JPS6373640A - Semiconductor device - Google Patents

Abstract

PURPOSE:To enable the trimming process to be performed by stable Al melting down process with excellent reproducibility by a method wherein a semiconductor region immediately below a specific part of an interconnection is formed into an island region electrically isolated from any other semiconductor regions while the surface of this island region is formed into a highly resistant region. CONSTITUTION:A part of Al interconnection 5 is formed into a bottleneck part 6 while a semiconductor Si layer 2a immediately below a trimmed part (narrow width part) 6 as an island region electrically isolated by an isolation P diffused layer 3 is potentially floating. Furthermore, the surface of island region 2a in this semiconductor is formed into a highly resistant layer as it is an epitaxial layer. Therefor, even if the Al interconnection 5 is melted down at the bottleneck part 6 making the Al interconnection 5 shortcircuit with the Si layer 1 due to a damaged SiO2 film as a primary layer and any residual Al, the conduction resistance can be notably stiffened by the floating Si layer or highly resistant surface of the same so that the Al interconnection may be melted down for trimming process interdependently upon said two reasons to achieve the purpose of this invention.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wiring trimming technique in a semiconductor integrated circuit device (IC, LSI).

[Prior art]

In the manufacture of ICs, etc., a plurality of diffused resistors R+R with different resistance values are placed on the surface of a semiconductor substrate as shown in FIG.
A drawer of resistors that are unnecessary, such as R, R,..., forming t Rs......!
A trimming technique is known in which only the necessary resistance (R1) is left by trimming (partially cutting) the wiring.

As a method for this trimming, there is generally a method in which the resistance value of each diffused resistor is measured by a probe test, and an overcurrent is passed through the lead wire of the unnecessary resistor through a glove needle. Temptation! There is a method of trimming silver alloy resistors etc. on a film (Resistance laser trimming on dielectric material published by Kogyo Kenkyukai Co., Ltd., Electronic Materials, May 1985, P118-124).

In the present invention, a trimming method using a probe test will be explained as an example. Normally, the probe needle 8 is brought into contact with the external terminal (ponding pad) 7 connected to the input wiring 5 as shown in FIG. Delivery! ! An overcurrent is applied while the other end of the wire 5 is at ground potential, and the current is concentrated in the narrow portion 6 formed at a portion of the AJ13 wiring, causing it to melt.

[Problem that the invention seeks to solve]

In the above trimming method, as shown in FIG. 5, there is a risk that the Sing film 4, which is the base insulating film of the blown portion of the AA wiring 5, may melt or disappear due to the high energy during the KAA blowing. As a result, the cut human wiring may be short-circuited with the Si substrate 1, or may be connected through the Si substrate, resulting in a conductive state. For this reason, there is a problem in trimming by manually cutting the wiring.

The present invention has been made in consideration of the above problems.

That is, an object of the present invention is to provide a semiconductor device whose performance is not impaired by A2 melting due to trimming.

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 to solve the problem]

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

That is, A formed on a semiconductor substrate with an insulating film interposed therebetween.
A semiconductor device having a specific part for trimming by fusing or the like in a part of the A wiring, wherein the semiconductor region directly under the specific part of the A2 wiring is an island region electrically isolated from other semiconductor regions. In addition, the surface of the island region of the semiconductor described above is made into a high resistance region.

[Effect]

According to the above-mentioned means, people! Even if the underlying 5-inch film deteriorates due to the energy generated when the wiring is fused, the semiconductor region immediately below it is electrically "floating" from other regions.
The purpose of trimming can be achieved without conduction.

〔Example〕

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a plan view of a semiconductor device having a trimming portion in a part of the AA wiring, and FIG. -A sectional view.

1 is a p-type Si semiconductor substrate, and 2 is an n"" Si layer epitaxially grown on the substrate.

4 is a surface oxide film (Sin, film), 5 is a person! It's the wiring.

A narrow part 6 for trimming is formed in a part of the A2 wiring 5, and the semiconductor layer 2a directly under this trimming part (narrow part) 6 is separated from the surrounding semiconductor region by the ainlation P diffusion layer 3. It is an electrically isolated island region and is electrically floating. Note that the surface of this semiconductor island region 2a remains a high resistance layer as an epitaxial layer.

In such a wiring structure, if the probe needle is brought into contact with one end of the It wiring (for example, a bonding pad) and the narrow portion 6 is blown, the underlying 5iOt film of the fused portion will be damaged and the A2 residue will cause damage to the underlying 5iOt film. Man! Even if one side of the wiring is short-circuited to the Si layer, conduction will not occur because the Si layer is floating. Also, A was fused! Even if both sides of the wiring are short-circuited, the conduction resistance can be extremely large because the surface of the Si layer has a high resistance. Coupled with these factors, the intended A2 wiring can be fused and trimmed.

As above, the invention made by the present inventor has been specifically explained based on the examples, but the present invention is not limited to the above-mentioned examples, and various changes can be made without departing from the gist thereof.

For example, in order to obtain a semiconductor region with a high resistance surface, n-
``When forming the Si layer, an epitaxial Si layer with a small amount of n-type impurity doping or no n-type impurity doped is formed on the surface portion.

The present invention is most effective when applied to the manufacture of high-performance, high-precision ICs and LSs.

The present invention is based on A! using the illustrated probe needle. In addition to fusing, it can also be applied to trimming using a laser.

Among the inventions disclosed in the present invention, the effects obtained by typical ones are briefly explained below.

That is, the present invention enables stable and highly reproducible trimming by A2 fusing. Since trimming is easy and high yield is possible, high-performance LSIs can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a semiconductor device showing one embodiment of the present invention. FIG. 2 is a sectional view taken along the line AA in FIG. 1. FIG. 3 is a circuit diagram of multiple resistors for selective trimming. FIG. 4 is a partial plan view of a semiconductor chip showing one form of trimming using probe inspection. Figure 5 is the person after trimming! FIG. 3 is a cross-sectional view showing the form of wiring. 1...p-5i substrate, 2...epitaxial n-8
i layer, 2a... island region, 3... isolene 5 f9
Layer, 4... Oxide film (Sin, film), 5... Person! Wiring, 6...Narrow part (trimming part). Agent Patent Attorney Katsuo Ogawa

Claims (1)

[Claims] 1. A wiring layer formed on a semiconductor substrate through an insulating film has a part for trimming, and the semiconductor region under the insulating film in the part of the wiring layer is other than the wiring layer. A semiconductor device characterized in that it is electrically separated from a semiconductor region. 2. The semiconductor device according to claim 1, wherein at least a surface portion of the electrically isolated semiconductor region in contact with the insulating film has a high resistance. 3. The semiconductor device according to claim 1, wherein the trimming is performed by cutting the wiring layer. 4. The semiconductor device according to claim 1, wherein the electrically isolated semiconductor region comprises an epitaxial semiconductor layer.