JPH0878419A - Manufacture of bump and semiconductor device using the same - Google Patents

Abstract

PURPOSE: To simlify the manufacturing process of a semiconductor device and reduce the manufacturing cost, by using a bump which simplifies the manufacturing of a semiconductor device, and its manufacturing method. CONSTITUTION: In the manufacturing method of a semiconductor device, a bump body 19 is constituted of Pn-Sn solder. An antireaction film 20 composed of an Au film 14 and a Cu film 15 is formed on the bump body 19 in the part where the electrode of the semiconductor device body is in contact with the bump body 19, so that a bump 90 is constituted. Since the bump 90 has the antireaction film 20, the bump can be bonded to the electrode 12 of the semiconductor device 11, without forming an antireaction film on the semiconductor device to be bonded to the bump 90.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bump and a method of manufacturing a semiconductor device using the bump, and more particularly to a bump formed by a transfer method and a semiconductor device using the bump.

In recent years, the demand for higher integration of semiconductor elements and higher packaging density of electronic parts has increased as the performance of semiconductor devices has increased.

For this reason, a technique for increasing the mounting density has been actively used by the surface mounting method in which the package is mounted without forming the insertion hole in the circuit board. Among them, the flip-chip type package has a package structure that particularly satisfies the requirements of high packaging density and low price. The flip-chip package has a structure in which a projecting terminal called a bump is used to connect to a circuit board instead of a lead terminal that has been conventionally used for connecting an electrode of a semiconductor chip and an external electrode.

Bumps have the advantage that they can be manufactured at a lower cost than pin-shaped terminals in addition to having a small lead pitch (the pitch of the leads of a semiconductor chip or a package, which is an index of mounting density).

Therefore, the development of a bump having a small lead pitch and which can be manufactured at low cost and a semiconductor device using the bump contributes to downsizing and cost reduction of electronic equipment.

[0006]

2. Description of the Related Art As one of the bump manufacturing methods, there is a transfer method.

The structure of the conventional transfer type bump and the manufacturing method will be described below with reference to FIGS.

FIG. 4 is a diagram for explaining the steps in order, and FIG. 5 shows the state of each manufacturing step of the transfer bump. The transfer-type bump manufacturing method is a method in which the electrodes 2 for joining the bumps are provided on the semiconductor device main body 1 and the bumps are separately provided on the formation substrate 8 and transferred to the semiconductor device main body 1 by thermal evaporation. .

That is, in the transfer-type bump manufacturing, the semiconductor device body 1 and the bumps 9 are subjected to different treatments and finally joined, and there is no need for a time-series correlation between the treatments.

The process of joining the bumps 9 to the semiconductor device body 1 is mainly a process for providing a reaction preventive film called a barrier metal. Currently, Al is used for the electrodes of the semiconductor device main body 1 and the material for the bumps is Pb.Sn.
The structure which is solder is general. Reaction prevention film is Pb
-A metal film having a function of preventing the reaction between the Sn solder and Al so that they do not react with each other and cause mutual diffusion to reduce electric conduction or reduce the strength of the connection when they are joined. is there.

In FIG. 5, processing steps for the semiconductor device body 1 are shown by (a) to (e), and processing steps for the formation substrate 8 are shown by (f) and (g).

In FIG. 5A, a passivation film 3 which is an insulating film is provided on an aluminum (Al) electrode 2 provided on the semiconductor device body 1, and the electrode 2 is exposed by patterning the upper portion of the electrode 2. Shows the state. The steps up to this point are shown as steps 51 to 53 in FIG.

FIG. 5B shows a state in which a nickel (Ni) film 5 and an Au film 4 which are reaction preventing films are formed on the electrodes 2, respectively. This step corresponds to step 54 and step 55 in FIG.

Next, FIG. 5C shows a state in which a mask made of the resist 6 is formed by a series of processes relating to the coating and exposure of the resist 6 for patterning the reaction preventive film 10. This step is shown as step 56 and step 57 in FIG.

Next, FIG. 5D shows a state in which the reaction preventing film 10 has been completely etched using the mask of the resist 6 formed in the step (c) described above. This step corresponds to step 58 in FIG.

Finally, as shown in FIG. 5 (e), the resist 6 is peeled off to form the reaction preventing film 10 on the electrode 2 of the semiconductor device main body 1 and the bumps 9 can be connected. This step is step 59 in FIG. 4, and the processing performed on the semiconductor device body 1 is completed.

Next, the formation of bumps will be described. First, the bump forming substrate 8 is coated with the resist 7, and the bump forming die 7 is provided by a process related to exposure. This process is shown in Figure 4.
In step 60. However, the passivation film 3 formed in the step of forming the forming die and the step 53 described above.
The patterning process is also performed through the processes of steps 56 to 59 similar to the patterning of the reaction preventive film, but since there is no difference from the invention described below, the description of each photolithography process will be simply omitted. This is referred to as patterning or formation process.

Substrate 8 on which solder material is formed using resist 7 as a mask
When it is deposited on the bumps 9 using the resist 7 as a mold, the solder material is not adhered to the resist 7 which is a resin material and is deposited only on the formation substrate 8 and the solder material adhered to the formation substrate 8.
It is molded into the shape of.

The bumps 9 that have been formed on the formation substrate 8 are transferred to the electrode 2 provided with the reaction preventive film 10 of the semiconductor device body 1 by thermocompression bonding as shown in step (h) of FIG. 5 and step 62 of FIG. It is connected.

The bumps formed in the steps 60 and 61 are shown in FIGS. 6 (a) and 6 (b).
(A) is a top view, (b) is a line A- of a top view (a).
It is an arrow line view along A '. The resist 7 used as the molding die for the bumps 9 may be reused or removed.

The reaction prevention film 1 is formed on the electrode 2 of the semiconductor device body 1.
When 0 is provided, patterning by a mask process is used.

The mask process includes a resist coating process 56,
Process exposure 57, resist peeling process 58, and many steps,
In addition to being complicated, an etching device for generating plasma, or an equipment such as a dedicated etching tank for an object to be etched or an etching solution is required. The etching apparatus and the etching tank are expensive equipment, which increases the manufacturing cost of the semiconductor device.

In the mask process, the semiconductor device body 1
It is necessary to perform an alignment work for providing the reaction prevention film 10 in accordance with the position of the electrode of 1., and if the alignment work is hindered, the manufactured semiconductor device becomes defective and the process yield is reduced. become.

In view of the above points, the present invention has developed a transfer type bump which can be more easily bonded to a semiconductor device body, and a method of manufacturing a semiconductor device more easily by using this bump, thereby reducing the mask process. The purpose is to simplify the process and reduce the manufacturing cost.

[0025]

In order to solve the above problems, the present invention has the following configuration.

The bump of claim 1 is a bump to be bonded to an electrode of a semiconductor device, wherein the bump body is provided on a portion of the bump body to be bonded to an electrode of the semiconductor device. The present invention is characterized in that it is configured by a reaction preventing film that prevents reaction with the electrodes.

In the bump of claim 2, the bump body is made of Pb.
It is composed of Sn solder and the reaction prevention film is made of Au.
It is characterized in that the film and the metal layer are made of a Cu film.

According to a third aspect of the present invention, there is provided a method for manufacturing a semiconductor device, which comprises manufacturing a semiconductor device body having electrodes for bonding bumps and providing a molding die for bump molding on a bump forming substrate, and a molding die. From the top, a step of forming a bump body by applying a bump body forming material to be the body of the bump on a formation substrate, and a material having a function of preventing the electrode and the bump from reacting on the formed bump body. And a step of forming a reaction-preventing film, the bumps are manufactured, and the bumps are bonded to the electrodes of the semiconductor device via the reaction-preventing film on the bumps.

The method of manufacturing a semiconductor device according to a fourth aspect is characterized in that the bump forming material is Pb.Sn solder and the reaction preventing film is a metal layer composed of an Au film and a Cu film. is there.

[0030]

According to the first aspect of the invention, the bumps joined to the electrodes of the semiconductor device are connected to the electrodes of the semiconductor device at the joints.
By forming the reaction prevention film, it becomes unnecessary to form the reaction prevention film on the semiconductor device body.

In the invention of claim 2, the bump main body is made of P
By using an Au film that is composed of b.Sn solder and has good adhesion when thermocompression-bonded with Al and does not cause mutual diffusion, it is bonded to the Al electrode of the semiconductor device body. In doing so, the reliability and strength between the electrodes of the semiconductor device body and the bumps were improved.

Further, by selecting a Cu film having a strong bonding force with Pb.Sn solder as the structure of the reaction preventing film, the bonding force between the bump body and the reaction preventing film is strengthened.

According to the third aspect of the present invention, the step of providing the reaction preventive film on the semiconductor device main body is not necessary because the bump main body is provided with the reaction preventive film.

Further, since a mask is not required in the step of providing the reaction preventive film on the bumps, one mask step is omitted in the manufacturing of the semiconductor device, and the steps involved in this step are simplified.
In addition, the time and cost can be reduced.

In the invention of claim 4, the bump is made of Pb.
In addition to being composed of Sn solder, the reaction preventive film has good adhesiveness when thermocompression-bonded with Al and does not cause mutual diffusion.
By selecting the u film, a highly reliable process condition between the electrode and the bump of the semiconductor device body when the Al electrode and the bump of the semiconductor device body were joined was obtained.

Further, by selecting a Cu film having a strong bonding force with Pb.Sn solder for the structure of the reaction preventing film, a process condition in which the bonding force between the bump body and the reaction preventing film is strong is obtained.

[0037]

First, an embodiment of the bump of the invention described in claims 1 and 2 will be described.

Schematic block diagrams of the bumps are shown in FIGS. 3 (a) and 3 (b).

FIG. 3A is a top view showing a transfer type bump 90 having the reaction preventive film 20 formed in this embodiment. Further, (b) is an arrow view taken along a line BB ′ shown in (a). On the substrate 18 on which the bump 90 is formed, the bump 90 composed of the bump body 19 having the Au film 14 serving as the reaction preventing film 20 and the Cu film 15 is provided.

The bump body 19 according to this embodiment is made of Pb.
Reaction preventive film 20 made of Sn solder and provided with a reaction preventive film 20 at the joint portion with the electrode of the semiconductor device main body 11 so that the electrode of the semiconductor device main body 11 can be joined without providing the reaction preventive film. The film 20 is composed of a two-layer metal film of a Cu film 15 directly formed by sputtering on the bump body 19 made of Pb.Sn solder and an Au film 14 similarly formed thereon by sputtering. The film thickness is about 0.1 to 1 μm.

With this structure, the alignment when forming the reaction preventive film on the electrode is not necessary and the reliability of the alignment accuracy is improved.

A member forming the reaction preventive film 20 is
By selecting the u film 14, the adhesion with the electrode was improved. Further, by selecting the Cu film 15, the adhesion between the reaction preventive film 20 and the underlying Pb.Sn solder was improved.

Next, an embodiment of the invention described in claims 3 and 4 will be described.

1 and 2 show steps of a method of manufacturing a semiconductor device using the bump 90.

FIG. 1 is a diagram for explaining the steps in sequence, and FIG. 2 shows the state of each manufacturing step of the transfer bump.

In FIG. 2, only the process shown in FIG. 2A is a process performed on the semiconductor device body 11, and FIGS. 2B to 2E are processes for forming the bumps 90 on the formation substrate 18.

First, the processing steps applied to the semiconductor device body 11 will be described.

The process up to the step of forming the passivation film 13 on the Al electrode 12 provided on the semiconductor device main body 11 and patterning it to expose the upper surface of the electrode 12 is the same as the conventional process. This step is described in steps 71 to 73 in FIG. However, in the present embodiment, there is no subsequent processing performed on the semiconductor device main body 11, and the bump 90 can be connected in the above manner.

Next, a method of forming the bump 90 will be described.

As shown in FIG. 2B, a resist 17 is applied to the formation substrate 18 on which the bumps 90 are to be formed, and a molding die for molding the bump body 19 by photolithography is prepared. This step is shown as step 74 in FIG.

Subsequently, as shown in FIG. 2C, Pb.Sn solder is applied on the molding die by a plating method so that the Pb.Sn solder follows the molding die made of the resist 17. The bump main body 19 is formed by molding.
This step corresponds to step 75 in FIG.

Further, in this embodiment, as shown in FIG. 2D, the Cu film 15 is formed by the sputtering method here. At this time, the Cu film 15 which is a metal is not formed on the resist 17 which is a resin material without using a mask,
The Cu film 15 is deposited only on the bump main body 19 made of solder, so that the Cu film 15 is formed only on the surface of the bump main body 19 exposed from the resist 17. This step corresponds to step 76 in FIG.

The film thickness of the Cu film 15 may be about 0.1 μm to 1 μm. The Cu film 15 has a low electric resistance in addition to the effect of preventing the reaction, and the bump body 19 and the electrode 1 have a characteristic.
The joint of No. 2 has a low resistance and has a high adhesion with Pb.Sn solder.

Next, as shown in FIG. 2E, the Cu film 15 is formed.
Like the Cu film 15, the Au film 14 is formed on the upper surface of the bump 19 without a mask in the same manner as the Cu film 15 from 0.1 μm to 1 μm.
To a film thickness of. Since the Au film 14 also does not ride on the resist 17 like the Cu film 15, the bump body 19 and the Cu film 15 are also adhered only to the portions exposed from the resist 17. This step is shown as step 77 in FIG.

In addition to the effect of preventing the reaction, the Au film 14 has the effect of forming an Au.Al alloy by thermocompression bonding with the electrode 12 to further increase the strength with which the bump body 19 is bonded to the electrode 12.

Next, the passivation film 13 is formed on the electrode 12.
A process of joining the semiconductor device main body 11 provided with and the cap 90 will be described.

In step (f) of FIG. 2 and step 78 of FIG. 1, the semiconductor mounting body 11 is connected to the bump 90 via the electrode 12 and the reaction preventive film 20.
For the connection, a thermocompression bonding method is used in which the joint portion is heated to about 200 ° C. This heating softens the surface of the electrode made of Al, and pressurizes it to bond the Au.A.
l Alloy.

From the resist 17 to the bump body 19 and Cu
Since the exposed portion of the film 15 exactly corresponds to the bonding portion with the electrode 2, the semiconductor device manufactured by the above method has only the reaction preventing film 2 at the bonding portion between the bump 90 and the electrode 12.
It becomes the structure which has 0.

By the steps described above, the semiconductor device mounted by the flip chip method is completed. In addition, TAB (tape automated b) is further formed on the bump 90.
If a lead terminal is connected, a TAB-type mounted semiconductor device is obtained.

As described above, in the method of manufacturing the semiconductor device of this embodiment, the mask step is not used to form the reaction preventing film 20. Therefore, it is possible to provide a semiconductor device at a low cost by reducing the man-hours, the time, personnel, and manufacturing cost required for this.

[0061]

As described above, according to the bump of the invention of claim 1, in order to provide the reaction preventive film on the bump itself,
It is possible to directly bond the bump without providing a reaction preventive film on the electrode of the semiconductor device body that is bonded to the bump.

Therefore, since alignment is not required when the reaction preventive film is provided on the electrode, the process of joining with the electrode is simplified and the reliability is improved.

According to the bump of the invention of claim 2,
By using Au for the structure of the reaction preventive film, the electrodes of the semiconductor device main body and the bumps can be bonded with the Au.Al alloy, so that the bonding strength can be increased and the connection resistance can be decreased.

Further, by using Cu for the structure of the reaction preventing film and using Pb.Sn solder for the bump body, it is possible to increase the bonding strength between the bump body and the reaction preventing film.

According to the semiconductor device manufacturing method of the third and fourth aspects of the present invention, it is possible to form the reaction prevention film between the electrodes of the semiconductor device main body and the bumps without using a mask. Therefore, there is an effect that the semiconductor device can be provided at low cost by simplifying the manufacturing process and reducing the cost associated therewith.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of an embodiment of the inventions of claims 3 and 4;

FIG. 2 is a diagram showing a state of each manufacturing process of FIG.

FIG. 3 is a schematic configuration diagram of an embodiment of the inventions of claims 1 and 2.

FIG. 4 is a diagram showing a conventional transfer bump manufacturing process.

FIG. 5 is a diagram showing a state of each manufacturing process of FIG. 4;

FIG. 6 is a schematic configuration diagram showing a conventional transfer bump.

[Explanation of symbols]

 1, 11 Semiconductor device main body 2, 12 Electrode 3, 13 Passivation film 4, 14 Au film 15 Cu film 6 Resist 7, 17 Resist 8, 18 Forming substrate 9 Bump 19 Bump body 10, 20 Reaction preventive film 90 Bump

Claims (4)

[Claims] 1. A bump to be bonded to an electrode of a semiconductor device, wherein the bump body is provided on a portion of the bump body to be bonded to the electrode of the semiconductor device, the bump body being the electrode of the semiconductor device. A bump comprising a reaction-preventing film for preventing reaction with the bump. 2. The bump main body is made of lead (Pb) / tin (S).
n) The bump according to claim 1, wherein the bump is formed of solder and the reaction prevention film is a metal layer formed of a gold (Au) film and a copper (Cu) film. 3. A step of manufacturing a semiconductor device main body having electrodes for bonding bumps and providing a molding die for molding the bumps on a substrate on which the bumps are formed, and a step of forming the bumps from the molding die. A step of forming a bump body by applying a bump body forming material to be a body on the formation substrate, and a material having a function of preventing the electrode and the bump from reacting on the formed bump body. A semiconductor device, wherein bumps are manufactured by a step of forming a reaction prevention film, and the bumps are bonded to the electrodes of the semiconductor device via the reaction prevention film on the bumps. Manufacturing method. 4. The bump forming material is lead (Pb) .tin (S).
4. The method of manufacturing a semiconductor device according to claim 3, wherein the reaction prevention film is a metal layer made of a gold (Au) film and a copper (Cu) film, together with n) solder.