JPS58148447A - Semiconductor device - Google Patents

Abstract

PURPOSE:To contrive improvement in reliability for an element as well as to obtain the semiconductor device which can be utilized for LSI by a method wherein a film, to be used for prevention of alpha rays and having obtuse-angled corners or curved corners, is formed on the surface of a chip, thereby enabling to prevent the exfolia-of a resin film. CONSTITUTION:The polyimide resin film 21, located on an IC silicon semiconductor substrate chip 11, is formed in the thickness of 30-100mum or thereabout as the film which will be used for prevention of rays. Also, an edgy pattern is formed into an obtuse angle as shown by the corner part 31 of a pattern edge on the polyimide resin film 21. As a result, it has been provided that the exfoliation of polyimide resin, as has been experienced in the past, is not generated at all. The curve, as shown by the corner part 311 of the polyimide resin film 211 located on the IC silicon semiconductor substrate chip 111, may be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device that prevents peeling and peeling of a protective film in a highly integrated semiconductor memory element.

In 1978, T., C., and May et al. discovered the phenomenon of inverting stored data when strong ionizing radiation passes through the memory array area, developing sidynamic RAM and COD.
Published on 16th AnnualProc
eeding of 1978 International
nal Pe1ability Ph)rsicsL
) ymposium.

This OvL phenomenon is called a "soft error" because the device will not be destroyed since it will operate normally if the cell is rewritten. α, which is generated when natural radioactive elements such as uranium and thorium, which are present in ppm units in the cage material or glass frit, decay in the cage material or glass frit. It is a line.

The α particles generated from the package material vary depending on the material, but KO01 to 30 α particles are generated for 171 hours. The energy of alpha rays is 9 MeV% maximum, about 5 M·ma on average, and α rays of 5 MeV penetrate silicon at about 301 m
During the 1 s run, 1.4×10 electron-hole pairs are generated.

Of the electron-hole pairs created, the holes are PM! In the case of a substrate n-channel MOS device, it flows down to the substrate side electrode. In addition, electrons are collected in the active region, which causes the nuisance operation. For this collection, 10=100ng
It takes.

When 1.4×10 electrons are collected at the electrode for 100 ns, a current of about 2 μA (D) flows through it.

In other words, a! The fact that I is applied is equivalent to the generation of a leak current of 2 μm.

As mentioned above, the influence of alpha rays was first brought into question by C
CD memory and dynamic MO8RAM were used, but static MO8RAM%, especially MOS static RAM that uses high resistance polycrystalline silicon as a load, is also considered to be easily affected by alpha rays.

This is because the stain current is reduced by using a load resistance of KMρ or more in order to reduce power consumption.

There are four main types of α-ray countermeasures:

(1) Reduce alpha rays emitted by the package ◇ (2)
Paint something on the surface of the chip to stop alpha rays.

(This will be dealt with with a 337” vise design.

(4) By the way, it can be saved systemically by correction etc.
Although it is possible to lower the alpha rays to some extent by improving the material, the ultimate limit for any type of cage is about 0.01 to 0.1 alpha cm = hr-''.

Furthermore, in order to make it resistant to alpha rays, there are two main ways to improve the f-vis design:

(1) A method of increasing the storage charge capacity of a memory cell in a memory section.

(2) - For tysai y:rs, seyxa 7f1
How to increase your g-degree.

There are two.

However, these improvements in r-device design have problems such as an increase in chip area. As a result, coating an organic material on an integrated circuit chip is the most reliable method.

The conventional chip coating method is to assemble the chip into a package and then drop a drop of polyimide or silicone resin.
It is heated and cured. This method has serious problems in terms of reliability, as contact between the electrode wire and the resin may occur, the wire Fc tension may become loose, and wire breakage may occur.

Therefore, a method can be considered that removes the pad area on the chip where the wires are connected and covers only the memory area with resin to protect it from alpha rays. Covering U/consisting of limide resin.

Although this method is effective in preventing alpha rays and does not cause any trouble with wire bonding, the problem is that cracks may occur in the silicon substrate due to the resin o ml m.

Here, a conventional method for preventing peeling of polyimide resin will be explained with reference to FIG. FIG. 1(b)) is a plan view, and FIG. 1(g) to FIG. 1(d) are side views of FIG. 1(G&). This figure 1 (a
) to FIG. 1(b), 1 is an integrated circuit board chip formed on a silicon semiconductor substrate, and 2 is a polyimide resin film on this integrated circuit board chip 1. Also,
1 (-, 3 shown in FIG. 1(e) is a peeled portion at two ends of the 4-limide resin film.

The turns of the polyimide resin f [2] are formed in an acute-angled pattern, as shown by the peeled portion 3 in FIG. 1 (&). Therefore, during the curing process by heating the polyimide resin, the sharp corners shrink more than other parts.
As shown in point 3, the integrated circuit board chip 1 is more likely to peel off.

Once the polyimide resin film 2 peels off from the integrated circuit board chip 2, the curing speed of the peeled portion 3 is approximately twice as fast as that of other non-peeled portions. That is, this is because the polyimide resin 1 and 2 are dried from the upper and lower surfaces.

As a result of ζO, an extremely large tensile stress #i is generated at the boundary between the peeled portion 3 and the unpeeled portion. Therefore, as the curing progresses, the integrated circuit board chip itself will crack and peel off. The part indicated by the reference numeral 4 in FIG. 91(d) indicates this crack peeling part. If this crack peeling portion 4 occurs, the integrated circuit will be destroyed and will no longer function, which is a problem that will cause serious defects.

This invention has been made to eliminate the above-mentioned conventional drawbacks, and aims to provide a semiconductor device that prevents peeling of the resin film, improves the reliability of the element, and can be used as an LSIK.

Hereinafter, the actual semiconductor device of the present invention will be explained based on the drawings. #! FIG. 2 is a plan view showing the arm turn of the imide resin in Example 1. In FIG. 2, there is an integrated circuit silicon semiconductor substrate chip as a 1lFi semiconductor substrate chip, and 21 is a polyimide resin film on the integrated circuit silicon semiconductor substrate chip 11 as a coating for preventing alpha rays. This polyimide resin film 21 is formed to have a thickness of about 30 μm to 100 μm.

Further, 31 indicates a corner portion of the pattern of the polyimide resin film 21, and as shown in this corner portion 31, the corner pattern is made at an obtuse angle. Therefore, it was found that the polyimide resin did not peel off at all by the conventional method.

That is, a photolithography method is generally used to form the pattern of the polyimide resin film 21. In this example as well, a process of applying a polyimide resin film and paking, further applying a photosensitive photoresist on the polyimide resin film, applying no light to a predetermined pattern, developing the process, and then etching the polyimide resin using the photoresist as a mask. Thus, a pattern of the polyimide resin film 21 is formed.

e) Since the IJ lithography method is a well-known method, detailed explanation will be omitted.

As explained above, in the first embodiment, since the corner portion 31 of the arm turn of the polyimide resin film 21 is obtuse, the polyimide resin film 21 does not peel off from the integrated circuit silicon semiconductor substrate chip 11. This has the advantage that a highly reliable integrated enclosure can be formed.

In the example of #gl above, ? Although it has been explained that the double corner pattern of the limide resin film 21 forms an obtuse angle pattern,
As shown in FIG.
As shown in the figure, it is also possible to have a shape with a radius.

By forming the corner portions 311 into a rounded shape, the polyimide resin film 211 is formed on the integrated circuit silicon semiconductor substrate chip 111 as in the tenth embodiment.
No peeling was observed at all, and the inventors confirmed that the same effect as in the first example was achieved.

Furthermore, in the first and second embodiments, polyimide resin [21,2110I! The turns were formed by a photolithography method, but as a third embodiment, although not shown, they were formed by a screen printing method, and through a heating process, /IP turns similar to those in the first and second embodiments were formed. As a result, the inventors confirmed that the polyimide resin film did not peel off from the integrated circuit silicon semiconductor substrate chip as in the first and second embodiments.

Note that the screen printing method is a method widely used for manufacturing thick film integrated circuits, and detailed explanation will be omitted.

Furthermore, in each of the above embodiments, the case of polyimide resin was explained as an example, but it is not limited to polyimide resin, and it can be said that any film material that can block alpha rays will have the same effect. As described above, according to the semiconductor device of the present invention, the corner portions of the coating for preventing alpha rays on the semiconductor substrate chip are shaped to have an obtuse angle or a radius. It can be stably formed on a semiconductor substrate chip without peeling off from the substrate. Along with this, the reliability of elements has improved steadily, and L
It can be used for SI.

[Brief explanation of the drawing]

Figure 1-) is a plan view of the polyimide resin film on the conventional integrated circuit board lug, and Figure 1G)) to iml) are respectively the states in which the polyimide resin film shown in Figure 1 is peeled off from the integrated circuit board chip. FIG. 2 is a plan view of one embodiment of the semiconductor device of the present invention, and FIG. 3 is a plan view of another embodiment of the semiconductor device of the present invention. 11.1"11...Integrated circuit silicon semiconductor substrate chip, 21,211...Polyimide resin film, 31°31
1... Corner part. Procedural amendment August 31, 1980 Kazuo Wakasugi, Commissioner of the Patent Office 1, Indication of the case 1981 Patent application No. songs 2, Name of the invention Cattle conductor device 3, Person making the amendment Relationship to the case Patent Applicant C029) Oki Electric Industry Co., Ltd. Kinsha 4, Agent 5, Date of amendment order Showa year, month, day (1
弗) 6. IjIOI # Detailed explanation column 7 of the specification to be amended Contents of the amendment 1) II Specification, page 1, line 19 [Pe1iabllit7
Correct J to “Re1iabi11t)’ J. 2)lii At the end of page 31, correct Lymposium J to r S
Corrected as FmposlumJ. 3) On page 3, line 8, correct "And" t - "It is". 4) On page 7, line 16, "photoresist cloth" is corrected to "photoresist coating."

Claims (2)

[Claims] (1) A semiconductor device characterized in that a coating for preventing alpha rays is formed on the surface of a semiconductor substrate chip, the corners of which have obtuse angles or rounded corners. (2) The semiconductor device according to claim 1, wherein the coating for preventing alpha rays is made of polyimide resin with a thickness of 30 μm to 100 μm.