JPH11150150A - Board for semiconductor mounting and its manufacture and mounting method for semiconductor chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method, in which a board for semiconductor mounting mounted with an electrical connection mechanism and with a mechanical connection mechanism is manufactured at low cost in the board for semiconductor mounting, onto which a semiconductor chip is flip-chip mounted, and to provide its mounting method. SOLUTION: In a board for semiconductor mounting, an adhesive insulating resin 16, which is softened by heating and which reveals adhesive property is formed on the surface of a wiring board 11, and conductor terminals 18 for electrical connection are formed on the surface of the adhesive insulating resin 16 by copper etching or conductive-paste printing. A semiconductor chip is heated and pressurized by being pressed to the board for semiconductor mounting. The adhesive insulating resin 16 is softened. The conductor terminals 18 are embedded and passed through so as to be connected electrically. The semiconductor chip is fixed and bonded to the board for semiconductor mounting by the adhesive insulating resin 16, so as to achieve mechanical connection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor mounting substrate for mounting a semiconductor chip by flip-chip connection, a method of manufacturing the same, and a method of mounting a semiconductor chip.

[0002]

2. Description of the Related Art In recent years, with the demand for higher functionality and lighter, thinner and smaller electronic devices, high-density integration and high-density mounting of electronic components have been advanced, and semiconductors used in these electronic devices have been developed. Packages are becoming smaller and more multi-pin than ever before.

[0003] With the miniaturization of semiconductor packages,
Since the miniaturization of a package using a conventional lead frame has reached its limit, it has recently been proposed to mount a chip on a circuit board and use a BGA (Ball G
Rid Array) and CSP (Chip Scale)
A new package method of area mounting type such as “Package” has been proposed. In these semiconductor packages, the electrical connection between the electrodes of the semiconductor chip and the terminals of the substrate made of various insulating materials such as plastics and ceramics called a semiconductor mounting substrate having the function of a lead frame of a conventional semiconductor package and conductive wiring. As a method, a wire bonding method or TAB (Tape)
Automated Bonding (FC) systems and FC (Flip Chip) systems are known. Recently, BGA and CSP structures using FC connection systems that are advantageous for miniaturization of semiconductor packages have been actively proposed. In this FC connection method, generally, connection bumps are formed in advance on the electrodes of a semiconductor chip by electroplating, and the bumps and the terminals on the substrate are aligned and connected by thermocompression bonding. The process of forming bumps is complicated, and bump manufacturing costs are incurred.
In addition, in order to obtain the moisture resistance reliability of the bump connection part, it is necessary to fill the gap between the chip and the substrate with an insulating resin called underfill to seal the bump connection part, and to fill and cure this underfill. Therefore, there is a problem that the manufacturing process is complicated and the manufacturing cost is increased.

Therefore, attention has been paid to a method of using an anisotropic conductive sheet as a connection material for electrically connecting and mechanically bonding a semiconductor chip and a substrate without forming a bump on the semiconductor chip. The anisotropic conductive sheet is provided with an adhesive property. Normally, an anisotropic conductive sheet is first attached to a substrate, and then a semiconductor chip is mounted, and electrical connection and mechanical connection are simultaneously performed. Such an anisotropic conductive sheet method has been increasingly attracting attention as an effective means for reducing the size and cost of semiconductor packages, and the following anisotropic conductive sheet has been proposed.

[0005] Conventionally, conductive fine particles are dispersed in a thermoplastic or thermosetting resin, and the resin flows during thermocompression bonding, so that the conductive fine particles sandwiched between the connection terminals make the electrical conduction in the thickness direction possible. Anisotropic conductive sheets (FIG. 4) for obtaining connections are well known, and include a liquid crystal display panel and a TCP (Tape).
Carrier Package). The anisotropic conductive sheet having the above structure is characterized in that it can be manufactured by a relatively simple process such as dispersing conductive fine particles in a resin, and that the alignment at the time of bonding to a substrate can be performed relatively roughly. However, since the electrical connection is obtained by the conductive fine particles that are stochastically present between the electrode of the semiconductor chip and the terminal of the substrate, it is necessary to disperse the conductive fine particles more finely as the pitch becomes narrower. As a result, the density of fine particles is increased and the distance between the fine particles is reduced, so that the electrical insulation property is reduced. Further, the connection area between the fine particles and the electrode and the terminal is reduced, so that the connection resistance is increased. There is a problem. Recently, a small through hole was drilled in a resin film using a drill or laser, and then the inside of the through hole was filled with a conductor by plating or conductive paste printing, and an adhesive layer was formed on the surface of the resin film. An anisotropic conductive sheet (FIG. 5) has been proposed, in which an adhesive layer flows at the time of thermocompression bonding, a conductor is exposed, and an electrical connection is obtained by a conductor sandwiched between connection terminals. The anisotropic conductive sheet having the structure described above is characterized in that since the conductors are arranged opposite to the electrodes of the semiconductor chip and the terminals of the substrate, the electrical conductivity is excellent and the electrical insulation between adjacent conductors is also excellent. And However, since fine drilling with high positional accuracy is required, drilling with laser is required, and there is a problem that the manufacturing cost is increased due to the low productivity and high running cost, which are the drawbacks of laser. In addition, the formation of a conductor in a minute hole is usually performed by plating. However, as the hole diameter decreases, uniform plating becomes more difficult, the height of the conductor tends to vary, and electrical connection cannot be performed at the time of connection. There is a problem of decline. Further, the anisotropic conductive sheet must be positioned with high precision on both the substrate and the semiconductor chip to be bonded thereto, and there is a problem that the positioning process is complicated and the mounting yield is poor.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned various problems of a conventional method for electrically and mechanically connecting a semiconductor chip and a substrate by plating bumps or anisotropic conductive sheets. It has been made as a result of earnest research, and it is possible to manufacture and provide a semiconductor mounting substrate having a function of electrical and mechanical connection with a semiconductor chip at a low cost. An object of the present invention is to provide a chip mounting method.

[0007]

In order to achieve the above object, a semiconductor mounting substrate according to the present invention has a structure in which a surface of a wiring board on which a semiconductor chip is mounted has a softening property and an adhesive property by heating. An adhesive insulating resin that is developed is formed, and independent conductor terminals are formed at positions on the adhesive insulating resin that connect the electrodes of the semiconductor chip and the conductor wiring of the wiring board.

Further, according to the method of manufacturing a semiconductor mounting substrate of the present invention, an adhesive insulating material which exhibits softness and adhesiveness when heated with a copper foil is provided on a surface of a wiring substrate on which a semiconductor chip is mounted, on which a conductive wiring is formed. The method includes a step of bonding a two-layer sheet made of resin by heating and pressing, and a step of selectively etching the copper foil of the two-layer sheet to form a conductor terminal.

Further, according to the present invention, there is provided a method of manufacturing a substrate for mounting a semiconductor device, comprising the steps of: providing an adhesive insulating material which exhibits softness and adhesiveness by heating with a copper foil on a surface of a wiring substrate on which a semiconductor chip is mounted; A step of applying and drying a resin; and a step of printing and curing a conductive paste on the adhesive insulating resin to form conductor terminals.

Further, in the method of mounting a semiconductor chip on a semiconductor mounting substrate according to the present invention, there is provided a step of aligning a conductor terminal of the semiconductor mounting substrate with an electrode of the semiconductor chip so as to face each other; And a step of pressing the semiconductor terminal parallel to the semiconductor mounting substrate while heating the semiconductor terminal vertically through the adhesive insulating resin layer so as to be connected to the connection terminal of the semiconductor mounting substrate and to simultaneously bond the semiconductor chip.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIGS. 1A to 1D show a first embodiment of a manufacturing method for obtaining a substrate for mounting a semiconductor according to the present invention.

First, a wiring board 11 and a two-layer sheet 17 are prepared (FIG. 1A). The wiring board 11 includes at least a connection terminal for connecting the insulating resin 13 to the electrode of the semiconductor chip and a conductor wiring 12 including a connection terminal for connecting to the terminal of the mounting board. The solder resist 14 may be formed on the surface as shown in FIG.
Metals such as d, In, Pb, Sn and alloys thereof may be applied by electroless plating or electrolytic plating,
Flexible wiring boards with an insulating layer of polyimide resin or polyester resin, rigid wiring boards with an insulating layer of epoxy resin or phenolic resin, or even Al2
A ceramic wiring board using a ceramic such as O3 or AlN as an insulating layer can be used. Two-layer sheet 17
The thickness of the adhesive insulating resin 16 at the portion sandwiched between the conductor terminals 18 and the conductor wirings 12 described later is changed to the thickness of the conductor terminals 18 by applying a liquid adhesive insulating resin on the surface of the copper foil 15. It can be obtained by adjusting the coating amount so as to fall within a range of 0.7 to 1.5 times the thickness including the thickness of the treatment, applying uniformly, and then drying. The thickness of the adhesive insulating resin 16 at the portion sandwiched between the conductor terminal 18 and the conductor wiring 12 is 0.7 of the thickness of the conductor terminal 18 plus the thickness of the surface treatment 19.
If it is smaller than twice, the conductive terminal 18 becomes a pillar in mounting of the semiconductor chip described later, and the semiconductor chip and the adhesive insulating resin 1 are used.
6, there is a problem that the semiconductor chip cannot be bonded and the electrical reliability is easily lowered, and if it is more than 1.5 times, the conductive terminal 18 cannot penetrate the adhesive insulating resin 16 and the conduction cannot be obtained. Tends to occur. Adhesive insulating resin 1
Numeral 6 is made of a thermoplastic resin, a thermosetting resin, or a resin obtained by mixing them, and uses a resin that exhibits softening properties and adhesiveness when heated. Specifically, epoxy resin, polyamide resin, polyester resin, polyimide resin, maleimide resin, fluorine resin, urethane resin, polystyrene resin, acrylic resin, silicone resin, synthetic rubber resin, etc. It is formed by adding a curing agent, an inorganic filler, various coupling agents, and the like to one or a mixture of a plurality of resins.

Next, the two-layer sheet 17 is laminated on the surface of the wiring substrate 11 on the side on which the semiconductor chip is mounted by heating and pressing (FIG. 1B).

Next, copper foil 15 and solder resist 14
A photosensitive resist film is formed on both sides of the substrate, and conductor terminals 18 are formed through the steps of pattern exposure, resist development, copper etching, and photosensitive resist peeling (FIG. 1C). Here, the photosensitive resist formed on the surface of the solder resist 14 is provided for the purpose of protecting the conductor wiring 12 from an etchant.

Next, a surface treatment 19 is applied to the conductor terminal 18 (FIG. 1D). This is done to prevent copper oxidation and to improve the electrical connection performance. Au, Ni, Pd, P
A method of electroless plating a metal or alloy such as b, Sn, In, or the like, or a Pb-Sn alloy by a flow solder method can be used. As described above, the semiconductor mounting substrate of the present invention can be obtained.

FIGS. 2A to 2D show a second embodiment of the manufacturing method for obtaining the semiconductor mounting substrate of the present invention.

First, a wiring board 21 is prepared (FIG. 2).
(A)). As the wiring board 21, a flexible wiring board, a rigid wiring board, and a ceramic wiring board having the configuration described in the first embodiment can be used.

Next, a liquid adhesive insulating resin is applied to the surface of the wiring substrate 21 on the side where the semiconductor chip is mounted, and the thickness of the adhesive insulating resin 26 at a portion sandwiched between the conductor terminals 28 and the conductor wiring 22 to be formed later. Was adjusted so that the thickness was in the range of 0.7 to 1.5 times the thickness of the conductor terminal 28 plus the thickness of the surface treatment 29 described later, and the coating was performed so that no unevenness was generated. After drying (FIG. 2 (b)). Adhesive insulating resin 2
6 can use the resin described in the first embodiment.
If the thickness of the adhesive insulating resin 26 is out of the above range, the problem described in the first embodiment occurs.

Next, on the surface of the adhesive insulating resin 26,
The conductive paste is printed in a terminal shape by screen printing and cured to form the conductor terminal 28 (FIG. 2C). Metals mixed in the conductive paste are Cu, Ag, Au, S
Fine particles such as n, Pb-Sn, and In are used. As described above, the semiconductor mounting substrate of the present invention can be obtained.

FIGS. 3A and 3B show an embodiment of a method for mounting a semiconductor chip on a semiconductor mounting substrate according to the present invention.

First, the semiconductor mounting substrate 32 according to the present invention is placed at a predetermined position on the substrate receiving base 34 of the bonding apparatus. Next, a heating and pressing tool 33 having a chip suction mechanism
The semiconductor chip 31 is adsorbed onto the semiconductor chip 31 and the positioning mark formed in advance on the semiconductor mounting substrate 32 and the semiconductor chip 31 is read by an image recognition device using a conductor terminal 35 and an electrode 36
Face each other for accurate positioning. Simultaneously with the alignment, the semiconductor chip 31 is heated to a predetermined temperature via a heating and pressing tool (FIG. 3A). If necessary, a heater may be incorporated in the substrate receiving base 34 to heat the semiconductor mounting substrate, and the adhesive insulating resin 37 may be softened in advance. Further, depending on the combination of the joining metal material of the conductor terminal 35 and the electrode 36, it is also possible to obtain higher connectivity by using ultrasonic waves together.

Next, the heating / pressing tool 33 is lowered, and the semiconductor chip 31 is pressed against the semiconductor mounting substrate 32 in parallel with a predetermined pressure. When the conductor terminals 35 and the electrodes 36 come into contact with each other, the heat of the semiconductor chip 31 is transmitted to the adhesive insulating resin 37 via the conductor terminals 35 and softened, and at the same time, the conductor terminals 35 penetrate the adhesive insulating resin 37 and The bottom is connected to the connection terminal of the semiconductor mounting substrate 32. Further, by maintaining the heating and pressurizing for a predetermined time, the semiconductor chip 31
And the semiconductor mounting substrate 32 are fixed by an adhesive insulating resin 37 (FIG. 3B). As described above, the semiconductor chip 31 is electrically and mechanically mounted on the semiconductor mounting substrate 32 (FIG. 3C).

[0023]

As described above in detail, according to the present invention, a semiconductor mounting substrate having an electrical and mechanical connection function with a semiconductor chip can be manufactured and provided at low cost.
Furthermore, an easy and highly productive mounting method can be provided.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a method for manufacturing a semiconductor mounting substrate according to the present invention.

FIG. 2 is a second embodiment of the method for manufacturing a semiconductor mounting substrate according to the present invention;

FIG. 3 shows an embodiment of a mounting method using a semiconductor mounting substrate according to the present invention.

FIG. 4 shows a mounting example of a conventional semiconductor chip using an anisotropic conductive sheet in which conductive fine particles are dispersed.

FIG. 5 is a mounting example of a conventional semiconductor chip using an anisotropic conductive sheet in which a conductor is filled in a through hole.

[Explanation of symbols]

 11, 21: Wiring board 12, 22: Conductor wiring 13, 23: Insulating resin 14, 24: Solder resist 15: Copper foil 16, 26, 37: Adhesive insulating resin 17: Two-layer sheet 18, 28, 35: Conductor Terminals 19, 29: Surface treatment 31, 41, 51: Semiconductor chip 32, 42, 52: Semiconductor mounting substrate 33: Heating / pressing tool 34: Substrate receiving base 36, 44, 54: Electrode 43: Disperse conductive fine particles Anisotropic conductive sheet 45: Conductive fine particles 53: Anisotropic conductive sheet having through holes filled with a conductor 55: Conductor

Claims (5)

[Claims] 1. A semiconductor mounting substrate on which a semiconductor chip is mounted by flip-chip connection, wherein an adhesive insulating resin which is softened by heating and exhibits adhesiveness is formed on a surface of the wiring substrate on a side on which the semiconductor chip is mounted. A semiconductor mounting substrate, wherein independent conductive terminals are formed at positions connecting the electrodes of the semiconductor chip on the adhesive insulating resin and the conductive wiring of the wiring substrate. 2. The method according to claim 1, wherein the thickness of the conductor terminal is in the range of 0.7 to 1.5 times the thickness of the adhesive insulating resin which develops softness and adhesiveness by heating formed immediately below. The substrate for mounting a semiconductor according to claim 1, wherein: 3. A two-layer sheet made of a copper foil and an adhesive insulating resin exhibiting softness and adhesiveness by heating is heated and pressed on the surface of the wiring board on which the semiconductor chip is mounted, on which the conductive wiring is formed. A method of manufacturing a substrate for mounting a semiconductor, comprising a step of bonding and a step of forming conductive terminals by selectively etching the copper foil of the two-layer sheet. 4. A step of applying an adhesive insulating resin exhibiting softness and adhesiveness by heating to a surface of the wiring board on which the semiconductor chip is mounted on which the conductor wiring is formed, and drying the applied adhesive insulating resin. A method of manufacturing a substrate for mounting a semiconductor, comprising a step of printing a conductive paste thereon and curing the same to form a conductor terminal. 5. A step of positioning the conductor terminals of the semiconductor mounting substrate according to claim 1 so as to face the electrodes of the semiconductor chip mounted thereon, and positioning the conductor terminals on the semiconductor mounting substrate while heating the semiconductor chip from the back surface. A method of mounting a semiconductor chip, comprising the steps of: pressing a conductor terminal in parallel, vertically penetrating and penetrating an adhesive insulating resin, connecting the terminal to the connection terminal of the semiconductor mounting substrate, and simultaneously bonding the semiconductor chip.