JPH08203953A - Structure of bonding pad part of semiconductor device - Google Patents

Abstract

PURPOSE: To improve resistance to electromigration, by forming a metal silicide layer between an upper wiring layer and a lower wiring layer, in a wiring layer constituted of two or more layers whose main component is aluminum. CONSTITUTION: An insulating film 110 is formed on a semiconductor substrate 100. A first aluminum layer 120 is formed. After the first aluminum layer 120 is worked into a desired wiring form, an interlayer insulating film 130 is formed. After sintering treatment, a metal silicide layer 150 and a second aluminum layer 160 are formed. The metal silicide layer 150 and the second aluminum layer 160 are formed by using a DC magnetron sputtering method or the like, similarly to the first aluminum layer 120. Thereby resistance to electromigration can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a bonding pad portion of a semiconductor device having a multilayer wiring of aluminum or an alloy mainly containing aluminum on the surface of a semiconductor substrate.

[0002]

2. Description of the Related Art As a wiring material of a semiconductor device made of a substrate material typified by silicon, an alloy mainly containing aluminum and containing silicon, boron, copper, palladium, titanium, scandium or the like is usually used. Hereinafter, these will be collectively referred to as "aluminum alloys". Further, a case where there are a plurality of aluminum wiring layers that connect elements that form a semiconductor device is referred to as “multilayer aluminum wiring”, and a case where the aluminum layer that forms one wiring layer is composed of two or more aluminum layers and / or a conductive layer. It is called "laminated aluminum wiring".

Conventionally, in a semiconductor device using a multilayer aluminum or aluminum alloy as wiring,
The bonding pad portion is formed by using two or more aluminum wiring layers. The following structure is considered as a technique for forming a bonding pad portion by using two or more aluminum layers. Second aluminum layer (upper layer) / metal layer / first aluminum layer (lower layer), second aluminum layer (upper layer) / first aluminum layer (lower layer) / metal silicide layer, second aluminum layer ( Upper layer) / titanium compound layer / first aluminum layer (lower layer), second aluminum layer (upper layer) / first aluminum layer (lower layer), second aluminum layer (upper layer) / polycrystalline silicon layer / first Is an aluminum layer (lower layer).

The above-mentioned conventional examples will be further described below.
First, as a structure of a bonding pad portion composed of a second aluminum layer / metal layer / first aluminum layer, which is a first conventional example, one disclosed in Japanese Patent Laid-Open No. 3-1539 is known. . 3 shows a cross section of this structure of FIG. An insulating film 210 is formed on the semiconductor substrate 200, and a first aluminum layer 220 and a metal layer 25 are formed on the insulating film 210.
0, the second aluminum layer 260 is laminated. Two
70 is a protective film. In this conventional example, vanadium is used as the metal layer 250 between the aluminum layers,
The vanadium layer 250 absorbs the impact when bonding the copper wire. Similarly, as the structure of the bonding pad portion having the metal layer 250 between the second aluminum layer 260 and the first aluminum layer 220, the first aluminum layer 220 and the nickel layer 25 are used.
A stack of 0 and the second aluminum layer 260 in this order is disclosed in JP-A-4-164332. This is intended to improve the adhesive strength between the copper wire and the bonding pad by alloying each layer by heat treatment.

As a structure of a bonding pad portion composed of a second aluminum layer / a first aluminum layer / a metal silicide layer, which is a second conventional example, Japanese Patent Laid-Open No. 297042/1992 has been proposed.
The one disclosed in Japanese Patent Publication is known. FIG. 4 shows a cross section of this structure. In this structure, an aluminum alloy layer containing copper is used as the first aluminum layer 320, and
A pure aluminum layer or an aluminum alloy layer containing silicon is used as the aluminum layer 360 of the above, and bonding is performed between the second aluminum layer 360, which is softer than the first aluminum layer 320, and the bonding wire. It is designed to improve the adhesive strength of the aluminum pad.

As a structure of a bonding pad portion composed of a second aluminum layer / titanium compound layer / first aluminum layer, which is a third conventional example, for example, Japanese Patent Laid-Open No. Hei 5-
The one disclosed in Japanese Patent No. 6915 is known. Figure 5
Shows the cross section of this structure. This structure includes a layer of pure aluminum or aluminum alloy as the second aluminum layer 460, a layer of titanium or titanium nitride as the titanium compound layer 450, and a layer of pure aluminum or aluminum alloy as the second aluminum layer 420. There is. This prior art is a laminated aluminum wiring structure in which a pure aluminum layer or an aluminum alloy layer having good adhesion to the underlying insulating film 410 of the bonding pad is provided between the titanium compound layer 450 having poor adhesion to the underlying insulating film. This prevents the interlayer insulation between the underlying insulating film 410 and the bonding pad due to stress during wire bonding.

FIG. 6 shows a structural cross section of a multilayer aluminum wiring bonding pad portion constituted by a second aluminum layer / first aluminum layer which is a fourth conventional example. This structure is known, for example, from Japanese Patent Application Laid-Open No. 61-80836, and it is intended to improve the processing accuracy of the bonding pad portion without using at least one layer of the three layers of aluminum wiring as a bonding pad. Also, an aluminum alloy having good bondability is used for the second aluminum layer 560, and
By forming a bonding pad portion using an aluminum alloy layer 20 having a high corrosion resistance or an aluminum alloy layer having a high electromigration resistance, a structure for improving bondability and moisture resistance or electromigration resistance is formed. It is known from JP-A-62-195149 and JP-A-3-284847. Further, as a structure having a second aluminum layer / first aluminum layer as a constituent element in a bonding pad portion, there is a conventional technique for preventing scratches on a prober or the like and intrusion of water, as disclosed in Japanese Patent Laid-Open No. 62-242333. A conventional technique for reducing the impact at the time of bonding the bonding wire and the damage due to the thermal strain of the mold resin etc. after bonding is disclosed in Japanese Patent Laid-Open No. 2-8.
It is known from Japanese Patent No. 4733.

Further, FIG. 7 shows a structural cross section of a multilayer aluminum wiring bonding pad portion constituted by a second aluminum layer / polycrystalline silicon layer / first aluminum layer which is a fifth conventional example. This structure is known, for example, from Japanese Patent Laid-Open No. 3-24731, and the semiconductor substrate 600, the insulating film 610, the first aluminum layer 620,
It is composed of a polycrystalline silicon layer 650, an interlayer insulating film 630, a second aluminum layer 660 and a protective film 670. In this structure, since the polycrystalline silicon layer 650 reduces the impact of wire bonding, it is possible to easily bond a wire having high hardness such as a copper wire.

[0009]

However, the above-mentioned conventional examples have the following problems.

First, in the structure of the bonding pad portion composed of the second aluminum layer / metal layer / first aluminum layer, which is the first conventional example, the metal layer located in the middle of both aluminum layers is , To react with silicon mixed in the first aluminum layer to prevent alloy pits generated at the contact portion between the first aluminum layer and the diffusion layer of the semiconductor substrate, and absorb the silicon to form a silicide. The silicon content in the first aluminum layer decreases and the silicon content in the first aluminum layer falls below its solid solubility. This causes alloy pits in the silicon substrate at the contact portion between the first aluminum layer and the diffusion layer formed in the silicon substrate. Further, in order to prevent such alloy pits from being generated, it is conceivable to excessively mix silicon for the reaction of silicidation into the first aluminum layer in advance. However, excess silicon reacts with the metal layer. Prior to silicidation, a high-resistance silicon mass is deposited by solid-phase epitaxial growth at the interface between the first aluminum layer and the diffusion layer, which causes an initial failure such as contact failure and is not preferable.

In the structure of the bonding pad portion composed of the second aluminum layer / first aluminum layer / metal silicide layer, which is the second conventional example, there is a problem that electromigration resistance is deteriorated due to the crystal structure of the aluminum film. There is a point. That is, in the semiconductor device having such a structure, the second aluminum layer is formed in order to secure the continuity of the contact between the wiring formed by the first aluminum layer and the wiring formed by the second aluminum layer. As a pre-treatment before the etching, it is necessary to carry out sputtering etching using plasma of an inert gas, generally argon gas. This is to remove the aluminum oxide film, which is an insulator formed on the surface of the first aluminum layer, after forming the first aluminum layer and before forming the second aluminum layer. By this sputtering etching pretreatment, the aluminum oxide film on the surface of the first aluminum layer is removed, so that the aluminum crystal grains that form the second aluminum layer are different from the aluminum crystal grains that form the first aluminum layer. It is formed continuously. As a result, the aluminum crystal grains that form the bonding pad become columnar crystals in the thickness direction. In such an aluminum layer in which the grain boundaries of the aluminum crystal grains cross the aluminum layer from the surface to the aluminum / insulating film interface, when voids are formed by the electromigration phenomenon, the voids grow along the grain boundaries. Therefore, since the aluminum layer grows until it is broken, there is a problem that electromigration resistance is lowered.

In the structure of the bonding pad portion composed of the second aluminum layer / titanium compound layer / first aluminum layer which is the third conventional example, when metal titanium is used as the titanium compound, the metal layer is Similar to the case of the first conventional example used as the intermediate layer, a problem occurs due to alloy pits or silicon solid phase epitaxial growth. When the titanium nitride layer is used as a single layer as the intermediate layer, nitrogen in the titanium nitride layer nitrides the aluminum layer to form an aluminum nitride layer as an insulator. This aluminum nitride layer is apt to cause an increase in wiring resistance and an increase in contact resistance, which is one of the causes of defects. In order to prevent such nitridation of the aluminum layer, also in the case of a laminated structure in which a titanium metal layer is formed below the titanium nitride layer as an intermediate layer, alloy pits or A defect due to silicon solid phase epitaxial growth becomes a problem.

In the structure of the bonding pad portion constituted by the second aluminum layer / first aluminum layer of the fourth conventional example, the second aluminum layer / first aluminum of the second conventional example is used. As in the case of the bonding pad structure composed of the layer / metal silicide layer, the aluminum crystal grains forming the first aluminum layer and the aluminum crystal grains forming the second aluminum layer are continuously formed, The aluminum crystal grains forming the bonding pad become columnar crystals in the thickness direction, which causes a problem of low electromigration resistance. Further, in the structure in which the bonding pad portion is formed by using an aluminum alloy having good bondability for the second aluminum layer and an aluminum alloy layer having high corrosion resistance or an aluminum alloy layer having high electromigration resistance for the first aluminum layer, In addition to the above problem, the element such as copper added to the first aluminum layer diffuses when forming the second aluminum layer, and as a result, the hardness of the second aluminum layer increases and the bondability deteriorates. There is a problem. In FIG. 8, an aluminum alloy containing 1% silicon having good bondability is used for the second aluminum layer, and an aluminum alloy layer containing 0.5% copper + 1% silicon having high electromigration resistance is used for the first aluminum layer. The element distribution in the depth direction of the sample in which the bonding pad portion is formed is shown. This analysis is performed by Auger electron spectroscopy (AES method). From this figure, it can be seen that since copper has diffused to the upper second aluminum layer, the hardness of the second aluminum layer becomes high and bondability deteriorates.

Next, in the structure of the bonding pad portion composed of the second aluminum layer / polycrystalline silicon layer / first aluminum layer, which is the fifth conventional example, the polycrystalline layer formed in the middle of the aluminum layer is used. Since the silicon layer causes the resistance of the aluminum wiring to increase, problems such as increase in power consumption of the semiconductor device occur. This is because impurities that require a substrate temperature higher than the melting point of aluminum cannot be activated on the aluminum layer, so that the resistivity of the polycrystalline silicon layer cannot be sufficiently lowered.

The present invention has been made by paying attention to the above-mentioned conventional problems, and improves the electromigration resistance, the corrosion resistance and the stress migration resistance, and reduces the resistance value. An object of the present invention is to provide a structure of a bonding pad portion of a semiconductor device which can improve bond strength at the time of bonding and improve bondability.

[0016]

In order to solve the above-mentioned problems, the invention according to claim 1 has a structure of a bonding pad portion of a semiconductor device having two or more aluminum-based wiring layers, and the two or more layers are provided. The gist is that a metal silicide layer is formed between an upper wiring layer and a lower wiring layer in the aluminum-based wiring layer.

According to a second aspect of the invention, in the structure of the bonding pad portion of the semiconductor device according to the first aspect,
The gist is that the metal silicide layer is a tungsten silicide.

According to a third aspect of the present invention, in the structure of the bonding pad portion of the semiconductor device according to the first or second aspect, the wiring layer is composed mainly of aluminum and at least silicon, copper, palladium, titanium, scandium or boron. The gist is to be made of an alloy containing any element.

According to a fourth aspect of the invention, in the structure of the bonding pad portion of the semiconductor device according to the first aspect,
The upper wiring layer is made of either pure aluminum or an alloy mainly containing aluminum, and the lower wiring layer is mainly made of aluminum being an alloy containing silicon and at least one element of copper, palladium, titanium or scandium. Is the gist.

[0020]

In the invention of claim 1, the upper wiring layer is formed by sputtering etching with an inert gas by forming a conductor layer made of a metal silicide between the upper wiring layer and the lower wiring layer mainly composed of aluminum. The aluminum crystal grains and the aluminum crystal grains forming the lower wiring layer can be discontinuous in the thickness direction. As a result, it is possible to prevent the aluminum layer from being cut due to the voids generated by the electromigration phenomenon becoming independent in the lower wiring layer and the upper wiring layer and being continuous in the thickness direction, thereby improving the electromigration resistance. Is possible. Further, although silicon is usually mixed in aluminum of the lower wiring layer, since the metal silicide layer does not absorb the silicon in the lower wiring layer, alloy pits are not formed on the silicon substrate. Therefore, it is not necessary to add an excessive amount of silicon to the lower wiring layer in order to prevent the generation of alloy pits, and therefore no conduction failure due to solid phase epitaxial growth of silicon occurs. Normally, it is considered that such a problem does not occur because a contact to the silicon substrate is not formed immediately below the bonding pad portion. However, it is considered that such a problem does not occur. Since defects occur in the contact portion, such alloy pits and non-conductivity of the contact portion are also important problems. Furthermore, since the metal silicide has a resistivity of 10 to 100 μΩ · cm, which is lower than the resistivity (1000 μΩ · cm or more) of polycrystalline silicon or the like, bonding is performed as compared with the case where the conductor layer is formed of polycrystalline silicon or the like. It is possible to reduce the resistance of the pad portion, which is effective in reducing the power consumption of the semiconductor device and improving the operation speed. In particular, it is effective in the bonding pad portion of the power semiconductor device that handles high current.

According to the second aspect of the present invention, the metal silicide layer is made of tungsten silicide (WSi ₂ ), whereby the formation of a compound by the reaction with the wiring layer mainly containing aluminum and the increase in the resistance of the wiring layer due to the compound. It becomes possible to suppress. This is WSi ₂ , MoSi ₂ , TiSi which is a metal silicide generally used for semiconductor devices.
_This is because the reaction temperature between W and aluminum is 650 ° C., which is higher than 450 ° C. for Ti and 460 ° C. for Mo, among the elements constituting _2, etc.

In a third aspect of the present invention, the wiring layer forming the bonding pad portion is made of an alloy mainly containing aluminum and containing at least one element of silicon, copper, palladium, titanium, scandium or boron. This makes it possible to improve electromigration resistance, stress migration resistance or corrosion resistance.

In the invention of claim 4, the upper wiring layer is made of pure aluminum or an alloy mainly containing aluminum, and the lower wiring layer is mainly aluminum and at least one of copper, palladium, titanium or scandium. When an alloy containing an element and silicon is used, the metal silicide layer prevents diffusion of an additive element such as copper contained in the lower wiring layer into the upper wiring layer, and the hardness of the upper wiring layer does not increase. Therefore, the bonding strength at the time of bonding is increased and the bondability is improved.

[0024]

EXAMPLE An example of the present invention will be described below with reference to FIG. The insulating film 110 is formed on the semiconductor substrate 100. As the insulating film 110, a PSG film formed by a CVD method, B
A PSG film or the like is used. Next, the first aluminum layer 120 is formed. The first aluminum layer is 1
It is general to form aluminum containing about wt% of silicon by a DC magnetron sputtering method or the like. Also, it can be formed by an EB vapor deposition method, a CVD method, or the like. In this case, electromigration resistance, stress migration resistance, and corrosion resistance can be improved by adding copper, palladium, titanium, scandium, boron or the like to the first aluminum layer in addition to silicon. After processing the first aluminum layer 120 into a desired wiring shape through a photolithography process and an etching process, an interlayer insulating film 130 is formed to insulate the first aluminum layer 120 and the second aluminum layer 160. This interlayer insulating film 1
Although 30 may be a single-layer insulating film formed by the CVD method, the silicon oxide film 131 may be used in order to improve the coverage in the step portion of the second aluminum layer 160 by planarizing the inside of the semiconductor device. , SOG coating film 132, and silicon oxide film 133 are preferable. As the silicon oxide films 131 and 133, a PSG film formed by a CVD method, an O ₃ -TEOS film,
A P-TEOS film or the like formed by the plasma CVD method can be used. Furthermore, as the SOG coating film 132, an inorganic SOG film, an organic SOG film, or the like can be used.

Next, after forming a contact portion through a photolithography process and a silicon oxide film etching process, sintering heat treatment is performed. For the purpose of improving the electrical characteristics of a transistor portion or the like formed on the semiconductor substrate 100 in advance, it is desirable to perform sintering with hydrogen or a gas containing hydrogen. In addition, the interlayer insulating film 130
When a three-layer film is used as this, this sintering treatment is contained in the SOG film 132 exposed in the contact opening portion and deteriorates the film quality of the aluminum layer, or causes moisture, organic gas, etc. It also has the role of discharging.

After the sintering treatment, the metal silicide layer 15
0 and a second aluminum layer 160 is formed. These metal silicide layer 150 and second aluminum layer 160
Similarly, the first aluminum layer is formed by using the DC magnetron sputtering method or the like. At this time, it is desirable that the metal silicide layer 150 and the second aluminum layer 160 be continuously formed in a vacuum so that an insulating oxide film is not formed between the layers. Also, the metal silicide layer 150
As a film forming pretreatment, the aluminum oxide film formed on the surface of the first aluminum layer 120 is treated with an inert gas,
For example, it is desirable to remove it by etching using plasma such as argon or xenon.

As the second aluminum layer 160, an aluminum layer containing about 1% by weight of silicon is generally formed. However, in addition to silicon, copper, palladium, titanium, scandium, boron or the like is used. By adding, electromigration resistance, stress migration resistance, and corrosion resistance can be improved. However, when importance is attached to the adhesion strength at the time of bonding, it is preferable to use a soft pure aluminum layer or an aluminum layer containing about 1% by weight of silicon as the second aluminum layer 160. Now, as an example, the second aluminum layer 160 is provided with an aluminum alloy containing 1% silicon and a metal silicide layer 15 having good bondability.
0 is a tungsten silicide layer and the first aluminum layer 120 is an aluminum alloy layer containing 0.5% of copper and 1% of silicon having high electromigration resistance, and the depth of the bonding pad is measured by Auger electron spectroscopy (AES method). The element distribution in the direction is shown in FIG.
As shown in this figure, the second aluminum layer 1
It can be seen that the copper in 60 is below the noise level and has not diffused from the first aluminum layer 120. Therefore, by forming the metal silicide layer 150 between the first aluminum layer 120 and the second aluminum layer 160, the hardness of the second aluminum layer 160 can be kept low, and thus the bonding wire and the bonding wire can be bonded. The adhesion strength of the pad portion does not decrease.

After the formation of the second aluminum layer, a photolithography process and an etching process of the second aluminum layer 160 are carried out to process the second aluminum layer into a desired shape, and then the sintering is carried out if necessary. Perform heat treatment. Then, as the protective film 170, a PSG film, a plasma SiN film, or a composite film of these is formed by using the CVD method. In order to perform wire bonding, the protective film 170 is subjected to a photolithography process and a protective film etching process to form an opening portion for wire bonding.

The specific embodiments have been described above, but the present invention is not limited to the above embodiments, and the following items (1) to (4) can be applied. The first aluminum layer is a laminated film structure on which a titanium compound such as titanium, titanium silicide, or titanium nitride or a composite film of these is used as an underlayer in order to improve contact resistance with a diffusion layer forming a transistor or the like on a semiconductor device. Also good.
Although the embodiments have been described with respect to the semiconductor device having the two-layer aluminum wiring layer, the present invention can be applied to the semiconductor device having three or more layers of aluminum wiring layers. Regarding wire bonding, aluminum wires can be used in addition to gold wires.

[0030]

As described above, according to the invention of claim 1, since the metal silicide layer is formed between the upper wiring layer and the lower wiring layer in the two or more aluminum-based wiring layers, the upper layer is formed. The aluminum crystal grains forming the wiring layer and the aluminum crystal grains forming the lower wiring layer can be discontinuous in the thickness direction. Therefore, voids generated by electromigration are independently formed in the upper wiring layer and the lower wiring layer, the upper and lower aluminum layers are not simultaneously cut at the same place, and the electromigration resistance can be improved. When silicon is contained in the aluminum of the lower wiring layer, the metal silicide layer does not absorb the silicon in the aluminum, so that alloy pits are not formed in the silicon substrate. Therefore, it is not necessary to add an excessive amount of silicon to the aluminum layer in order to prevent the generation of alloy pits, and therefore conduction failure due to solid phase epitaxial growth of silicon does not occur. Since the metal silicide has a resistivity of 10 to 100 μΩ · cm, which is lower than the resistivity of polycrystalline silicon (1000 μΩ · cm or more), the bonding pad portion is different from the case where the conductor layer is formed of polycrystalline silicon or the like. It is possible to reduce the resistance, and it is particularly effective in reducing the power consumption and improving the operating speed of the power semiconductor device that handles a high current. Since two or more aluminum layers are used for the bonding pad portion, even if each wiring layer is formed by a relatively thin aluminum layer that can be patterned by dry etching capable of fine processing, the total number of layers can be increased by forming a multilayer structure. Since it is possible to secure the thickness of the aluminum layer, it is possible to suppress the current density to a low level, and it is possible to improve both electromigration resistance and fine workability. Since the bonding pad portion is thick, damage during wire bonding can be reduced. In particular, the structure in which the metal silicide layer is sandwiched between the upper and lower aluminum layers causes silicon precipitation to occur independently in the upper aluminum layer and the lower aluminum layer. It is possible to make the silicon deposition smaller than that in the case of 1., and the deposited silicon blocks pushed by the bonding wire during wire bonding do not cause cracks in the insulating film such as the silicon oxide film underlying the bonding pad. Since the metal silicide layer suppresses the infiltration of moisture from the outside of the bonding pad, it is possible to suppress the occurrence of the disconnection failure due to the progress of corrosion even to the lower aluminum wiring. Even when a scratch is generated when the probe inspection is performed in the inspection of the semiconductor device, the metal silicide layer can suppress the progress of corrosion due to the infiltration of water due to the scratch as described above, and The damage can be reduced. Furthermore, when the SOG film is used as the interlayer insulating film for the upper and lower wiring layers, the metal silicide layer having higher corrosion resistance than aluminum is
In order to prevent the SOG film from directly contacting the exposed portion of the SOG film in the bonding pad portion, it is possible to prevent the aluminum layer from being corroded by impurities or water contained in the SOG film. it can.

According to the inventions described in claims 2 to 4, in addition to the effects of the invention described in claim 1, there are the following effects.

According to the second aspect of the present invention, since the metal silicide layer is made of tungsten silicide, a compound is formed by a reaction with the upper and lower wiring layers mainly composed of aluminum, and the resistance of the bonding pad portion is increased by the compound. Can be suppressed. This is tungsten silicide (WS) which is a metal silicide generally used in semiconductor devices.
i ₂ ), molybdenum silicide (MoSi ₂ ), titanium silicide (TiSi ₂ ), and the like, the reaction temperature of W and aluminum is 650 ° C., and that of Ti is 450 ° C. or Mo.
This is because the temperature is higher than 460 ° C.

According to the third aspect of the present invention, the wiring layer is an alloy mainly containing aluminum and containing at least one element of silicon, copper, palladium, titanium, scandium or boron. In addition to the property, the resistance to stress migration can be further improved.

According to the fourth aspect of the present invention, the upper wiring layer is made of pure aluminum or an alloy mainly containing aluminum, and the lower wiring layer is mainly made of aluminum of copper, palladium, titanium or scandium. Since the alloy contains at least one of the elements and silicon, the metal silicide layer can suppress the diffusion of additional elements such as copper contained in the lower aluminum into the upper aluminum and keep the hardness of the upper wiring layer low. it can. Therefore, the adhesion strength at the time of bonding can be improved and the bondability can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a structure of a bonding pad portion of a semiconductor device according to the present invention.

FIG. 2 is a diagram showing an element distribution in a depth direction by Auger electron spectroscopy in the above-mentioned example.

FIG. 3 is a vertical cross-sectional view showing a first conventional example of a structure of a bonding pad portion of a semiconductor device.

FIG. 4 is a vertical sectional view showing a second conventional example.

FIG. 5 is a vertical cross-sectional view showing a third conventional example.

FIG. 6 is a vertical sectional view showing a fourth conventional example.

FIG. 7 is a vertical sectional view showing a fifth conventional example.

FIG. 8 is a diagram showing an element distribution in a depth direction by Auger electron spectroscopy of the fourth conventional example.

[Explanation of symbols]

 100 semiconductor substrate 110 insulating film 120 first aluminum layer (lower wiring layer) 130 interlayer insulating film 150 metal silicide layer 160 second aluminum layer (upper wiring layer)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number for FI Technical indication H01L 21/3205 21/321 9169-4M H01L 21/92 602 J

Claims (4)

[Claims] 1. A structure of a bonding pad portion of a semiconductor device having two or more aluminum-based wiring layers, wherein a metal silicide is provided between an upper wiring layer and a lower wiring layer in the two or more aluminum-based wiring layers. A structure of a bonding pad portion of a semiconductor device, which is characterized by forming layers. 2. The structure of a bonding pad portion of a semiconductor device according to claim 1, wherein the metal silicide layer is tungsten silicide. 3. The semiconductor device according to claim 1, wherein the wiring layer is made of an alloy mainly containing aluminum and containing at least any one element of silicon, copper, palladium, titanium, scandium and boron. Bonding pad structure. 4. The upper wiring layer is made of pure aluminum or an alloy mainly containing aluminum, and the lower wiring layer mainly contains aluminum and at least one element of copper, palladium, titanium or scandium and silicon. The structure of a bonding pad portion of a semiconductor device according to claim 1, wherein the structure is made of an alloy containing the same.