JPH07263451A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a bare chip mounting method having circuit selectivity, as a general mounting method having mass-productivity. CONSTITUTION:The title semiconductor device is provided with a protruding electrode 25 constituted of solder on a connection electrode pad of a connection terminal 26a of a semiconductor device 21, and a protruding electrode 25 constituted of solder whose melting point is higher than that of the protruding electrode 25 of the connection terminal 26a of the semiconductor device 21 on the connection electrode pad of a circuit selection terminal 26b of the semiconductor device 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection between a substrate and a protruding electrode made of solder provided on a semiconductor device.

[0002]

2. Description of the Related Art Bare-chip mounting, which has a small mounting area and a small mounting thickness, has been widely used in mounting semiconductor devices because of the strong demand for light, thin, short and small electronic devices. Furthermore, as product development has become more intense, the cycle of new products has become shorter, and it is important to develop products in a short period of time. Semiconductor device manufacturers are responding with methods such as gate arrays and standard cells.

Further, in recent years, bare chip mounting with circuit selectivity, which can be handled by an assembly maker, has been receiving attention. As the bare chip mounting having the circuit selectivity, the mounting examples described below are known.

According to this conventional example, a semiconductor device having a plurality of protruding electrodes having different heights formed on connection electrode pads of the semiconductor device and a substrate are electrically conductive in the thickness direction and electrically conductive in the lateral direction. Connect using an anisotropic conductive adhesive that does not have.

At this time, by selecting and mounting the size of the conductive particles of the anisotropic conductive adhesive, it is possible to select conduction or insulation between the terminal and the substrate.

As a result, the external resistance element and capacitance element of the semiconductor device are built in the semiconductor device,
Trimming can be done in the mounting process. If this technique is further developed, circuits for each function can be built in the semiconductor device, and an arbitrary circuit can be selected in the mounting process.

This conventional example will be described with reference to FIGS. 5, 6, and 7. 5 and 6 are cross-sectional views showing a structure in which the semiconductor device 21 and the connection electrode 12 arranged on the substrate 11 are connected using an anisotropic conductive adhesive 28, and FIG. 7 is a semiconductor device 2
It is sectional drawing which shows the jig for pressing 1 and the board | substrate 11. FIG.

First, the mounting structure of this conventional example will be described. As shown in FIG. 5, the terminals 26a for connecting to the substrate 11 on both ends of the resistance element 30 provided in the semiconductor element formation region of the semiconductor device 21 and the circuit selection terminal 26b in the central portion of the resistance element 30 are arranged. The semiconductor device 21 provided with the protruding electrodes 25, the substrate 11 having the connection electrodes 12 formed on the surface of the substrate 11, and the anisotropic conductive adhesive 28 composed of the main material 28a, the conductive particles 28b, and the non-conductive particles 28c. Constitute.

The projection electrode 25 of the circuit selection terminal 26b of the semiconductor device 21 is characterized in that it is formed to be lower than the projection electrode 25 of the connection terminal 26a.

In the mounting structure shown in FIG. 5, the protruding electrode 25 of the circuit selecting terminal 26b of the semiconductor device 21 is connected to the substrate 1.
1 so that the conductive particles 28b contained in the anisotropic conductive adhesive 28 have a height dimension of the protruding electrode 25 of the connecting terminal 26a and a height of the protruding electrode 25 of the circuit selecting terminal 26b. A size smaller than the size of the anisotropic conductive adhesive 28 plus the size of the non-conductive particles 28c is selected and connected.

As an example, the protruding electrode 2 of the connection terminal 26a
5 has a height of 20 μm, the protruding electrode 25 of the circuit selection terminal 26b has a height of 15 μm, and the anisotropic conductive adhesive 28 is used.
When the size of the non-conductive particles 28c is 8 μm, the size of the conductive particles 28b of the anisotropic conductive adhesive 28 is less than 13 μm.

In the case of the mounting structure shown in FIG. 5, the semiconductor device 2
Since the protruding electrode 25 of the first circuit selection terminal 26b is not electrically connected to the substrate 11, the resistance value of the resistance element 30 formed on the semiconductor device 11 is at both ends of the connection electrode 12 arranged on the substrate 11.

The mounting structure shown in FIG. 6 has a semiconductor device 2
The anisotropic conductive adhesive 28 used in FIG. 5 so that the protruding electrode 25 of the first circuit selection terminal 26b is electrically connected to the substrate 11.
13 μm or more, which is larger than the conductive particles 28 b in FIG.

In the case of this mounting structure, the resistance value at one end of the connection electrode 12 arranged on the substrate 11 is half that of the resistance element 30 formed on the semiconductor device 11.

Next, the manufacturing method of this conventional example will be described. As shown in FIG. 5, the resistance element 30 is formed of an impurity diffusion layer or a polysilicon layer in the semiconductor element formation region of the semiconductor device 21.

Terminals 26a for connecting to the substrate 11 are provided at both ends of the resistance element 30, and a circuit selection terminal 26b is provided at the center of the resistance element 30.

A protective film 23 is formed so that the connection electrode pad 22 made of aluminum provided on the surface of the semiconductor device 21 on which the semiconductor element is formed is exposed. This protective film 23 is generally an inorganic film such as a silicon oxide film or a silicon nitride film containing phosphorus, an organic film such as a polyimide resin, or the like.
These laminated structures are used.

Further, a metal multi-layer film of aluminum, chromium, copper, nickel, titanium or the like is formed as the common electrode film 24 on the entire surface of the semiconductor device 21 by a method such as a sputtering method or a vacuum evaporation method.

Further, a plating resist made of a photosensitive resin is formed, and a plating process is performed to form a protruding electrode 25 on the common electrode film 24 of the connecting terminal 26a.

After removing the plating resist, the plating resist is formed again, and a plating process is performed to form the protruding electrode 2 on the common electrode film 24 of the connection terminal 26a and the circuit selection terminal 26b.
5 is provided.

For the protruding electrode 25, a metal film of copper, gold, nickel, aluminum or the like and a metal multilayer film are used.

The semiconductor device 21 having the protruding electrode 25 of the circuit selecting terminal 26b, which is formed to have a height lower than that of the protruding electrode 25 of the connecting terminal 26a by removing the unnecessary common electrode film 24 and the plating resist, is provided. Complete.

The substrate 11 is made of an organic material such as paper phenol or paper epoxy, an inorganic material such as alumina ceramic or crystallized glass, or an organic inorganic material such as glass epoxy.

The connection electrode 12 is formed on the entire surface of the substrate 11 by a metal such as copper, silver or gold by a plating method, a rolling method, a vacuum deposition method, a sputtering method or the like.

In the case of a liquid crystal display device, the substrate 11 is made of glass and the connection electrode 12 is made of indium tin oxide.

A wiring pattern is formed on the connection electrode 12 by photolithography and etching using a resist made of a photosensitive resin. After that, the resist that is no longer needed is removed.

The anisotropic conductive adhesive 28 is composed of a main material 28a made of an inorganic material such as glass paste or an organic material such as epoxy resin or polyester resin, and a plastic made of an elastic copolymer of styrene and divinylbenzene. Conductive particles 28b obtained by plating beads with a metal such as nickel, aluminum, gold, and silver, or one or more of them, and inorganic materials such as glass fiber and metal oxide, and high hardness such as polymethylmethacrylate It is composed of non-conductive particles 28c made of beads formed of an organic material.

The anisotropic conductive adhesive 28 is prepared by mixing the main material 28a with the conductive particles 28b and the non-conductive particles 28c by roll kneading, applying an appropriate amount on the substrate 11 on which the connection electrodes 12 are arranged by a printing method, and pre-baking.

As shown in FIG. 7, anisotropic conductive adhesive 28
After aligning the substrate 11 and the semiconductor device 21, which have been calcined, an upper die 31 and a lower die 32 on which a heater 33 is installed.
And the anisotropic conductive adhesive is cured while applying pressure at high temperature.

As described above, by selecting and mounting the size of the conductive particles 28b of the anisotropic conductive adhesive 28, the resistance element 30 formed inside the semiconductor device 21 can be trimmed.

Further, in addition to the resistance element, it can be applied to a capacitance element and the like, and if an inverter circuit is built in, the signal can be inverted.

[0032]

In the above-mentioned conventional example,
It is assumed that an anisotropic conductive adhesive is used. Since the connection between the projection electrode of the semiconductor device and the connection electrode of the substrate is only mechanical connection of the conductive particles of the anisotropic conductive adhesive, there are variations in the height of the projection electrode and the conductive particles of the anisotropic conductive adhesive. It is also susceptible to variations in the size of the non-conductive particles.

In particular, since the projection electrodes of a semiconductor device are processed in a wafer having a large diameter, it is very difficult to form the projection electrodes having a uniform height. Although it depends on the height of the protruding electrodes and the sizes of the conductive particles and the non-conductive particles of the anisotropic conductive adhesive, it is necessary to suppress all variations within the range of at least 1 to 2 μm. Therefore, it is not suitable for mounting a large semiconductor device with fine multi-terminals.

Furthermore, since the anisotropic conductive adhesive is cured at a high temperature while applying pressure, a special jig such as an upper mold and a lower mold is required. There is a strong demand for parallelism and flatness between the surface of the upper mold for pressing the semiconductor device and the surface of the lower mold for disposing the substrate.

The object of the present invention for solving this problem is to:
It is to provide bare chip mounting with circuit selectivity as a general mounting with mass productivity.

[0036]

In order to solve the above problems, the semiconductor device of the present invention adopts the following structure.

In the semiconductor device of the present invention, the protruding electrode made of solder on the connection electrode pad of the connection terminal of the semiconductor device and the connection terminal of the semiconductor device on the connection electrode pad of the circuit selection terminal of the semiconductor device And a protruding electrode made of solder having a melting point higher than that of the protruding electrode.

[0038]

The protruding electrode of the circuit selecting terminal provided on the semiconductor device employs solder having a higher melting point than the protruding electrode of the connecting terminal of the semiconductor device. Therefore, by controlling the melting temperature of solder for connecting the substrate and the semiconductor device, bare chip mounting with circuit selectivity is realized.

[0039]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are cross-sectional views showing a mounting structure of a semiconductor device, FIG. 3 is a cross-sectional view showing a semiconductor device in which a protruding electrode is formed, and FIG. 4 is a connection electrode of a substrate at a connection portion with the semiconductor device. FIG.

First, the mounting structure of the semiconductor device and the substrate will be described with reference to FIG. As shown in FIG. 1, the resistance element 30 provided in the semiconductor element formation region of the semiconductor device 21.
26a for connecting to the substrate 11 at both ends of the
0, the semiconductor device 21 provided with the projecting electrode 25 made of solder and arranged on the circuit selection terminal 26b in the central portion of 0, the connection electrode 12 formed on the surface of the substrate 11, and the connection electrode 12 at the connection portion of the semiconductor device 21. A substrate 11 having a cover insulating film 13 formed so that the openings are exposed, and a semiconductor device 2
1 and the sealing resin 27 disposed between the substrate 11.

Next, the structure of the semiconductor device will be described with reference to FIG. As shown in FIG. 3, a protective film 23 is provided so that the connection electrode pad 22 on the semiconductor element formation surface of the semiconductor device 21 is exposed and the common electrode film 24 and a protruding electrode 25 made of solder are formed on the surface of the connection electrode pad 22. To form. The protruding electrode 25 of the circuit selecting terminal 26b is formed of solder having a higher melting point than the protruding electrode 25 of the connecting terminal 26a.

Next, the structure of the substrate will be described with reference to FIG. As shown in FIG. 4, the substrate 11 is composed of the connection electrode 12 and the cover insulating film 13. The cover insulating film 13 is also formed on the surface of the connection electrode 12 at the connection portion with the semiconductor device so that the connection electrode 12 at the connection portion with the semiconductor device is exposed and the protruding electrode that does not melt does not come into contact with the connection electrode 12. It is provided in an island shape.

In the mounting structure shown in FIG. 1, the semiconductor device 21
Without melting the protruding electrode 25 of the circuit selection terminal 26b of
The temperature at which the protruding electrode 25 of the connection terminal 26a is melted is controlled and connected.

In the mounting structure shown in FIG. 2, the temperature for melting both the protruding electrode 25 of the circuit selecting terminal 26b of the semiconductor device 21 and the protruding electrode 25 of the connecting terminal 26a is controlled and connected.

As described above, the semiconductor device 21 and the substrate 11
By controlling the heat treatment temperature for connection with
It is possible to arbitrarily select conduction or insulation between the protruding electrode 25 of the circuit selection terminal 26b arranged on the semiconductor device 21 and the connection electrode 12 arranged on the substrate 11.

Next, a method of manufacturing the above-mentioned mounting structure will be described. As shown in FIG. 3, the method of forming the bump electrode is to form the resistive element 30 in the semiconductor element forming region of the semiconductor device 21,
It is formed of an impurity diffusion layer or a polysilicon layer.

A protective film 23 is formed on the entire surface of the semiconductor device 21 including the connection electrode pads 22 made of aluminum provided on the semiconductor element formation surface. The protective film 23 is generally formed of a silicon oxide film containing phosphorus, an inorganic film such as a silicon nitride film, an organic film such as a polyimide resin, or a laminated structure of these, and the film thickness to be formed is 1 to 5 μm. is there.

After that, the protective film 23 is opened so that the connection electrode pads 22 are exposed by photolithography and etching in which exposure and development processing is performed using a predetermined mask.

Further, a metal multilayer film of aluminum, chromium, copper, nickel, titanium or the like is used as the common electrode film 24 on the entire surface of the semiconductor device 21 with a thickness of 0.1 to 10 μm, such as a sputtering method or a vacuum deposition method. To form.

Further, a plating resist made of a photosensitive resin is applied to a thickness of 1 to 10 μm, and an opening is provided on the connection electrode pad 22 of the connection terminal 26a by photolithography. After that, the protruding electrode 25 made of solder made of lead and tin is formed by the plating method.

The protruding electrode 25 of the connection terminal 26a is formed of a composition of tin: lead = 62: 38 and has a melting point of about 183 ° C.
Is. The formed film thickness is about 50 to 100 μm.

After that, the unnecessary plating resist is removed. Further, the solder can be formed not by the plating method but by the vacuum deposition method using a metal mask.

Next, using a metal mask, a protruding electrode 25 made of solder made of lead and tin is formed on the connection electrode pad 22 of the circuit selection terminal 26b by a vacuum evaporation method.

The protruding electrode 25 of this circuit selecting terminal 26b
Is composed of tin: lead = 5: 95 and has a melting point of about 30.
It is 0-315 degreeC. The film thickness to be formed is the connection terminal 26.
It has the same film thickness as a.

Further, as another method of forming the protruding electrode 25 of the circuit selecting terminal 26b, a plating resist is applied again and the connection electrode pad 22 is formed by photolithography.
It is also possible to form an opening on the top and use the common electrode film 24 as an electrode to form the protruding electrode 25 made of solder by a plating method.

Further, flux is applied and heat treatment is performed to round the protruding electrodes 25 into a semi-spherical shape, after which the common electrode film 2 is formed using the protruding electrodes 25 as an etching mask.
4 is removed, and the semiconductor device 21 is completed.

A method of manufacturing the substrate 11 will be described. As shown in FIG. 1, the substrate 11 is made of an organic material such as paper phenol or paper epoxy, an inorganic material such as alumina ceramic or crystallized glass, or an organic inorganic material such as glass epoxy.

A metal such as copper, silver, or gold is plated on the entire surface of the substrate 11 by a plating method, a rolling method, a vacuum deposition method, a sputtering method, or the like to have a thickness of 10 to 100 μm.
Form 2. A wiring pattern is formed on the connection electrode 12 by photolithography and etching using a resist made of a photosensitive resin. After that, the resist that is no longer needed is removed.

A plating resist made of a photosensitive resin is patterned on the surface of the substrate 11 by photolithography to form a metal such as copper, silver or gold by an electroless plating method, and the unnecessary plating resist is removed. However, the connection electrode 12 can be formed.

Next, as shown in FIG. 4, the cover insulating film 13 is formed on the surface of the substrate 11 and the wiring electrodes 12 formed on the substrate 11, and the connection electrode 12 at the connection portion with the semiconductor device 21 is exposed and melted. In order to prevent the protruding electrode 25 which is not allowed to contact the connection electrode 12, an island shape is formed by screen printing on the surface of the connection electrode 12 at the connection portion with the semiconductor device 21.

The cover insulating film 13 may be patterned in a cross shape or a trapezoidal shape other than the island shape.

For the cover insulating film 13, a solder resist such as epoxy acrylate resin, epoxy acrylate resin, epoxy resin is used. The film thickness to be formed is
Although it depends on the height of the protruding electrode 25, it is 10 to 40 μm.

It is also possible to pattern by photolithography using a photosensitive dry film resist.

As shown in FIG. 1, the semiconductor device 21 on which the protruding electrodes 25 are formed is aligned with the substrate 11 on which the connection electrodes 12 are arranged and then heat-treated to melt the protruding electrodes 25 made of solder of the semiconductor device 21. And connect.

In the mounting structure shown in FIG. 1, the semiconductor device 21
Without melting the protruding electrode 25 of the circuit selection terminal 26b of
The temperature at which the protruding electrode 25 of the connection terminal 26a is melted, 18
Heat treatment is performed at 3 to 299 ° C. to connect.

Further, the mounting structure shown in FIG.
The temperature at which both the protruding electrode 25 of the first circuit selecting terminal 26b and the protruding electrode 25 of the connecting terminal 26a are melted, 315 ° C.
The above is heat-treated and connected.

After that, the sealing resin 2 made of an organic material such as epoxy is provided in the gap between the substrate 11 and the semiconductor device 21.
7, and heat treatment is performed at 80 to 150 ° C. to cure the sealing resin, and the structure shown in FIGS. 1 and 2 is obtained.

As shown in FIG. 1, the circuit selection terminal 26b.
When the substrate 11 and the semiconductor device 21 are connected at a temperature at which the protruding electrode 25 of FIG.
The resistance between the two is the resistance element 30 formed in the semiconductor device 21.
become.

As shown in FIG. 2, the circuit selection terminal 26b.
When the substrate 11 and the semiconductor device 21 are connected at a temperature at which the protruding electrode 25 of FIG. 1 is melted, the resistance between the connection electrodes 12 arranged on the substrate 11 is 2
It becomes one-third.

As described above, by selecting the temperature of the heat treatment for connecting the semiconductor device 21 and the substrate 11, it is possible to select a circuit having an arbitrary resistance value at the time of mounting.

Connection terminals 26 formed on the semiconductor device 21
Solder composition of the protruding electrode 25 of a (tin: lead = 62: 3)
8) and the solder composition (tin: lead = 5: 95) of the protruding electrode 25 of the circuit selecting terminal 26b are examples, and the protruding electrode 25 of the circuit selecting terminal 26b has a higher melting point than the protruding electrode 25 of the connecting terminal 26a. If the condition to use high quality solder is satisfied,
There is no problem in using any composition of solder.

It is also possible to use solder having a low melting point or a high melting point in which materials such as indium, cadmium, bismuth, antimony, silver and gold are added to tin and lead.

In the embodiment of the present invention, one terminal for circuit selection 26b is formed in the center of the resistance element 30 built into the semiconductor device 21, but a plurality of terminals are formed in the order of melting point and resistance is increased in several steps. It is possible to change the value.

Further, in addition to the resistance element, a capacitance element or the like can be applied. If an inverter circuit is built in the semiconductor device 21, it is possible to invert a signal or add a delay circuit.

[0075]

As is apparent from the above description, in the mounting structure of the semiconductor device according to the present invention, the protruding electrode made of solder of the connecting terminal of the semiconductor device and the semiconductor device of the circuit selecting terminal of the semiconductor device are connected. And a protruding electrode made of solder having a melting point higher than that of the protruding electrode of the working terminal. As a result, bare chip mounting with circuit selectivity is realized by the flip chip mounting method that is popular in the world. Further, since the temperature is controlled by the heat treatment for connecting the semiconductor device and the substrate, the reproducibility of the melting of the solder is good and the mounting is very mass producible.

[Brief description of drawings]

FIG. 1 is a sectional view showing a mounting structure of a semiconductor device according to an embodiment of the invention.

FIG. 2 is a cross-sectional view showing a mounting structure of a semiconductor device in an example of the present invention.

FIG. 3 is a cross-sectional view showing a protruding electrode structure of a semiconductor device used for the semiconductor device in the example of the present invention.

FIG. 4 is a plan view showing a substrate used for a semiconductor device in an example of the present invention.

FIG. 5 is a cross-sectional view showing a mounting structure of a semiconductor device for explaining a conventional example.

FIG. 6 is a cross-sectional view showing a mounting structure of a semiconductor device for explaining a conventional example.

FIG. 7 is a cross-sectional view showing a jig for pressing a semiconductor device and a substrate for explaining a conventional example.

[Explanation of symbols]

 11 substrate 12 connection electrode 13 cover insulating film 21 semiconductor device 25 protruding electrode

Claims (1)

[Claims] 1. A projecting electrode made of solder on a connection electrode pad of a connection terminal of a semiconductor device and a solder on a connection electrode pad of a connection terminal of a semiconductor device on a connection electrode pad of a circuit selection terminal of a semiconductor device. And a bump electrode made of solder having a melting point higher than that of the bump electrode made of.