JPS63199459A - semiconductor equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor device, and particularly to a technique that is effective when applied to a semiconductor device having a junction such as a diode.

[Prior art]

A varicap diode is a diode whose capacitance value changes depending on the applied voltage.
p, 383-P, 387, Ohmsha). Conventionally, for example, in a resin-molded varicap diode, a pnn junction is formed in a super-super step junction in order to increase the capacitance change ratio. As the electrode of the pn junction, an aluminum (A1.) film or an aluminum-silicon (Al-3
i) Alloy membranes are commonly used. In recent years, in varicap diodes, the pn junction depth has become shallower in order to increase the capacitance change ratio.

[Problem that the invention seeks to solve]

However, the inventors of the present invention have found that when the junction depth of the pn junction becomes shallow, for example, about 1.3 μm or less, the following problem occurs when measuring the electrical characteristics of a diode. That is, when a probe is placed on an electrode to measure the electrical characteristics of a diode, if the needle pressure of the probe is high, the stress generated by this probe pressure reaches the high impurity concentration region of the pn junction through the electrode. For this reason, when a reverse bias is applied to the diode by a probe for measurement, an electric field is generated due to this stress, and as a result, the withstand voltage of the diode appears to increase or decrease, resulting in a decrease in the sorting yield. invite. In this case, if the stylus pressure is lowered, the stress will be smaller and the above-mentioned drop in withstand voltage will not occur, but if the stylus pressure is lowered, the contact between the probe and the electrode will not be good, which may reduce the accuracy of electrical measurements. I don't like it because it is.

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique that can eliminate the adverse effects of probe stylus pressure when measuring electrical characteristics.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

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

That is, an electrode provided at the junction, a material layer partially provided on this electrode and having higher hardness than this electrode, and a material layer provided at least on this material layer and connected to the electrode. It is equipped with a metal film.

[Effect]

According to the method described in -, the stress caused by the stylus pressure that occurs when a probe is placed on a metal film during measurement of electrical characteristics is absorbed by the hard material layer, so that the stress caused by the stylus pressure does not reach the bond. Therefore, it is possible to eliminate the adverse effects caused by the needle pressure of the probe.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described using the drawings.

Note that throughout the description of the embodiments, parts having the same functions are given the same reference numerals, and repeated explanations thereof will be omitted.

FIG. 1 is a plan view of a varicap diode according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line X--X in FIG. 1.

As shown in FIGS. 1 and 2, in the varicap diode according to this embodiment, an epitaxial layer 2 made of, for example, n-type silicon is provided on a semiconductor substrate l, such as an n++ type silicon substrate, and Further, on this epitaxial layer 2, for example, silicon dioxide (SiO2
) is provided with an insulating film 3 such as a film. This insulating film 3
For example, an opening 3a having a substantially square planar shape is provided in the epitaxial layer 2 in a portion corresponding to the opening 3a, and an n° type semiconductor region 4 and a p
A +4 type semiconductor region 5 is provided. These semiconductor regions 4.5 form a pn junction, which is a hyperstep junction with a shallow junction depth.

An electrode 6 made of, for example, an aluminum film is provided on the semiconductor region 5 inside the opening 3a. Since this electrode 6 is provided over almost the entire surface of the semiconductor region 5, the contact resistance of this contact portion can be made extremely small. The code 7 is, for example, S
i The insulating film 7 is generally a hard insulating film such as an O2 film or a silicon nitride (Si3N4) film, and the insulating film 7 is coated in such a way that it covers, for example, only one corner of the electrode 6 and the insulating film 3. An open lower lower a is provided. For example, an A1 film, an Al5j
A metal film 8 for probe measurement, which will be described later, is provided. A part of this metal film 8 extends over the insulating film 7, and a probe 9, which will be described later, can be set up in this part to measure the electrical characteristics. This metal film 8
is smaller in size than the semiconductor region 5 and is located inside the semiconductor region 5, so that the metal film 8 and the insulating film 7.3
The stray capacitance due to the capacitor formed by the epitaxial layer 2 and the epitaxial layer 2 can be almost ignored.

When measuring the electrical characteristics of the diode according to this embodiment, a probe 9 is erected on the metal film 8 extending on the insulating film 7, as shown in FIG. At this time, this probe 9
Stress due to the stylus pressure is generated in the metal film 8, but this stress is absorbed by the insulating film 7, which has high hardness, or even if it is not completely absorbed, it is significantly reduced. Therefore, the stress caused by the needle pressure does not reach the electrode 6 and the semiconductor region 4.

As a result, even if a reverse bias is applied to the junction by the probe 9 when measuring the electrical characteristics, it is possible to prevent the breakdown voltage of the diode from decreasing due to the effect of electric field concentration caused by stress due to the stylus pressure, and the screening yield can be reduced. No deterioration or variation occurs.

Therefore, the adverse effects caused by raising the probe needle 9 can be eliminated. Furthermore, since the stylus pressure can be made sufficiently high, good contact between the probe 9 and the metal film 8 can be achieved, and therefore, it is possible to improve the precision of the electrical characteristics.

Next, an example of a method for manufacturing a diode according to this embodiment configured as described above will be described.

As shown in FIGS. 1 and 2, an epitaxial layer 2 is first formed on a semiconductor substrate 1 by epitaxial growth, and then an insulating film 3 is formed by thermally oxidizing the surface of this epitaxial layer 2.

Next, a predetermined portion of this insulating film 3 is removed by etching to form an opening 3a. Next, an n-type impurity is ion-implanted into the epitaxial layer 2 through this opening 3a to form a semiconductor region 4. Next, for example, a photoresist (not shown) having an opening slightly larger than the opening 3a is provided on the insulating film 3, and using this photoresist as a mask, p-type impurity ions are ionized into the epitaxial layer 2=7- By implanting, a semiconductor region 5 is formed. Next, for example, an aluminum film is formed on the entire surface, and this aluminum film is patterned into a predetermined shape by etching to form the electrode 6. Next, after forming an insulating film 7 on the entire surface by, for example, CVD, a predetermined portion of this insulating film 7 is removed by etching to form an open lower a. Next, after forming a metal film 8 on the entire surface, this metal film 9 is patterned into a predetermined shape by etching to complete the intended diode.

The present invention has been specifically explained above based on examples, but
It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit thereof.

For example, instead of the insulating film 7, a film of a high-hardness, high-melting point metal such as tungsten, molybdenum, titanium, or tantalum, or a silicide film of these metals may be used. Further, the shape of the portion where the insulating film 7, high-melting point metal film, etc. cover the electrode 6 can be changed as necessary; for example, these may be provided only under the metal film 8 where the probe 9 is erected. It's okay. Furthermore, the present invention can be applied to various semiconductor devices having junctions such as Zener diodes with shallow junctions and Schottky barrier diodes with low current-voltage characteristics.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, it is possible to eliminate the adverse effects caused by the stylus pressure of the probe when measuring electrical characteristics.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a varicap diode according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line XX in FIG. 1. In the figure, 1... semiconductor substrate, 2... epitaxial layer,
3... Insulating film, 4.5... Semiconductor region, 6... Electrode, 7... Insulating film (material layer) 8... Metal film, 9 - Probe.

Claims (1)

[Claims] 1. A semiconductor device having a junction, comprising: an electrode provided at the junction; and a semiconductor device partially provided on the electrode;
A semiconductor device comprising: a material layer having a harder hardness than the electrode; and a metal film provided at least on the material layer and connected to the electrode. 2. The semiconductor device according to claim 1, wherein the material layer is an insulating film. 3. The semiconductor device according to claim 2, wherein the insulating film is a silicon dioxide film or a silicon nitride film. 4. The semiconductor device according to claim 1, wherein the material layer is a metal film or a metal silicide film with high hardness. 5. The semiconductor device according to any one of claims 1 to 4, wherein the electrode is made of an aluminum film or an aluminum-silicon alloy film. 6. The semiconductor device according to any one of claims 1 to 5, wherein the semiconductor device is a varicap diode, a Zener diode, or a Schottky barrier diode.