JPH11135533A - Electrode structure, silicon semiconductor element provided with the electrode, its manufacture, circuit board mounting the element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form a solder bump by completely covering the whole exposed surface of a first metal layer making ohmic junction with a silicon semiconductor with a second metal layer whose corrosion resistance against organic acid is higher and solder wettability is higher than the metal of the first metal layer. SOLUTION: The first metal layer 2 is formed on the face of the silicon semiconductor element 1 in prescribed thickness. Then, the second metal layer 3 is stacked in prescribed thickness so that the whole exposed surface of the first metal layer 2 is covered with it. Metal making ohmic junction with the silicon substrate is selected as metal used for the first metal layer 2 in electrode structure. Higher corrosion resistance against organic acid than the metal of the first metal layer 2, satisfactory solder wettability and satisfactory adhesive strength with the silicon semiconductor 1 and the first metal layer 2 are required as the selection reference of metal used for the second metal layer 3. Thus, the thickness of solder is easily controlled, bonding height can be taken to be large and heat resistance can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode structure for a silicon semiconductor device, an electrode having the structure, which can be directly connected to and mounted on a circuit board without using a bonding wire. Height between (bonding height)
TECHNICAL FIELD The present invention relates to a silicon semiconductor element capable of obtaining a large amount, a method of manufacturing the same, a circuit board having the same mounted, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, equipment of almost all fields, regardless of the manufacturing department, administrative department, transportation or home of a company,
Machines and appliances are being digitized, and the range and types of electronic components used are becoming wider.
In such a wide variety of computerization, mounted circuit boards on which electronic control semiconductor elements are set have been extremely widely used, and the applicable range, types and number of used circuit boards have been remarkably increasing.

[0003] Many types of such semiconductor-mounted circuit boards are generally put into practical use. In particular, electronic devices in which various semiconductor elements (ICs, various bumps, etc.) are directly mounted on the circuit board are used. The rate of adoption for the purpose of miniaturizing equipment and improving reliability is increasing. Thus, when mounting various semiconductor elements on a circuit board,
It is considered necessary or desirable to provide a certain amount of space (usually 50 to 100 μm) between the circuit board and the semiconductor element for injecting the sealing resin or as a buffer against heat generation. .

Many proposals have been made to provide this space (hereinafter, this space may be referred to as "bonding height"). For example, a method of connecting a circuit portion on a printed board and an electrode of an element component with a conductive adhesive,
A method of connecting the circuit part on the printed board and the element by melting solder bumps formed on the element side by plating, plating copper to the required height on the board electrode on the printed board and the element electrode of the semiconductor element, Further, after Au plating, a method of connecting the same with eutectic solder, a method of connecting with Au ball bumps (stud bumps), a method of connecting with conductive polymer bumps, a method of connecting Au plated resin balls,
There are a microcapsule anisotropic conductive film connection method using an insulating resin ball as a core, and a microcapsule type anisotropic conductive film connection method using a metal ball as a core.
In addition to the above, there is an Au ball bump direct connection method and the like. However, this method is expensive and is limited to the use of a special circuit board.

Conventionally known methods for securing these bonding heights have the problem that when a relatively high-resistance conductive material such as a conductive resin is used for connection, the connection resistance is large. When connecting using a solder plating substrate that has been performed in a typical way, it is performed to activate the electrode on the semiconductor element side,
The process is complicated, the spreadability of the solder is poor, the bonding height is not uniform, and the connection reliability of the semiconductor element is low. Therefore, the connection of the silicon semiconductor element to the circuit board is highly reliable,
There is a need for a means for forming a solder bump on a silicon semiconductor device that has a low connection resistance and allows the bonding height to be freely selected.

[0006]

According to the present invention, a solder bump (in the present invention, a solder layer of 50 to 100 microns or more on a silicon semiconductor provided with an electrode is referred to as a "solder bump"). Of an electrode structure for a silicon semiconductor device that can be directly connected to a circuit board without using a bonding wire, high reliability, low contact resistance, and a method of manufacturing the same. Provided is a solder-coated silicon semiconductor device capable of freely selecting a bonding height and a method for manufacturing the same, and an electrode structure capable of easily forming a solder bump on a connection portion (electrode portion) to freely select a bonding height, and the like. It is intended to provide a manufacturing method.

[0007]

According to the present invention, there is provided [1] a first metal layer provided on a silicon semiconductor surface and forming an ohmic junction with a silicon semiconductor, and a completely exposed surface of the first metal layer. A second metal layer laminated so as to cover the first metal layer, the metal of the second metal layer has higher corrosion resistance to organic acids and better solder wettability than the metal of the first metal layer. An electrode structure of a silicon semiconductor element comprising

[2] The first metal layer is made of Cu, Al,
The second metal layer is made of one of Ti, W, and an Al-based alloy, and the second metal layer is one of Cu, Ni, or Au (a metal different from Cu when the metal of the first metal layer is Cu). [3] Ni or Cr between the first metal layer and the second metal layer (however, when the second metal layer is Ni, the electrode structure is limited to Cr) ) Wherein the intermediate metal layer completely covers the entire exposed surface of the first metal layer, and the second metal layer completely covers the entire exposed surface of the intermediate metal layer. The electrode structure according to [1] or [2], [4] wherein the entire exposed surface of the second metal layer excluding a predetermined area is shielded by an insulator.
The electrode structure according to any one of [3],

[5] A silicon semiconductor substrate, a first metal layer provided on the silicon semiconductor substrate and forming an ohmic junction with the silicon semiconductor, and laminated so as to completely cover all exposed surfaces of the first metal layer. A second metal layer having higher corrosion resistance to an organic acid than the first metal and having better solder wettability, and a solder bump mounted on a surface of a predetermined range of the second metal layer. Solder-coated silicon semiconductor devices,

[6] A first metal layer is laminated on a silicon substrate, a second metal layer is laminated so as to completely cover all exposed surfaces of the first metal layer, and then the second metal layer is laminated. After coating the entire surface of the layer with the coating material, a predetermined portion of the coating material is etched away to open a window in a predetermined area on the surface of the second metal layer, and then the second metal layer of the window portion is formed. A method for manufacturing a solder-coated silicon semiconductor element, which comprises selectively imparting adhesiveness to the adhesive portion, attaching solder powder to the adhesive portion, and heating and melting the solder powder.

[7] A circuit board in which a solder-attached silicon semiconductor element and a solder-attached circuit board are mounted with the solder mounting portions overlapped with each other.

[8] Adhesiveness is selectively imparted to the exposed metal portion of the circuit board, and solder powder is adhered to the adhesive section, and then the solder powder is heated and melted to obtain a solder-coated circuit board. A method of manufacturing a circuit board, comprising: laminating a solder bump of a solder-bonded silicon semiconductor element on a solder bump, melting and joining the gap, and filling a gap between the two with an insulating resin for sealing, and [9] a solder-bonded circuit board The above object has been achieved by developing the method for manufacturing a circuit board according to the above [8], wherein the solder used for each solder bump of the solder-coated silicon semiconductor element has a different melting point.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The electrode structure of a silicon semiconductor device of the present invention comprises a first metal layer which is in ohmic contact on the side in contact with a semiconductor, and an organic acid on the side on which a solder layer is mounted. Since the second metal layer made of a metal having high corrosion resistance and good solder wettability was used, and all the exposed surfaces of the first metal layer were completely covered,
A highly reliable electrode structure with good contact between the semiconductor and the electrode, easy mounting of the solder layer, high corrosion resistance to a flux containing an organic acid and the like. In addition, since the solder-coated silicon semiconductor element in which solder is mounted on the electrode structure imparts adhesiveness to the portion on which the solder is mounted and adheres the solder powder, the thickness of the solder layer is changed by changing the particle size of the solder powder to be adhered. Can be easily controlled, and the height of the bonding can be freely selected. In addition, since the solder-coated silicon semiconductor device of the present invention can be directly connected to a solder-coated circuit board or the like, the connection resistance is low, the reliability is high, and the size can be reduced. In the present invention, it is also possible to easily control the thickness of the solder layer by imparting adhesiveness to the connection portion and attaching a solder powder to the semiconductor element having the electrode structure of the present invention. The adjustment of the bonding height can be easily performed.

Other objects and features of the present invention will become apparent from the following detailed description with reference to the accompanying drawings. In the electrode structure of the present invention, as shown in FIG. 1, a first metal layer 2 is formed on a surface of a silicon semiconductor device 1 to a predetermined thickness by a vacuum deposition method, a sputtering method, or the like. The second metal layer 3 is laminated to a predetermined thickness so as to completely cover the entire exposed surface of the second metal layer 3. The first of the above electrode structures
As the metal used for the metal layer 2, a metal that forms an ohmic junction with the silicon substrate 1 is selected. Examples of the metal forming an ohmic junction with silicon include Al- containing 95% or more, preferably 97% or more of Al, Cu, Ti, W and Al.
Al-based alloys such as Si, Al-Ti, and Al-W are mentioned. After forming any layer of these first metals on a silicon semiconductor element, ohmic contact is performed by heat treatment. When an Al-based alloy is used, the thermal expansion coefficient is close to that of silicon.

The first metal layer 2 is covered with a second metal so as to completely cover all exposed surfaces of the layer. The selection criteria for the metal used for the second metal layer 3 are as follows:
It has higher corrosion resistance to organic acids than the metal of the metal layer, good solder wettability,
Should have good adhesion to the metal layer. Specifically, Cu, Ni, and Au are mentioned, and when Cu is used as the metal of the first metal layer, Cu different from the first metal is used.
Use other metals. The selection of the metal of the second metal layer can be determined in consideration of compatibility with the brazing material used when mounting the semiconductor element on the circuit board and adhesion to the silicon substrate and the first metal layer. preferable. The second metal layer 3 is formed so as to completely cover the first metal layer 2 by a vacuum deposition method, a sputtering method, a plating method, or the like.
Configure the electrodes.

The electrode formed on the surface of the semiconductor 1 is basically composed of the first metal layer 2 and the second metal layer 3 as described above, but as shown in FIG. Metal layer and second
It is preferable to provide an intermediate metal layer 4 of Ni or Cr (but limited to Cr when the second metal layer is Ni) between the metal layers. This intermediate metal layer 4 is
Is laminated so as to completely cover the second metal layer 3.
Are laminated so as to completely cover the intermediate metal layer 4. The intermediate metal layer 4 has an effect of improving the strength of the second metal layer 3 as a surface electrode.

Next, a description will be given of a solder-coated silicon semiconductor element in which a solder layer (solder bump) having a thickness of 50 to 100 μm or more is mounted on the silicon semiconductor element having the above-mentioned electrode structure. After an electrode is formed on one surface of the silicon semiconductor device 1 as shown in FIG. 1, the entire exposed surface of this semiconductor is shielded by an insulator 5 such as SiO ₂ , Si ₃ N ₄ , glass, polyimide [FIG. )]. Next, in the insulator layer 5 covering the electrode structure, the insulator at a predetermined position is removed by a conventional method or a mask is used as shown in FIG.
As shown in FIG. 4B, a window is opened, and only the metal circuit exposed portion (the second metal layer) of the window is selectively provided with adhesiveness. 4) After the solder powder 7 is adhered as shown in FIG.
A solder bump 8 is formed as shown in FIG. In particular, in the present invention, in order to form a thick solder layer (solder bump) having a thickness of 50 to 100 microns or more, a semiconductor provided with an electrode having a structure in which a first metal layer is covered with a second metal layer. After covering the element with a resist material, the resist material is etched by a usual method to expose a metal electrode (second metal layer), selectively imparting tackiness to the exposed metal portion, and In the case where a solder bump is formed by adhering and melting solder powder, it is effective that the depth of the resist material constituting the window is at least 10 microns.

In order to impart tackiness to only the above-mentioned exposed metal parts, a naphthotriazole-based derivative, benzotriazole-based derivative, imidazole-based derivative, benzimidazole-based derivative, mercaptobenzothiazole-based derivative and benzothiazolethiofatty acid-based derivative can be used. It is carried out by immersing in an aqueous solution containing at least one of the above or by applying an aqueous solution. (USP 5,556,0
No. 23, US Pat. No. 5,713,997)

The condition at this time is, for example, a processing temperature of 30.
The treatment is performed at 、 60 ° C. for 5 seconds to 5 minutes. The concentration of the treatment agent is 0.05 to 20% by weight of at least one of naphthotriazole derivatives, benzotriazole derivatives, imidazole derivatives, benzimidazole derivatives, mercaptobenzothiazole derivatives and benzothiazole thiofatty acid derivatives. In particular, it is preferable to use a solder tackifying liquid containing 50 to 1000 ppm of copper ions and being a slightly acidic liquid. Although the tackifying liquid in this case is relatively stable, it has a strong corrosive property against Al and the like used for the first metal layer, and there is a great risk of side-etching the electrode. However, when the coating is imperfect, the defect rate increases even without side etching, so that it is necessary to completely cover the second metal layer as described above.

As described above, after the entire electrode of the semiconductor element is completely shielded by the insulator, the window is opened, and then the adhesive is selectively applied to the second metal layer in the window portion. The feature of the method of applying the solder powder is that not only does it not require troublesome operations such as positioning, but also can easily apply the solder powder automatically. According to this method, not only is the thickness of the solder layer obtained by one treatment thick, but also the solder layer can be easily adhered thereon, and by selecting the particle size of the solder powder, The thickness can be freely adjusted. Further, while it is difficult to increase the thickness in the conventional plating method, etc., in the method of the present invention, when the required solder bump thickness cannot be ensured in one process, the solder powder is removed. Once the attached semiconductor element is heated and melted once, the solder coated part is again provided with tackiness in the same process, solder powder is adhered here, and heated and melted to increase the thickness of the solder bump layer. It can be done easily.

In the above description, a method of forming solder bumps on a semiconductor element has been described. If necessary, the same processing is performed on a circuit board on which the semiconductor element is mounted, and Similarly, a circuit board having a sufficiently large bonding height can be formed by forming a solder bump on the connection portion and joining the semiconductor element on which the solder bump has been formed and the solder bumps of the circuit board. In the circuit board on which the semiconductor element is mounted as described above, the gap between the element and the substrate is filled with a sealing insulating resin as necessary. For example, if the bonding height is 50-100
When manufacturing a micron circuit board, the height of the bump on the semiconductor element side (the height of the electrode + the height of the solder bump)
However, if the bump height on the circuit board side is set to 30 to 100 microns and the solder height is set to 30 to 100 microns, a bonding height of 50 to 100 microns can be secured even if both solder layers are melted and connected.

In this case, it is advantageous to slightly change the composition of the solder powder on the semiconductor element side and the composition of the solder powder on the circuit board side and to change the melting points thereof, in order to maintain the shape and secure the bonding height. is there. This is because alloying with solder having a low melting point starts before the solder bump having a high melting point is melted, so that the height of the bump can be maintained. For example, the semiconductor element side is Sn-Pb
80% Pb-20% Sn alloy or 95% Pb-5% Sn alloy having a higher melting point than the eutectic system, and the circuit board side is Sn-P
A method such as b-eutectic soldering can also be advantageously used.

As described above, the solder-bonded silicon semiconductor device of the present invention can be connected to a circuit board or the like without using a bonding wire. For this reason, the semiconductor element to be bonded using the bonding wire is considerably larger than the size of the semiconductor element chip itself because the resin is molded including the stem for protecting the bonding wire, and the area occupied on the circuit board is increased. However, the semiconductor element of the present invention does not require a bonding wire, which is extremely advantageous for miniaturizing the entire circuit. Further, in the semiconductor element of the present invention, a metal having good solder wettability is selected as the second metal layer, so that the bonding can be performed easily and reliably for mounting. The semiconductor device can be directly mounted on a semiconductor having high conductivity and high strength, and the reliability at the time of mounting can be greatly improved.

In the circuit board thus obtained, the bonding height can be adjusted relatively freely by selecting the solder bump height, and a circuit board having a high tolerance and a high bonding height can be obtained. As a result, even if the same material and the same semiconductor element are used, it is possible to avoid a problem caused by heat generation, which has been a problem in the past, and the design of a circuit board has been facilitated.

[0025]

EXAMPLES Next, examples of the present invention will be described, but the present invention is not limited to the following examples. (Example 1) As structure 1, 1 μm thick silicon chip 11
Of Al (aluminum) 12 is vacuum-deposited, and then C is deposited on the Al 12 so as to cover the entire exposed surface of Al.
u 13 was vacuum-deposited to a thickness of 1 μm to form an electrode as shown in FIG. As structure 2, 1 μm thick silicon chip 11
Of Cu 13 is vacuum-deposited, and Ni 14 is then coated on the Cu 13 to a thickness of 3 μm so as to cover the entire exposed surface of Cu.
m was vacuum-deposited to form an electrode as shown in FIG. As structure 3, 1 μm thick silicon chip 11
Of Al 12 is vacuum-deposited, and Cu 13 is then deposited on the Al 12 to a thickness of 1 μm so as to cover the entire exposed surface of Al.
m, vacuum-deposited, and a 10 micron thick SiO ₂ 15
5C, the entire Cu surface is shielded, a predetermined portion is etched to open a window, and the Cu electrode surface 13 is exposed.
The electrode as shown in FIG.

As a structure 4, a 1 μm thick (Al-2% Si alloy) 16 is vacuum-deposited on the silicon chip 11, and then the Al—Si is deposited on the (Al-5% Si alloy) 16. Cu 13 was vacuum-deposited to a thickness of 1 μm so as to cover the entire alloy to form an electrode as shown in FIG. Next, for comparison, as structure 5, a silicon chip was used.
Al 12 is vacuum-deposited to a thickness of 1 μm on the substrate 11, and then Cu 13 is deposited to a thickness of 1 μm on the upper surface excluding the side portions of the Al 12.
m was vacuum-deposited to form an electrode as shown in FIG. As structure 6, a 1 μm thick silicon chip 11
Of Cu 13 was vacuum-deposited, and then Ni 3 was vacuum-deposited to a thickness of 3 μm on the upper surface excluding the side portions of Cu 13 to form an electrode as shown in FIG.

Each of the silicon chips with electrodes (32 electrodes, electrode pitch 250 μm, electrode diameter 90 μmφ) having the structure shown in FIGS. 5A to 5F is pre-treated with a sulfuric acid aqueous solution, and then treated with acetic acid. The pH was adjusted to about 4.5 by adding a 2-wt% aqueous solution of 2-undecylimidazole represented by the following chemical formula (1) to a tackifying solution comprising 40% by weight.
C. and immersed for 5 minutes.

[0028]

Embedded image

Next, these six silicon elements were taken out, washed with water, dried, and then subjected to 20% Sn having an average particle size of 120 μm.
A −80% Pb solder powder was sprinkled over the entire surface of the silicon element, and excess powder other than the electrode portion was blown off with air. At this time, the state of adhesion of the solder powder was as shown in Table 1.

[0030]

[Table 1]

The silicon element to which the solder powder has been adhered is heated in a nitrogen stream at 170 ° C. for 30 seconds to fix the solder powder. Then, a water-soluble flux is applied, and a nitrogen gas having an oxygen content of 500 ppm is flowed. In a reflow furnace, the solder powder was melted at a preheating temperature of 150 ° C. and a reflow temperature of 300 ° C. to form solder bumps. After washing with hot water, the state of formation of the solder bumps and their height and standard deviation (sigma) of the height were measured. Table 2 shows the results. The electrode structure shown in FIGS. 5A to 5D can be used stably for a circuit board.

[0032]

[Table 2]

(Embodiment 2) As shown in FIG. 6, a silicon element 20 is placed on a silicon surface 21 (inverted).
1 μm thick Al 22 is vacuum deposited and then the Al 2
2 on top of Cu 2 to a thickness of 1 μm so as to cover the entire exposed surface.
Thus, an electrode was formed by vacuum evaporation. This silicon device with electrodes (32 electrodes, electrode pitch 250 μm, electrode diameter 90 μmφ) was pretreated with an aqueous sulfuric acid solution, and then adjusted to a pH of about 4.5 with acetic acid. % Solution was heated to 40 ° C. and immersed in the solution for 5 minutes.

Next, the device is taken out of the solution, washed with water,
After drying, 20% Sn-80% Pb solder powder was sprinkled, and excess powder was blown off with air. The silicon element to which the solder powder has been attached in this manner is placed in a nitrogen stream at 170
After heating at 30 ° C. for 30 seconds to fix the solder powder, a water-soluble flux was applied on the fixed solder, and a preheating temperature of 150 ° C. and a reflow temperature of 300 ° C. were applied in a reflow furnace flowing nitrogen gas having an oxygen content of 500 ppm. Then, the solder powder was melted to form solder bumps 25. Thereafter, it was washed with hot water to obtain a solder-coated silicon element 20.

On the other hand, as shown in FIG. 7, on a substrate 31 having a copper paste circuit 32 having a width of 90 μm and a pitch of 250 μm, a predetermined position of the copper paste circuit 32 (corresponding to the position of the solder bump 25 of the silicon element 20). Is 90 μm × 90 μm
Then, a substrate 31 was prepared, which was exposed to the same size and the other part was covered with a resist resin. The substrate 31 is first pickled with an aqueous sulfuric acid solution, adjusted to a pH of about 4.5 with acetic acid, and heated at 40 ° C.
The substrate was immersed in a tackifier made of a 2 wt% aqueous solution of 2-undecylimidazole heated for 5 minutes, and then the substrate was washed with water and dried to give tackiness to the exposed copper-clad circuit portion. A Sn-37% Pb eutectic solder powder having a particle size of 70 to 90 μm was sprinkled on the substrate, the solder powder was attached to the adhesive portion, and excess solder powder other than the one attached to the adhesive portion was blown off with air to remove. After heating the printed circuit board to which the solder powder was attached in a nitrogen stream at 170 ° C. for 30 seconds to fix the solder powder, a water-soluble flux was applied on the fixed solder powder, and a nitrogen gas having an oxygen content of 500 ppm was flowed. The solder was melted by heating to 200 ° C. in a reflow furnace to form solder bumps 33. Finally, the substrate was washed with hot water to obtain a solder-coated printed circuit board 30 having solder bumps 33 at predetermined positions on the printed circuit board as shown in FIG. A flux is applied to both of these solder bumps 25 and 33, and the solder is melted at a preheating temperature of 150 ° C. and a reflow temperature of 200 ° C. in a reflow furnace in which a nitrogen gas having an oxygen content of 500 ppm is flowing, and joined as shown in FIG. did. Table 3 shows the heights of the bumps after bonding.

[0036]

[Table 3]

[0037]

The semiconductor device of the present invention has excellent solder corrosion resistance and solder wettability, and thus has excellent solder adhesion. When an intermediate metal layer is inserted between the first metal layer and the second metal layer, the strength of the surface electrode is improved. In addition, since these metal layers completely cover the lower metal layer, the lower metal is not eroded by the solder or side-etched by a chemical for imparting tackiness.
Further, when the solder powder is applied, the thickness of the solder can be easily controlled by selecting the particle size of the solder powder to be applied. When mounting this solder-attached silicon element on a circuit board, the bonding height can be increased by forming the solder bumps on the circuit board in the same way and mounting, so that the same material and the same semiconductor element can be used. Even when used, the heat resistance can be increased, and the design of the substrate has been facilitated. In this way, mounting without bonding wires became possible, so connection resistance was reduced,
The connection strength can be maintained high, and the connection is solder / solder connection, so the reliability is high.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of an electrode structure used in a silicon semiconductor device according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the electrode structure used in the silicon semiconductor device according to the present invention.

3A is a cross-sectional view showing a state in which electrodes of the semiconductor device of FIG. 1 are shielded by an insulator, and FIG. 3B is a diagram in which a window is opened in the device of FIG. Sectional drawing of the state provided.

FIG. 4A is a cross-sectional view showing a state in which solder powder is adhered to an adhesive portion in FIG. 3B, and FIG. 4B is a view showing a state in which the solder powder in FIG. Sectional drawing of the formed semiconductor element.

FIG. 5A is an explanatory view showing an electrode structure of a structure 1 formed on a semiconductor element surface in Example 1. (B) is an explanatory view showing the electrode structure of Structure 2 formed on the semiconductor element surface in Example 1. (C) is an explanatory view showing the electrode structure of Structure 3 formed on the semiconductor element surface in Example 1.
(D) is an explanatory view showing the electrode structure of Structure 4 formed on the semiconductor element surface in Example 1. (E) is an explanatory view showing an electrode structure of a structure 5 formed on a semiconductor element surface for comparison. (F) is an explanatory view showing an electrode structure of a structure 6 formed on a semiconductor element surface for comparison.

FIG. 6 is a sectional view of a junction of a circuit board using the silicon element of the present invention.

FIG. 7 is a plan view of a circuit board before bonding a silicon element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Semiconductor element 2 1st metal layer 3 2nd metal layer 4 Intermediate metal layer 5 Insulator 6 Adhesive part 7 Solder powder 8 Solder bump 11 Silicon chip 12 Al 13 Cu 14 Ni 15 SiO ₂ 16 Al-5% Si alloy REFERENCE SIGNS LIST 20 solder-attached silicon element 21 silicon substrate 22 Al 23 Cu 24 insulating resin 25 solder bump 30 solder-attached circuit board 31 printed circuit board 32 copper-attached circuit 33 solder bump

Claims (9)

[Claims] 1. A first metal layer provided on a silicon semiconductor surface and forming an ohmic junction with a silicon semiconductor, and a second metal layer laminated so as to completely cover all exposed surfaces of the first metal layer. Wherein the metal of the second metal layer is the first metal
The electrode structure of a silicon semiconductor device, which has higher corrosion resistance to organic acids and better solder wettability than the metal of the metal layer. 2. The method according to claim 1, wherein the first metal layer comprises Cu, Al, Ti,
The second metal layer is made of Cu, Ni or Au (the metal of the first metal layer is C
2. The electrode structure according to claim 1, wherein the electrode structure is made of one of the following: 3. The method according to claim 1, wherein the first metal layer and the second metal layer have N
an intermediate metal layer of i or Cr (but limited to Cr when the second metal layer is Ni), which completely covers the entire exposed surface of the first metal layer; 3. The electrode structure according to claim 1, wherein the second metal layer completely covers the entire exposed surface of the intermediate metal layer. 4. The electrode structure according to claim 1, wherein an entire exposed surface of the second metal layer except for a predetermined area is shielded by an insulator. 5. A silicon semiconductor substrate, a first metal layer provided on the silicon semiconductor substrate and forming an ohmic junction with the silicon semiconductor, and laminated so as to completely cover all exposed surfaces of the first metal layer. A solder comprising a second metal layer having higher corrosion resistance to organic acids than the first metal and having better solder wettability, and a solder bump mounted on a predetermined area of the surface of the second metal layer. Deposited silicon semiconductor device. 6. A first metal layer is laminated on a silicon substrate, and a second metal layer is formed so as to completely cover all exposed surfaces of the first metal layer.
Then, after covering the entire surface of the second metal layer with a coating material, a predetermined portion of the coating material is removed by etching to form a window in a predetermined area on the surface of the second metal layer. And then selectively imparting adhesiveness to the second metal layer in the window portion, attaching a solder powder to the adhesive portion, and heating and melting the solder powder. Manufacturing method. 7. A circuit board in which a solder-attached silicon semiconductor element and a solder-attached circuit board are mounted with their solder mounting portions overlapped with each other. 8. An adhesive is selectively applied to an exposed metal portion of a circuit board, a solder powder is attached to the adhesive section, and the solder powder is heated and melted to form a solder-coated circuit board. A method for manufacturing a circuit board, comprising: laminating a solder bump of a solder-coated silicon semiconductor element on a bump, performing fusion bonding, and filling a gap between the two with an insulating resin for sealing. 9. The method for manufacturing a circuit board according to claim 8, wherein the solder used for each of the solder bumps of the soldered circuit board and the soldered silicon semiconductor element has a different melting point.