention.
The leads 14 and connector wires 15 are the same as those exemplified in the conventional example, and the cap 8 is
The base 12 is made of, for example, ceramic. [Effect] By applying a flux such as glaze to the through hole and firing it, a window that can be irradiated with ultraviolet rays is formed, so it can be used as a transparent glass. There is no need to prepare a special board, therefore,
There is no need for a transparent glass bonding process, and there is no problem with bonding between the cap and the transparent glass plate as in the past.
The overall thickness of the package can be increased.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the above Examples, and it should be noted that various changes can be made without departing from the gist of the invention. Not even. For example, as shown in FIG. 6, the shape of the through hole can be rectangular. In this case, it is necessary to provide the hole 10 at an appropriate depth so that the thickness of the light-transmitting layer does not become insufficient even if the through-hole 11 is large. Furthermore, it is preferable to divide the memory array in the EPROM chip 13 in the same manner as the through holes 11. For example, in the case of FIG. 6, it is preferable to divide the memory array into eight parts. (9) In the above embodiment, the through hole was provided on the outside of the cap, but the through hole 11 may be provided inside the cap and the hole 10 may be provided above the through hole 11. It is preferable to use the above-mentioned embodiment because there is a risk that foreign matter may adhere to the hole 10.

[Field of use]

The present invention can be applied to all hermetically sealed semiconductor memory devices having a cap.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a semiconductor memory device showing a conventional example, FIG. 2 is a plan view of the cap portion, FIG. 3 is a sectional view of the cap showing an embodiment of the present invention, and FIG. 4 is a plan view of the same cap. 5 is a sectional view showing an example of a semiconductor memory device using the cap of the present invention, and FIG. 6 is a plan view showing another example of the present invention @1...
Cap, 2... Through hole, 3... Transparent glass plate, 4
...Semiconductor element, 5...Base, 6...Connector wire, 7...Lead, 8...Cap, 9...
・Ceiling board, 10... hole, 11... through hole, 12...
・Base, 13... Semiconductor element, 14... Lead,
15... Connector wire 3 Figure 4

Claims (1)

[Claims] 1. A photo-erasable semiconductor storage device comprising a cap with a plurality of through holes penetrating to the outside of the cap, and a flux applied to the through holes solidifying to form a light transmitting window. . 2. The photo-erasable semiconductor device according to claim 1, in which the flux is a glass powder. 3. The photo-erasable semiconductor memory device according to claim 1, in which the flux is glaze.