JP2793400B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to an improvement in a protection circuit connected to a bonding pad.

[0002]

2. Description of the Related Art Conventionally, a protection circuit has been connected to a bonding pad of a semiconductor device. When a high voltage is applied from the outside of the semiconductor device due to static electricity or the like, it is necessary to prevent damage to internal transistors and other elements. I'm preventing.

FIG. 4 is an equivalent circuit diagram showing a configuration of a general protection circuit. In FIG. 4, a diffusion layer resistor 12 and a transistor 13 which form a diode with a semiconductor substrate are provided.
Is provided between the bonding pad and the internal element.

FIG. 5A is a plan view showing a state in which the protection circuit shown in FIG. 4 is actually formed on a P-type semiconductor substrate. The bonding pad 11 and the protection circuit are made of metal forming the bonding pad. The connection is made using aluminum as the conductor layer as it is. FIG. 5B shows FIG.
It is sectional drawing of the cc line part of (A). In FIG. 5A, the diffusion layer resistor 12 shown in FIG. 4 is formed by the N-type impurity region 3, and as a result, a diode is formed with the P-type semiconductor substrate. At the end of the N-type impurity region, the gate (G) and the source (S) of the polycrystalline silicon 5b are fixed to a ground potential with aluminum 6b.
It is connected to the drain (D) of the S-type transistor.

If such a protection circuit is provided between the bonding pad and the internal element, when a positive high voltage is applied to the bonding pad, the PN junction of the diode breaks down and charges are transferred to the substrate. It is possible to prevent the internal elements from being destroyed by escaping. When a negative high voltage is applied to the bonding pad, M
The OS-type transistor is turned on to release electric charge to the wiring supplying the ground potential.

In FIG. 5B, the reason why the polycrystalline silicon 5a is provided at the connection with the bonding pad is that when a high voltage is applied, heat is generated by the resistance of the connection and the aluminum 6a is formed. This is for preventing an alloying reaction between the P-type semiconductor substrate 1 and the silicon of the N-type impurity region 3 from occurring and causing a short circuit with the P-type semiconductor substrate 1.

[0007]

However, in the above-mentioned conventional protection circuit, there is still a possibility that a short circuit occurs between aluminum and the semiconductor substrate. This will be described below.

Referring to FIG. 5B again, the region around the N-type impurity region 3 forming the diffusion layer resistance is covered with a thick oxide film 4, and under the thicker oxide film, a P-type semiconductor is formed. A P-type impurity region 2 of the same conductivity type as the substrate and higher in concentration than the P-type semiconductor substrate is provided as a channel stopper. This high-concentration P-type impurity region 2 has a parasitic M
A conductive layer of a conductivity type opposite to that of the substrate is formed under the thick oxide film by the OS transistor effect, and is provided for the purpose of preventing a leak from occurring between adjacent elements.

In the protection circuit having such a structure, when a positive high voltage is applied to the bonding pad, a break is first caused between the P-type impurity region 2 and the N-type impurity region 3 having a higher concentration than the substrate. Down happens. As a result, a large amount of heat is generated in this portion, and when an aluminum wiring exists on this portion, the aluminum film easily melts and breaks the oxide film, which may cause a short circuit with the semiconductor substrate.

FIG. 6 is a cross-sectional view schematically showing a state where a short-circuit 15 has occurred with the semiconductor substrate due to penetration of aluminum at the same place as in FIG. 5B.

[0011]

SUMMARY OF THE INVENTION A feature of the present invention is a bond.
A protecting pad, a protection circuit, and a predetermined circuit from the protection circuit.
Extends in width and has a connection part at the tip to provide the function of diffusion resistance
An impurity region having a conductivity type opposite to that of the substrate;
Conductive layer for electrically connecting a connecting pad and the connection portion
Oite the semiconductor device having the door, the metal conductor layer,
Crossing over the PN junction formed by the connection portion and the substrate
Without being connected to the connection portion, and from above the connection portion
The portion having the function of the resistor in the impurity region is formed by
The protection circuit does not cross over the PN junction formed by the substrate.
In a semiconductor device extending toward a road . Or
The features of the present invention include a bonding pad, a protection circuit,
The protective circuit is connected to the
With a part parallel to one side of the padding pad and connected to the tip
An impurity region having a conductivity type opposite to that of the substrate;
Metal for electrically connecting the bonding pad and the connection portion
A semiconductor device comprising: a conductive layer;
The layer traverses over the PN junction between the connection and the substrate
Without being connected to the connection and from above the connection
On the parallel portion of the impurity region, the portion and the substrate
To the protection circuit without traversing the PN junction
The semiconductor device has a portion that has been extended. This
In these semiconductor devices, the connection portion has the predetermined width.
Preferably, it has a wider width. Also, the metal
The conductor layer is a metal conductor below the bonding pad.
Can be

Another feature of the present invention is that the bonding
Head, a protection circuit, and a tip connected to the protection circuit.
A first impurity region having a connection portion and having a conductivity type opposite to that of the substrate;
And electrically connecting the bonding pad and the connection portion.
A semiconductor device comprising a metal conductor layer
The first impurity region is formed by folding a first portion and the first portion.
The second part, which is bent and provided with the connection portion at its tip,
The metal conductor layer is formed by the connection portion and the substrate.
Connected to the connection without traversing the joint,
From the connection portion to the second portion of the first impurity region
Crossing over the PN junction formed by the second part and the substrate.
And extending from the second portion to the first portion.
Over the first portion of the pure region, the first portion and the substrate
To the protection circuit without traversing the PN junction
The semiconductor device has an extended portion . This
Here, the connection portion is opposed to the connection portion of the first impurity region.
Form a second impurity region of the opposite conductivity type to the substrate at a distance from the substrate.
When a high voltage is applied to the bonding pad.
The generated charges are released through the second impurity region.
Preferably.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1A is a plan view showing a first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along a line AA in FIG. 1A. In both FIGS. 1A and 1B, parts having the same functions as those in FIGS. 5A and 5B used in the description of the related art are denoted by the same reference numerals.

FIG. 1 differs from the prior art in that aluminum 6 for connecting the protection circuit and the bonding pad is used.
a is at a position away from the connection with the protection circuit, N
The point is that it crosses the boundary of the impurity region 3 and then passes through the inside of the N-type impurity region 3 to reach the connection with the protection circuit.

By connecting the aluminum 6a to the protection circuit in this way, even if a high positive voltage is applied to the bonding pad and a large amount of heat is generated at the boundary of the N-type impurity region 3, the aluminum 6a remains in the portion. Is not present, so that there is no short circuit with the semiconductor substrate through the oxide film. Further, only the portion crossing the boundary portion of the N-type impurity region 3 is located at a position away from the connection portion with the protection circuit, and the heat generation amount is much smaller than the connection portion due to the function of the diffusion layer resistance. In this part, a short circuit with the semiconductor substrate is extremely unlikely to occur.

FIG. 2 is a plan view showing a second embodiment of the present invention. The difference from the first embodiment is that the bonding pad 11 is formed of a metal conductor layer higher than the aluminum 6a. It is a point. In FIG. 2, the aluminum 6a connected to the bonding pad by the contact hole 14 has the shape shown in the first embodiment.

FIG. 3A is a plan view showing a third embodiment of the present invention, and FIG. 3B is a sectional view taken along the line BB of FIG. 3A. The embodiment shown in FIGS. 3A and 3B shows a state in which the present invention is applied to a protection circuit having a different configuration from the protection circuit described so far. FIG. 3 (A),
In (B), two N-type impurity regions 3a and 3b
However, when a positive high voltage is applied to the bonding pad, a part of the charge is provided to face the N-type impurity region 3a. It is configured to peel off to the N-type impurity region 3b. Note that N-type impurity region 3b is fixed to the ground potential.

Also in the third embodiment, the portion of the boundary between the N-type impurity regions 3a close to the connection with the bonding pad is configured such that aluminum does not pass over the boundary, and heat is generated. Prevents aluminum from penetrating into the semiconductor substrate.

In the above description, a protection circuit formed on a P-type semiconductor substrate has been described. However, it is apparent that the present invention can be applied to a protection circuit formed on an N-type semiconductor substrate. Further, the configuration of the protection circuit is not limited to those described above.

[0021]

As described above, the present invention relates to a semiconductor device having an impurity region of a conductivity type opposite to that of a substrate in a part of a protection circuit connected to a bonding pad via a metal conductor layer. Forming a protection circuit in the vicinity of a connection portion between the bonding pad and the protection circuit such that the metal conductor layer does not pass over a portion which is a boundary between the impurity region of the opposite conductivity type to the substrate; This has the effect of preventing the metal conductor layer from penetrating into the semiconductor substrate due to heat generation at the boundary.

[Brief description of the drawings]

FIG. 1 is a plan view and a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a plan view showing a second embodiment of the present invention.

FIG. 3 is a plan view and a sectional view showing a third embodiment of the present invention.

FIG. 4 is a circuit diagram of a protection circuit.

FIG. 5 is a plan view and a cross-sectional view showing a conventional protection circuit.

FIG. 6 is a cross-sectional view of a conventional protection circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 P-type semiconductor substrate 2 P-type impurity region 3, 3a, 3b N-type impurity region 4 Oxide film 5a, 5b Polycrystalline silicon 6a, 6b Aluminum 11 Bonding pad 12 Diffusion layer resistance 13 Transistor 14 Contact hole 15 Short

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 27/04 H01L 21/3205 H01L 21/336 H01L 21/822 H01L 29/78

Claims (6)

(57) [Claims] 1. A bonding pad, a protection circuit, and
Extends a predetermined width from the protection circuit and provides a connection at the tip
With the function of diffusion resistance and opposite conductivity type to the substrate
Area, the bonding pad and the connection portion are electrically connected.
Placed in a semiconductor device having a metal conductor layer connected to
The metal conductor layer is formed by the connection portion and the substrate
Connected to the connection without crossing over the N-junction, and
From the top of the connection part,
Crossing over the PN junction formed by the portion and the substrate
A semiconductor device extending toward the protection circuit without using the semiconductor device. 2. A bonding pad, a protection circuit, and
Connected to the protection circuit and extends at a predetermined width to
Has a portion parallel to one side of the
An impurity region having a conductivity type opposite to that of the substrate;
Metal pad for electrically connecting the connecting pad to the connecting pad.
In the semiconductor device having a body layer, wherein the metal conductor layer
Crosses over the PN junction formed by the connection portion and the substrate
Connected to the connection part without and from above the connection part
On the parallel portion of the impurity region, the portion and the substrate are formed.
To the protection circuit without crossing over the PN junction
A semiconductor device having a portion extending through the semiconductor device. (3) The connecting portion has a width wider than the predetermined width.
3. The device according to claim 1, wherein
Semiconductor device. (4) The metal conductor layer is bonded to the bonding pad.
The metal conductor is a lower layer than the metal conductor.
The semiconductor device according to claim 1. (5) Bonding pad, protection circuit, front
With a substrate connected to the protection circuit
A first impurity region of the opposite conductivity type and the bonding pad;
And a metal conductor layer for electrically connecting the connection portion.
In the semiconductor device provided, the first impurity region is
Part 1 and bent from the first part to the front end
A second portion provided with the connection portion, wherein the metal conductor layer
Crosses over the joint between the connection portion and the substrate
Without being connected to the connection part, and
The second portion of the impurity region of FIG.
Extends and crosses over the PN junction of the plate
The second portion from above The first impurity region
Traverses over the PN junction between the first portion and the substrate
Without extending to the protection circuit
A semiconductor device comprising: 6. Facing the connecting portion of the first impurity region;
And a second impurity of a conductivity type opposite to the substrate at a distance from the connection portion.
Object area, and a high voltage is applied to the bonding pad.
Through the second impurity region.
The half according to claim 5, characterized in that it is made to escape.
Conductor device.