JP3294721B2 - Semiconductor device manufacturing method and bump manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device.
And it relates to a method of manufacturing a bump, and a method of manufacturing a semiconductor device for joining the bumps in particular by transfer method relates to the manufacturing method of the bumps that are produced by a transfer method.

In recent years, there has been an increasing demand for higher speed, smaller size, higher packing density, and lower power consumption of electronic components using semiconductor elements.

Various means are conceivable for satisfying the above-mentioned requirements, and connecting a semiconductor device mounted with a semiconductor chip to a mounting substrate with low resistance is one of the effective means.

That is, if a semiconductor device is mounted on a substrate with a low resistance, the speed of an electric signal propagating between the semiconductor devices is increased, so that the speed of an entire electronic device operated by the semiconductor device can be increased and power consumption can be increased. Is also smaller. Further, since heat generated when the semiconductor element operates is reduced, the distance between the semiconductor devices is reduced, which enables high-density mounting, and is also advantageous for miniaturization of electronic equipment.

In order to connect the semiconductor device and the mounting board with a low resistance, the resistance of the terminal attached to the semiconductor device itself and used for connecting to the mounting board may be reduced.

2. Description of the Related Art Reducing the resistance of bumps, which are terminals for surface mounting, can contribute to speeding up, miniaturization, and power saving of electronic equipment.

As one of the bump manufacturing methods, there is a transfer bump method which is versatile for semiconductor chips and has a low manufacturing cost.

The configuration of a conventional method of manufacturing a bump by a transfer method will be briefly described below.

To form a bump, first, a formation substrate is prepared. This bump forming substrate is usually made of a glass material or Al.
It is made of N. An ITO film (Indium Tin Oxide) is formed on the bump forming substrate. I
The TO film is used as a transfer metal film and plays an important role when the formed bump is removed from the formation substrate in a later step. Next, a resist is applied from above the ITO film, and is patterned by a photolithography process to form a mold for forming a bump. A metal member to be a bump is deposited on the molding die by plating, vapor deposition, sputtering, or the like. At present, gold (Au) is generally used as a metal material for bumps.

Next, the bumps are connected to appropriate connection portions of the semiconductor device. When the connection portions of the electrodes and leads of the semiconductor device are plated with Sn, an Au-Sn eutectic alloy is used. -Joining by Au thermocompression bonding.
At this time, it is necessary that the bumps come off the formation substrate quickly. Therefore, the adhesive force between the bump forming substrate and the bump must be smaller than the bonding force between the connection portion on the semiconductor device side and the bump. A and ITO film formed earlier
The bonding force with u is relatively weak, and has a function of quickly separating the bump from the formation substrate in the step of separating the bump from the formation substrate.

[0010] The adhesive force between the members increases as the molecular structure and the molecular size of the member to be bonded and the attaching member are closer to each other.

[0011]

The demand for higher speed and higher density of electronic equipment is increasing, and the resistance when mounting a semiconductor device using a bump made of Au is not yet enough to meet this demand. high. In addition, Au is an expensive noble metal, which increases the manufacturing cost of the semiconductor device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a method of manufacturing a semiconductor device and a method of manufacturing a bump capable of improving electrical characteristics and realizing low cost. It is.

[0013]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a semiconductor device body having electrodes ;
A step of providing a transfer metal film made of vanadium (V), the mold for molding the bump forming material on the transfer metal layer is provided, followed made of copper (Cu) with low resistance metals as the bump forming material Forming a bump on the transfer metal film on the formation substrate using the molding die, and forming the bump; and transferring the bump from the formation substrate to the electrode. Is what you do .

According to a second aspect of the invention, there is provided a method of manufacturing a semiconductor device, wherein a low-resistance metal is formed on a formation substrate by a deposition, sputtering, or plating method .

According to a third aspect of the present invention , in the method of manufacturing a bump to be joined to an electrode provided on a semiconductor device body, a transfer metal film made of vanadium (V) is formed on a formation substrate. Providing a forming mold for forming a bump forming material on the transfer metal film, and then forming a mold from copper (Cu).
It becomes a low resistance metals as the bump forming material, and characterized by comprising the step of the bump by molding using a deposited to adhere to the transfer metal film on the formation substrate, and molding die Is what you do .

[0016] In the production method of the bumps according to claim 4, Oh characterized in forming deposited forming substrate resistance <br/> metals, sputtering, or by a film forming method of plating
You.

[0017]

According to the first aspect of the present invention, the bump member is made of A
By using a low-resistance metal made of Cu having a lower electric resistance than u, the electric resistance when connecting the half device to the electronic apparatus can be further reduced . In addition, low resistance gold of Cu
By using V as the transfer metal for the genus,
Bumps can be quickly removed from the substrate
You.

According to the second aspect of the present invention, the method of depositing the low-resistance metal on the formation substrate is performed by a deposition, sputtering, or plating method, so that the low-resistance metal has a uniform thickness. And the reliability of the semiconductor device can be improved .

According to the third aspect of the present invention, by replacing the Au bump of the conventional semiconductor device with a Cu member having a lower electric resistance, the semiconductor device can be mounted with a lower resistance without changing the configuration of the semiconductor device body. to. In addition, Cu
By using V as a transfer metal for low-resistance metals,
Promptly peel off molded bumps from forming substrate
Can be.

According to the fourth aspect of the present invention, the method of depositing the low-resistance metal on the formation substrate is performed by a deposition, sputtering, or plating method, so that the low-resistance metal has a uniform thickness. Get higher. Therefore, the reliability of the semiconductor device can be improved without changing the configuration of the semiconductor device body.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a semiconductor device 1 according to an embodiment of the present invention will be described.
FIG. 3 shows a schematic configuration of.

In FIG. 3, reference numeral 7 denotes a semiconductor device body 7 of the semiconductor device 1. This embodiment can be applied to any semiconductor device body having a configuration in which bumps are joined.
A surface mount type LSI package called a GA (ball grid array) is used.

The semiconductor device body 7 constructed in this embodiment is
Semiconductor chip 1a on substrate 1b made of glass epoxy resin
Was fixed with die bonding epoxy 1d. The chip electrode 1e formed on the semiconductor chip 1a and the electrode 8 are connected with the wire 1c, and the mold resin 1f is connected to the substrate 1b.
The semiconductor chip 1a, the wire 1c, and the like are sealed by, for example, potting on the upper surface of the semiconductor chip 1a. The semiconductor device 1 includes a semiconductor device 7 having a completed Cu bump 6 by bonding the Cu bump 6 according to the invention of claim 6 to an electrode 8 formed on the semiconductor device body 7. The device 1.

Conventionally, the bumps have been manufactured using Au as a material. However, by using the Cu bumps 6, the electrical resistance with the electrodes 8 becomes lower than before. Therefore, the electrical resistance when mounting the semiconductor device 1 is reduced.

Referring to FIG. 1, a method of manufacturing a semiconductor device and a method of manufacturing a bump 6a according to an embodiment of the present invention will be described. FIG. 2 collectively shows the steps used in the examples.

Since the method for manufacturing the semiconductor device 1 and the method for manufacturing the bump 6 have many common steps, the respective manufacturing methods will be described together.

In FIG. 1A, reference numeral 2 denotes a bump forming substrate made of a glass material. First, a Cr film to be the electrode 3 is formed on the bump forming substrate 2. The electrode 3 functions as an electrode when a bump is formed using electroplating described later. Further, a transfer metal film 4 is formed on the electrode 3.
Is formed to a thickness of 1 μm by sputtering.
Incidentally, the material of the transfer metal film 4 is not limited to V, and for example, application of Cr, Ti, or the like can be considered. These metals have proper bonding strength to a bump material (Cu) described later.

The above is the process shown as step 1 (hereinafter, step is abbreviated as s) and s2 in FIG. Next, as shown in FIG. 1 (b), a mold 5 for bump molding is formed on the formation substrate 2 in the state shown in FIG. 1 (a) and the transfer metal film 4 thereon using a negative resist or a photosensitive resin. It is formed by a photolithography process. This step corresponds to s3 in FIG.

Next, as shown in FIG. 1C, Cu, which is a low-resistance metal 6a, is deposited on the transfer metal film 4 provided on the formation substrate 2 through a molding die 5 by plating. Since the low-resistance metal 6a is deposited only on the transfer metal film 4 exposed from the molding die 5, the low-resistance metal 6a is molded into a bump shape along the molding die 5. In this embodiment, Cu is used as the material of the low-resistance metal 6a. As described above, Cu is a member having lower electric resistance than Au.

In addition, the plating method controls the deposition thickness of the film,
In addition, since the method is highly accurate, the heights of the bumps to be formed are uniform, and the yield of the process is improved. The above steps correspond to s4 in FIG.

Although the low-resistance metal 6a is formed by plating in this embodiment, a method of forming the low-resistance metal 6a by vapor deposition or sputtering instead of plating may be used. Even when any of these methods is used, the uniformity of the low-resistance metal 6a formed is ensured. Subsequently, FIG. 1 (d)
Cu formed by plating from the molding die 5 as shown in FIG.
The bump 6 made is removed. At this time, the molding die 5 may be removed by using a dry or wet resist stripping process, or may be left as it is for reuse. FIG. 1D shows the removed state. However, if the mold 5 is used repeatedly, the number of steps can be further reduced, and the time and cost required for mask production can be reduced.

In this embodiment, it is required that the bonding strength between the Cu bump 6 and the object to be bonded is sufficiently strong, and that the bonding strength between the Cu bump 6 and the V as the transfer metal film 4 is sufficiently small. It is also possible to remove the Cu bump 6 from the molding die without removing the molding die 5 because it is filled. Further, since Cr and Ti are members that satisfy the condition that the bonding force with Cu is small similarly to V, they can be used as the transfer metal film of the bump 6 made of Cu. This step corresponds to s5 in FIG.

Finally, the position is adjusted as shown in FIG.
The u bump 6 was bonded to the electrode 8 of the semiconductor device 7 by forming an Au.Al alloy by thermocompression bonding. This is because the surface is oxidized and the electrical conductivity is reduced if Cu is exposed as it is and is kept in contact with the atmosphere, so the surface is plated with Au and thermocompression bonding is used. This corresponds to s6 in FIG.

In this embodiment, a glass material is used for the formation substrate 2. However, the formation of the electrodes 3
Can be omitted.

In general, a semiconductor device is constructed on the basis of a glass material. Therefore, a process relating to the semiconductor device is designed mainly on the glass material. For this reason, a glass material is used for the formation substrate in this embodiment as well. However, consistency in the process is often required due to differences in expansion and deformation characteristics due to heat. Therefore, even if it is a metal, a method using a metal substrate is also possible if a member having a similar thermal expansion coefficient and melting point (for example, Mo) is used for a substance such as Si.

The electric resistance of Au is 2.4 × in volume resistivity.
Although the member is relatively low at 10 ⁻⁸ Ω · m, the volume resistivity of Cu is even lower at 1.72 × 10 ⁻⁸ Ω · m. Therefore Au
If the bump is formed of Cu instead of the semiconductor device 1, the semiconductor device 1 will be mounted on the electronic device with a lower resistance.

Further, since Cu is a low-priced member as compared with Au, the semiconductor device body 7 conventionally used or a general-purpose product can be used without changing the configuration of the semiconductor device body 7 by the bumps 6. By applying the method described above, the manufacturing cost of the semiconductor device 1 can be reduced.

As described above, Cu is a member having advantages over Au in forming bumps.

With the configuration described above, the electrical resistance when mounting the semiconductor device 1 on a circuit board is reduced.
In addition to increasing the propagation speed of an electric signal, heat generated when the semiconductor device operates is reduced, so that the speed, size, and density of the electronic device can be increased.

Further, the use of Cu, which is inexpensive as compared with Au, for the bump makes it possible to reduce the manufacturing cost of the semiconductor device.

Originally, the bumps formed by the transfer method were developed to replace the relatively expensive pins in order to increase the number of terminals of the semiconductor device and not to increase the cost. Therefore, changing the bump to a low-cost material has an effect in accordance with the purpose of developing the bump.

[0042]

As described above, according to the present invention, a method of manufacturing a semiconductor device and, and a manufacturing method and a bump of bumps of the semiconductor device of the present invention, the invention of claim 1, wherein, when connecting the halves device to the electronic device By further reducing the electrical resistance of the semiconductor device, the speed of propagation of electrical signals between the semiconductor devices is increased,
In particular, it can be applied to a semiconductor device requiring a high speed. In addition, the amount of heat generated due to the operation of the semiconductor device is suppressed, so that the mounting density of the semiconductor device can be increased, the size can be reduced, and malfunction due to heat can be suppressed . Ma
It was, compared to a conventional semiconductor device having an Au-made bumps
Te, it is possible reduce the manufacturing cost of semiconductors devices. Therefore, an electronic device on which a large number of semiconductor devices are mounted can be provided at low cost. In addition, the molded bumps
Can be quickly peeled off. Thus the formed van
Eliminate troubles such as deformation of the pump and improve process yield
Can be planned.

According to the second aspect of the present invention, the method of depositing the low-resistance metal on the formation substrate is performed by vapor deposition, sputtering, or plating to form a uniform film thickness of the low-resistance metal. In addition, the height of the formed bump can be made uniform.

Therefore, the reliability of the semiconductor device using the bump can be improved .

According to the third aspect of the present invention, it is not necessary to change the configuration of the semiconductor device body by replacing the Au bump of the conventional semiconductor device with a Cu member having a lower electric resistance, so that a general-purpose semiconductor device can be used. As a result, it can be mounted with a lower resistance . Further, the manufacturing cost of the semiconductor device can be reduced. Therefore, there is no need to change the configuration of the semiconductor device main body, and an electronic device in which a large number of semiconductor devices are mounted using general-purpose semiconductor devices can be provided at low cost. Also, the molded bumps can be quickly removed from the forming substrate.
Can be peeled. Deformation of the formed bumps
To improve process yield by eliminating problems
it can.

According to the fourth aspect of the present invention, the method of depositing the low-resistance metal on the formation substrate is performed by forming the film by vapor deposition, sputtering, or plating so that the film thickness of the low-resistance metal is made uniform. In addition, the height of the formed bump can be made uniform.

Therefore, there is no need to change the configuration of the semiconductor device main body, and the reliability of a semiconductor device using bumps using a general-purpose semiconductor device can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing steps of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a process of an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a semiconductor device configured in one embodiment of the present invention.

[Explanation of symbols]

 1 A semiconductor device having a Cu bump. Reference Signs List 2 bump forming substrate 3 electrode 4 transfer metal film (V) 5 bump forming die (resist) 6a low resistance metal 6 Cu bump 7 semiconductor device body 8 electrode of semiconductor device body

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-291428 (JP, A) JP-A-6-120228 (JP, A) JP-A-4-269834 (JP, A) JP-A-2- 248066 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/60

Claims (4)

(57) [Claims] A step of forming a semiconductor device main body having electrodes; a step of providing a transfer metal film made of vanadium (V) on a formation substrate; and forming a bump forming material on the transfer metal film. step mold provided, followed made of copper (Cu) with low resistance metals as the bump forming material, using a molded-type mold and deposited on the transfer metal film on the formed substrate to form a bump Transferring the bump from the formation substrate to the electrode. 2. The method according to claim 1 , wherein the low-resistance metal is formed on the formation substrate by a deposition, sputtering, or plating method. 3. A method for manufacturing a bump is bonded to the electrode provided on the semiconductor device main body, on the formation substrate, a step of providing a transfer metal film made of vanadium (V), the bump formed on the transfer metal layer provided mold for molding the timber, followed by a low resistance metals made of copper (Cu) as the bump forming material, deposited to adhere to the transfer metal film on the formation substrate, and a molding A method for producing a bump, comprising a step of forming a bump by molding using a mold. 4. The method according to claim 1 , wherein said low-resistance metal is deposited on said forming substrate,
Forming by filming method of sputtering or plating
4. The method for manufacturing a bump according to claim 3, wherein: