JPH0714843A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To greatly improve the reliability of junction part between an Al electrode and a bump electrode in a transfer system in which the bump electrode is formed on the Al electrode of a semiconductor element. CONSTITUTION:After a resin film 24, having an aperture 25 on the part corresponding to the Al electrode 13 of a semiconductor element 12, has been formed on a bump electrode forming substrate 10, a bump electrode 11 is formed in the aperture 25 in such a manner that the head of the bump electrode 11 will be protruding from the aperture 25. Then, after the bump electrode 11 and the Al electrode 13 have been aligned, the Al electrode 13 is pressure-welded to the head of the bump electrode 11. Then, a part of the Al electrode 13 and a part of the head of the bump electrode 11 are alloyed by heating the pressure- welded Al electrode 13 and the bump electrode 11, and at the same time, the aperture 25 is widened by contracting the resin film 24. Then, the bump electrode 11 is separated from the bump electrode forming substrate 10, and the separated bump electrode 11 is connected to the wiring electrode of the wiring substrate.

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 more particularly to a technique for mounting semiconductor elements in high density, thinness and compactness.

[0002]

2. Description of the Related Art In recent years, the number of electronic devices using a large number of semiconductor elements has been rapidly increasing, and, for example, memory cards, liquid crystals, EL displays and the like are known. Each of these has a requirement that a plurality of LSI chips must be mounted on a substrate having a constant area in a high density and in a thin shape.

A micro bump bonding method (hereinafter referred to as MBB method) is known as an effective means for mounting LSI chips at high density in this way. In this method, the protruding electrode formed on the AL electrode of the LSI chip and the wiring electrode of the wiring board are pressed against each other by a photo-curing insulating resin, and the two electrodes are electrically connected only by the contracting force of the resin. To do.

In the above method, as described above, L
It is necessary to form a protruding electrode on the AL electrode of the SI chip, and in order to form the protruding electrode, a multilayer metal film conventionally called a barrier metal such as Cr-Cu or Ti-Pd is formed on the AL electrode of the LSI chip. Then, a method of forming a projection electrode called a bump on this by electroplating is adopted.

However, in order to form the protruding electrode on the AL electrode of the LSI chip as described above, a large number of vapor deposition steps, photolithography steps and etching steps are required. For this reason, the LSI chip is damaged in the middle of these steps, which causes the yield to decrease, and also causes the mounting cost to increase and the reliability to decrease.

Further, the L having the above-mentioned protruding electrode is formed.
It is difficult to obtain an SI chip, and there is a problem that it lacks versatility.

As a method for solving the above problem, LS is used.
A method of directly joining a protruding electrode on the AL electrode of the I-chip by a transfer method has been adopted.

The MB described above will be described below with reference to FIGS. 5 and 6.
A method of directly joining by a transfer method will be described together with the process of the B method.

In FIGS. 5 and 6, 10 is a substrate for forming a protruding electrode, 11 is a protruding electrode made of Au, 12 is a semiconductor element, and 13 is an Al electrode of the semiconductor element.

First, as shown in FIG. 5A, the protruding electrode forming substrate 10 and the semiconductor element 12 face each other, and the protruding electrode 11 on the protruding electrode forming substrate 10 and the Al electrode 13 of the semiconductor element 12 face each other. Align as you would.

Next, as shown in FIG. 5B, the protruding electrode 11 and the Al electrode 13 are pressed and heated by a pressing tool 14 having a vacuum suction hole 14a. By this pressurization and heating, the bump electrode 11 on the bump electrode forming substrate 10 is bonded to the Al electrode 13 of the semiconductor element 12.

Next, as shown in FIG. 5C, when the semiconductor element 12 is peeled from the bump electrode forming substrate 10 by sucking the semiconductor element 12 by the vacuum suction hole 14a of the pressure tool 14, The protruding electrode 11 is transferred and joined to the Al electrode 13. In this case, the bump electrode 1 made of Au
1 and Al electrode 13 have a slight Au-A in the interface layer between them.
l alloy is formed and joined. In addition, the protruding electrode 11
The shape and size of the do not change much when they are formed. That is, the temperature, pressure, and time required to form a small amount of Au-Al alloy in the interface layers of both are applied. Specifically, the temperature is about 380 to 460 ° C., the pressure is 7 to 10 g per protruding electrode, and the time is 1 sec.

Next, as shown in FIG. 6A, the wiring substrate 1 having the semiconductor element 12 to which the protruding electrode 11 is transferred and bonded and the wiring electrode 16 at a position corresponding to the protruding electrode 11.
7 is aligned, and a photocurable insulating resin 18 is applied to a region of the wiring board 17 facing the semiconductor element 12.

Next, as shown in FIG. 6 (b), the protruding electrode 11 is brought into pressure contact with the wiring electrode 16 by the normal temperature hot pressing tool 14. By doing so, the photo-curable insulating resin 18 interposed between the semiconductor element 12 and the wiring board 17 is pushed to the surroundings, and the protruding electrode 11 and the wiring electrode 16 are electrically connected completely. become. At this time, the protruding electrode 1
1 needs to be greatly deformed. For example, the protrusion electrode 11 having a height of about 10 μm before pressurization has a thickness of 4 to 5 μm.
Deform to a certain degree. The load required for this is 90 to 100 g per protruding electrode.

Next, as shown in FIG. 6 (c), ultraviolet rays 20 are irradiated from the back surface or side surfaces of the wiring board 17 to cure the photocurable insulating resin 18.

Next, as shown in FIG. 6 (d), when the pressure is released, the connection between the protruding electrode 11 and the wiring electrode 16 is completed.

As described above, in the prior art,
By fixing the wiring board 17 and the semiconductor element 12 under pressure without heating and fixing them with the photo-curable insulating resin 18, the problems which have hitherto been solved are improved, and the operational effects as shown below are obtained. Is getting

(1) Since it is an unheated connection, it can be connected without applying thermal stress.

(2) Since the connecting portion is only pressure-contacted (contacted), thermal stress at the joint portion due to the difference in thermal expansion coefficient is not received.

(3) Since the connecting portion is not a joint having a metal bond, it is possible to cope with a narrow pitch.

[0021]

However, the above-mentioned conventional method has the following problems.

First, in the bonding step shown in FIG. 7A, the bump electrode 1 formed on the bump electrode forming substrate is formed.
1 is Au-Al between the Al electrode 13 of the semiconductor element 12 and
Transfer due to the formation of the intermetallic compound of alloy 21
To be joined. This Au-Al alloy 21 is
Since it is necessary to form only an amount necessary for peeling off the projection electrode forming substrate from the substrate, a very thin layer is formed. In addition, such a small amount of Au-Al alloy 21
Since it only needs to be formed, the transfer condition is that the bonding temperature is 3
The load is 80 to 460 ° C., and the load is low and the time is short.
Specifically, the load is 8 to 10 g / bump per bump electrode, and the time is 1 to 2 sec. Therefore, the protruding electrode 1
1 is transferred onto the Al electrode 13 with almost no deformation.

However, such an extremely thin Au--
The Al alloy 21 is insufficient in terms of bonding reliability, and when subjected to a reliability test such as high temperature storage, the connection resistance at the interface between the bump electrode 11 and the Al electrode 13 increases in a relatively short test time, and further, If it continues, it will be completely electrically disconnected.

Therefore, in order to form a sufficient Au-Al alloy 21 between them, the load is further increased and the bump electrode 11 and the Al electrode 13 are sufficiently pressure-welded to each other. Therefore, it is necessary to form an intermetallic compound of both.

However, when the load is increased in a heated state, the hardness of the protruding electrode 11 made of Au is lowered by heat, and therefore the deformation of the entire protruding electrode 11 is dominant as shown in FIG. 7B. Will be.

Therefore, according to the conventional method, the intermetallic compound between the bump electrode 11 and the Al electrode 13 cannot be made sufficient.

Further, in the MBB method, the height variations of the protruding electrodes 11 and the wiring electrodes 16 formed on the wiring board 17 are used.
The bump electrode 11 is partially plastically deformed in order to absorb the variation in thickness. Therefore, the protruding electrode 11 is transferred,
In the step of joining, it is desirable that the deformation of the bump electrode 11 is as small as possible and the intermetallic compound between the bump electrode 11 and the Al electrode 13 is sufficient.

In view of the above problems, it is an object of the present invention to provide a joining method capable of improving the connection reliability of the joining portion between the bump electrode and the Al electrode.

[0029]

In order to achieve the above object, the present invention forms a protruding electrode in the opening of a resin layer so that the head protrudes from the opening, and By pressing the metal electrode of the semiconductor element, the head of the protruding electrode and the metal electrode of the semiconductor element are pressed into contact, and then the protruding electrode and the metal electrode are heated to partially cover the head of the protruding electrode and the metal electrode. It is an alloy with a part.

Specifically, the solution means taken by the invention of claim 1 is directed to a method for manufacturing a semiconductor device in which a metal electrode of a semiconductor element and a wiring electrode of a wiring board are connected via a projection electrode, and a projection electrode is formed. A step of forming a resin film having an opening at a portion corresponding to the metal electrode of the semiconductor element on the substrate for use, and a step of forming a protruding electrode in the opening so that a head of the protruding electrode projects from the inside of the opening. A step of aligning the protruding electrode with a metal electrode of the semiconductor element, and a step of pressing the semiconductor element against the protruding electrode forming substrate to press the metal electrode against the head of the protruding electrode By heating the pressure-contacted metal electrode and the protruding electrode, a part of the metal electrode and a part of the head of the protruding electrode are alloyed and the resin film is contracted to expand the opening. A step, a configuration and a step of connecting the protruding electrodes and the step of separating the substrate for a protruding electrode forming, the breakaway protrusion electrodes to the wiring electrodes of the wiring board.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the resin film is made of a heat-shrinkable resin.

According to a third aspect of the present invention, in the structure of the first aspect, in the step of connecting the protruding electrode to the wiring electrode of the wiring board, the protruding electrode and the wiring electrode of the wiring board are in contact with each other. A configuration is added, which is a step of fixing the semiconductor element and the wiring board with an insulating resin interposed therebetween.

[0033]

According to the structure of claim 1, the step of pressing the semiconductor element against the substrate for forming the protruding electrode to press the metal electrode of the semiconductor element against the head of the protruding electrode, and the metal electrode and the protruding electrode in the pressed state. And a step of alloying a part of the metal electrode and a part of the head of the protruding electrode by heating
Since the metal electrode of the semiconductor element is pressed against the head of the bump electrode at room temperature and only the head of the bump electrode receives the pressing load, the two are sufficiently deformed at the interface between the two to be pressed and contacted in a wide area. Since a part of the metal electrode and a part of the head of the bump electrode, which are pressed against each other in a wide area, are alloyed with each other, a large number of parts are alloyed.

According to the second aspect of the invention, since the resin film is made of a heat-shrinkable resin, when the metal electrode and the protruding electrode are heated, the resin film contracts and the opening thereof spreads smoothly.

According to the third aspect of the present invention, the semiconductor element and the wiring board are fixed to each other by the insulating resin interposed therebetween in a state where the protruding electrode and the wiring electrode of the wiring board are in contact with each other.
The protruding electrode and the wiring electrode of the wiring board are surely connected.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a semiconductor device according to an embodiment of the present invention will be described below with reference to the drawings.

1 and 2 are cross-sectional views for explaining each step of the method of manufacturing a semiconductor device according to one embodiment of the present invention.

First, as shown in FIG. 1A, the protruding electrode forming substrate 10 and the semiconductor element 12 face each other, and the protruding electrode 11 on the protruding electrode forming substrate 10 and the Al electrode 13 of the semiconductor element 12 face each other. Align as you would. The detailed structure of the bump electrode forming substrate 10 used here is as shown in FIG. 3, and the bump electrode forming substrate 10 has a three-layer structure. That is, the transparent conductive film 23 is formed over the entire surface of the insulating electrode 22 of the bump electrode forming substrate 10. A heat-resistant glass substrate was used as the insulating substrate 22, and an ITO (indium tin oxide) film was used as the transparent conductive film 23. An opening 25 is formed by applying a photosensitive insulating resin 24 on the transparent conductive film 23 and exposing and developing only a portion of the semiconductor element 12 corresponding to the Al electrode 13. Then, the transparent conductive film 2
The protruding electrode 11 is formed in the opening 25 by the electrolytic plating method of Au using 3 as one electrode. Further, as the photosensitive insulating resin 24, a positive photoresist, a polyimide resin or the like was used.

Next, as shown in FIG. 1B, the protruding electrode 11 and the Al electrode 13 are pressed by the pressing tool 14. By this pressurization, the protruding electrode 11 on the protruding electrode forming substrate 10 and the Al electrode 13 of the semiconductor element 12 are sufficiently deformed at the interface thereof and are pressed into contact with each other.

Next, as shown in FIG. 1C, heating is performed by the heating tool 19 while maintaining the state where the protruding electrode 11 and the Al electrode 13 are in pressure contact with each other. By doing so, an Au—Al alloy is formed between the protruding electrode 11 and the Al electrode 13. At the same time, the insulating resin 24 formed on the protruding electrode forming substrate 10 contracts due to the heat of the heating tool 19, and the opening 25 has a forward taper shape, so that the formed protruding electrode 11 is formed. Is in a state of being easily separated from the substrate 10 for forming the bump electrode.

This state will be described in detail with reference to FIG.
That is, as shown in FIG. 4A, in the step of applying pressure by the pressing tool 14, the bump electrode 11 and the Al electrode 13 are pressed against each other and sufficiently deformed and pressed against each other. At this time, since the protruding electrode 11 has the insulating resin 24, the load is applied only to the hemispherical head 26 protruding upward, and the deformation occurs only in this portion. Due to this deformation, the oxide film on the surface of the Al electrode 13 is sufficiently extruded to the periphery, and the newly formed Al surface is in contact with the bump electrode 11.

After that, as shown in FIG. 4B, when the both are heated by the heating tool 19, the protruding electrodes 11 and A
A sufficient intermetallic compound made of the Au—Al alloy 21 is formed at the interface with the 1-electrode 13. At the same time, the insulating resin 24 is contracted by the heat of the heating tool 19 and the opening 2
5 is widened so that the protruding electrode 11 is easily separated from the protruding electrode forming substrate 10. The load, heating temperature and time at this time are 20 to 50 g / bump and 380, respectively.
˜480 ° C., 1˜3 sec. In particular, the load varies depending on the size of the protruding electrode 11, but it is necessary to set the load so that the protruding electrode 11 is pushed in to about 1/3 to 2/3 of the thickness of the Al electrode 13. Further, the pressure tool 14 and the heating tool 19 may be the same. However, in this case, it is necessary to provide a mechanism capable of heating after pressurizing. For example, the above mechanism is possible by using a pulse heat tool.

Next, as shown in FIG. 1 (d), after removing the heating tool 19, a carrying jig 27 having a vacuum suction hole is formed.
When the semiconductor element 12 is pulled up by adsorption by the, the transfer and bonding of the bump electrode 11 to the Al electrode 13 is completed. At this time, the bump electrode 11 and the Al electrode 13 made of Au have sufficient and high reliability in the interface layer between them.
1 (see FIG. 4B).

Next, as shown in FIG. 2A, the semiconductor element 12 to which the protruding electrode 11 is transferred and bonded, and the protruding electrode 1
Wiring board 17 having wiring electrode 16 in a portion corresponding to 1
Align and. In this case, a silicon substrate or a glass substrate is used as the wiring board 17, and Cr-Au, Ti-Pd-Au, ITO or the like is used as the material of the wiring electrode 16. After that, the photocurable insulating resin 18 is applied to the area of the wiring board 17 where the wiring electrodes 16 are formed.

Next, as shown in FIG. 2B, the semiconductor device 12 and the wiring board 17 are brought into pressure contact with each other by the pressure tool 14, and ultraviolet rays 20 are irradiated from the back surface or the side surface of the wiring board 17 to perform photo-curing. The insulating resin 18 is cured.

Next, as shown in FIG. 2 (c), when the pressure is released, the connection between the protruding electrode 11 and the wiring electrode 16 is completed.

[0047]

As described above, according to the method of manufacturing the semiconductor device of the first aspect of the present invention, the semiconductor element is pressed against the substrate for forming the protruding electrode, so that the metal electrode of the semiconductor element is connected to the protruding electrode. The method has a step of press-contacting the head part, and a step of heating the metal electrode and the protruding electrode in a press-contact state to alloy a part of the metal electrode and a part of the head part of the protruding electrode with each other. Since the metal electrode is pressed against the head of the bump electrode at room temperature and only the head of the bump electrode receives the pressing load, the two electrodes are sufficiently deformed at the interface between them to be pressed and contacted in a wide area. Since a part of the metal electrode and a part of the head of the protruding electrode that are pressed together by the alloy are alloyed with each other, there are many parts to be alloyed. Therefore, a good and highly reliable joint at the interface between the metal electrode and the protruding electrode. Is obtained.

Therefore, when the present invention is applied to the flip chip system and the MBB system, the connection reliability of the entire semiconductor device can be greatly improved.

According to the method of manufacturing a semiconductor device of the second aspect of the present invention, since the resin film is made of heat-shrinkable resin, when the metal electrode and the protruding electrode are heated, the resin film shrinks and the opening is formed. Since it spreads and the protruding electrode is smoothly separated from the protruding electrode forming substrate, the joint between the metal electrode and the protruding electrode is not damaged.

According to the method of manufacturing a semiconductor device of the third aspect of the present invention, the semiconductor element and the wiring board are fixed to each other with the insulating resin interposed therebetween while the protruding electrode and the wiring electrode of the wiring board are in contact with each other. Therefore, the protruding electrode and the wiring electrode of the wiring board can be reliably connected.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing each step of a method for manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing each step of the method for manufacturing the semiconductor device.

FIG. 3 is a cross-sectional view of a substrate for forming a bump electrode in the method of manufacturing the semiconductor device.

FIG. 4 is an enlarged cross-sectional view showing a joint between the head of the protruding electrode and the wiring electrode of the wiring board in the method of manufacturing a semiconductor device.

FIG. 5 is a cross-sectional view showing each step of a conventional method for manufacturing a semiconductor device.

FIG. 6 is a cross-sectional view showing each step of a conventional method for manufacturing a semiconductor device.

FIG. 7 is an enlarged cross-sectional view showing a joint between a protruding electrode and a wiring electrode of a wiring board in a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 10 Substrate for Forming Projection Electrode 11 Projection Electrode 12 Semiconductor Element 13 Al Electrode (Metal Electrode) 14 Pressure Tool 16 Wiring Electrode 17 Wiring Board 18 Photocurable Insulating Resin 19 Heating Tool 20 Ultraviolet 21 Au-Al Alloy 22 Insulating Substrate 23 Conductive film 24 Insulating resin 25 Opening 26 Head

Claims (3)

[Claims] 1. A method of manufacturing a semiconductor device, wherein a metal electrode of a semiconductor element and a wiring electrode of a wiring board are connected via a projection electrode, which corresponds to the metal electrode of the semiconductor element on a projection electrode forming substrate. A step of forming a resin film having an opening portion in the portion; a step of forming a protruding electrode in the opening portion such that its head protrudes from the opening portion; and the protruding electrode and the metal electrode of the semiconductor element. A step of aligning, a step of pressing the semiconductor element against the substrate for forming a protruding electrode to press the metal electrode against the head of the protruding electrode, and heating the pressed metal electrode and the protruding electrode. Thereby alloying a part of the metal electrode and a part of the head of the protruding electrode and contracting the resin film to expand the opening, and forming the protruding electrode on the protruding electrode forming base. A method of manufacturing a semiconductor device, comprising: a step of separating from a plate; and a step of connecting the separated protruding electrode to a wiring electrode of a wiring board. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the resin film is made of a heat-shrinkable resin. 3. The step of connecting the protruding electrode to the wiring electrode of the wiring board, the semiconductor element and the wiring board are interposed between the protruding electrode and the wiring electrode of the wiring board in a state of being in contact with each other. The method for manufacturing a semiconductor device according to claim 1, wherein the step is a step of fixing with an insulating resin.