JPS58162042A - Semiconductor device and preparation thereof - Google Patents

Abstract

PURPOSE:To reject alpha ray and alleviate warpage of wafer by forming a silicon nitride film and then a polyimide resin film sequentialaly on the element region of semiconductor substrate. CONSTITUTION:When a silicon nitride film 14 is formed by the PRD method on a silicon substrate 11, a stress by the PRD method works on the silicon substrate 11 in the direction where it elongates, causing the substrate 11 to be warped upward. Then, a polyimide resin is coated in the thickness of 30-100mum on a nitride film 14 and it is converted into the polyimide by the baking. When the polyimide resin film 15 is formed, the polyimide resin is contracted, warping downward the substrate 11. Accordingly, the substrate 11 becomes flat. Thereafter, a resist pattern is formed on the resin film 15, the resin film 15 and nitride film 14 of the bonding pad and scribe line are removed by sequentially etching the resin film 15 and nitride film 14, and moreover element is heated. Thereby, the alpha ray rejecting and protecting film consisting of the silicon nitride film 14 and polyimide resin film 15 can be obtained on the element region 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device having a highly integrated semiconductor memory element having an α-ray blocking protective film, and a method for manufacturing the same.

Line 19: A phenomenon in which stored data is reversed when radiation with a strong ionizing effect passes through the memory array area.
1978 T, CMay, etc., Dynaic RA
Published on M, COD, 16th Ann
ual Proc@@d1ng off 97
8 InternationalBeliall 1
1tF PhFsias S)rmposium. This phenomenon means that if you write to the cell again, it will operate normally, so the device will not be destroyed.
This is called a "soft error." This "soft error"
The radiation with a strong ionizing action that causes ions is α rays, which are present in ppm units in hard cage materials, glass frits, and lits, and are generated when natural radioactive elements such as ion and thorium decay.・Arm cage material A・
The α particles generated from
0.1 to 30 occur per hour.

The energy of alpha particles is maximum 9M・ma, average 5M5v@degrees. and the mass of the α particle4.
Sum of 00260 amu 232.03383 amu
0.00438x93 from 0.00438xu subtracted from the mass of the nucleus of t-""Th 232.03821amu
1=4.08 May.

The range Ra1t of 4M5v α particles in the air is 3.5
3, the range in To, j, si is the mass of Sl t-28
If the density ρ = 2.33 f/ed, that is, 4 M@v of energy is lost in 25 μm, and 5? − becomes.

Therefore, the α ray of 4 Mev travels through St for about 25 μm, and at this time, the number n of electrons generated per 1 μm is 3.6825, which is 1.1×10a/25 μm.

Of the electron-hole pairs created, the holes flow down to the substrate-side electrode in the case of an n-channel MOB device with a p-type substrate. Electrons are collected in the active region, causing malfunctions. 1. I X Igs electrons are approximately 10
Once 0 ns is collected at the electrode, a current of about 2 μ flows through it. In other words, being hit by α rays is equivalent to generating a nollus-like leak current of 2 μA.

As mentioned above, the effects of alpha rays first became an issue with COD memory and dynamic MOS RAM, but static MO8RAM, especially static MO8RAM that uses high resistance polycrystalline silicon as a load, was also affected by alpha rays. considered to be easily affected. This is because the current is reduced (by using a load resistance of MΩ or more) to reduce power consumption.

Countermeasures against alpha rays mentioned above can be roughly divided into three: ■ Reducing alpha rays emitted by the package, ■ Dealing with device design, and ■ Stopping 0αiI by coating the surface of the device.
There is one.

Although it is possible to lower alpha rays to some extent by improving the cage material, the limit for any Taigu /I package is about 0.01 to 0.1 cm-"hr-". .

There are two main ways to improve device design in order to make it resistant to alpha rays.

(1) A method to increase the storage charge capacity of storage cells in the memory section. (11) A method to increase the sense sensitivity in the sensor/sensing section. However, these improvements in device design require The disadvantage is that it increases.

As a result, the most reliable method for preventing "interval errors" is to coat an integrated circuit chip with an organic material tube.

In the conventional chip coating method, after assembling the chip plate or coating, a coating of BORI-KEN or silicon Is4 resin is applied.
It is then heated and cured. However, this method poses a major problem in terms of reliability, as the contact between the pole wire and the resin may cause tension on the wire, resulting in disconnection (ToJ).

To solve this problem, there is a method in which the pad portion is removed after applying resin to the wafer surface, or alternatively, a method in which the resin is applied to areas other than the grooves using a screen printing method. Consideration is being given to prevent contact. However, the method of Koboku et al. has a problem in that the wafer warp becomes extremely large due to shrinkage of the resin due to heating after resin coating.

Figure 1 shows the relationship between wafer edge and resin film thickness.
As can be seen from the figure, when the resin film thickness is 50 μm, it is approximately 11
A concave warp of 00j@degrees is given to the wafer. Furthermore, since vacuum chucking of the wafer to the apparatus stage is not possible, it is also impossible to proceed with the process.

This will be explained with reference to jIZ diagram) and (b) t-#. In FIG. 2(a), 1 is a silicon substrate, and 2 is an integrated circuit active chip portion formed on the silicon substrate 1.

3, the integrated circuit active chip part 2t- is mounted on the silicon substrate l.
It is polyimide*m* coated over it. After coating the silicon substrate 1 with a polyimide resin film 3t-, this 't-
When a heating process is performed on the rounded material to be converted into polyimide, the result is shown in Figure 2 (b).
), the silicon substrate 1 warps in a concave shape, and even if the substrate 11 is attempted to be suction-chucked by the substrate vacuum decking section 4 of the integrated circuit manufacturing apparatus, chucking by suction becomes impossible.

This invention attempts to eliminate the above-mentioned conventional drawbacks, and by forming a silicon nitride film on the element region of a semiconductor substrate and forming a polyimide resin film on this nitride film, αat It is an object of the present invention to provide a semiconductor device and a method for manufacturing the same that can prevent warping of a wafer and reduce warping of a wafer.

The following is an example of this invention shown in Figs. 3 (&) to (@).
't- will be explained with reference to.

3(&) to (e) h A method for manufacturing a semiconductor device according to an embodiment of the present invention is shown in order of steps. In FIG. 3(&), 11 is a silicon substrate, and 12 is an integrated circuit formed on the silicon substrate 11. It is a circuit active chip part. FIG. 3(b) shows a state in which a silicon nitride film is formed by the plasma deposition method (hereinafter referred to as PRD method) on the Ueno film shown in FIG. 3(a). 13 is plasma. In this process, as shown in Figure 3(a),
Silicon nitride film 1 with a thickness of 1 to 5 μm on a silicon substrate 1
form 4. The stress produced by the PRD method 1 acts on the silicon substrate 1 in an elongated direction, causing the silicon substrate 1 to deflect into a convex shape, as shown in FIG. 3(c). And PR
It was discovered that the silicon nitride film produced by the D method has the advantage that no cracks occur even when the film thickness is increased.
As shown in d), a polyimide resin is applied to a thickness of 30 to 100 μm on the silicon nitride film 14 and baked to form a polyind film, thereby forming a polyimide resin film 15. In this step, since the polyester resin shrinks, the silicon substrate 11, which had been convex, is made into a concave shape, and the silicon substrate 11tl is flattened. Thereafter, a negative type photoresist (T) is coated on the polyimide resin film and baked, and a predetermined portion is exposed to Tμ light and developed to obtain a resist arm turn. Thereafter, the polyiside resin Jfi15f: is etched using a hydranone etchant, and the lower silicon nitride film 14' formed by the PRD method is further etched using CFA-based plasma to form the resin film 1 on the bonded and oxidized portions and the squeezable line portion.
5 and after removing the nitride film 14.

By removing the lenost and further heating, Figure 3 (
As shown in step 6), a semiconductor device having an α-ray blocking protective film made of 7-licon nitride 14 and polyind resin JI 115 on the element region of the semiconductor substrate 11 is obtained.

As mentioned above, in one embodiment of the present invention, the drawback that the silicon substrate warps into a concave shape due to shrinkage due to heating of the I-imide resin film is overcome by the advantage that no cracks occur even when the film thickness is 5 μm or more. Silicon nitride by the PRD method can be deposited on a silicon substrate in advance to make the substrate convex and offset the concave warpage, thereby flattening the silicon substrate and eliminating the warpage. and,
This manufacturing process uses conventional automated LSI manufacturing equipment to easily form a polyimide resin film with 9 turns, blocks alpha rays from the integrated circuit chip container, and achieves high performance and high performance. A highly reliable LSI can be obtained.

As explained above, the semiconductor device of the present invention is provided.

On an element region of a semiconductor substrate having highly integrated elements.

Since we provided an α-ray blocking protective film consisting of a silicon nitride film formed by the PRD method and a polyimide resin film formed on the nitride film, the thickness of the semiconductor substrate was reduced and the polyimide 11 resin film was It can be formed to a thickness of t-30 to 100 μm or more, has the effect of reliably preventing "soft errors" caused by alpha rays, and can be used for VLSI. First, the method for manufacturing a semiconductor device according to the present invention has the effect that a semiconductor device having the above-mentioned α-ray blocking ia film can be easily manufactured using conventional manufacturing equipment.

[Brief explanation of the drawing]

Figure 1 is a diagram illustrating the bending of a silicon substrate using a polyimide resin film, and Figures 2 (a) and (b) are a round cross-sectional view after applying polyimide resin to a silicon substrate, and a cross-sectional view after heating the polyimide resin film. Figures 3<->) to 3(e) are cross-sectional views showing a method for manufacturing a semiconductor device according to an embodiment of the present invention in the order of steps. DESCRIPTION OF SYMBOLS 11... Silicon substrate, 12... Integrated circuit active chip part, 13... Glazma, 14... Silicon nitride film, 15... Polyimide resin film. Patent Applicant: Oki Electric Industry Co., Ltd. Figure 1; t," Ri (Mill Rumor tt Jl! J! Saku pm) Figure 2 Figure 3 Procedural Amendment August 31, 1980 Commissioner of the Patent Office ＊＊＊＊ Hall 1, Display of the incident Showa s7 year tatami permission request number shi tsss number 2 @@
04 name conductor device and its preparation 2F machine 3, relationship with the case of the person making the amendments Akira Tatami Applicant (01.) Oki Electric Co., Ltd. Kinsha 4, Agent 5, Date of amendment order Showa year, month, day (Yu-
) ``To do 11ab breath 10FJ&revise.

Claims (2)

[Claims] (1) One layer is placed on the element area of a semiconductor substrate having highly integrated elements.
A silicon nitride film formed by plasma deposition M/ method,
α formed on this nitride film and consisting of a nine polyide resin film
1. A semiconductor device comprising a radiation blocking protective film. (2) a step of forming a highly integrated element on a semiconductor substrate; a step of forming a silicon nitride film on the semiconductor substrate having the highly integrated element; The polyimide resin film is coated and heated to form a polyimide resin film, and the polyimide resin film and silicon nitride are coated on the polyimide resin film, heated, non-lighted, and subjected to an ampere treatment. A semiconductor characterized by comprising a step of removing the film to leave an α-ray blocking protective film made of a silicon nitride film and a polyimide resin film on the element region, and a step of removing the V-stride and heating before and after. Method of manufacturing the device.