JPS61144847A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To realize an Al wiring equipped with moisture-proof and electromigration resistance by a method wherein an Al alloy is employed containing 0.1-0.2wt% of Pd or Pt and the Pd or Pt is precipitated as a simple substance or as a intermetallic compound. CONSTITUTION:The percentage of Pd should be 0.005-23% for corrosion resistance and not less than 0.1% for electromigration resistance. An alloy is therefore to be preferably composed of 0.1-2% of Pd, 0.1-3wt% of Si, and the rest Al. The alloy of Al-Pd or Al-Si-Pd is attached by spattering to a thermal Si oxide film. Next, solution annealing is accomplished by a 10-30min process at 480-530 deg.C, to be followed by a 20-60min process accomplished at 380-480 deg.C for the precipitation of Pd along the Al grain boundary. A 60-180min process is further accomplished at 330-380 deg.C for the precipitation of an Al-Pd intermetallic compound. By this method, a highly reliable Al alloy wiring is obtained. The same procesure is to be followed when Pt is used instead of Pd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention mainly relates to a resin-sealed semiconductor device, and particularly to a semiconductor device having an aluminum alloy wiring film having both moisture resistance and electromigration resistance.

[Background of the invention]

At-Cu alloy, At-3, to suppress electromigration of aluminum wiring film on semiconductor elements.
It is known to form a wiring film using an i-Cu alloy or the like. However, these have low corrosion resistance and may corrode depending on the package.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 57-170549, an At Cu Mn alloy is used for corrosion, 'sv
A method is known that satisfies the reliability of both chromatography and migration.

Regarding At-Pd, it is known that the corrosion resistance of At can be improved by adding 0.1% or more of PD, as disclosed in JP-A-57-1241.

[Purpose of the invention]

The object of this invention is the conventional At-8i-Cu alloy.

It is an object of the present invention to provide a semiconductor device having an At alloy interconnection film having both corrosion resistance and electromigration resistance in place of an At-Pd alloy, and a method for manufacturing the same.

[Summary of the invention]

In the present invention, a wiring film on a semiconductor element is formed of an At alloy containing α1 to 2% by weight of at least one of PD and PT, or an At alloy further containing 0.1 to 3% by weight of silicon. In addition, in the At alloy, Pd, pt, and S
At least one of t needs to be precipitated as a simple substance or in the form of an intermetallic compound.

Conventionally, electromigration resistance and corrosion resistance are not compatible, and in particular, Cu, which improves electromigration resistance, lowers the corrosion resistance of the λ base.

Corrosion resistance is achieved by adding an appropriate amount of Pd, which increases kA corrosion resistance, and by dispersing and precipitating intermetallic compounds.

It has been found that it is possible to form an A/alloy wiring film that exhibits excellent electromigration resistance. Pd
A4 alloy film with α1~2s added or At-2%8
A problem with i-alloy films is that pitting occurs. On the other hand, the problem with corrosion of the wiring film is the corrosion of the bonding pad, but the area of the pad is usually 100
It was found that there was no problem even if some pitting occurred as wide as μff1×100 μm. The range of α005 to 2 cm Pd is effective in preventing At film pad corrosion in actual semiconductor devices sealed with epoxy resin;
K: Therefore, when the At base is anodically polarized, A
This is thought to be because the oxide film on the surface of the t-film is strengthened.

In the electro-or migration, when a current flows, the crystal grain boundaries of the At film move, leading to disconnection in the wiring portion, and electromigration resistance can be improved by strengthening the crystal grain boundaries. P into A4 base
Since the solid solubility limit of d is 0.11, Pdt of 0.1 or more
By adding it to -At, intermetallic compounds of A/ and -Pd can be precipitated. The heat treatment for this purpose involves heating the At film formed by vapor deposition or sputtering at 510C for 10 minutes to uniformly dissolve Pd in At.

Next, by heating at 400C for 30 minutes, PD is moved to the grain boundaries and precipitates are formed at the grain boundaries. Next, in order to precipitate unprecipitated Pd at 400C,
Heating is performed at 50C for 1 hour. In this final heat treatment,
Fine precipitates can be formed around the At-Pd precipitates that were precipitated at 400C.

By the three-step heat treatment described here, At! Pd can be precipitated at the grain boundaries of X, and electromigration resistance can be improved.

The amount of pd added is defined as 0.005 to 2% from the viewpoint of corrosion resistance, and 1 tlj or more from the viewpoint of electromigration resistance, and the composition range that satisfies both is 0.1 to 2%.
2- is given. The amount of Si is 0.1 to 3 weight.

In addition, heat treatment to improve electromigration resistance is not limited to the above-mentioned temperature and heating holding time; slight variations are possible as long as the structure of the At film has a structure in which precipitates are deposited at grain boundaries. be.

Specifically, solution treatment is carried out by heating and holding at 480-530C for 10-30 minutes, precipitation treatment is heating and holding at 380-480C for 20-60 minutes, and 60-18C is heated at 330-380C.
Precipitates can be precipitated by performing a reheating treatment in which the temperature is maintained for 0 minutes.

What I have said above also applies to PT.

[Embodiments of the invention]

Examples of the present invention will be described below in detail. An At-pd alloy film and an At-2 5i-pd alloy film are deposited on thermally oxidized silicon by sputtering under conditions of an Ar partial pressure of 6 Pa and a high frequency output of 2 kl. However, the AL on the substrate is 1 μm thick.
The method for forming the -Pd or At-8i-Pd alloy thin film is not limited to the sputtering method, but may also utilize electron beam vacuum evaporation, CVD, or the like. Wiring and electrodes are made from this thin film by wet etching or chemical dry etching.
510C for 10 minutes, 400C for 30 minutes, 350tl
A three-step heat treatment was performed at l' for 1 hour.

After that, it is divided into Si chips and attached to a metal lead frame.
The chips are bonded using A11-S j bonding or Ag paste, and the At wiring film and lead frame are directly bonded using i3Gμ.
Wire bonding was performed using m0Au wire.

After bonding, it was molded at 150C using epoxy resin, and heated at 150C for 2 hours to harden the resin.

P CT (Pressure Cooker
Figure 1 shows the relationship between the amount of PD added and the time t and o until half of the samples break due to corrosion. Addition of pd of o, oos to 2- can improve At or ht-zssio corrosion resistance.

In the electromigration test, the current density was maintained at 2 x 10' A/cm2 in an oven at 200C, and the time until the wiring reached disconnection due to electromigration was measured. As a result, the relationship between the time tso until half of the samples reach disconnection and the amount of Pda added is shown in FIG. It can be seen that adding PD of 0.1 inch or more is effective.

Next, the influence of heat treatment was examined on AL-2'48 i-1 attack Pd. When evaluating the electromigration properties of a film formed by sputtering, heated at 450C for 1 hour and heat treated at 510C for 10 minutes,
The former is TSO and 10 hours, while the latter is 125 hours and 12 hours.
．． 450C, which was found to be five times more reliable.
The structure after heating for 1 hour is shown in FIG. 3, and the structure after three-step heat treatment is shown in FIG. 4.

Incidentally, in order to improve the electromigration resistance, it is not necessary to use the favorable heat treatment conditions described here, but it is sufficient that the structure of Atji[ is as shown in FIG. 4]. The special numbers 1 in the figure indicate precipitates and 2 indicate grain boundaries.

FIG. 5 shows the structure after the first stage heat treatment in the three stage heat treatment of the present invention.

FIG. 6 shows the structure when precipitation treatment is performed after solution treatment. At--Pd intermetallic compounds precipitate at At grain boundaries. In this structure, the grain boundaries of At are suppressed, so the electromigration resistance is significantly improved.After that, by reheating at 330 to 380G for 60 to iso minutes, it becomes a solid solution without precipitating as shown in Figure 4. It is possible to further precipitate the pd or pt intermetallic compound near the At grain boundaries or smoke grain boundaries. As a result, the electromigration resistance can be further improved.

FIG. 7 shows the electromigration resistance of wiring films subjected to various heat treatments with rcht-2ms + -1*pdo composition. Also, for comparison, 45 At-2181 wiring films were used.
A conventional example treated at 0C for 1 hour will also be shown. [Effects of the Invention] According to the present invention, a wiring film for semiconductors having excellent corrosion resistance and electromigration resistance can be obtained. As a result, the high density of resin mold or ceramic mold,
It can be applied to fine wiring patterns and improve the reliability of devices.

[Brief explanation of the drawing]

Figure 1 shows At in the present invention and p in At-21SR.
Figure 2 is a characteristic diagram showing the relationship between the amount of d added and the PCT corrosion time. Figure 3 is a tissue diagram of At-21S +-X ChiPd heated at 450C for 1 hour, Figure 4 is a tissue diagram of At-2 Chi 5t-xspd after three-step heat treatment according to the present invention, and Figure 5 is a diagram of At-21S + - The organization diagram after the first stage heat treatment, Figure 6 is 2
FIG. 7 is a diagram showing the structure after the step heat treatment, and is a characteristic diagram showing the electromigration test results for the conventional wiring film and the wiring film according to the present invention. 1... Precipitates, 2... Grain boundaries.

Claims (1)

[Scope of Claims] 1. In a device having a wiring film on a semiconductor element, the wiring film contains at least one of palladium and platinum.
1 to 2% by weight, the remainder substantially consisting of aluminum, and at least one of the palladium and the platinum.
1. A semiconductor device characterized in that the semiconductor device is composed of an alloy in which the elements are precipitated in the form of a single substance or an intermetallic compound. 2. In a device having a wiring film on a semiconductor element, the wiring film contains at least one of palladium and platinum.
an alloy containing 1 to 2% by weight and 0.1 to 3% by weight of silicon, the remainder substantially consisting of aluminum, and in which at least one of the palladium, the platinum, and the silicon is precipitated alone or in the form of an intermetallic compound. A semiconductor device comprising: 3. After forming an alloy thin film containing 0.1 to 2% by weight of at least one of palladium and platinum and the remainder substantially aluminum on the wiring film formation area on the semiconductor element, the film is heated at 480 to 530°C for 10 to 30% by weight. A method for manufacturing a semiconductor device characterized by performing solution treatment by heating and holding for 380 to 480°C for 20 to 60 minutes, and reheating treatment by heating and holding at 330 to 380°C for 60 to 180 minutes. .