JP3416979B2 - Joining equipment - Google Patents

Abstract

PURPOSE:To enable security of a bonding condition and reduction of the thermal stress resulting from thermal strain to be achieved by a method wherein uniformity in temperature both in a plane direction of a bond object and in the thickness direction can be kept by irradiating the bond object from both sides with optical beams which pressurized materials transmit. CONSTITUTION:Beams conducted with an optical fiber 8 are gathered with a condenser 9. A glass receiver 7 and a glass substrate 2 transmit the beams, and a bonded face between an IC chip and the glass substrate is irradiated therewith. Further, glass is used as a receiver in contact with the IC chip, and a glass head 13 is held with a head holder 14 wherein an area capable irradiating all surface of the IC chip 1 with optical beams 10 from its upper surface exists. All the IC chip is heated with the optical beams 10 which the glass receiver 7 and the glass substrate 2 transmit and with which the bonded surface is irradiated, and the optical beams 10 which the glass head 13 transmits and with which an upper surface of the IC chip 1 is irradiated.

Description

Detailed Description of the Invention

[0001]

[Industrial application] IC chips and glass substrates, or TAB tapes and glass substrates on which IC chips are mounted,
Alternatively, the present invention relates to a joining device that joins by pressing and heating when at least one of a glass substrate and a glass substrate is a light transparent body.

[0002]

2. Description of the Related Art A method of mounting an IC chip is a W method using a gold wire between an output terminal of the IC chip and an IC lead frame.
B package (wire bond bonding) and subsequent IC package method by resin molding, and thermocompression bonding between the copper foil lead wire formed on the flexible tape and the bump formed on the output terminal of the IC chip. TAB method by resin molding (TAPE-AUTOMATED-
Bonding method) or TCP method (TAPE-
CARIER-PACKAGE method) and the like are known. These mounting methods are not optimal mounting methods for high-density mounting because the plane area of the final form is larger than the plane area of the IC chip.

Therefore, a method is adopted in which the planar area of the final form is equal to the planar area of the IC chip, that is, the IC chip is mounted as it is. When the object to be bonded to the IC chip is glass, the COG method (CHIP-ON
-GLASS method).

In the COG type bonding, bumps are formed on the output terminal of the IC chip or the output of the IC chip in order to establish electrical continuity between the output terminal of the IC chip and the conductive part of the glass to be bonded. When forming a bump on a terminal part and further forming a paste on a pump, there is a case where a conductive ball is interposed and mediated without forming a bump. In addition, to protect the conductivity from temperature and humidity disturbances and shocks,
A resin such as an adhesive is put between the IC chip and the object to be bonded, and the resin is bonded by pressure and heat to ensure reliability.

As described above, although there are inherent differences in the COG method of joining, the joining method is basically a joining method of thermocompression bonding which requires pressurization and heating. As an apparatus that realizes this method, the IC chip and the glass substrate are sandwiched between the pedestal and the head for pressurization, and the head for pressurization is heated to perform heating by heat conduction from the head to the IC chip. There is known a joining device that performs pressurization and heating with a single mechanism and simultaneously. Alternatively, in the above apparatus, a heating means for irradiating a light beam to the IC chip and the glass substrate from the side of the glass receiving stand is made of glass without heating the head for pressurization, and a glass. By doing so, a joining device is known in which the pressurizing means and the heating means are independent.

[0006]

The characteristics of COG bonding are:
The objects to be joined are the joining of rigid bodies such as the IC chip and the glass substrate, and the two-dimensional joining, that is, the surface joining determined by the arrangement of the terminals for conduction of the IC chip. Due to these things, there are the following problems.

The temperature distribution of the IC chip to be joined in the joining process of the conventional device tends to be non-uniform. That is, there is non-uniformity in the plane direction of the IC chip and non-uniformity in the thickness direction. First, the non-uniformity of the temperature in the plane direction is
The entire surface does not fit within the margin of the temperature condition required for the joining process, and the originally required joining state cannot be created. In particular, the peripheral portion of the IC chip is a place where the temperature is likely to be lower than that of other portions, and a joint failure is likely to occur in the joint quality evaluation.

Next, there is the non-uniformity of the temperature in the thickness direction. I
The C-chip has a good thermal conductivity and is a relatively good material for achieving temperature uniformity.
A temperature gradient in the thickness direction of about 10 degrees is generated. Due to this temperature gradient, thermal stress is generated in the IC chip, which appears as stress strain at the end of the bonding process, leading to the occurrence of defective bonding.

[0009]

Therefore, the present invention solves the above problems and provides the following device.

In a joining device for joining a joining object A and a joining object B, at least one of which is an optical transparent body, by pressing and heating, a pressurizing member C which constitutes a pressing means and is in contact with the joining object A, Similarly, the pressurizing means is configured to form the joining target B.
Both the pressurizing object D in contact with the pressurizing object D is a light transparent body, and a light beam that passes through the pressurizing object C and the pressurizing object D, respectively, is applied to the pressurizing object A and the joining object B. C
And a heating unit that heats the bonding target A and the bonding target B by irradiating from both sides of the pressed object D.

Further, in a joining device for joining a joining object A which is a light transparent body and a joining object B which is a non-light transparent body by pressurization and heating, a pressurizing means is configured to contact the joining object A. The pressure object C is an optically transparent body, and the pressure object D, which constitutes the pressure means and is in contact with the joining target B, has rigidity equivalent to that of metal and has a thermal conductivity of 0.01 (cal / cm).
.Sec..degree. C.) or less, and a heating means for heating the bonding target A and the bonding target B by irradiating a light beam that passes through the pressurizing object C.

[0012]

[Operation] In COG bonding by pressure / heat bonding between rigid bodies, temperature uniformity in the planar direction and thickness direction of the bonding target in the bonding process can be maintained, and the bonding conditions are secured and thermal stress due to thermal strain is reduced. Peels off and leads to stabilization of bonding quality.

[0013]

EXAMPLES The examples mainly apply to the case where the bonding target A is an IC chip and the bonding target B is a glass substrate which is an optical transparent body.

First, the construction of a conventional joining apparatus is shown in FIGS. 8 and 9. Further, here, it is assumed that the IC chip 1 and the glass substrate 2 are bonded to each other via the adhesive 3. FIG. 8 is composed of a pedestal 4 and a head 5 as a pressing means, and the IC chip 1 and the glass substrate 2 are sandwiched between them. The heating means is realized by heating the heater 6 embedded in the pressurizing head 5. Heater 6
The heat generated by the heat is transferred to the head, further conducted inside the head, and finally transferred to the IC chip which is a heating target. For this reason, iron or the like, which has good thermal conductivity and rigidity, is used for the head.

Next, in FIG. 9, a light beam 10 is used as a heating means unlike the case of FIG. Therefore, the pedestal is the light-transmissive glass pedestal 7 and the optical fiber 8
The light guided by is condensed by the condensing lens 9, passes through the glass pedestal 7 and the glass substrate 2, and is applied to the bonding surface between the IC chip and the glass substrate. By separating the pressurizing means and the heating means, the joining process can be optimized.

However, the problems described in the problems occur in the joining device according to FIGS. 8 and 9, and the following joining device is effective as a method for fundamentally solving these problems.

FIG. 1 shows an embodiment of claim 1. A glass receiving stand 7 which is a light transparent body is arranged as a receiving stand so as to be in contact with the glass substrate 2, and the light guided by the optical fiber 8 is condensed by the condenser lens 9 and transmitted through the glass receiving stand 7 and the glass substrate 2. Then, the joint surface between the IC chip and the glass substrate is irradiated. Further, a glass, which is an optical transparent body, is used as a pedestal that contacts the IC chip 1, and the IC is viewed from the upper surface of the glass.
The glass head 13 is held by the head holder 14 in which there is a region where the light beam 10 can be applied to the entire surface of the chip 1. Thus, in the bonding step, the light beam 1 that is transmitted through the glass pedestal 7 and the glass substrate 2 and is irradiated onto the bonding surface 1
The whole is heated by 0 and the light beam 10 which passes through the glass head 13 and is irradiated onto the upper surface of the IC chip 1. As a result, the IC chip 1 that is the bonding target
The glass substrate 2 and the adhesive 3 constitute heating means separated from the pressurizing means, enabling pressurizing, heating and separating joining. In addition, the objects to be joined can be heated from both sides, which improves the heating capacity and ensures the temperature uniformity of the objects to be heated. In particular, the temperature distribution in the thickness direction of the IC chip becomes uniform, the joining process is completed without thermal stress occurring in the IC chip 1, and the joining quality is improved.

Next, FIG. 2 shows another embodiment of claim 1. Similar to FIG. 1, a glass receiving stand 7 which is a light transparent body is arranged as a receiving stand so as to be in contact with the glass substrate 2, and the light guided by the optical fiber 8 is condensed by the condensing lens 9 to form the glass receiving stand 7. The light passes through the glass substrate 2 and is irradiated onto the bonding surface between the IC chip and the glass substrate. Further, a glass head 13 which is a light transparent body is used as a head on the surface in contact with the IC chip 1, and a mirror 11 for reflecting light is provided obliquely with respect to the IC chip 1 in the middle of the head.
Therefore, the glass head 13 is arranged so that light is emitted from the lateral direction of the glass head 13 at a position where the glass head 13 is under pressure, and the light is reflected by the mirror 11 of the glass head 13 and is emitted to the upper surface of the IC chip 1. To do. Similar to the light from the side of the glass pedestal, this light may be the light guided by the optical fiber 8 condensed by the condenser lens 9 or may be the light directly irradiated without being condensed by the optical fiber. Thus, similarly to the embodiment of FIG. 1, the temperature distribution in the thickness direction of the IC chip becomes uniform, the joining process is completed without the generation of thermal stress, and the joining quality is improved. Furthermore, in this joint structure, only the head material and structure are changed instead of the conventional head, and the structure is not changed drastically.

Further, FIG. 3 shows an embodiment in which an additional function is added to FIG. That is, by using the half mirror 12 as the mirror of the glass head 13 and disposing the temperature sensor and the CCD 17 above the glass head 13, it becomes possible to monitor the temperature state of the upper surface of the IC chip in the bonding process. As a result, the intensity of the light beam 10 can be sequentially controlled, and more appropriate bonding quality can be ensured.

Further, FIG. 4 shows another embodiment of claim 1. Similarly to FIG. 2, a glass receiving stand 7 which is a light transparent body is arranged as a receiving stand so as to be in contact with the glass substrate 2, and the light guided by the optical fiber 8 is condensed by the condensing lens 9 so that the glass receiving stand. 7 and the glass substrate 2 are transmitted, and IC
The joint surface between the chip and the glass substrate is irradiated. Furthermore, I
A glass head 13 which is a light transparent body is used as a head on the surface in contact with the C chip 1, and a mirror 11 for reflecting light is provided obliquely to the IC chip 1 in the middle of the head. Unlike the case of FIG. 2, the mirror 11 is arranged in two symmetrical planes so that the light beam can be emitted from both sides of the glass head 13. Further, the optical fibers 8 arranged on both sides can be changed in the vertical arrangement, and the irradiation position of the light beam irradiated in the vertical direction can be changed. This mechanism is a mechanism for making the temperature distribution uniform by selectively irradiating the low temperature part in accordance with the nonuniformity of the temperature distribution in the plane direction of the IC chip 1. Specifically, the temperature of the peripheral portion of the IC chip 1 is likely to be lower than that of the central portion with only the light beam from the side of the glass pedestal 7, and it is effective to make the temperature uniform. C
For the OG, the IC chip is often used in an elongated shape instead of the shape close to the conventional square shape, and temperature nonuniformity in the longitudinal direction is likely to occur, which is particularly effective.

Next, FIG. 5 shows an embodiment of claim 2. A glass receiving stand 7 which is a light transparent body is arranged as a receiving stand so as to be in contact with the glass substrate 2, and the light guided by the optical fiber 8 is condensed by the condenser lens 9 and transmitted through the glass receiving stand 7 and the glass substrate 2. Then, the joint surface between the IC chip and the glass substrate is irradiated. On the other hand, the glass head 13 in contact with the IC chip 1 has the same shape as the head of FIG. 9 of the conventional example, but the material is not a material having a high thermal conductivity such as iron, and has a certain degree of rigidity capable of withstanding a pressing force. The main feature is to use the low thermal conductivity head 15 made of ceramics or glass. The thermal conductivity is lower than that of carbon steel and stainless steel by almost one digit, 0.01 (cal / cm).
・ Sec · ° C) or less, and ceramics or glass corresponds to this. The effect in joining obtained by this is shown in FIG. The horizontal axis represents the position in the plane direction of the IC chip, and the vertical axis represents the temperature, showing the temperature distribution curves of the upper and lower surfaces of the IC chip for the conventional iron head and the ceramics or glass head of this system. . According to this, first, the temperature reached at each place is rising, and it can be seen that the temperature efficiency is greatly improved. Further, it can be seen that the temperature difference (temperature difference in the plane direction) for each location of the IC chip is reduced, and further, the temperature difference between the upper surface and the lower surface of the IC chip (temperature difference in the thickness direction) is also reduced. In this way, a great effect can be seen only by changing the material of the head to one having a low thermal conductivity.

Next, FIG. 7 shows another embodiment of claim 2. 7- (a) is an example of the head mechanism of FIG.
-(B), FIG. 7- (c), and FIG. 7- (d) are examples of the improvement. In the case of FIG. 6, although the temperature efficiency of the IC chip and the temperature distribution in the thickness direction are improved, the temperature gradient in the plane direction remains, although it is small. This method improves this. That is, by changing the material of the head itself to one with a low thermal conductivity, and by changing the shape of the head or mixing a material with a different thermal conductivity into the head, the temperature reached in the peripheral area of the head becomes the same as that in the central area. To do. FIG. 7- (b) is realized by the difference in material thickness by reducing the thickness of the central portion.
(C) realizes this by partially arranging a material having a high thermal conductivity in the central portion, and FIG. 7- (d) shows a shape that prevents the heat radiation from the IC chip by overhanging the head periphery. By doing so, each is realized. By positively utilizing the above method, it is possible to partially increase the temperature distribution of the IC chip or lower it.

[0023]

EFFECTS OF THE INVENTION By utilizing the characteristics of light, such as high response and high non-contact property, the joining process can be performed with high precision selective energy supply, short-time intensive energy supply and non-contact. Since it can be realized by effectively utilizing the separation of heat and force due to the energy supply, optimum process control for the joining process becomes possible.

As a result, the degree of freedom with respect to the required joining quality such as the quality for the temporary joining for aligning the IC chip and the glass panel and the quality for the final joining for the final joining is increased. Therefore, a wide variety of process selections and high quality joints can be easily realized.

[Brief description of drawings]

FIG. 1 is a view of a bonding apparatus according to claim 1 of the present invention.

FIG. 2 is a diagram of a joining device according to claim 1 of the present invention.

FIG. 3 is a diagram of a bonding apparatus according to claim 1 of the present invention.

FIG. 4 is a diagram of a bonding apparatus according to claim 1 of the present invention.

FIG. 5 is a view of a bonding apparatus according to claim 2 of the present invention.

FIG. 6 is a temperature characteristic improvement diagram according to claim 2 of the present invention.

FIG. 7 is a diagram of a head mechanism according to claim 2 of the present invention.

FIG. 8 is a view of a conventional joining device.

FIG. 9 is a view of a conventional joining device.

[Explanation of symbols]

1: IC chip 2: Glass substrate 3: Adhesive 4: cradle 5: Head 6: heater 7: Glass cradle 8: Optical fiber 9: Condensing lens 10: Light beam 11: Mirror 12: Half mirror 13: Glass head 14: Head holder 15: Low thermal conductivity head 16: Base 17: Temperature sensor and CCD camera

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI H05K 3/36 H05K 3/36 Z (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00-35 / 00 C03C 27/00-29/02 H01L 21/447 H01L 21/60-21/603 B29C 65/00-65/82

Claims (2)

(57) [Claims] 1. A joining device for joining a joining object A and a joining object B, at least one of which is an optical transparent body, by pressurization and heating, wherein a pressurizing object C constituting a pressurizing means and coming into contact with the joining object A. When,
Similarly, both the pressurizing means and the pressurizing object D in contact with the joining target B are light transparent bodies, and the pressurizing object C and the pressurizing object are applied to the joining target A and the joining target B. Bonding, characterized by comprising heating means for heating the bonding target A and the bonding target B by irradiating light beams respectively passing through D from both sides of the pressing target C and the pressing target D. apparatus. 2. A joining device for joining a joining target A which is a light transparent body and a joining subject B which is a non-light transparent body by pressurization and heating, which constitutes a pressurizing means and which is in contact with the joining target A. The pressure object C is a light-transparent material, and the pressure object D, which constitutes a pressure means and is in contact with the joining target B, has rigidity equivalent to that of a metal and has a thermal conductivity of 0.01 (cal / cm · se
c or ° C) or less, and by irradiating with a light beam that passes through the pressurizing material C,
A bonding apparatus having a heating unit for heating the bonding target A and the bonding target B.