JPS60171749A - Semiconductor memory device - Google Patents

Abstract

PURPOSE:To enable to erase according to light stored informations even for a resin sealed semiconductor memory device by a method wherein the upper surface of a semiconductor element is covered with ultraviolet transmitting resin, and moreover the part not provided with the resin thereof is sealed with another resin. CONSTITUTION:A tab 2 mounting a semiconductor element 3 and a part of connector wires 4 are covered with ultraviolet transmittable resin 7, and after the resin is hardened, the whole is resin-molded using resin being different from the above-mentioned resin 7 and to be used for usual resin sealing, epoxy resin for example, leaving a part of leads 6. After then, the resin sealing body 8 on the upper surface of the semiconductor element 3 is cut to be removed up to expose the transparent resin 7 in a rectangular shape, for example, and an opening part 80 is formed to enable to project ultraviolet rays to the semiconductor element (semiconductor memory) 3 through the opening part 80 and the transparent resin 7. Informations are stored to a circuit element in the semiconductor element 3 from the outside leads 60, and the stored informations thereof can be erased by the irradiation of ultraviolet rays permeating the transparent resin 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a semiconductor memory device, and particularly to a technique that is effective when applied to a resin-sealed photo-erasable semiconductor memory device that has good sealing properties and is transparent to ultraviolet light.

[Background technology]

Conventional ultraviolet erase type rewritable semiconductor memory device (E
FROM) generally uses a hermetic seal type ceramic glass sealed hackage to allow ultraviolet light to pass through, and an opening is drilled in the camp and glass is fitted into the opening. It was resolved by that.

jIO It is possible to consider an EFROM that is resin-sealed using a resin material such as epoxy resin that is normally used for resin-sealing of general semiconductor devices, but in this case, optical erasure is not possible. It simply allows information to be written to memory.

Therefore, it is conceivable to perform resin sealing by using an ultraviolet-transparent transparent resin over the entire surface of the resin used for the resin sealing.

However, according to the study of the present inventor, in a semiconductor memory device in which the entire resin sealing body is made of transparent resin, since the entire memory is transparent, light enters from all angles.
There is a drawback that the stored contents of the memory are unnecessarily erased by ultraviolet rays.In addition, in this case, the transparent resin composition used to enable ultraviolet rays to transmit does not contain any substances that may impede ultraviolet rays transmittance or transparency. It is necessary to remove fillers, carbon, etc., and this reduces the moisture resistance of the no-no-cage (:
J'J retention) also has the drawback of causing problems.

[Purpose of the invention]

An object of the present invention is to provide a resin-sealed, light-erasable semiconductor memory device that has good blocking properties and is capable of transmitting ultraviolet light.

The above and other objects and novel objects of the present invention:
The characteristics will become clear from the description of this specification and the accompanying drawings.

[Summary of invention]

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

That is, in the present invention, a transparent resin that can transmit ultraviolet rays is coated on a semiconductor memory in advance by potting, and after curing, ordinary resin molding is performed, and then the mold resin is partially coated (semiconductor Since the top surface of the memory is scratched off, there is transparent resin on the semiconductor memory, which allows ultraviolet rays to pass through.

〔Example〕

Next, an embodiment of the present invention will be described according to an example of a process for manufacturing the device of the present invention.

First, as shown in FIGS. 1 and 2, the semiconductor element 3 is mounted on the tab 2 of the lead frame 1.

FIG. 2 is an enlarged sectional view taken along line 1.1m in FIG. 1.

The lead frame 1 is made of copal alloy, for example. The semiconductor element 3 is made of, for example, a silicon single crystal substrate, and a large number of circuit elements are formed within this chip using a well-known technique to provide one circuit function.

A specific example of the circuit element is a MOS transistor, and this circuit element forms the circuit function of, for example, a memory.

An example of this semiconductor memory is an EFROM.

This semiconductor cable 3 is mounted (mounted) by A u-8
A well-known incorporation technique such as the i-eutectic alloy method may be used.

After attaching the pellets, wire bonding is then performed using the connector wire 4, as shown in FIGS. 1 and 2. That is, one end of the connector wire 4 is bonded to a bonding pad (electrode) 5 of the semiconductor element 3, and the other end of the wire 4 is bonded to a pad (not shown) of the board 6 of the lead frame 1. For example, a thin aluminum wire is used for the connector wire 4, and wire bonding is performed by a well-known ultrasonic bonding method, etc., and the semiconductor element 3 and the lead frame 1 glue 6 are electrically connected by such bonding.

Next, as shown in FIG. 3, the tab 2 on which the semiconductor element 3 is mounted and a part of the connector wire 4 are coated with UV-transmissible resin 7. The resin 7 is coated with, for example, a liquid resin. A suitable amount of the resin is gradually dropped onto the semiconductor element 3 and cured into a semicircular shape as shown in FIG. 3 by the surface tension of the resin. Method).

This ultraviolet I%! As the transferable resin, a resin that can erase the information stored in the semiconductor memory by irradiation with light in a predetermined wavelength range is used, and a transparent resin that can transmit light is preferably used (hereinafter referred to as transparent resin).

After the transparent resin is potted and cured, as shown in FIG. 4, a part of the lead 6 is left and an epoxy 7 resin, for example, which is used for ordinary resin sealing different from the transparent resin, is used. For example, the whole can be molded using the well-known transfer molding method (
Transfer molding). As shown in FIG. 4, a resin-sealed semiconductor device having a resin-sealed body 8 having a structure in which a transparent resin 7 and the like are wrapped is obtained.

Next, as shown in FIG. 5, the resin sealing body 8 on the upper surface of the semiconductor element 3 is cut away, for example, in a rectangular shape until the transparent resin 7 is exposed, thereby forming an opening 80. In the obtained semiconductor mounting, the semiconductor element (semiconductor memory) 3 is irradiated with ultraviolet rays through the opening 80 and the transparent resin 7, and other resins are removed except for the exposed portion of the transparent resin 7. It is sealed with (mold resin) 81. Information is stored in the circuit element within the semiconductor element 3 from an external lead 60 formed by bending the lead 6, and the stored information can be erased by irradiation with ultraviolet light that has passed through the transparent resin 7. For example, a ceramic camp may be inserted into the opening section 80 to prevent information from being accidentally erased.

[Effect 41L] (1) When the entire body was sealed with molded resin, it was impossible to erase it with light. Since it is made to be able to pass through the bag, even if the semiconductor storage device is made of resin, it can be made into a semiconductor storage bag p in which stored information can be erased by light.

12+ It is possible to eliminate the malfunction of the memory and the deterioration of the blocking performance due to careless light erasure, which are disadvantages when the entire 12+ is sealed with a transparent resin that can transmit ultraviolet rays. In other words, only a part of the transparent 4■ fat is exposed, and the entire part is sealed with normal mold resin except for this mist part, so it is less likely to be accidentally erased by light. In addition, regular mold resin such as epoxy resin, which has good moisture resistance and good adhesion to wires and lead frames, can be used for sealing, ensuring sealing performance and highly reliable optical erasure of resin sealing. type semiconductor memory device.

(3) According to the present invention, a resin-sealed photo-erasable semiconductor memory device has become possible, so costs can be reduced compared to conventional hermetically sealed semiconductor memory devices.

Although the invention made by the present inventor has been comprehensively explained based on the examples above, the present invention is not limited to the above-mentioned examples, and it should be noted that various changes can be made without departing from the gist of the invention. Not even.

[Application field]

In the above explanation, the invention made by the present inventor was mainly applied to a dual in-line panpage (DILP) type plastic pancake, which is the field of application in which the invention was made, but the invention is not limited thereto. , for example, the Franto Basok package (
The present invention can be applied to all resin-blocked photo-erasable semiconductor memory devices such as PPP) type packages.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is a plan view illustrating how a semiconductor element is mounted on a lead frame and wire bonded, FIG. 2 is a sectional view taken along line I-I in FIG. 4 is a sectional view of a device formed by molding another resin, and FIG. 5 is a sectional view of a semiconductor memory device of the present invention. DESCRIPTION OF SYMBOLS 1...Lead frame, 2...Tab, 3...Semiconductor element, 4...Con, Kuku wire, 5...Ponding pad, 6...Lead, 7...UV transmittance Resin, 8... Resin sealing body, 60... External lead, 80
...opening, 81...other resin (mold resin)
2゜1st Figure 1-+ Figure 2

Claims (1)

[Scope of Claims] 1. A resin-sealed semiconductor memory device incorporating a semiconductor element that stores information and in which the stored information is erased by irradiation with light in a predetermined wavelength range, wherein at least the upper surface of the semiconductor element is What is claimed is: 1. A semiconductor memory device characterized in that the semiconductor memory device is coated with an ultraviolet-transparent resin, and further, the portions where the resin is not provided are sealed with another resin. 2. The storage device according to claim 1, wherein the other resin on the ultraviolet-transparent resin covering the semiconductor element is removed down to the ultraviolet-transparent resin surface.