JPH06232204A - Manufacture of semiconductor apparatus - Google Patents

Abstract

PURPOSE:To ensure the operation of packaging a bumped bare IC chip It, face down, on a flexible wiring substrate without adversely affecting productivity and to prevent the short-circuit condition of adjacent circuits from occurring at the packaging step. CONSTITUTION:A circuit pattern 14 is formed by a silver paste on a PET substrate 13. A bare IC chip 15 is so constructed that a bump 19 is projected from the side of an insulating protective film 18 of a silicon substrate 17. The face-down packaging of the bare IC chip 15 on the PET substrate 13 comprises a step of applying a nonconductive adhesive 20 over the PET substrate 13, a next step of positioning the bare IC chip 15 to come in contact with the circuit pattern 1.4, and a pressure impressing step of holding the bare IC chip 15 pressed to the PET substrate 13 side by the heating and pressurizing device until the bare IC chip 15 and the PET substrate 13 are bonded by the nonconductive adhesive 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a bare IC with bumps.
The present invention relates to a semiconductor device manufacturing method in which a chip (so-called flip chip) is mounted face down on a flexible wiring board.

[0002]

2. Description of the Related Art In recent years, in a delivery system such as a courier service, it has been attempted to automate the sorting work of the collected parcels by computer management. As a delivery system of this type, for example, Japanese Patent Laid-Open No. 61-203021. The one described in Japanese Patent Publication is known. The electronic tag used when constructing such a delivery system is attached to a package separately from a handwritten delivery slip, and has a memory that stores identification data such as the delivery destination of the package. , A response circuit having a transmission / reception function of answering back the identification data of the memory in response to an inquiry signal transmitted from the interrogator by radio waves, a power supply battery, and the like. Then, when carrying the luggage attached with the electronic tag as described above on the belt conveyor of the sorting line such as a distribution center, the question signal and the identification data are provided between the interrogators and the electronic tag installed in various places of the line. With the configuration in which the delivery is performed, it becomes possible for the interrogator side to identify the delivery destination of the package in a contactless manner and to automatically sort the package.

Such an electronic tag generally comprises a printed wiring board on which circuit elements such as ICs, resistors and capacitors, and parts such as batteries are mounted. In addition to making each circuit element into a one-chip IC, a so-called flip chip in which a bump is provided on a bare chip of this IC is mounted face-down on a printed wiring board to reduce the overall thickness and size. And cost reduction can be achieved.

Further, since it is preferable that the electronic tag can be deformed to some extent in handling,
As the wiring board used for the electronic tag, it is desirable to use a flexible type instead of a rigid type. In order to meet such requirements, it is considered that a circuit pattern is formed on a PET (polyethylene terephthalate) substrate with silver paste and a bare IC chip is mounted face down on the circuit pattern. However, when such a mounting method is adopted, the PET substrate is inferior in heat resistance and the silver paste is unsuitable for soldering, so that mounting by soldering is impossible, and a mounting means which is an alternative to this method. Need to be used.

As a structure for mounting a bare IC chip facedown without using solder, there is a conventional structure disclosed in Japanese Patent Laid-Open No. 2-8.
Those described in Japanese Patent No. 4747 or Japanese Patent Application Laid-Open No. 51-101469 are known. That is, JP-A 2-8
The one disclosed in Japanese Patent No. 4747 discloses a conductive resin (containing conductive particles) between a conductor pattern provided on the substrate (not a flexible substrate) side and an aluminum pad formed on the bare IC chip side. It is configured to be connected and electrically connected by an adhesive.

Further, as disclosed in Japanese Patent Laid-Open No. 51-101469, as shown schematically in FIG. 4, the bump 3 is formed from the diffusion surface side of the insulating protective film 2 on the silicon substrate 1.
A bare IC chip 4 formed by projecting
An anisotropic conductive resin 6 (having metal particles 6a in the resin (for easy understanding in the drawing, which has conductivity in a thickness direction and an insulating property in a surface direction with respect to the wiring substrate 5 (Shown in an exaggerated state) dispersed in a predetermined state), and the anisotropic conductive property between the bumps 3 on the bare IC chip 4 side and the circuit pattern 5a on the wiring substrate 5 side in the bonded state. The resin 6 is electrically connected. At the time of the adhesion, the bare IC chip 4 is held in a state of being pressed against the wiring substrate 5 side, and in this state, the anisotropic conductive resin 6 is cured by, for example, heat treatment.

[0007]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2-84747
When the amount of the conductive resin connecting the conductor pattern on the substrate side and the aluminum pad on the bare IC chip side at the time of mounting the bare IC chip is larger than that in the normal state, Alternatively, when the viscosity of the conductive resin becomes smaller than usual, the conductive resin is more likely to come into contact with the adjacent conductive resin. This causes a problem of short circuit between patterns (or between aluminum pads). On the contrary, when the amount of the conductive resin is smaller than that in the normal state, there is a high possibility that connection failure may occur. Therefore, the method disclosed in Japanese Patent Application Laid-Open No. 2-84747 has a problem that it is difficult to control the amount and viscosity of the conductive resin when the bare IC chip is mounted, and the productivity thereof is poor. It was

In the device disclosed in Japanese Patent Laid-Open No. 51-101469, since the wiring board 5 is formed of a rigid board, the bumps 3 of the bare IC chip 4 and the circuit pattern 5a are formed as shown in FIG. The metal particles 6a portion of the anisotropic conductive resin 6 is compressed in the thickness direction only at the portion sandwiched between the bumps 3 and the circuit pattern 5a, and at other portions, the metal particle 6a portion is Since it is not compressed in both the thickness direction and the surface direction, and its insulating property is maintained, there is no problem in practical use. However, when the wiring board 5 is formed of a flexible board in order to make the one described in this publication suitable for an electronic tag, the following problems will occur.

That is, as shown in FIG. 5, when the wiring substrate 7 made of a flexible substrate is used, the wiring substrate 7 may be formed depending on the conditions of pressure and heat applied when the bare IC chip 4 is bonded. The bumps 3 are deformed, and the bumps 3 bite into the wiring board 7. In such a state, the anisotropic conductive resin 6 is pressed on the entire diffusion surface of the bare IC chip 4 (the surface on which the insulating protection film 2 is provided), so that there is a space between the bumps 3 and the circuit pattern 7a in the thickness direction. At the same time, the metal particles 6a are brought into a state of electrical continuity in the surface direction at the same time, which may cause a short circuit between the adjacent circuit patterns 7a.

The present invention has been made in view of the above circumstances, and an object thereof is to mount a bare IC chip with bumps face down on a flexible wiring board.
It is an object of the present invention to provide a method of manufacturing a semiconductor device, which can achieve the mounting work reliably without lowering the productivity and eliminates the possibility that an adjacent circuit is short-circuited in the mounting work stage. .

[0011]

In order to achieve the above object, the present invention provides a method of manufacturing a semiconductor device in which a bare IC chip with bumps is mounted face down on a flexible wiring board, wherein the flexible wiring board is provided. A pattern forming step of forming a circuit pattern with a conductive paste thereon, a coating step of applying a non-conductive adhesive to a mounting position of the bare IC chip on the flexible wiring board or a bump forming surface of the bare IC chip, The bare IC chip is positioned such that its bumps come into contact with predetermined positions of the circuit pattern, and in this state, the period until the bare IC chip and the flexible wiring board are bonded by the non-conductive adhesive is The pressure application process that keeps the bare IC chip pressed against the wiring board Is obtained by a configuration in which the line.

[0012]

In the semiconductor device manufactured through the above-mentioned steps, the bumps on the bare IC chip side are pressed into contact with the circuit pattern made of the conductive paste on the flexible wiring board side to connect them. Definitely done.
In this case, since the adhesive that bonds the bare IC chip and the flexible wiring board is non-conductive, it is not necessary to strictly control the amount and viscosity of the adhesive, which improves productivity and There is no risk of adjacent circuits being short-circuited via the adhesive.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment in which the present invention is applied to an electronic tag used in a delivery system for a home delivery service will be described with reference to FIGS.
Will be described with reference to. In FIG. 3, a delivery slip 11 as an electronic luggage tag is composed of a plurality of slip pieces 11a to 11d provided with a copy-type handwritten entry field A group, and is attached to a parcel delivery bag, for example, the bottommost slip piece 11d. An RF circuit unit 12 (corresponding to the semiconductor device in the present invention) is integrally fixed to the. Handwriting entry field A above
Is a part in which the client of the parcel delivery service fills in the information regarding the delivery destination and the shipping origin of the parcel, and also the sorting code indicating the delivery destination and the delivery charge at the delivery agent. Further, the RF circuit unit 12 has a function of storing identification data such as a delivery destination of a package and a transmission / reception function by radio waves. Data input to the RF circuit unit 12 is performed by a radio wave using a dedicated issuer. By non-contact communication.

As shown concretely in FIG. 2, the RF circuit unit 12 has a circuit pattern 14 formed on a PET substrate 13 as a flexible wiring substrate, and a bare IC chip 15 corresponding to the circuit pattern 14. Further, for example, a paper type battery 16 is mounted and configured.

In this case, the circuit pattern 14 is formed by performing a pattern forming step of screen-printing a conductive paste, for example, a silver paste on the PET substrate 13, and the pattern 1 constituting the transmitting / receiving antenna is formed.
4a and 14b, as well as these antenna patterns 14
wiring patterns 14c and 14d connected to a and 14b
And a wiring pattern 14e independent of them. The terminals (+) and (-) of the battery 16 are connected to the wiring patterns 14e and 14d. The battery 16 is mounted on the PET substrate 13 using, for example, a silver paste or an anisotropic conductive film. Also,
The bare IC chip 15 has wiring patterns 14c to 14e.
The bare IC chip 15 and its mounting method will be described below with reference to FIG.

That is, FIG. 1 schematically shows a cross-sectional structure of the RF circuit unit 12, and in this FIG.
The C chip 15 has a structure in which an insulating protective film 18 is diffused and formed on the surface of a silicon substrate 17 in which a memory, an RF circuit and the like are formed, and bumps 19 (only two are shown) are projected from the insulating protective film 18. The bumps 19 are used for face-down mounting on the PET substrate 13.

In this face-down mounting, first, P
A coating step of coating the non-conductive adhesive 20 made of, for example, a thermosetting adhesive on the ET substrate 13 is performed. Next, in the bare IC chip 15, the bumps 19 thereof have wiring patterns 14c to 14e (14 in FIG. 1) of the circuit pattern 14.
(only c and 14d are shown in the figure), and the bare IC chip 15 and the PET substrate 13 are bonded by the non-conductive adhesive 20 in this state until the bare IC chip 15 and the PET substrate 13 are bonded by the heating / pressurizing device. IC chip 15 is PE
A pressure applying step of holding the state of pressing the T substrate 13 side is performed. In this case, the heating and pressurizing in the pressure applying step are performed, for example, under the condition of 170 ° C.-20 Kgf / cm ² -20 seconds. Further, if necessary, in order to protect the bare IC chip 15, the bare IC chip 15 may be molded with a resin having a heat shrinkage ratio close to that of the PT substrate 13.

The bare IC chip 15 receives the identification data stored in the memory when the interrogation signal transmitted from the interrogator (not shown) by radio waves is received through the antenna patterns 14a and 14b.
It is configured to answer back as a radio signal via a and 14b. In this case, the identification data stored in the memory is composed of fixed data and variable data. As the fixed data, the slip number (a signal indicating the identification code of the parcel) of the delivery slip 11 is input when the slip is issued. Also, as the variable data, a sorting code indicating the delivery destination of the parcel, a telephone number of the delivery destination, and the like are input at the time of the agency at the home delivery agency.

In the RF circuit unit 12 manufactured through the above steps, however, the bumps 19 of the bare IC chip 15 are affected by pressure and heat in the pressure applying step, as shown in FIG. Since the circuit pattern 14 made of the silver paste on the PET substrate 13 bites into and is pressed into contact with the circuit pattern 14, the electrical connection between the bare IC chip 15 and the PET substrate 13 is surely performed, and as a result, It is less likely that a poor connection will occur. in this case,
The above-described configuration with less defective connections can be realized by using the relatively inexpensive PET substrate 13 formed by forming the circuit pattern 14 by screen printing of silver paste, so that the cost of the electronic tag can be reduced at the same time. I will get it.

The PET substrate 1 of the bare IC chip 15 is also provided.
Since the adhesion to 3 is performed by the non-conductive adhesive 20, it is not necessary to strictly control the amount and the viscosity of the non-conductive adhesive 20 as in the conventional case, and the productivity is improved. In addition, unlike the conventional configuration using the anisotropic conductive resin as the adhesive, there is no possibility that the adjacent wiring patterns 14c to 14e (between the bumps 19) are short-circuited. Therefore, as described above, the yield is improved in combination with the fact that the poor connection is unlikely to occur, and the cost can be reduced also from this aspect.

In the above embodiment, the non-conductive adhesive 20 is used.
In the coating process of, the non-conductive adhesive 20 is coated with PET.
The bare IC chip 1 is formed by coating on the substrate 13 side.
It is also possible to adopt a configuration in which it is applied to the 5 side. Further, in the above-described embodiment, the thermosetting adhesive is used as the non-conductive adhesive, but a thermoplastic or photocurable adhesive may be used. Further, a manganese battery or a lithium battery can be used as the battery 16 in the above-described embodiment, and the shape thereof is not limited to a paper type and may be a coin type.
It is also possible to adopt a configuration in which it is directly formed on the ET substrate 13.

[0022]

As is apparent from the above description, according to the method of manufacturing a semiconductor device of the present invention, a circuit pattern of a conductive paste is formed on a flexible wiring board on which a bare IC chip is mounted, and The bare IC chip is mounted on the flexible wiring board, or the bump forming surface of the bare IC chip is coated with a non-conductive adhesive.
The C chip is positioned such that its bumps come into contact with the predetermined position of the circuit pattern, and in this state, the bare IC chip and the flexible wiring board are bare until the non-conductive adhesive bond them. Since the pressure applying step of holding the IC chip pressed to the wiring board side is executed, the work of mounting the bare IC chip face down on the flexible wiring board is surely performed without lowering productivity. In addition to being possible, there is no possibility that adjacent circuits will be short-circuited during the mounting operation stage, and it is possible to achieve an excellent effect that the yield can be improved as a whole.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part schematically showing an embodiment of the present invention.

FIG. 2 is a plan view of an RF circuit unit.

[Figure 3] Front view of the delivery slip

FIG. 4 is a vertical sectional view schematically showing a conventional configuration.

FIG. 5 is a view corresponding to FIG. 4 for explaining the problems of the conventional configuration.

[Explanation of symbols]

In the drawings, 11 is a home delivery slip, 12 is an RF circuit unit (semiconductor device), 13 is a PET substrate (flexible wiring board), 14 is a circuit pattern, 14a and 14b are antenna patterns, 14c to 14e are wiring patterns, and 15 Is a bare IC chip, 16 is a battery, 19 is a bump, and 20 is a non-conductive adhesive.

Claims (1)

[Claims] 1. A method of manufacturing a semiconductor device by mounting a bare IC chip with bumps face down on a flexible wiring board, comprising: a pattern forming step of forming a circuit pattern of a conductive paste on the flexible wiring board; A coating step of applying a non-conductive adhesive to a mounting position of the bare IC chip on the flexible wiring board or a bump forming surface of the bare IC chip; and the bare IC chip having bumps at predetermined positions of the circuit pattern. The bare IC chip and the flexible wiring board are held in contact with each other, and the bare IC chip is kept pressed against the wiring board until the bare IC chip and the flexible wiring board are bonded by the non-conductive adhesive in this state. A method of manufacturing a semiconductor device, comprising: performing a pressure applying step.