JPH04129227A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent static electricity from short-circuiting a floating line and a supply line by arranging floating lines not to overlap other lines connected electrically to a semiconductor substrate. CONSTITUTION:A wiring structure is provided in which floating signal lines 5 exist only on the same layer as supply lines, so theoretically the signal line and the supply line will never be short-circuited by static electricity. In this structure, floating lines are arranged not to vertically intersect other lines that are electrically connected to the semiconductor substrate. Therefore, a weak spot at a step in an insulating film will not destroy by static electricity. This prevents a short circuit between a floating line and a supply line.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to metal wiring for semiconductor devices.

[Conventional technology]

In recent years, semiconductor integrated circuits have become highly integrated, and metal wiring has also become multilayered, such as two or three layers. On the other hand, wiring that is not electrically connected to the board (floating wiring)
Since there were no problems with single-layer wiring, there were no restrictions on the handling of multi-layer wiring.

FIG. 3 shows an example of the structure of a conventional floating wiring.

FIG. 3(a) is a plan view, and FIG. 3(b) is a sectional view.

Semiconductor elements are not shown. The signal wiring 5 is connected to a package bin (not shown) through a bonding wire (not shown). Further, the signal wiring 5 is connected to a lower layer signal wiring 7 through a through hole 6. This lower layer wiring 7 is not connected to the silicon substrate 1. In other words, it is a floating wiring. Furthermore, a plasma nitride film 3 is provided on the signal wiring 7, and a power supply wiring 4 is further provided on top of the plasma nitride film 3.

[Problem to be solved by the invention]

In this conventional floating wiring structure, when static electricity is applied to the signal wiring 5, it is in a floating state, so there is no place for it to escape, and weak spots 8 of the plasma nitride film 3 (exist where there is a step in the lower layer) ) and discharged to the power supply wiring 4, resulting in a short circuit between the signal wiring 5 and the power supply wiring 4.

[Means to solve the problem]

The semiconductor device of the present invention has a structure characterized in that the floating wiring does not overlap the wiring electrically connected to the semiconductor substrate.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, with FIG. 1(a) being a plan view and FIG. 1(b) being a sectional view. In this example, the signal wiring 5, which is a floating wiring, exists only in the same layer as the power supply wiring 4, and therefore, it is theoretically impossible for the floating wiring and the power supply wiring to be short-circuited due to static electricity or the like.

FIG. 2 shows an embodiment in which the signal wiring 5, which is a floating wiring, is present in the lower layer of the power supply wiring 4. In FIG. In this example, since the structure is such that the lower layer signal wiring 7 and the upper layer power supply wiring 4 do not overlap, there is no power supply wiring above the weak spot 8 of the plasma nitride film 3, and therefore the floating wiring and the power supply wiring are exposed to static electricity. There will be no short circuit.

〔Effect of the invention〕

As explained above, since the present invention has a structure in which the floating wiring does not intersect with the wiring electrically connected to the semiconductor substrate in the vertical direction, the weak spots of the insulating film between the eyebrows caused by the step difference in the base due to static electricity etc. are destroyed. death,
This has the effect of preventing short-circuits between the floating wiring and the power supply wiring.

FIG. 4 shows data obtained by measuring electrostatic breakdown voltage in order to confirm the effects of the present invention. As can be seen from this, the conventional structure has large variations in electrostatic breakdown voltage, but the structure of the present invention has little variation and has sufficient electrostatic breakdown voltage.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are a plan view and a sectional view of one embodiment of the present invention, FIGS. 2(a) and (b) are a plan view and a sectional view of another embodiment, and FIG. a) and (b) are a plan view and a sectional view of a conventional structure. FIG. 4 is a diagram showing the relationship between the floating wiring structure and electrostatic breakdown voltage. The symbols in the figure are as follows. 1... Silicon substrate, 3... Plasma nitride film, 4.
...Power wiring, 5...Signal wiring, 6...Through hole, 7...Signal wiring, 8...Weak spot.

Claims (1)

[Claims] One type or multiple types of semiconductor elements are placed on a semiconductor substrate.
1. A semiconductor device including one or more metal wirings that are not electrically connected to a semiconductor substrate, wherein the metal wirings do not overlap with wirings that are electrically connected to the semiconductor substrate.