JPS6091656A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To transfer and join a metallic projection into an electrode leading-out region efficiently and positively by forming an organic thin-film for bonding on the electrode leading-out regin in a semiconductor element or the metallic projection formed on a substrate. CONSTITUTION:Electrode leading-out regions 3 in Al are formed on an Si substrate 2 to which an element 1 is shaped, a thin-film 4 consisting of polyimide group resin, etc. having adhesive properties more or less at the normal temperature or at several 100 deg.C is applied, and windows 5 for pushing in protruding electrodes are formed. Metallic projections 8 are formed on a glass plate 7 through Pt or Mo films, which have excellent plating properties and can be peeled and transferred easily. The element 1 is sucked and fixed to a tool 9, and the metallic projections corresponding to the electrode leading-out regions 3 are positioned and pressed 10, and transfered and joined on the regions 3 through the resin film 4. The temperature of the tool is kept properly, and the metallic projections can be transferred and joined on the leading-out regions efficiently and positively under pressure by low pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing high-density, thin packaging for semiconductor devices and the like.

2. Description of the Related Art Structures of Conventional Examples and Their Problems In recent years, semiconductor elements such as ICs and LSIs have been introduced into the fields of various home appliances and industrial equipment.

In order to conserve resources and power, and to expand the scope of use of these household electrical appliances and industrial equipment, the so-called bothamolarization of 16K, smaller size, and thinner products is being promoted.

In order to respond to the portupling of semiconductor devices,
There is a growing demand for smaller and thinner packaging. After the diffusion process and electrode wiring process have been completed, the silicon slice is cut into chips for each semiconductor element, and electrode leads are taken out from the aluminum electrode terminals provided around the chip to external terminals for easy handling and for mechanical protection. packaged for. Normally, DXL, chip carrier, frisoptic tape carrier methods, etc. are used for pancaging these semiconductor devices, but DIL,
In a chip carrier or the like, the electrode terminals of the semiconductor element are connected to the external terminals one by one using ultrafine wires of 25 to 35 .mu..phi. or A7j. For this reason, as the number of electrode terminals on a semiconductor device increases, not only does the reliability of the connection points decrease, but the number of external terminals also increases at regular intervals, which also increases the size of the packaging. do.

LSI for memory and microcomputers! : In connected LSIs such as Ilo, as the number of functions increases, the number of terminals per electrode increases significantly to 60 to 100 terminals, and as mentioned above, the size of the disconnection is
Several tens of af are required to handle semiconductor elements of only a few tens of af.
It gets bigger.

This has hindered the promotion of smaller and thinner devices.

On the other hand, there is a flip-chip tape carrier method that has high reliability at connection points and can provide packaging that is smaller and thinner. In packaging a semiconductor device using a chip carrier or tape carrier method, a multilayer metal film called a barrier metal is provided on the electrode terminals on the semiconductor device, and metal protrusions are further provided on this multilayer metal film by an electroplating method. In the case of the flip-chip method, the metal protrusions are made of solder material, and the metal protrusions and the wiring pattern on the circuit board are aligned and bonded all at once by reflowing the solder.On the other hand, in the film carrier method In this case, metal lead terminals are placed on a long polyimide tape of a constant width, and the metal protrusions on the electrode terminals of one semiconductor element and the lead terminals are simultaneously connected all at once, regardless of the number of electrode terminals. Therefore, in both methods, the reliability of the connection points is higher than in the wire bonding method described above, in which ultra-fine wires are connected to the electrode terminals one by one. Since the terminal has a breaking strength of 40 g or more, the semiconductor element can be held only with bumps or lead terminals. Furthermore, for this reason, devices can be mounted by simply applying a thin protective coat to the surface of the semiconductor element, making it possible to implement thin,
Can be used as miniaturized packaging.

In this way, flip-chip and tape carrier methods offer reliability, small size, and thin packaging, and in the case of tape carrier methods, they can be handled in the form of long tapes, making them easy to operate at production sites where semiconductor devices are mounted. It has many characteristics such as being outstanding. However, a problem with this flip chip and tape carrier method is the formation of metal protrusions on the electrode terminals of the semiconductor device.

In other words, it is assembly factories for televisions, radios, videos, etc. that produce portable devices that are smaller and thinner. These assembly factories must purchase semiconductor elements from semiconductor manufacturers to be assembled into equipment. The problem at this time is that one semiconductor manufacturer
The reality is that we do not necessarily have the ability or equipment to form metal protrusions on all semiconductor devices.Packaging technology that allows for miniaturization and thinning also increases the product appeal of equipment in assembly factories. unable to perform.

Furthermore, even if a semiconductor manufacturer were able to form metal protrusions, there would be the following problems.

First, a conventional method for forming metal protrusions on a semiconductor element in a conventional flip-chip or tape carrier method will be described with reference to FIG. A barrier metal 4 is formed on the electrode terminal 3 which is covered with the protective film 2 on the semiconductor element 1 and is partially opened and exposed (FIG. 1a).

Barrier metal 4 is Or-Cu, Ti-Pa,
It consists of a multi-layered vapor deposited film such as Ni-Cu, which is formed by continuous vapor deposition in a high degree of vacuum, and includes Or, Ti,
) Materials such as ii function to have adhesive strength with the electrode terminal 3.

Next, a photosensitive resin is applied to the entire surface of the semiconductor element 1,
A photosensitive resin pattern 6 with holes 6 formed only on the electrode terminals 3 is formed (FIG. 1b). By using the barrier metal 4 made of a multilayer vapor deposited film as a negative electrode and performing electrolytic plating (for example, using a solder material in the flip-chip method and a mu-U material in the film carrier method), the first layer is applied only to the area 6 in which the photosensitive resin pattern 6 has holes. As shown in Figure C, the metal protrusions can be formed to a desired height.

Next, the photosensitive resin pattern 6 is removed, and a second photosensitive resin is newly applied, leaving the second photosensitive resin pattern 8 only around the metal protrusion 7 (Fig. 1d). The structure shown in FIG. 1e can be obtained by removing the exposed barrier metal using the second photosensitive resin pattern 8 as an etching mask and also removing the unnecessary second photosensitive resin pattern 8. In the case of the flip-chip method, the wiring pattern is aligned with the wiring pattern on the circuit board in the state shown in FIG.

In the case of the film carrier method, the metal protrusions 7 on the completed semiconductor element 1 are overlaid with the metal leads 10 formed on the polyimide resin 9, and both are bonded by pressing and heating with a jig 11 as shown in 12. Can be joined. If the metal protrusion T is U and the metal lead 1° is Su plated,
By applying heat and pressure, a eutectic of human u-Sn can be formed and bonded (FIG. 1f).

However, such conventional processes have the following problems.

(2) Since the barrier metal has a multilayer metal structure, it is necessary to pay attention to the adhesion between the metal films and the occurrence of barrier resistance in the metal layer. That is, if the adhesion between the metal films is weak, simply applying an external force to the metal lead 10 will cause separation between the metal films or separation between the barrier metal and the protrusion, making it impractical. However, an increase in barrier resistance similarly impairs the original electrical properties of the semiconductor device.

■ In order to carry out such a conventional process, a wide range of highly precise processes are required, including a metal film formation process, an agate process - a metal film etching process, and a photoetch process. Not only does this increase the cost of filling, but it also causes a decrease in yield.

■ Also, since highly dangerous chemicals are used to etch the barrier metal, they are harmful to the human body and require investment in pollution prevention. For example, potassium ferrinanide and caustic soda solutions must be used for etching Or, and HF-based solutions must be used for etching Ti.

■ In the film carrier method as shown in FIG. Since it is a eutectic, it causes cracks in the protective film 2, reducing the protective effect of the electrode terminal 3 and lowering reliability.

OBJECTS OF THE INVENTION The present invention relates to a method for collectively bonding metal protrusions onto electrode terminals of semiconductor devices, etc., and is a method for bonding metal protrusions at once on electrode terminals without performing any treatment on the electrode terminals, the method comprising:
The purpose is to achieve reliable bonding with high reliability through a significantly simple process, and to reduce mounting costs.

Structure of the Invention The present invention provides an adhesive organic thin film material that is formed on an electrode lead-out area of a semiconductor element or on a metal protrusion formed on a substrate to be transferred, and then is applied to the electrode lead-out area of the semiconductor element. The transfer and bonding of the metal protrusions is carried out efficiently and reliably.

DESCRIPTION OF EMBODIMENTS First, an embodiment in which an organic thin film material is formed on an electrode lead-out region of a semiconductor element will be described.

In FIG. 2a, an electrode lead-out region 3 made of aluminum or the like is formed on a silicon substrate 2 on which a semiconductor element 1 is formed, and an organic thin film material 4 is deposited on at least a region including the electrode lead-out region 3. be done. Organic thin film material 4
is thinly placed on the electrode extraction area 3, for example, from several hundred to several micrometers.
The material of the substance 4 is polyimide,
It is preferably an epoxy-based, acrylic-based, or silicone-based resin that has some adhesiveness at room temperature or at a temperature of several 100°C. Further, the organic thin film material 40 can be formed on the semiconductor element by dipping method, spin coating method using a spinner,
A method such as a spray method or a deposition method using a plasma polymerization method is used.

FIG. 2 shows a hole 5 formed in the organic thin film material 4 on the electrode extraction region 3, and a hole 6 formed on a metal protrusion, which will be described later.
This is an example of a structure aimed at more effective transferability.

Next, a method for transferring and bonding metal protrusions onto the semiconductor element having the structure shown in FIG. 2 will be explained with reference to FIG. 3.

The metal protrusion forming substrate 6 has metal protrusions 8 formed on an insulating base 7 made of glass, ceramic, etc., with a conductive film for plating (not shown) interposed therebetween. The conductive film has good plating properties and is not peelable.

It is made of a material with good transferability, and as a result of experiments,
Pt, ITO, SuS, Mo, Pd films, etc. were optimal.

The semiconductor element 1 is suctioned and fixed to a tool 9 that can be pressurized and heated, and the electrode extraction area 3 and the metal protrusion 8 on the substrate 6 formed at the corresponding position are aligned to align the electrode extraction area 3 and the metal protrusion 8 formed at the corresponding position as shown in FIG. 3a).
, when pressure is applied in the direction of arrow 1o, the metal protrusion 8 is transferred onto the electrode extraction area 3 via the organic thin film material 4 on the electrode extraction area 3.

are joined (Fig. 3b).

The pressure and heating temperature of the tool 9 depend on the properties of the organic thin film material 4 formed on the semiconductor element, but if the material has a relatively adhesive property, the pressure and heating temperature of the tool 9 will simply be several grams to several tens of grams per metal protrusion. Pressurization alone is sufficient. If the substance does not have adhesive properties at room temperature but becomes adhesive when the temperature is increased, the temperature of the tool 9 may be raised to a temperature at which the substance exhibits adhesive properties and pressure may be applied.

Next, another example of a state in which metal protrusions are formed will be explained with reference to FIG. In this example, the organic material is formed on the surface of the metal protrusion rather than on the electrode extraction area of the semiconductor element. The substrate 6 on which the metal protrusions are formed has a conductive path film 11 for plating formed on an insulating material 7 such as glass, ceramic, or resin.
A semi-permanent plating mask pattern 12 made of SiO2, Si3N4° glass, and an organic material film is provided. A plurality of metal protrusions 8 are formed on the substrate 6 through a plating mask pattern 12 at positions corresponding to the electrode extraction areas of the semiconductor element, and the above-mentioned organic thin film material 4' is provided on the metal protrusions 8. There is. The method of transferring and bonding the metal protrusion 8 on the substrate 6 to the electrode lead-out area on the semiconductor element is exactly the same as that described in FIGS. 3a and 3b.

Next, the metal protrusions are peeled off and transferred from the substrate onto the electrode extraction area on the semiconductor element via the organic thin film material, and then bonded to the leads of the film carrier and the circuit board in the sixth step. This will be explained with reference to FIG.

A metal protrusion 8 formed by transferring and bonding a Cu lead 21 on a semiconductor element 1 to a Cu lead 21 of a film carrier in which a Cu lead 21 plated with Sn or black plated is formed on a long film 20 of polyimide, epoxy, or the like having a dilated portion. and then pressurized and heated with the tool 22. At this time, C
The u1J-dead 21 and the metal protrusion 8 are
If it has been plated with n, it will be bonded with an alloy of mu*sn, and if it has been plated with mu, it will be bonded by thermocompression bonding of mu and mu. Further, the aluminum electrode in the electrode extraction region 3 of the semiconductor element 1 and the metal protrusion 8 are bonded with an alloy of MU and ME, and the organic thin film material 4 formed on the surface of the semiconductor element is pressed by the tool 22.

By heating, even if the metal protrusion 8 is interposed between the electrode extraction region 3, it is pushed out from between the metal protrusion 8 and the electrode extraction region 3, and a good connection between MU and E can be obtained. This state is shown in FIG.

FIG. 6 shows metal protrusions 8 on a circuit board 25 on which a circuit wiring pattern 24 is formed on an insulating substrate 23 made of glass, ceramic, etc.
This shows a state in which the semiconductor element 1 onto which the image is transferred is bonded.

The metal protrusions 8 on the semiconductor element 1 and the circuit wiring pattern 24 on the circuit board 26 are aligned, and pressure is applied with the tool 22'.
The metal protrusion 8 and the circuit wiring pattern 24 are bonded together by heating. At this time, by applying ultrasonic vibration to the tool 22' at the same time as pressurizing and heating, even higher bonding can be obtained.

Regarding organic thin film materials, when transferring and bonding metal protrusions to the electrode extraction area on a semiconductor element through an organic thin film material, it is possible to simply pressurize or use a material that can obtain adhesive properties at low temperatures. , it is sufficient to apply pressure and low temperature at the same time.

Next, when bonding to the leads of the film carrier or the circuit wiring pattern on the circuit board, the pressure and heating temperature will be higher than the pressure and heating temperature during the transfer process, so a non-contact thin film material that sublimates and disappears at the bonding temperature is used. Also good. In this case, at the same time as the organic thin film substance sublimates and disappears, the metal protrusion and the electrode lead-out region on the semiconductor element are bonded even more strongly due to higher pressure and temperature than during transfer.

Alternatively, if the organic thin film material is composed of a material that softens during bonding, it will generate fluidity when heated and will completely cover the vicinity of the electrode extraction area and the bonding surface, and will also play a role as a protective film. become.

Effect of the invention ■ Metal protrusions can be transferred at low temperatures.

When transferring and bonding metal protrusions to the semiconductor element side, Au-
It is conceivable to form an alloy of Al and bond it to the semiconductor element side. In this case, Au-471! In order to form an alloy, it is necessary to apply a pressure of at least 320°C or more and a pressure of 30 g or more per metal protrusion, and to bond the metal protrusion transferred and bonded to the twisted semiconductor element side and the lead or wiring board. When doing so, it is necessary to repeat pressurization and heating (approximately 300° C. or higher) again. However, according to the present invention, sufficient transfer can be performed at a temperature that softens the organic thin film resin (approximately 200° C. or less). Therefore, Au-A
7! There is no need to form more alloy than necessary and reduce the strength. Further, since the degree of pressurization and heating is small, the impact force and thermal shock applied to one semiconductor element are also small, so reliability can be maintained high.

Furthermore, since the impact force and thermal shock on the substrate on which the metal protrusions are formed are small, durability is increased and mounting costs can be reduced.

■ After the metal protrusions are transferred and bonded onto the semiconductor element, the organic thin film resin flows due to the temperature at which it is bonded to the lead or wiring board and covers the electrode extraction area on one semiconductor element - this is the bonding surface. To fully protect the
This will further improve reliability.

[Brief explanation of the drawing]

Figures 1(a) to (e) are cross-sectional views of the process of forming metal protrusions on a conventional semiconductor element, and Figure 1(f) is a process cross-sectional view of a conventional film carrier method for connecting leads and metal protrusions. 2(a) and 2(b) are cross-sectional views of the structure of a semiconductor element used in the present invention, and FIG. Figure 4 is a cross-sectional view of the structure of the transfer substrate of the present invention, Figure 6 is a cross-sectional view showing the transferred metal protrusions bonded to the leads of the film carrier, and Figure 6 is the transferred metal protrusions bonded to the circuit board. 1. Semiconductor element, 3. River, electrode extraction area.
4゜4'...Organic thin film substance, 6...Substrate, 8...Mark/Metal protrusion, 9...Tool, 21
・Mountain...Leet, 25...Circuit board. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (2)

[Claims] (1) An electrode lead-out area on a semiconductor element with an organic thin film material formed on the surface is brought into pressure contact with a metal protrusion formed on a substrate, and the metal protrusion on the substrate is peeled off and transferred and bonded to the electrode lead-out area. and a step of bonding the metal protrusion on the electrode extraction area to a pattern of a circuit board having a film-like conductor lead or circuit wiring. (2) A step of bringing the metal protrusions on the substrate on which the organic thin film material is formed into pressure contact with the electrode lead-out areas on the semiconductor element, peeling off the metal protrusions on the substrate, and transferring and bonding them to the electrode lead-out areas. and a step of bonding the metal protrusion on the electrode extraction area to a pattern of a circuit board having a film-like conductor lead or circuit wiring.