JPH09115911A - Semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form a barrier metal layer and a solder bump on an electrode pad by the non-plating method by transferring a junction layer including a second metal which can be subjected to solid-phase diffusion with a first metal on an elastic sheet onto a connection pad, causing a solid-phase diffusion reaction between both metals, and joining the junction layer on the connection pad. SOLUTION: A copper foil 5b where gold coating 5a coats one surface of a resin film and nickel layer 5c/metal layer 5d are coated on the other surface in this order is punched. Then, a punched barrier metal lamination body 5 and a connection pad 3 on a semiconductor substrate 1 are aligned and the barrier metal lamination body 5 is transferred onto the connection pad 3 on the semiconductor substrate 1, where the barrier metal lamination body 5 is heated to a temperature where the barrier metal lamination body 5 and the connection pad 3 cannot be melted and a diffusion reaction is generated between the connection pad 3 of the semiconductor substrate 1 and the junction layer 5a consisting of gold coating on the barrier metal layer 5b, thus joining the covering of the barrier metal lamination body 5 on the connection pad 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a connection pad, a barrier metal film and a solder bump electrode.

[0002]

2. Description of the Related Art In recent years, a variety of LSIs connected to a circuit board have been diversified due to rapid development of electronics and deviceization. Further, due to the demand for high-density mounting, flip-chip mounting has been performed in which an LSI is directly mounted on a connection pad of a circuit board by using a solder bump electrode (bump).

However, solder bumps are not always formed on the electrode pads of commercially available semiconductor elements, which is an obstacle to mounting on a circuit board. That is, when solder bumps are formed on all the semiconductor elements mounted on the circuit board, mounting by batch reflow is easily possible. However, if there is even one semiconductor element without solder bumps formed, it cannot be connected by batch reflow, and a semiconductor element without solder bumps must be mounted in a separate process after forming gold bumps on the electrode pads. Either, or connection by wire bonding will be made. The reason why mounting is performed in a separate process is that the semiconductor element chip A
The l electrode pad does not get wet with the solder, and it is difficult to form the solder bump directly on the Al electrode pad.

On the other hand, as a method for forming bump type electrodes on the electrode pads of the semiconductor element by soldering, there is disclosed in Japanese Patent Laid-Open No.
As described in 199631 and JP-A-4-155835, there are an electroplating method and a pulse plating method described in JP-A-4-157728. In either method, a plating base metal layer (barrier metal) is formed on the electrode pad, a photoresist is formed by opening only the bump formation region, solder bumps are formed by electroplating, and then the photoresist is removed. The metal layer for plating is etched to form solder bumps on the electrode pads of the semiconductor device. In order to form solder bumps by electroplating, it is essential to form a base metal layer that will serve as an electrode during plating, and the base metal layer on the silicon wafer where semiconductor elements cannot be formed is used as the plating electrode. ing. However, in each of the diced individual semiconductor chips, there is no extra space that can serve as a plating base electrode, and it is difficult to form a solder bump by using a plating method.

Tin-lead (Sn-Pb) based solder is often used as a material for mechanically connecting these semiconductor devices and other electronic components to a circuit board to form an electric circuit.

However, in recent years, from the solder connection portion connecting the semiconductor device and other electronic parts to the circuit board,
Pb in the solder begins to melt, which poses a serious problem because it impairs health and pollutes the environment. It is considered that this Pb elution in the solder is difficult to recycle, and is caused by exposing the solder connection part of the circuit board left to be exposed to rain with strong acidity. Therefore, as a solder for connecting the semiconductor device and other electronic parts to the circuit board, P
The use of solder that does not contain b (Pb-free solder) is desired.

Further, in the plating method, when binary solder such as Sn-Pb-based solder is used, it is possible to form solder bumps by controlling the composition, but multi-component solder containing no Pb is used. When used, it is difficult to control the composition to form solder bumps, and there is a problem that some of the constituent elements of multi-component solder cannot be plated. Also, depending on the composition, there are also multi-component solders that are difficult to process into sheets of the desired thickness,
Such solder has a problem that solder bumps cannot be formed even by using the punching transfer method.

[0008]

In forming a solder bump electrode on an electrode pad of a conventional semiconductor element, a base metal layer (protective layer) is formed on the electrode pad in order to ensure the reliability of the semiconductor element connecting portion. It is formed and this base metal layer is used as a plating electrode. Therefore, on the silicon wafer, it was easy to form the solder bumps by the plating method by using the portions where the semiconductor elements were not formed as the plating electrodes, but on the electrode pads of the diced semiconductor chip with no extra space. However, there is a problem in that it is not possible to take a plating electrode for forming a solder bump by a plating method.

Therefore, a first object of the present invention is to provide a method of manufacturing a semiconductor device in which a barrier metal layer and a solder bump can be easily formed on an electrode pad of a semiconductor device without using a plating method. is there.

A second object of the present invention is to provide a highly reliable semiconductor device by forming a barrier metal layer and a solder bump on an electrode pad of the semiconductor device without using a plating method. Especially.

Further, in forming a solder bump electrode on an electrode pad of a conventional semiconductor device, a base metal layer is formed on the electrode pad in order to secure the reliability of a semiconductor device connecting portion, and the base metal layer is formed. Is used as a plating electrode, a photoresist is opened in the region where the bump electrode is formed, and the solder bump electrode is formed while controlling the composition by electroplating. The composition that can be easily controlled by this electroplating method is Sn-
It is a binary solder such as Pb-free, Pb-free
With multi-component solder such as solder, it is difficult to form solder bump electrodes by electroplating while controlling the composition.

Therefore, a third object of the present invention is to provide a method of manufacturing a semiconductor device capable of forming a composition-controlled solder bump electrode without using a plating method. Furthermore, a fourth object of the present invention is to provide a highly reliable semiconductor device by forming a solder bump electrode whose composition is controlled without using a plating method.

[0013]

In order to solve the above-mentioned problems, the present invention firstly provides a semiconductor having a plurality of connection pads containing a first metal and a bonding layer formed on the connection pads. In the method of manufacturing the device, a second base material sheet having elasticity, which is capable of solid-phase diffusion reaction with the first metal,
The step of forming a transfer sheet having a die-bonded bonding layer by arranging the metal-containing joining layer and punching it from the bonding layer side to the transfer base material sheet using a male die; The step of aligning the bonding layer with the connection pad, and heating and pressurizing the bonding base sheet from the transfer base sheet side to transfer the die-bonded bonding layer onto the connection pad, and And a step of causing a solid-phase diffusion reaction between the metal and the second metal to bond the bonding layer on the connection pad.

Secondly, the present invention is a semiconductor device having a plurality of connection pads containing the first metal and a bonding layer formed on the connection pads, wherein the elastic base material sheet is provided with A bonding layer containing a first metal and a second metal capable of solid-phase diffusion reaction was sequentially arranged, and a male mold was used to form a transfer sheet by punching from the bonding layer side to a base material sheet, which was die-cut. The bonding layer is aligned with the connection pad, heated and pressed from the base material sheet side to be transferred onto the connection pad, and a solid phase diffusion reaction is performed between the first metal and the second metal. A semiconductor device is provided which is raised and the bonding layer is bonded onto the connection pad.

In the first and second inventions, it is preferable that the first metal is made of aluminum, the second metal is made of gold, and a barrier metal layer made of copper is further formed on the bonding layer.

In the first and second inventions, after the joining step, the solder sheet is arranged on a solder transfer base sheet having elasticity, and the solder sheet is placed by using a male mold. By preparing a solder transfer sheet having stamped solder by punching upward, aligning the stamped solder with the connection pad, and heating and pressing from the base sheet side to position It is preferable that the method further comprises a step of transferring the combined solder onto the bonding layer.

Thirdly, according to the present invention, the step of forming the solder material layer transfer sheet by arranging the solder material layer on the resin sheet having elasticity and punching the solder sheet on the resin sheet using a male die is punched out. A method of manufacturing a semiconductor device, comprising: aligning a solder material layer with a connection pad of a semiconductor device; and transferring the solder material layer onto the connection pad to form a protruding electrode. .

Fourthly, the present invention uses a solder material layer transfer sheet formed by arranging a solder material layer on a resin sheet having elasticity and punching the resin material sheet using a male die. Provided is a semiconductor device having a bump electrode formed on a connection pad by transferring a punched solder material layer.

In the third and fourth inventions, the solder material layer preferably includes at least two different metal material layers or alloy layers. In the third and fourth inventions,
More preferably, the solder material layer also contains at least two selected from the group consisting of tin, bismuth, zinc, antimony, indium, silver, and copper.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. First, a semiconductor device according to the first invention and the second invention will be described. FIG. 1 is an enlarged view showing an example of a connection portion of a diced semiconductor chip.
As shown in the figure, the connection pad 3 formed on the insulating film 2 of the semiconductor chip 1 has a protective film (passivation film) 4
Has a structure in which the end portion of the pad is covered.

In the present invention, a transfer sheet is used to form a bonding layer and a barrier metal layer on the connection pad 3. FIG. 2 is a schematic sectional view showing an embodiment of the transfer sheet used in the first and second inventions. This transfer sheet is composed of a resin film 9 having elasticity and a plurality of laminates 5 formed on the resin film 9 and die-cut at a predetermined pitch. As the laminated body 5, here, one laminated in the order of gold / nickel / copper / gold from the resin film side is used. Here, nickel is preferably provided as an antioxidant for copper and can be applied not only to one side of copper but also to both sides thereof.

This transfer sheet is obtained by a punching transfer method. In order to punch a transfer sheet, first, a gold coating 5 is formed on one surface of the resin film 9.
a, a copper foil 5b coated with a nickel layer 5c / a gold layer 5d on the other surface in this order is stacked so that its diffusion bonding surface, that is, one surface faces upward, and then punched by a male die for pressing. FIG. 3 shows a schematic cross-sectional view showing a state where the transfer sheet is punched out. As shown in FIG. 3, a die-cut gold layer 5d / nickel layer 5c is formed on the resin film 9.
The laminate 5 consisting of / copper layer 5b / gold layer 5 is punched out.
At this time, it is desirable to install a pad 11 for supporting the resin film 9 below the resin film 9.
The resin film 9 is deformed by the press as shown in FIG. 3, and the punched-out barrier metal layer is gripped from the periphery and acts as a female mold. The resin film 9 pressed and deformed by the male mold returns to its original state when the male mold is released, and a transfer sheet as shown in FIG. 2 is obtained.

Next, the punched-out barrier metal laminated body 5 and the connection pad 3 of the semiconductor substrate 1 are aligned with each other, and the barrier metal laminated body 5 is transferred onto the connection pad 3 of the semiconductor substrate 1. FIG. 4 is a schematic view showing how the barrier metal laminate of the transfer sheet and the connection pads of the semiconductor substrate are aligned. At this time, using the heater in the mounter head 12 and the heater in the stage of the mounter, the barrier metal laminate 5 on the semiconductor substrate 1 and the resin film 9 is not melted to the extent that the barrier metal laminate 5 and the connection pads 3 are not melted. Of the barrier metal layer 5b by causing a diffusion reaction between the Al connection pad 3 of the semiconductor substrate 1 and the bonding layer 5a made of gold coating on the barrier metal layer 5b. The coating according to No. 5 is joined.

FIG. 5 is a schematic sectional view showing a connecting portion of the semiconductor device to which the barrier metal laminate is transferred and joined. At this time, the opening of the connection pad 3 and the barrier metal laminated body 5
5, the barrier metal laminated body 5 is preferably set to be smaller than the opening portion of the connection pad 3, as shown in FIG. This is because if the barrier metal laminated body 5 is larger than the opening of the connection pad 3, the protective film 4 is destroyed in the transfer process, and in the soldering process or the like, contact between the connection pad 3 and the flux or flux in the air moisture. This is because the components are melted and corrosion or the like occurs in the connection pad 3, which causes a decrease in connection reliability of the semiconductor device. Further, even if the size of the barrier metal laminated body 5 and the size of the opening of the connection pad 3 are the same, the barrier metal laminated body 5 destroys the protective film 4 due to the positional deviation in the transfer process.
This will reduce the reliability of the semiconductor device as described above.

FIG. 6 shows the connection pad 3 and the barrier metal layer 5
FIG. 3 is a diagram for explaining a step of joining b using a solid phase diffusion reaction, and by heating while applying pressure from the barrier metal layer 3 side, Al of the connection pad 3 and the barrier metal layer 5b
Diffusion occurs between the upper Au bonding layers 5a to form Au and Al diffusion layers 6, whereby the connection pads 3 and the barrier metal layers 5b are diffusion bonded. The diffusion layer 6 is made of Almofus, a solid solution, or an intermetallic compound, and changes into an intermetallic compound layer as the diffusion reaction proceeds. Also,
In this case, when the diffusion reaction proceeds, A in the intermetallic compound layer
u ₄ Al increases and becomes stable.

By the way, if the barrier metal laminated body 5 is smaller than the opening portion of the connection pad 3, A of the connection pad 3 is practically used.
l cannot be covered with a film made of the barrier metal laminate 5. However, in the present invention, the barrier metal layer 5
When a diffusion reaction is caused between the Au bonding layer 5a on b and the Al of the connection pad 3 to make a connection by diffusion bonding of Al and Au, this diffusion reaction region is used as a connection pad under the protective film 4. As a result, the diffusion layer 6 generated by the diffusion reaction covers the surface of the connection pad 3 in a portion that could not be covered with the barrier metal laminate 5, so that Al of the connection pad 3 is not directly exposed. can do. Further, the diffusion reaction does not require a special method, and the diffusion reaction can proceed to the lower side of the protective layer 4 by being heated at the time of punching transfer.

On the barrier metal laminate 5 thus formed, a solder transfer sheet obtained by punching a solder sheet on a resin film is arranged with the solder facing downward, and is placed on the barrier metal layer 3. Can be transferred to. FIG. 7 is a diagram showing a state in which the solder bumps 7 to be the protruding electrodes are formed on the barrier metal laminated body 5 by the punching transfer method. After the solder is punched out, the solder 7 and the Au layer 5d on the Ni oxidation preventing layer 5b are wetted by reflowing in a predetermined atmosphere, so that a solder bump electrode can be formed.

FIG. 8 is a schematic cross-sectional view showing the connection portion of the semiconductor device having the bump electrode formed in this way. As shown in FIG. 8, the solder bump 7 is formed on the connection pad 3 of the semiconductor substrate 1 with the barrier metal laminated body 5 including the barrier metal layer 5b joined to the connection pad 3 by the diffusion layer 6 as a core.

In the above-described embodiment, the barrier metal laminated body 5 is constructed such that the Au layer 5a / Cu layer 5b is arranged from the connection pad side.
/ Ni layer 5c / Au layer 5d, but Au / Cu, Au
/ Cu / Au, Au / Cu / Ni / Au, Au / Ni /
Cu / Ni / Au may be used, and the gold used as the uppermost bonding layer may be replaced with palladium or the like to replace Au / C.
u / Pd, Au / Cu / Ni / Pd or Au / Ni
It may be / Cu / Ni / Pd.

In the semiconductor device of the first and second inventions, the connection pad and the barrier metal layer are bonded by utilizing a diffusion reaction between the metal of the connection pad and the metal of the bonding layer formed on the barrier metal layer. Has been done. Here, even if the layer containing the barrier metal is set smaller than the connection pad, the intermetallic compound layer generated by the diffusion reaction covers Al of the connection pad to prevent deterioration of reliability of the connection portion due to corrosion or the like. can do. Further, according to the present invention, since the protruding electrode is formed by the punching transfer method without using the plating method, it is possible to easily form the protruding electrode together with the barrier metal layer on the connection pad of the semiconductor element formed into a semiconductor chip by dicing. can do.

The semiconductor device of the present invention will be described in detail below by showing specific manufacturing examples of the first and second inventions. In the present embodiment, the semiconductor chip uses the semiconductor substrate 1 in which the size of the connection pads 3 is 100 μm square, the pitch of the connection pads 3 is 220 μm, the number of connection pads is 64, and the size is 5 mm square.

When punching the barrier metal laminate, first, 0.6 μm is formed on one side of a commercially available 1 μm thick copper foil.
After forming high pressure Au by sputtering,
And Au were respectively formed by sputtering to have thicknesses of 0.3 μm and 0.6 μm, respectively, to form a gold-coated copper foil 8. The gold-coated copper foil 8 was placed on the resin film 9, and the barrier metal laminated body 5 was punched using a male mold for press whose circumference was 3 μm smaller than the opening of the connection pad 3 of the semiconductor device 1.

Next, using a mounter, the resin film 9
The connection pad 3 of the semiconductor substrate 1 is positionally transferred and transferred onto the upper barrier metal laminate 5, and 2 k is left as it is.
While pressurizing to g and heating to 300 ° C. and holding for 10 seconds, Al of the connection pad 3 of the semiconductor substrate 1 and Au5a of the barrier metal laminated body 5 were diffusion-bonded to obtain a semiconductor substrate with a barrier metal.

Then, a commercially available film of 0.
A Sn-Pb eutectic solder sheet having a thickness of 05 mm was placed, punched using a male die 11 for pressing, and transferred onto the barrier metal layer 5 of the semiconductor substrate with the barrier metal. Finally, reflow was performed at 220 ° C. in a nitrogen atmosphere to obtain a semiconductor device with solder bumps.

Each solder bump of the obtained semiconductor device is
The shear strength was measured using a shear tester. The shear strength was measured for all bumps of the semiconductor device, and the average strength per bump of each semiconductor device was obtained. Further, the semiconductor device is mounted on a resin wiring board, sealed with resin, and a thermal cycle test (−55 to + 125 ° C., 1 cycle / 1 hour) is performed up to 1000 cycles to obtain the semiconductor device and the wiring board. The reliability of the connection part was evaluated by checking the presence or absence of the connection.

The measurement results are shown in Tables 1 and 2. Also,
As a comparative sample, a semiconductor device having a solder bump formed by a conventional plating method was used, and the same test as the sample of this embodiment was conducted.

The measurement results are also shown in Tables 1 and 2. The barrier metal layer of the comparative sample had the same configuration as the barrier metal layer of the sample of this embodiment.

[0038]

[Table 1]

[0039]

[Table 2]

As shown in Table 1, even if the solder bumps of the semiconductor device are formed by using the punching transfer and the diffusion bonding method, the shear bumps are almost the same as those of the semiconductor device having the solder bumps formed by the conventional plating method shown in the comparative sample. Had strength. Further, no breakage of the solder bump was observed even after the thermal cycle test, and it was found that the solder bump had the same reliability as the solder bump connection portion formed by the conventional method.

In the present invention, as a method of coating the copper foil with gold or the like, a usual film forming method such as a plating method, a vapor deposition method, a sputtering method or a CVD method can be used. Further, its thickness is preferably about 0.2 to 1 μm. This gold coating does not necessarily have to be applied to both sides of the copper foil, but may be applied only to the side for diffusion bonding. Also,
If necessary, the surface of the copper foil on the protruding electrode side may be coated with Au, Pd, etc. to prevent oxidation of the copper surface, or a Ni layer may be provided between Cu and Au to enhance the bonding force between Cu and Au. .

Furthermore, in the present embodiment, Sn-Pb eutectic solder was used for forming the protruding electrodes, but Sn-Ag, Sn-Sb, Sn-Z are used instead of Sn-Pb eutectic solder.
n-based, Sn-In-based, Sn-Bi-based, Sn-Ag-Cu
System, Sn-Zn-In system, Sn-Zn-Ag system, Sn-
The protruding electrodes may be formed by using Pb-free solder (lead-free solder) such as Bi-Ag-Cu system.

The semiconductor device according to the first and second inventions using the punching transfer and the diffusion bonding described above has a wide application range and its industrial utilization effect is great. Next, the third and fourth inventions will be described.

FIG. 9 is an enlarged view showing the connecting portion of the semiconductor device. As shown in the figure, this connecting portion is connected to the semiconductor device 1
Connection pad 3 provided on the insulating layer 2 and the protective film 4 formed so as to hold the connection pad 3 from both sides.
And a barrier metal layer 55 formed on the connection pad 3 and a part of the protective film 4 on the connection pad 3. In the present invention, the solder bump is formed on the connection pad 3 of the semiconductor device by using the punching transfer method of the solder sheet.

In this solder sheet punching transfer method, first, a solder material layer is punched on a sheet 10 made of an elastic resin such as rubber. As the solder material, preferably at least two different metal material layers or alloy layers can be used. For example, on the electrode pad, a sheet composed of different constituent elements of the multi-component solder, an alloy sheet composed of at least two kinds of the constituent elements of the multi-component solder, or a combination of both, while controlling the composition,
A plurality of combined sheets can be punched and transferred to form a protruding electrode by multi-component solder on the semiconductor device.

FIG. 10 is a view for explaining punching of the solder material layer. For example, when using Sn-Bi-Ag-Cu quaternary solder, the Cu sheet 26c and the Sn-Bi alloy sheet layer 26b are stacked on the Sn sheet 26d, and the Ag sheet 26a is further stacked as illustrated. The solder material layer transfer sheet 20 is formed by arranging and punching on the resin sheet 101 using the male mold 29. The resin sheet 101 having elasticity by pressing is
As shown in FIG. 10, the solder material layer 26 which has been deformed and punched out is gripped from the surroundings and acts as a female mold.

FIG. 11 is a schematic sectional view showing an embodiment of the solder material layer transfer sheet used in the third and fourth inventions. The obtained solder material layer transfer sheet 20 is, as shown in the figure, on a resin sheet 101 having elasticity,
Sn layer 26d, Cu layer 26c, Sn-Bi alloy layer 26
b and the Ag layer 26a are laminated in this order.
In FIG. 10, the resin sheet 101 having elasticity of the solder material layer transfer sheet 20 is deformed by punching the male die 29, but returns to the original state when the male die 29 is released, and the solder material layer as shown in FIG. The transfer sheet 20 is obtained.

Here, the composition ratio of the solder can be easily adjusted by changing the thickness of each layer of the solder material layer. The solder material layer 26 on the solder material layer transfer sheet is aligned with the connection pad 3 on which the barrier metal 55 is formed and transferred. FIG. 12 is a diagram schematically showing a connecting portion of the semiconductor device to which the solder material layer is transferred. As shown in FIG. 12, the Ag layer 26 a, the Sn—Bi alloy layer 26 b, and the Cu layer 2 are formed on the barrier metal 55 by punching transfer.
6c, and a plurality of solder material layers composed of the Sn layer 26d are formed.

In the third and fourth aspects of the invention, the multi-component solder can be alloyed on the connection pads of the semiconductor device by a reflow process after punching and transferring a plurality of sheets.

The transferred solder material layer is reflowed to form Sn—Bi—Ag—Cu quaternary bump electrodes. FIG. 13 is a schematic view of a connection portion of a semiconductor device in which a reflowed protruding electrode is formed. As shown in the drawing, the solder material layer becomes a spherical projection electrode with the barrier metal layer 55 as a nucleus by reflow, and the solder material layer is alloyed.

In the third and fourth aspects of the invention, for example, by changing the thickness of each sheet of the solder material layer, the solder bump electrode having the target composition can be obtained. In addition, Sn-Bi-Ag-Cu
When using an element such as Bi, which is difficult to make a sheet with a solder constituent element alone like a quaternary system, punching transfer is performed by making a sheet by alloying with other solder constituent elements to form a sheet. A solder bump electrode having a composition can be formed. Of course, when it is easy to make a sheet of the bump electrode having the target composition, it is desirable to use the sheet having the solder bump electrode composition from the beginning. As described above, according to the present invention, even when it is difficult to produce a solder sheet having a solder bump electrode composition, a semiconductor device having a multi-element bump electrode formed as described above can be obtained. Further, each constituent element may be formed on the sheet serving as the base by a film forming method using a film forming method such as vapor deposition or sputtering.

The composition control of the solder bump electrode is performed not only by changing the thickness of each sheet of each punched solder material layer, but also by changing the size of the punched solder material layer, the same effect can be obtained. can get.

The solder material layer also preferably contains at least two kinds selected from the group consisting of tin, bismuth, zinc, antimony, indium, silver, and copper. Further, it is preferable that the multi-component solder does not contain Pb. Eliminating toxic Pb helps reduce environmental pollution.

As described above, according to the third and fourth inventions, it is possible to easily form the electrode on the electrode pad, the composition of which is controlled without using the plating method. Also,
Punching for punching and transferring a sheet made of simple constituent elements of multi-component solder having different thicknesses, an alloy sheet made of at least two kinds of multi-component solder constituent elements, or a plurality of sheets obtained by combining both of them, onto a connection pad. By using the transfer method, it becomes possible to easily form the protruding electrode of the multi-component solder, which was difficult to form by the plating method.

Another embodiment of the semiconductor device according to the third and fourth inventions will be described below. FIG. 14 is a schematic cross-sectional view of the vicinity of a connection portion in another embodiment of the semiconductor device according to the third and fourth inventions.

As shown in FIG. 14, in this embodiment,
The solder material layer 28 is the barrier metal layer 55 formed on the connection pad 3 of the semiconductor device 1 by the punching transfer method.
The Cu sputtered film 28b and the Ag sputtered film 28, which are transferred onto the Sn-Bi alloy sheet 28c, are formed on the Sn-Bi alloy sheet 28c.
a.

The composition of the solder material layer is obtained by combining a sheet consisting of the constituent elements of the multi-component solder having different thicknesses depending on the desired composition, an alloy sheet comprising at least two kinds of the constituent elements of the multi-component solder, or a combination of both. , Can be adjusted by punching and transferring these multiple sheets to form the protruding electrodes. In this case,
Sn-Bi alloy sheet 28c, Cu sputtered film 28b,
And the Ag sputtered film 28a can be adjusted by the film thickness of each film.

In the semiconductor device shown in FIG. 14, first, a Sn-Bi alloy sheet in which a sputtered film of Cu and Ag is formed on a resin film having elasticity is stacked so that the sputtered film surface faces upward, and solder projections are formed. A sheet of a solder material layer to be an electrode is obtained. Then, it is punched by a male die for pressing to obtain a solder material layer. FIG. 15 is a diagram showing a punched state of a solder material layer used in another embodiment of the semiconductor device of the third and fourth inventions. As shown in FIG. 15, the solder material layer 28 is placed on the resin film 101 and punched by the male press 29 to form the solder material layer 28 on the resin film 101. In addition, below the resin film 101, a metal plate 11 for supporting the resin film 101 is installed.
The resin film 101 is deformed by the press as shown in FIG. 15, and the punched-out solder material layer 28 is gripped from the periphery and acts as a female mold.

Next, the punched-out solder material layer and the connection pad of the semiconductor device are aligned with each other using a mounter or the like, and the solder material layer is transferred onto the connection pad of the semiconductor device. Next, the solder material layer is melted by reflow and alloyed to obtain a bump electrode similar to the solder bump electrode shown in FIG.

Here, the reflow may be performed by using ordinary hot air reflow, infrared reflow, or the like. However, a laser is used to locally heat the solder bump electrode forming sheet to alloy it to heat the semiconductor device. It is possible to prevent deterioration due to.

Semiconductor devices according to other embodiments of the present invention will be described in more detail below by showing specific manufacturing examples. As a semiconductor device, connection pads 3 are formed on a Si wafer.
Size is 100 μm square, and the pitch of connection pads 3 is 22
A device having a size of 0 μm, 64 connection pads and a size of 5 mm square was used.

The barrier metal layer 55 is provided to the opening provided on the connection pad 3 of the semiconductor device 1 by the photoresist method,
It was formed by sputtering. Further, the solder material layer 28 is
First, using 99.99% or more of Sn and Bi, a Sn-Bi alloy ingot having a Bi content of 12.4% by weight was prepared. Then, the Sn-Bi alloy ingot was rolled to obtain a sheet. Cu and Ag are deposited on the Sn-Bi alloy sheet by sputtering, and in some cases, the Sn sheet is overlapped with the Sn-Bi alloy sheet sputtered with Cu and Ag to form the solder bump electrode forming sheet 8 It was created. This solder bump electrode constituting sheet 28 was placed on the resin film 101, and the solder material layer 28 was punched out using a 100 μm square press male die 29.

Next, using a mounter, the resin film 1
The connection pad 3 of the semiconductor device 1 was aligned and transferred onto the solder material layer 28 on 01. The solder projection forming region of this semiconductor device was scanned with a laser to melt and alloy the solder material layer 28. The composition of the obtained solder bump electrode is shown in Table 1.

Then, the shear strength of each solder bump electrode of the semiconductor device was measured using a shear tester. The shear strength was measured for all the protruding electrodes of each semiconductor device, and the average value of one bump of each semiconductor device was obtained. Table 2 shows the results.

For the comparative sample, Sn-Pb eutectic solder bump electrodes were formed on the connection pads of the semiconductor device by the conventional plating method, and the same test as the sample of this embodiment was conducted. The results are also shown in Tables 3 and 4.

[0066]

[Table 3]

[0067]

[Table 4]

From Tables 3 and 4, according to the present invention, solder bump electrodes can be formed without using toxic lead,
At that time, depending on the thickness of the solder material layer used,
It can be seen that it is possible to accurately control the composition of the protruding electrode, and the strength of the obtained protruding electrode is also good.

[0069]

According to the first and second aspects of the invention, a semiconductor device having a barrier metal layer and a protruding electrode on a connection pad of a semiconductor element is formed by punching transfer and diffusion bonding without using a plating method. Can be easily obtained.
It is also possible to form the barrier metal layer on the connection pads of the diced semiconductor chip.

According to the first and second inventions, the barrier metal layer thus formed is used as a core to easily obtain the semiconductor device having the protruding electrode on the connection pad. The projection electrodes can be easily formed on the dicing semiconductor chip.

Further, according to the first invention and the second invention, it is preferable to set the barrier metal layer smaller than the connection pad in consideration of the positional deviation due to the punching transfer. By forming the intermetallic compound layer by the diffusion reaction also on the surface of the connection pad on which the barrier metal layer is not formed, the diffusion of the connection pad and the solder can be prevented, and a highly reliable semiconductor device can be obtained.

According to the third and fourth aspects of the invention, it is possible to obtain a semiconductor device having a highly reliable solder bump electrode formed without using a plating method. Further, even when using a multi-component solder that is difficult to form by the plating method, it is possible to accurately control the solder composition on the connection pad of the semiconductor device and form a protruding electrode having good strength, When using a solder material that is difficult to manufacture, it is necessary to form a film on the mother alloy sheet or the base metal,
By alloying a part of the solder composition to produce a sheet, punching transfer is possible and a projection electrode of multi-component solder can be obtained.

Further, according to the third and fourth inventions, as the solder material, it is possible to apply the multi-component solder which does not use lead. Solder that does not use lead has a wide application range and a large industrial use effect from the viewpoint of preventing environmental pollution.

Further, according to the present invention, by combining the first and second inventions with the third and fourth inventions, a barrier metal is formed on the electrode pad of the semiconductor device without using a plating method. It becomes possible to easily form the layer and the protruding electrode. This makes it possible to form a barrier metal layer and a composition-controlled multi-element projecting electrode not only on a normal semiconductor device but also on a dicing semiconductor chip. The obtained semiconductor device has good reliability.

[Brief description of the drawings]

FIG. 1 is an enlarged view showing an example of a connecting portion of a semiconductor chip.

FIG. 2 is a schematic diagram showing an embodiment of a barrier metal transfer sheet used in the first and second inventions.

FIG. 3 is a schematic view showing a state where the barrier metal transfer sheet is punched out.

FIG. 4 is a schematic view showing a state in which the barrier metal laminate of the barrier metal transfer sheet and the connection pads of the semiconductor substrate are aligned with each other.

FIG. 5 is a schematic view showing a connection portion of a semiconductor device to which a barrier metal laminate is transferred and joined.

FIG. 6 is a diagram for explaining a step of joining a connection pad and a barrier metal layer using a solid phase diffusion reaction.

FIG. 7 is a diagram showing a state in which solder is formed on the barrier metal laminated body by a punching transfer method.

FIG. 8 is a view showing a state in which a protruding electrode is formed with a barrier metal laminate as a core.

FIG. 9 is an enlarged view showing another example of the connection portion of the semiconductor device.

FIG. 10 is a view for explaining a punched state of a solder material layer used in one embodiment of the semiconductor device of the third and fourth inventions.

FIG. 11 is a view showing an embodiment of a solder material layer transfer sheet used in the third and fourth inventions.

FIG. 12 is a schematic view of a connection portion of an embodiment of a semiconductor device according to third and fourth inventions.

FIG. 13 is a schematic view of a connecting portion of a semiconductor device in which a reflowed protruding electrode is formed.

FIG. 14 is a schematic view of the vicinity of a connection portion of another embodiment of the semiconductor device according to the third and fourth inventions.

FIG. 15 is a diagram for explaining a punched state of a solder material layer used in another embodiment of the semiconductor device of the third and fourth inventions.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Semiconductor substrate 2 ... Insulating film 3 ... Connection pad 4 ... Protective film 5,55 ... Barrier metal laminated body 5a, 8a ... Gold layer 5b, 8b ... Copper layer 5c, 8c ... Nickel layer 5d, 8d ... Gold layer 6 ... Diffusion layer 7 ... Solder bump 8 ... Gold coated copper foil 9 ... Resin film 10 ... Press male mold 11 ... Patch 12 ... Mounter head 20 ... Solder material layer transfer sheet 26,28 ... Solder material layer 26a ... Ag sheet 26b, 8c ... Bi-Sn alloy sheet 26c ... Cu sheet 26d ... Sn sheet 28a ... Ag sputtered film 28b ... Cu sputtered film 29 ... Press male mold 101 ... Resin sheet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kuniaki Takahashi 2-9 Suehiro-cho, Ome-shi, Tokyo Incorporated Toshiba Ome Plant

Claims (12)

[Claims] 1. A method of manufacturing a semiconductor device having a plurality of connection pads containing a first metal and a bonding layer formed on the connection pads, wherein the first substrate is provided on an elastic transfer base sheet. A bonding layer containing a second metal capable of solid-phase diffusion reaction with the above metal is placed and punched from the bonding layer side to the transfer substrate sheet by using a male mold, thereby having a stamped bonding layer. By forming a transfer sheet, aligning the die-bonded bonding layer with the connection pad, and heating and pressing from the transfer base material sheet side,
Transferring the die-bonded bonding layer onto the connection pad, causing a solid phase diffusion reaction between the first metal and the second metal, and bonding the bonding layer onto the connection pad. A method for manufacturing a semiconductor device, comprising: 2. The first metal is made of aluminum, the second metal is made of gold, and a barrier metal layer made of copper is further formed on the bonding layer. A method for manufacturing a semiconductor device as described above. 3. After the joining step, the solder sheet is arranged on a solder transfer base sheet having elasticity, and the solder sheet is punched onto the solder transfer base sheet using a male die. Preparing a solder transfer sheet having die-cut solder, aligning the die-cut solder with the connection pad, and heating and pressing from the base sheet side to align the solder, The method of manufacturing a semiconductor device according to claim 1, further comprising a step of transferring the pattern onto the connection pad. 4. A plurality of connection pads including a first metal,
In a semiconductor device having a bonding layer formed on the connection pad, a bonding layer containing a second metal capable of solid phase diffusion reaction with the first metal is sequentially arranged on an elastic base material sheet. , Using a male mold, to form a transfer sheet by punching from the bonding layer side to the base material sheet, align the die-cut bonding layer with the connection pad, heat from the base material sheet side, pressurize, A semiconductor device, wherein the bonding layer is bonded onto the connection pad by transferring onto the connection pad and causing a solid phase diffusion reaction between the first metal and the second metal. 5. The first metal is made of aluminum, the second metal is made of gold, and a barrier metal layer made of copper is further formed on the bonding layer. The semiconductor device described. 6. A solder transfer formed by arranging a solder sheet on a solder transfer base sheet having elasticity and punching and transferring the solder sheet onto the solder transfer base sheet using a male mold. By preparing a sheet, aligning the punched solder with the connection pad, and heating and pressing from the base material sheet side to transfer onto the barrier metal layer, solder bump electrode on the bonding layer The semiconductor device according to claim 4, further comprising: 7. A solder material layer is arranged on a resin sheet having elasticity and punched on the resin sheet by using a male die.
Forming a solder material layer transfer sheet, aligning the punched solder material layer with a connection pad of a semiconductor device, and transferring the solder material layer onto the connection pad,
A method of manufacturing a semiconductor device, comprising the step of forming a protruding electrode. 8. The method of claim 7, wherein the solder material layer comprises at least two different metal material layers or alloy layers. 9. The method according to claim 8, wherein the solder material layer contains at least two kinds selected from the group consisting of tin, bismuth, zinc, antimony, indium, silver, and copper. 10. A solder material layer transfer sheet formed by arranging a solder material layer on a resin sheet having elasticity and punching the solder material layer on the resin sheet by using a male die, and using the punched solder material layer. A semiconductor device having a protruding electrode formed on a connection pad by transferring a semiconductor. 11. The semiconductor device according to claim 10, wherein the solder material layer includes at least two different metal material layers or alloy layers. 12. The solder material layer comprises tin, bismuth,
The semiconductor device according to claim 11, comprising at least two kinds selected from the group consisting of zinc, antimony, indium, silver, and copper.