JPH02266572A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve static electricity resistance and prevent element area from increasing by forming the plane shape of the contact for leading out an N-type conductive layer and that for leading out a P-type conductive layer longer in parallel to the junction part located between both contacts. CONSTITUTION:A P-type conductive layer lead-out contact 10 and an N-type conductive layer lead-out contact 11 are formed in longer shape being in parallel to a junction part 12. With this structure, it is possible to reduce effective current density flowing crossly through the junction part 12 when static electricity is applied to and it is not necessary to adopt a simple expansion method of junction area which has been made conventionally, thus improving static electricity resistance of a diode efficiently. Therefore, it is possible to improve static electricity resistance of a semiconductor device drastically and to prevent unneeded element area from increasing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a semiconductor device, and more specifically, to a diode structure formed on a chip that is highly effective in protecting against external static electricity.

Conventional technologyIn the handling process of integrated circuit semiconductor devices, static electricity is applied to the semiconductor chip housed in the outer enclosure through the external terminal leads, resulting in so-called electrostatic breakdown failure, which destroys the elements that make up the integrated circuit. Among them, diode junction breakdown is one of the most common electrostatic breakdown breakdowns.
It is one. For this reason, in the case of a diode that is directly connected to an electrode formed on the periphery of the chip by a metal wiring pattern for leading out to an external terminal, it is most susceptible to damage from static electricity, so static electricity countermeasures have been taken structurally.

Regarding the static electricity countermeasure structure of conventional diodes, see P in Figure 4.
The case of a diode in which an N-type conductive layer region is provided within the N-type conductive layer region will be described as an example. In the figure, a P-type conductive layer 1 and an N-type conductive layer 2 are electrically connected via contacts 5 and 6 to two metal wirings 3 and 4 arranged above a diode element, respectively. In this diode structure, the junction is approximately connected to the planar shape of the N-type conductive layer 2.
I will. Conventionally, the electric charge applied from the metal wiring 4 to the diode due to static electricity flows through almost the entire surface of the junction, that is, the entire planar shape of the N-type conductive layer 2, enters the P-type thick conductive layer 1, and is transferred to the metal wiring 3 via the contact 5. It was described as something to run away from. For this reason, as shown in the figure, a method has been used to increase the planar area of the N-type conductive layer 2 as much as possible to reduce the effective current density at the junction surface when static electricity is applied, and to improve the static electricity resistance of the diode.

Problems to be Solved by the Invention However, improving the electrostatic resistance of the diode by increasing the junction area in this way may of course lead to an increase in the element area, which may ultimately hinder the reduction of the chip area. Ta. Furthermore, the static electricity resistance may not be improved as much as expected, and it has been desired to develop an effective method for improving the static electricity resistance.

The present invention has been made in view of this point, and the raft shape allows the electric charge applied by static electricity to be applied not to the entire surface of the joint 2, but between the N-type conductive layer lead-out contact 6 and the P-type thick conductive layer lead-out contact 5. The present invention provides an effective structure for improving the static electricity resistance of a diode by discovering that the current flows across the junction 7 located at the junction 7.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides that the planar shape of the N-type conductive layer lead-out contact and the P-type thick conductive layer lead-out contact portion is approximately the same as the junction located between the two contacts. It has a parallel elongated structure.

According to the present invention, focusing on the fact that the discharge of the charge applied to the diode due to static electricity flows not across the entire junction area but across the junction located between the two contacts, the planar shape of both the contact parts is adjusted to the junction. Since the structure is formed in a long and narrow direction, it is possible to reduce the effective current density that flows across the joint when static electricity is applied. It is not necessary to remove the capacitance, and as a result, the electrostatic withstand capacity of the diode can be efficiently improved.

Example Next, the present invention will be explained by examples.

FIG. 1 is a plan view of the most basic diode according to the present invention having a structure in which an N-type conductive layer region 9 is provided within a P-type conductive layer region 8. In the figure, P-type thick electric layer lead-out contact 1
The 0 and N type conductive layer lead-out contacts 11 have an elongated structure parallel to the bonding portion 12. If the contact length in the longitudinal direction is 50 μm or more, sufficient electrostatic resistance can be obtained.

Unlike FIG. 1, FIG. 2 shows an example in which the contact portion is formed using a plurality of small contacts 13. In this case as well, the same effect as in the example of FIG. 1 can be obtained.

FIG. 3 shows an example in which the present invention is applied to a diode structure connected to a metal wiring I4 for a high potential power source and a metal wiring 15 for a low potential power source. Metal wiring for high potential power supply! 1I 114 is connected to the N-type conductive region 16 through a contact portion 17, and the low-potential power supply metal wiring 15 is connected to the P-type conductive region 18 through a contact 19. The contacts 19 of the P-type conductive region 18 are provided on both sides of the contact portion 17 of the N-type conductive region 16 in order to efficiently reduce the discharge current density of static electricity. In this case, it can be applied particularly effectively when the two metal interconnections 14 and 15 are arranged side by side so as to surround the chip internal circuit.

By adopting the contact structure for drawing out the diode as described above, it is possible to obtain a diode that is difficult to break down even when static electricity is applied.

Although this embodiment has been described using a diode in which an N-type conductive region is provided within a P-type conductive region, the same effect can naturally be obtained for a diode in which a P-type conductive region is provided within an N-type conductive region.

In addition, if the external terminal lead-out electrodes to which the contact lead-out wiring in the N-type conductive layer region and the P-type trench conductive layer region are connected are a high potential setting power supply terminal and a low potential setting power supply terminal, respectively, the high potential setting In the case of a power supply terminal and an external output terminal or an external input terminal, the present invention can be applied to any case of a low potential setting power supply terminal and an external output terminal or an external input terminal.

Effects of the Invention As described above, the semiconductor device having the diode of the present invention makes it possible to significantly improve the electrostatic resistance of the semiconductor device and to prevent unnecessary increase in element area.

[Brief explanation of drawings]

1, 2, and 3 are plan views of a diode according to an embodiment of the present invention, and FIG. 4 is a plan view of a conventional diode. 1... P-type thick electric layer region, 2... N-type conductive layer region, 3... Extract wiring from the P-type conductive layer, 4... Extract wiring from N-type conductive layer, 5
・・・・・・P type thick electric layer contact, 6・・・・・・N
type conductive layer contact, 7... junction located between contacts, 8... P type thick conductive layer region, 9...
...N-type conductive layer region, 10...P-type thick conductive layer contact, 11...N-type conductive layer contact,
12... Joint portion located between contacts, 13
...Small contact, 14...Metal wiring for high potential power supply, 15...Metal wiring for low potential power supply, 16...N-type conductive region, 17・・・・・・N
type conductive layer contact, 18...P type conductive region,
19...P-type thick electrical layer contact. Name of agent: Patent attorney Masaji Awano and one other person Figure 3

Claims (1)

[Claims] A planar shape of a contact portion for drawing out an electrode in an N-type conductive layer region and a contact portion for drawing out an electrode in a P-type conductive layer region constituting a planar diode formed on a surface portion of a semiconductor silicon substrate is between the two contacts of the diode. The contact lead wires are formed in a long and narrow shape approximately parallel to the PN junction located in the area and have a length of 50 μm or more, and each of the contact lead wires between the N-type conductive layer region and the P-type conductive layer region leads to different external terminals. A semiconductor device characterized by being connected to an electrode.