JPS5923542A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve the reliability of a high molecular resin-sealed device by forming high moisture resistance wirings of an alloy of Ni, si of specific compositions by weight and the residue of aluminum on a semiconductor substrate. CONSTITUTION:A wiring layer which contains 0.01-2.5wt% of Ni, 0.5-4wt% of Si and the residue of aluminum is formed on a semiconductor substrate which has a PSG or high molecular resin layer on the surface. Preferably, Ni is 0.1-1wt%, Si is 1-2wt%. If the contents of the Ni and Si are out of these range, the moisture resistance decreases. When the wiring layer is covered with polyimide and/or PIQ resin, the heat resistance is improved. This composition can effectively perform the effects in case of resin sealing, and even when this is applied to a multilayer wiring structure, the moisture resistance and reliability can be extremely improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device with improved moisture resistance reliability, and particularly to the semiconductor device sealed with resin.

A reliability problem in resin-sealed semiconductor devices is moisture resistance reliability. Under high temperature and high humidity conditions, moisture penetrates into the resin, reaches the semiconductor surface, corrodes the At wiring, and eventually causes the semiconductor device to fail.

To avoid such defects, complete sealing is possible, but the cost is about 10 times higher, so it is difficult to apply it to devices other than those that require particularly high reliability. In addition, a phosphorus-containing 5i02 (hereinafter referred to as phosphorus-containing glass or PSG) film is usually used as the first passivation film for the wiring substrate, and the penetrating moisture can cause phosphorus to be removed. was eluted, which acted to further accelerate the corrosion of At.

Furthermore, in response to the recent trends toward higher integration, the number of wiring layers has also increased to one layer.
Although the number of layers has increased from 2 layers to 3 layers to 1:1, as a wiring interlayer insulating film, the process cost is low, the wiring yield υ is high, and it is resistant to cracks against mold stress during resin encapsulation. Polyimide resin membranes or polyimide-in-indolo-quinazolinedione resin membranes that do not cause water are increasingly being used, but since these are also resin materials, they cannot completely prevent moisture from penetrating. Therefore, the first passivation M at the base of the wiring is PSG [
Then, a resin-sealed semiconductor device having a wiring structure protected by polyimide resin or a second layer,
The third layer wiring is configured via a polyimide insulating film,
Although the level of humidity resistance of resin-sealed semiconductor devices with wiring structures protected by a polyimide resin film is sufficient to meet the standards required for consumer-use semiconductor devices, it is still difficult to meet the standards required for industrial use. It could not be said that it was necessarily sufficient to satisfy the standard (Jl) required for semiconductor devices.

Therefore, the object of the present invention is to provide a new At
The object of the present invention is to provide a highly reliable semiconductor device, particularly a semiconductor device having an insulating layer made of a polymer resin, by using a base alloy as a wiring material.

In order to achieve the above object, the semiconductor device of the present invention has 0.
01-2.5 w 1% Nt, o, 5-4. Qwt%
A wiring conductor layer made of an alloy having a composition of S' and the remainder At, is provided on a semi-solid substrate. N
The desirable range of i amount is 0.1 to 1, □wt%, Si
A desirable range of the amount is 1.0 to 2, OW 1%. If the amount of Ni and the amount of Si are outside the above range, the moisture resistance reliability will decrease, which is not preferable.

In the semiconductor device of the present invention, at least a portion of the wiring conductor layer is normally corroded by a polymer resin.

Further, it is advantageous to use a semiconductor substrate having an insulating film on at least one surface, and in this case, the wiring conductor layer is at least a part of the semiconductor substrate, and in this case, the effects of the present invention are significantly observed. It will be done.

However, it is not necessary to be limited to this.

It is advantageous in terms of heat resistance to use polyimide resin and/or polyimide indolo quinazolinedione resin as the polymer resin covering the wiring conductor layer and the polymer resin constituting the insulating film. be.

The semiconductor device of the present invention may have a multilayer wiring structure. In this case, the wiring conductor layer has at least two layers, and the upper wiring conductor layer covers at least a part of the wiring conductor layer located below. It is particularly advantageous if the upper wiring conductor layer is formed on a polymer resin layer to be worn, and at least a part of the wiring conductor layer on the upper side is covered with the polymer resin. As this polymer resin, the aforementioned polyimide resin and/or polyimide/isoindotz/quinazolinedione resin can be used.

If necessary, the wiring conductor layer is connected to a predetermined portion of the -C semiconductor wafer via an opening in an insulating film on the surface of the semiconductor substrate. It goes without saying that the upper and lower wiring conductor layers can be connected to each other via predetermined openings in the interlayer insulating layer depending on the necessity.

Any of the above semiconductor devices of the present invention can be expected to have the same effect when used in a resin-sealed manner. but,
The present invention is applicable not only to the case of resin sealing but also to any case where the moisture resistance reliability of a semiconductor device is to be improved.

By the way, it is generally known that adding different metals has some effect on corrosion of A7, and N'+Fe+Cut'I'i+ Crt is an effective metal.
MO, wl P t+ Pd, etc. are listed, and the -
! On the contrary, Mg, Zn + Ag, M glue.

Sn, etc. are considered to be ineffective or harmful (Electrochemistry Handbook, edited by Electrochemistry Handbook, Maruzen, 1964, p. 927)
. However, these findings i1: were obtained from the structural phase material of At, semiconductor device 1g.

Extremely high-purity vapor-deposited At with a thickness of about 1 μm used for
It cannot be asserted that membranes are similarly effective.

Therefore, among the above-mentioned effective metals, a thin film alloyed with At was formed by vapor deposition, and some gold Fj was used to evaluate the moisture resistance reliability. The surface 1 humidity test is performed using the well-known Pressure Test (hereinafter referred to as PCT), which is often used for resin-sealed semiconductor devices.
(Leave it in water vapor at 1' and 2 atmospheres) was adopted. Two prototypes, A and B, were made for evaluation as follows.

That is, A is a PSG film (0°7 μm thick) formed on the surface of the 8′ substrate.Secondly, a wiring pattern (1 μm thick) was created, and a protective film made of polyimide resin (2.5 μm thick) was formed. . PIQ (trade name of Hitachi Chemical Co., Ltd.) was used as the polyimide resin. B is PIQ on Si substrate
A film (thickness: 2.5 μm) is formed, a wiring pattern (thickness: 1 μm) is formed on this, and a protective film (of PIQ) is formed.
A thickness of 2.5 μm) was formed.

1) C'I'' was applied to these test samples and the corrosion initiation time was evaluated. The results are shown in Table 1.

As a result, it was confirmed that most of the elements considered to be effective are effective when evaluated as thin films deposited, but there are significant differences in their effects, and some, like Ti, have very little effectiveness. There were also some cases that had no effect. However, ht-N
The best corrosion prevention effect was shown for Ni concentration of 1-2.5 wt% and At-Pd (at t%). This was a common trend for samples A and B.

Furthermore, At-P was the most effective combination for corrosion prevention.
A similar test was conducted using d and ht-Ni as a pace and adding a third element. The results obtained are shown in Table 2.

Table 1 Table 2 As a result, the combination of AA-Pd and other metal elements did not significantly improve the corrosion prevention effect. Combinations of small ht-Ni and other metals other than Si among gold elements did not show much improvement in effectiveness, but ht
- In the combination of Ni and Ss, even more synergistic effects were found. This was seen as a common tendency in sample A and sample 13.

Next, Table 3 shows the results of an investigation regarding the effective concentration range of Ni and Br in the ht-Ni-8i alloy sample. As a result, the effective concentration of each element is Nt: 0.01 to 2.5
It was found that wt% was 5ii0.5 to 4 wt%.

Hereinafter, the present invention will be explained in more detail using examples.

Table 3 Example 1 In FIG. 1, after forming the KPsG film 2 on the silicon wafer 1, the first wiring conductor /R3 was formed.

Next, an interlayer insulating film 4 was formed by PIQ, followed by through-hole processing, a second wiring conductor layer 5 was formed, and a vaginal protection film 6 was again formed by PIQ. The retention membrane 6 was provided with an opening for wire bonding with the outside.

In this structure, wiring conductor layers 3 and 5d were formed as follows. First, after steaming 500 At, Ni
30 people evaporated, then 150 people deposited Si, and then 9 people deposited At.
It was annealed at 400C to 450C using 500-person photoevaporation to form an alloy. Next, a υ wiring pattern was formed by photoetching. Regarding the interlayer insulating film and protective film t”l,
200C after spin coating PIQ prepolymer solution
It was formed by baking at 350C for 60 minutes and 30 minutes at 350C.

The film thickness was 2 μm. The through holes between wiring layers and the openings of the bonding pads were formed by using negative type OM 83 (trade name, manufactured by Tokyo Ohka Co., Ltd.) as a photoresist and using a mixed solution of hydrazine and ethylenediamine as an etchant.

The PSG film had a molar ratio of 5I02 to 5I02 of 12:88 in terms of P2O5 as determined by fluorescent X-ray analysis. The thickness is 0.
It was set to 7 μm.

Further, the wiring conductor layer thus formed is made of an At alloy containing approximately Q, 6 wt % of Ni and approximately 1.5 wt % of Si.

Wire bonding was performed using gold wire on the wiring formed as described above, and after resin sealing using epoxy resin, I'CT was performed. Then, the wiring resistance value was evaluated, and the first 201 hours at which an increase in the wiring resistance value began to be observed was evaluated. Evaluations were made by comparison with samples made of pure AA for both the 17th layer and the 2nd layer. As a result, the 201 hours during which the resistance change was observed for pure At was only a few hours for both the 11th layer and the 2nd layer, whereas the sample of this example had a resistance change of about 30 times for the 1st layer. The second layer required a 100 times longer period of time, and was extremely good as a side dish.

Example 2 A semiconductor device 1r1 having the structure shown in FIG. 1 was produced in the same manner as in Example 1 except that the Ni and SN contents in the At alloy forming the wiring conductor layer were changed. However, the first and second layers
The concentrations of Ni and Si in the wiring 2ξt1 layer were 0.01 wt% and 0.5 wt%, respectively.

The resistance change was observed in the first layer wiring by 20 times and in the second layer wiring by 70 times compared to that of pure At. Compared to Example 1, ht-N is slightly more sophisticated.
Compared to the binary system of i, it is much more monophagous and effective.

Example 3 N I-Jjj and 3 in At alloy forming wiring conductor layer
A semiconductor device having the structure shown in FIG. 1 was produced in the same manner as in Example 1 except that the amount of i was changed. However, the arrangement of the first and second layers +Vj! The concentrations of Ni and Si in the conductor were 2.5 wt% and 4 wt%, respectively.

The 201 hours required for the resistance change to begin was 20 times longer for the first layer wiring and 80 times longer for the second layer wiring than that for pure A7. Although it was a little harder than Example 1, a sufficient corrosion resistance effect was observed.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a semiconductor device according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Semiconductor wafer, 2... PSG film (first passivation film), 3... First layer wiring groove body, 4...
- Wiring interlayer insulating film, 5... Second layer wiring groove body, 6...
Protective film 165

Claims (1)

[Claims] 1, 0.01-2.5 W 1% Ni, o, s
~4. 1. A semiconductor device comprising, on a semiconductor substrate, a wiring conductor layer made of an alloy having a composition of owt% Si and the balance At. 2. The alloy strength 0.01-2.5 W 1% (7) Ni
, 1.0 to 2.0 Qwt% of Bi and the remainder is A4. 3. The alloy has o,i ~twt% of NlX0.5~
4. Q W The semiconductor device according to claim 1, having a composition of 1% Si and the remainder At. 4. Said alloy 75'' 0.1~i, o w 1% N
i, 1.0~2, Q w 1% Si and the remainder is A
The semiconductor device according to claim 1, characterized in that the semiconductor device has a composition consisting of t. 5. The semiconductor device according to any one of claims 1 to 4, wherein at least a portion of the wiring conductor layer is corroded by a polymer resin. 6. The polymer resin that corrodes at least a portion of the wiring conductor layer is at least one resin selected from the group consisting of polyimide resin and polyimide isoindolo quinazolinedione resin. The semiconductor device according to scope 5. 7. The semiconductor substrate has an insulating film on at least one surface, and at least a portion of the wiring conductor layer exists on the insulating film. 6. The semiconductor device according to any one of Item 6. 8. The semiconductor device according to claim 7, wherein the insulating film is made of glass containing phosphorus. 9. The semiconductor device according to claim 7, wherein the insulating film is made of a polymer resin. 10. The semiconductor according to claim 9, wherein the polymer resin constituting the insulating film is at least one resin selected from the group consisting of polyimide resin and polyimide isoindolo quinazolinedione resin. Device. 11. The wiring conductor layer is composed of at least two layers, and the upper wiring conductor layer is formed on a polymer resin layer covering at least a part of the wiring conductor layer located below, and Patent Nt”f characterized in that at least a part of the wiring conductor layer on the side is covered with a polymer resin
The semiconductor device according to any one of claims 5 to 10. 12. The semiconductor device according to any one of claims 1 to 11JI'J, characterized in that it is resin-sealed.