JP3106846B2 - Method for manufacturing semiconductor chip mounting board - Google Patents

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 chip mounting board used for various electronic devices.

[0002]

2. Description of the Related Art In recent years, semiconductor devices such as LEDs and microcomputers have been mounted in the form of bare chips in order to achieve various electronic devices that are easy to carry and have many functions while achieving small size and light weight. Has been required. In addition, a demand for a flexible circuit board (hereinafter, referred to as FPC) that can be freely wired on a curved surface or a gap of a housing in order to mount electronic components at high density in a thin electronic device is rapidly increasing.

Conventionally, as a method of mounting a semiconductor element in a bare chip state, after connecting an electrode pad of the semiconductor bare chip and each corresponding electrode on a circuit wiring board with a fine gold wire (wire), the semiconductor bare chip and the connection portion are made of resin. After connecting the electrode pads of the semiconductor bare chip and the corresponding electrodes of the circuit wiring board to the wiring board made of polyimide resin via gold bumps on a wiring board made of a polyimide resin, A TAB method of resin-sealing a connection portion is generally put to practical use.

In recent years, a ceramic substrate having extremely high smoothness is used as a circuit wiring board, and the electrode pads of the semiconductor bare chip and the corresponding electrodes of the circuit wiring board are connected by heating and bonding via a gold bump. A method of sealing the electrode bonding portion with a light-curing shrinkable sealing resin (hereinafter referred to as MB
As a method of directly mounting a semiconductor bare chip on a transparent electrode on a glass substrate of a liquid crystal display panel, a gold bump is formed on an electrode pad of a semiconductor bare chip, and a conductive adhesive is applied through the gold bump. A mounting method (hereinafter referred to as COB) in which the electrodes are bonded and connected to the corresponding electrodes on the glass substrate, and then the electrode bonding portions are sealed with a light-curing shrinkable sealing resin.
Is well known.

[0005]

However, in any of the above-mentioned conventional WB, TAB, MBB and COB mounting methods, a semiconductor bare chip and a connection portion thereof are protected by a sealing resin in order to protect the semiconductor bare chip and its connection portion from the external environment. It was necessary to seal. In the case of the WB method and the TAB method, there has been a problem that volume shrinkage during curing of the sealing resin remains as internal stress, which adversely affects connection reliability. Therefore, it is necessary to select the material properties of the sealing resin and delicately control the curing conditions.

Further, the sealing resin needs to be slowly cured over a long period of time so as not to leave stress inside, and thus there is a problem that productivity is poor. MBB
The method and the COB method require a very high degree of smoothness of the circuit board to be mounted, and it is necessary to approximate the thermal expansion coefficients of the circuit board and the semiconductor bare chip.

On the other hand, the mounting of a semiconductor bare chip on an FPC, which is thinner and lighter and has the possibility of being freely wired to the curved surface or gap of the housing, requires a smaller MB due to the smoothness and thermal expansion coefficient of the substrate.
The B method and COB method cannot be applied. WB method, TAB method is F
Although it can be applied to a PC, it is difficult to make the thickness of the sealing resin strictly constant, and thus has the same problems as described above.

[0008] The present invention is to solve the above problems,
It is an object of the present invention to provide a method of manufacturing a semiconductor chip mounting board which does not require resin sealing and can obtain stable connection reliability.

[0009]

In order to achieve the above object, the present invention provides a method for manufacturing a semiconductor device, comprising the steps of: overcoating with an insulating resist except for a part of a first conductive circuit pattern formed on an insulating substrate; A first circuit wiring board in which an electrode provided on one side of a semiconductor chip is adhered to a part of a conductive circuit pattern by an anisotropic conductive adhesive or a conductive adhesive; and the first circuit on another insulating base. After forming a second conductive circuit pattern including at least a position corresponding to each electrode pad on the other side of the semiconductor chip when facing the wiring board, the electrode pad on the other side of the semiconductor chip is formed. Except for the corresponding position, the second circuit wiring board overcoated with the insulating resist is opposed to sandwich the semiconductor chip with at least the insulating resist around the semiconductor chip. It is intended to connect the other side of the electrode pads of the semiconductor chip and the second electrically conductive circuit pattern are adhered by heating sea urchin pressurized and.

[0010]

Therefore, according to the present invention, the electrical connection between the second circuit wiring board and each electrode of the semiconductor chip is basically made by pressure contact, so that the insulating base of the circuit wiring board and the semiconductor chip are different from the conventional method. Even if the coefficient of thermal expansion is not strictly adjusted, it is always in a pressed state, and high reliability can be obtained.

In addition, since there is no need for resin sealing after joining the circuit wiring board and each electrode of the semiconductor chip, connection reliability can be improved without being affected by internal stress,
Further, the manufacturing process can be extremely shortened.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a semiconductor chip mounting board according to an embodiment of the present invention will be described below with reference to the drawings. 1A, 1B and 1C are schematic sectional views showing a method for mounting a semiconductor chip according to one embodiment of the present invention, wherein FIG. 1A is a first circuit wiring board, and FIG. 2 shows a circuit board, and (c) shows a semiconductor chip mounting board in which a first circuit board and a second circuit board are bonded together.

As shown in FIG. 1A, a part of the first conductive circuit patterns 2a, 2b, 2c formed on the insulating base 1 is exposed and overcoated with an insulating resist 3.
A conductive adhesive 4 is applied to an exposed portion of the conductive circuit pattern 2a, and an electrode provided on one surface of the semiconductor chip 5 is bonded to form a first circuit wiring board.

Next, as shown in FIG. 1B, an electrode pad 5 provided on the other side of the semiconductor chip 5 when facing the first circuit wiring board on the insulating base 6.
Second conductive circuit patterns 7a and 7b including at least positions 7c and 7d corresponding to c and 5d are formed, and conductive circuit patterns 7a and 7b corresponding to the electrode pads 5c and 5d on the other surface of the semiconductor chip 5 are formed. Each position 7 of
A second circuit wiring board is formed by overcoating the insulating resist 8 by exposing at least c and 7d. Although the insulating substrate 6 used in this example has flexibility, the insulating substrates 1 and 6 of the first circuit wiring board and the second circuit wiring board of the present invention may be either or both. One having flexibility can be used, and as the insulating resists 3 and 8, both or one of them can be an adhesive having thermoplasticity or an adhesive having thermosetting properties.

Next, the first circuit wiring board (a) and the second circuit wiring board (b) configured as described above are opposed to each other,
As shown in FIG. 1 (c), at least the insulating resists 3 and 8 at the peripheral portion of the semiconductor chip 5 are pressed and heated so as to sandwich the semiconductor chip 5, and are adhered to the second conductive circuit patterns 7c and 7d. 5 electrode pads 5c, 5
d is pressed.

One end of each of the second conductive circuit patterns 7a and 7b is connected to the first conductive circuit pattern 2b by an anisotropic conductive adhesive 9 or press contact. This can be performed using the circuit pattern 2b. In addition, it is also possible to use solder or a conductive adhesive instead of the anisotropic conductive adhesive 9.

When the semiconductor chip 5 is an LED, the insulating base 6 of the second circuit wiring board is made transparent or translucent, and the insulating resists 3 and 8 are eliminated or the insulating resists 3 and 8 are also made transparent or translucent. 2 can be illuminated. Further, as shown in FIG. 2, by forming the uneven portion 10 around the LED on the insulating base 6 of the second circuit wiring board, efficient light diffusion can be obtained. Many functions such as LED connection, physical protection and light diffusion illumination can be collectively provided to the two circuit wiring boards.

When the shape of the semiconductor chip 5 is large, a reinforcing plate (not shown) is attached to the back surface of the first or second circuit wiring board for physical reinforcement, or the insulating substrate 6 of the second circuit wiring board is provided. Is preferably set higher than the rigidity of the first circuit wiring board in order to stabilize the connection between each electrode pad of the semiconductor chip 5 and each corresponding electrode of the second circuit board. To ensure higher connection reliability, the semiconductor chip 5
Using gold as a material of each electrode pad, or providing gold bumps by gold plating, ultrasonic heating and fusion of gold wire lines, or the same as the semiconductor chip 5 at the corresponding electrode position of the second circuit wiring board It is possible to form a gold-resin bump by providing a gold bump by the method described above, or by screen-printing a gold-resin-based paste.

Since a minute gap is partially formed between the first and second circuit wiring boards, the insulating bases 1 and 6 used are used.
It is necessary to use a material having no or low moisture permeability.

The first and second circuit boards are bonded by pressure and heating as described above, and both the insulating resists 3 and 8 of the first and second circuit boards are pressed and heated. It is not necessary to use a material having adhesiveness due to pressure and heating, and the other is a material having no resist or having no adhesiveness due to pressure and heat. Good. The heating conditions under pressure vary depending on the insulating resist material or insulating base material used, but in the case of direct heating, it is generally necessary to heat at least 100 ° C. or more for 2 to 10 seconds or more in order to ensure reliability after bonding. . The heating time can be reduced to within 0.05 to 1 second by applying ultrasonic heating or high-frequency induction heating.

(Embodiment 1) Next, a first embodiment of the present invention will be described in more detail with reference to FIG.

Polyvinylidene chloride having a thickness of 75 μm (PV
DC) A first conductive circuit pattern 2 having a predetermined pattern is screen-printed and formed with a silver resin-based paste (Toyobo DW-250H) on an insulating substrate 1 made of a coated biaxially stretched polyethylene terephthalate film.
Dry in oven for 2 minutes. Next, a heat-adhesive insulating resist 3 (XB-804 manufactured by Fujikura Kasei) is formed in the same manner except for a portion where the LED chip 5 is arranged and a tail portion for external lead-out, and then a conductive adhesive 4 (FA-Facil manufactured by Fujikura Kasei) is used. 707)
Is applied, and the LED chip 5 is adhered.
After drying for 0 minutes, a first circuit wiring board was prepared.

Next, a second conductive circuit 7 is formed by printing a predetermined pattern including a position corresponding to the electrode of the LED chip 5 on the insulating substrate 6 made of an acrylic plate having a thickness of 300 μm using a silver resin-based paste (same as above). The insulating resist 8 was formed by printing except for the position corresponding to the electrode of the chip 5. Further L
A continuous uneven portion 10 having a pitch of 100 μm and a cross-sectional angle of 30 degrees is formed in a portion around the ED chip 5 except for the second conductive circuit 7.
The second circuit wiring board provided with was manufactured.

Next, the first and second circuit wiring boards were opposed to each other, and the periphery of the LED chip 5 was pressurized and heated at a pressure of 15 kgf / cm ² and a temperature of 150 ° C. for 4 seconds to be bonded.

In order to confirm the connection reliability of the thus prepared sample, i) 1000 hours in a high temperature and high temperature chamber at 85 ° C., ii) 1000 hours in a high temperature and high humidity chamber at 60 ° C. and 95% RH, iii) 85 ° C. After standing for 500 cycles, each of which was performed for one cycle at -40 ° C. for one hour, the brightness and VF characteristics of the LED were measured.
Further, the luminance was improved by 30% as compared with the case where the continuous uneven portion 10 was not provided on the second circuit wiring board.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIG.

A first conductive circuit 2a is formed by applying a conductive adhesive (SA-0426 manufactured by Fujikura Kasei) to the electrode land portions of the insulating substrate 1 made of a 25 μm thick polyimide film pasted with a 35 μm thick copper foil, On top of that, a microcomputer chip 5
Was cured at 200 ° C. for 30 seconds to form a first circuit wiring board. The insulating resist 3 (CF-30G manufactured by Shikoku Chemicals Co., Ltd.) was overcoated except for the microcomputer chip 5 and other component mounting parts. The gold bumps 11 were formed on the electrode pads of the microcomputer chip 5 in advance.

Next, second conductive circuit patterns 7a and 7b made of nickel-base gold plating are formed at positions corresponding to the electrodes of the microcomputer chip 5 on the insulating base 6 made of a four-layer wiring copper-clad glass epoxy laminated substrate having a thickness of 0.6 mm. Then, except for the positions corresponding to the electrodes of the microcomputer chip 5, the insulating adhesive 8 having heat adhesion shown in (Table 1) was formed by printing to produce a second circuit wiring board.

Next, a pressure of 15 kgf / cm ² is applied around the microcomputer chip 5 with the first and second circuit wiring boards facing ^{each other} .
Pressure bonding and heating were performed at a temperature of 190 ° C. for 4 seconds for bonding. Further, in this embodiment, since the microcomputer chip 5 has a large shape, a reinforcing plate 13 is attached via an adhesive 12 to a back surface of the insulating base 6 corresponding to the position of the microcomputer chip 5 to improve connection reliability.

In order to confirm the connection reliability of the sample thus prepared, i) 1000 hours in a high temperature and high humidity chamber at 85 ° C., ii) 1000 hours in a high temperature and high humidity chamber at 60 ° C. and 95% RH, iii) 85 ° C. The operation state of the microcomputer was confirmed after standing for 500 cycles, each of which was a cycle of 1 hour at -40 ° C. for 1 hour. As a result, no abnormality occurred under any of the test environment conditions.

[0031]

[Table 1]

(Example 3) Instead of bonding the first and second circuit wiring boards in Example 1 with each other by pressing and heating and bonding them, 35 kgf / cm ^{2 is} pressed with an ultrasonic horn and 0.2 kHz at 20 kHz. The third example was manufactured by ultrasonic heating and welding, and the same reliability as in Example 1 was obtained with this sample.

(Embodiment 4) In Embodiment 2, gold bumps are not formed as electrode pads of the microcomputer chip 5, gold is deposited, and the corresponding electrode positions on the second circuit wiring board are shown in (Table 2). Screen printing of gold paste 180
C. and dried for 3 minutes. Although the film thickness was 30 μm in the dry state, this sample was pressure-heated and bonded in the same manner as in Example 2, and the characteristics were measured. As a result, the same reliability could be obtained.

[0034]

[Table 2]

[0035]

As is apparent from the above embodiment, according to the present invention, there is no need to perform resin sealing for physical protection of the semiconductor component, and therefore, there is no obstacle to the semiconductor component due to internal stress of the sealing resin. It is possible to perform the connection work in a short time without any. Furthermore, since the connection with the second circuit wiring board is made by pressure welding, there is no need to strictly match the thermal expansion coefficients of the conductor component and the insulating base, and stable connection reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating a method for manufacturing a semiconductor chip mounting board according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the semiconductor chip mounting board manufactured by the method for manufacturing a semiconductor chip mounting board according to the first embodiment of the present invention;

FIG. 3 is a partial cross-sectional view of a semiconductor chip mounting substrate manufactured by the manufacturing method of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating base 2a, 2b, 2c First conductive circuit pattern 3 Insulating resist 4 Conductive adhesive 5 Microcomputer chip (semiconductor chip) 6 Other insulating bases 7a, 7b, 7c, 7d Second conductive circuit pattern 8 Insulating resist 9 Anisotropic conductive adhesive

Continuation of the front page (56) References JP-A-4-369846 (JP, A) JP-A-5-198694 (JP, A) JP-A-55-43871 (JP, A) JP-A-3-73559 (JP, A) JP-A-6-151635 (JP, A) JP-A-7-94861 (JP, A) JP-A 52-159163 (JP, U) JP-A 1-110469 (JP, U) 3-6867 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 23/00 H01L 23/12 H01L 21/60

Claims (12)

(57) [Claims] 1. After overcoating with an insulating resist except for a part of a first conductive circuit pattern formed on an insulating substrate, an anisotropic conductive adhesive or conductive material is applied to a part of the first conductive circuit pattern. A first circuit wiring board to which electrodes provided on one side of a semiconductor chip are adhered by a conductive adhesive, and the other of the semiconductor chip when facing the first circuit wiring board on another insulating substrate. After forming the second conductive circuit pattern including at least the position corresponding to each electrode pad on one surface, the second overcoated with an insulating resist except for the position corresponding to the electrode pad on the other one surface of the semiconductor chip The second conductive circuit board by pressing and heating at least the insulating resist at the peripheral portion of the semiconductor chip so as to sandwich the semiconductor chip. A method for manufacturing a semiconductor chip mounting board, wherein a turn is connected to an electrode pad on the other side of the semiconductor chip. 2. The method according to claim 1, wherein at least one of the insulating base and the other insulating base is a flexible insulating base. 3. The method according to claim 1, wherein the insulating substrate or another insulating substrate is an insulating substrate made of polyvinylidene chloride-coated biaxially stretched polyethylene terephthalate or acrylic or another insulating substrate. 4. An insulating resist for overcoating a first conductive circuit pattern or at least one of an insulating resist for overcoating a second conductive circuit pattern is an insulating resist having heat adhesion. Item 2. The method for manufacturing a semiconductor chip mounting substrate according to Item 1. 5. The method according to claim 1, wherein a part of the first conductive circuit pattern is connected to an electrode provided on one surface of the semiconductor chip by soldering or pressure welding instead of the anisotropic conductive adhesive or the conductive adhesive. Manufacturing method of a semiconductor chip mounting substrate. 6. The semiconductor chip is an LED, and at least another insulating base and an insulating resist forming the second circuit wiring board are transparent or translucent.
6. The method for manufacturing a semiconductor chip mounting board according to 4 or 5. 7. The semiconductor according to claim 1, wherein the electrode pad of the semiconductor chip connected to the second conductive circuit pattern is an electrode pad made of gold or an electrode pad formed with a gold bump on the electrode pad. Manufacturing method of chip mounting board. 8. A gold-resin bump is formed on a second conductive circuit pattern connected to an electrode pad of a semiconductor chip, or a gold-resin bump is formed by pattern printing with a gold powder-resin-based conductive paste. The manufacturing method of the semiconductor chip mounting board as described in the above. 9. The method according to claim 1, wherein an ultrasonic wave or a high frequency wave is used for heating under pressure. 10. The method for manufacturing a semiconductor chip mounting board according to claim 1, wherein a reinforcing plate is attached to the back surface of the insulating base of the first or second circuit wiring board. 11. The method for manufacturing a semiconductor chip mounting board according to claim 5, wherein a continuous uneven portion is formed on the surface of the second circuit wiring board around the LED. 12. The method according to claim 1, wherein the rigidity of the insulating base forming the second circuit wiring board is higher than the rigidity of the insulating base forming the first circuit wiring board.