JPS6373641A - Semiconductor device - Google Patents

Abstract

PURPOSE:To enable a semiconductor device to maintain the reliability doing no damage to a protective insulating film due to trimming process by a method wherein a covering film comprising a hard material taking a cover shape is formed above a trimming part. CONSTITUTION:A covering film 7 is in floating state electrically isolated from an Al interconnection 3 as a lower layer. A final protective insulating film 6 thickly coated with an organic insulating film such as e.g. a polyimide base resin to be hardened is provided with a window around a chip to expose a bonding pad as an extension of the Al interconnection. The bonding pad connected to the Al interconnection 3 with a specific part 4 for trimming process in contact with a probe is supplied with overcurrent to melt down the interconnection 3 at the specific part 4. An interlayer film 5 above the Al interconnection is simultaneously broken down as soon as the latter 3 is melted down to pick a a cavity 8. A part of melted down Al as residual Al 9 adheres to the bottom surface of covering film 7. Through these procedures, the inter-layer film 5 subjected to a damage can be blocked by the covering film 7 in floating state as the second Al film so that the surface protective film 6 may not be affected by the damage.

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 1 (IC, LSI).

[Prior art]

In ICs, etc., a plurality of diffused resistors R0R, R, . . . with different resistance values are placed on the surface of a semiconductor substrate as shown in Fig. 4.
..., and trimming (partially cutting) the drawer wires from unnecessary resistors, such as Rt and Rs...K, only the necessary resistor (R1) is formed. Trimming techniques that leave behind are known.

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 excessive current is passed through the lead A-13 wiring of the unnecessary resistor through a probe needle. There is a method of trimming a silver alloy resistor, etc. on a dielectric film using a laser beam (laser trimming of a resistor on a dielectric material, published by Kogyo Kenkyukai, Electronic Materials, May 1985, p. 118-124). The laser trimming method requires dog-heavy equipment and is not considered here.

In the present invention, a trimming method using the above-mentioned probe test will be explained as an example.

Normally, as shown in Figure 5, an external terminal (ponding pad) IOK probe needle 11 connected to the doll wiring is brought into contact with the doll wiring, and an overcurrent is applied with the other end of the AA wiring set to ground potential. A current is concentrated on the narrow part 4 formed at one part of the pipe to fuse it.

[Problem that the invention seeks to solve]

When the present inventor investigated the above-mentioned trimming method using fusing, it was found that the following problems occurred. That is, as shown in FIG. 6, when the AA wiring 3 is fused due to overcurrent, the protective insulating film 6 covering the wiring may also be melted and scattered at the same time, causing the protective film 6 to disappear or As the wiring became thinner, moisture from the outside attacked the wiring, significantly reducing the reliability of the IC.

The present invention has been made to overcome the above-mentioned problems.

An object of the present invention is to provide a wiring structure that can maintain reliability of a semiconductor device without damaging a protective insulating film 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.

In other words, the literati! A wiring is formed, a part of this 2 wiring has a specific part for IC trimming, and the top is covered with a second insulating film. A film made of A4 film or other hard material is provided as a lid via a second insulating film, and a third insulating film is further formed thereon as a protective film.

[Effect]

By providing a film made of the above-mentioned hard material in the shape of a lid at the trimming region, the reliability of the semiconductor device can be ensured without destroying the protective film during cutting for trimming, and the above object can be achieved.

〔Example〕

FIG. 1 and FIG. 2 show an embodiment of the present invention,
FIG. 2 is a plan view of a wiring pattern having a trimmed portion in a partial wiring structure of an IC and a cross-sectional view thereof.

1 is a Si semiconductor substrate, 2 is a semiconductor surface oxide film (SiOz
membrane). 3 is the A wiring, and 4 is a narrow portion for trimming. Reference numeral 5 denotes an interlayer insulating film made of, for example, PSG (phosphorus silicate glass) or Sin formed by CVD (chemical vapor deposition).

Reference numeral 7 denotes a lid-like membrane made of A2, which is provided at a position to cover the upper part of the narrow part 4. When the human stone wiring has a two-layer structure, the lid-like film is formed in the same process as the second layer (upper layer) AA wiring. The lid-like film 7 is in a floating state electrically isolated from the i-wire 3 in the lower layer.

Reference numeral 6 denotes a final protective insulating film, which is formed by applying a thick organic insulating film such as polyimide resin and curing it. Although not shown, this protective insulating film is opened around the chip A!
Expose the bonding pad, which is the wiring extension.

FIG. 3 shows the form of the wiring after trimming.

That is, referring to FIG. 5, a probe needle is brought into contact with a bonding pad to which an AA wiring 3 having a specific portion (narrow portion) 4 for trimming is connected, and an overcurrent is applied.
The wiring is fused at the specific location (4). At the same time as the person 2 wiring 3 melts, the glabellar membrane 5 above it is also destroyed, creating a void 8. There's a person at the top of this sword! Because of the existence of the lid-shaped portion 7, the protective film 6 thereon is not destroyed.

A portion of the melted A2 adheres to the lower surface of the lid-shaped portion 7 as an Ap residue 9.

In the wiring structure as described in this embodiment, when the first-layer Ak wiring is blown, the interlayer film 5 will be caught, but it will be blocked by the lid-shaped part 7, which is the second-layer film, which is in a floating state. The protective film on the surface is not affected.

In the past, trimming was difficult because it lowered the reliability of the IC, but as mentioned above, trimming is now easier without damaging the surface protective film due to the wiring melting, making it possible to create high-value-added ICs.
, LSI can be realized.

Although the invention made by the present invention has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above-mentioned Examples and can be modified in various ways without departing from the gist thereof. do not have.

For example, the lid-shaped part provided above the trimming area is A2
Hard films other than the film, such as Si nitride film (S;, N4)
A similar effect can be expected by using .

The present invention is applicable to all high performance LSIs.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the present invention, and is a plan view of a wiring pattern having a trimming portion in a semiconductor device. FIG. 2 is a sectional view taken along line AA in FIG. 1. FIG. 3 is a cross-sectional view of the wiring after trimming. FIG. 4 is a circuit diagram for selectively trimming a plurality of resistors. FIG. 5 is a partial plan view of a semiconductor chip showing one form of trimming using probe inspection. FIG. 6 is a sectional view showing the form of the wiring after trimming. 1... Si substrate, 2... First insulating film (SiOt)
, 3... First layer A2 wiring, 4... Trimming site (
narrow part), second insulating film (interlayer film, CVD-PS
G), 6... Third insulating film (protective film, polyimide resin), 7... Lid-like part (second layer A2 film), 8... Cavity part, 9... A [residue agent Person Patent Attorney Katsoo Ogawa 1. 7 ・te=” Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. A first insulating film formed on a semiconductor substrate.
A wiring layer is formed, a portion of the first wiring layer has a trimming portion, a second insulating film covers at least the first wiring layer, and at least the first wiring layer has a trimming portion. A semiconductor characterized in that an electrically floating lid-like film is provided on the wiring layer of the part via a second insulating film, and a third insulating film is further formed on the lid-like film. Device. 2. The semiconductor device according to claim 1, wherein the lid-like film is formed in the same process as the second wiring layer.