JPH10326805A - Flip chip connection method and flip chip mounting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flip chip connection method, wherein a self-alignment effect is provided easily, in flip chip mounting in which a pad and a chip on a circuit board are made to contact each other in a face-down method. SOLUTION: For a flip chip mounting method in face-down method, a solder 7 does not melt before a bump 2 of a bare chip 3 contacts to the solder 7 on a circuit board 5, and after the bump 2 of the bare chip 3 makes contact with the solder 7 on the circuit board 5, the solder 7 is melted, and the bare chip 3 is released from an attraction action by a heating tool 4, while the molten state of the solder 7 is kept.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip chip connection method, and more particularly to a flip chip in which a bare chip is sucked and heated by a heating tool, and is brought into contact with a pad on a circuit board in a face-down manner to melt and join the solder. The present invention relates to a connection method and a flip chip connection device.

[0002]

2. Description of the Related Art The flow of a conventional flip chip mounting method is shown in the order of steps with reference to the sectional views of FIGS. That is, in FIG. 6A, the bare chip 3 on which the bumps 2 are formed in advance is taken out from the storage tray 14 by the pickup head 13, and then, in FIG. 6B, the pickup head 13 is rotated by 180 degrees. It is delivered face down to a heating tool 4 that is constantly heated to a temperature equal to or higher than the melting point of the solder or a heating tool 4 that is heated instantaneously by a pulse current.

Next, referring to FIGS. 6C and 6D, the recognition of the posture of the circuit board 5 and the recognition of the posture of the bare chip 3 are performed using the camera 15 and the illumination 16 and a known image processing device. After that, the respective positions are corrected, and positioning is performed so that the bumps 2 on the bare chip 3 and the pads 6 on the circuit board 5 are in contact with each other. Thereafter, as shown in FIG. 7 (E), the heating tool 4 is lowered to bring the solder portion 7 provided on the pad 6 on the circuit board 5 into contact with the bump 2 on the bare chip 3 as shown in FIG. 7 (F). While heating, the solder portion 7 is melted and the bump 2 is wetted.

[0007] Finally, in FIG. 7 (G), when the wetting of the solder portion 7 is completed, the vacuum suction holding the bare chip 3 is released, and at the same time, the heating tool 4 is raised to complete the joining. In such a flip chip mounting method,
Since the heating tool holds the bare chip by suction until the joining is completed, the self-alignment effect due to the surface tension of the solder portion cannot be obtained, and a highly accurate flip chip mounting machine is required.

In order to solve such a conventional problem,
For example, as disclosed in JP-A-64-50538, by heating and melting the coating of the solder portion applied to one or both of the electrodes before the electrodes of the bare chip and the electrodes of the circuit board come into contact with each other. After that, a flip-chip mounting method using the self-alignment effect by surface tension has been proposed.

[0006]

However, in such a conventional method, the solder portion is melted in advance before the electrodes of both the bare chip and the circuit board come into contact with each other, and a self-alignment effect is obtained by the surface tension. Therefore, in order to keep the solder portion in a molten state for a long time, it is necessary to prevent the solder portion from being oxidized by bonding in a low oxygen concentration or using a flux.

Further, in a mode in which a solder portion is supplied onto a pad of a circuit board, in a circuit board having a relatively low heat resistance such as a resin-based printed wiring board, dimensional accuracy is deteriorated due to thermal expansion and a joint is broken due to stress. And so on. An object of the present invention is to provide a flip-chip connection method and a connection device thereof in a face-down system in which the above-described disadvantages of the prior art are improved and a self-alignment effect can be easily obtained. An object of the present invention is to provide a means for solving the problems of oxidation of the solder portion and thermal expansion of the circuit board.

[0008]

In order to achieve the above-mentioned object, the present invention employs the following basic technical structure. That is, as a first aspect according to the present invention, a bare chip is sucked and heated by a heating tool, and the bump portion of the bare chip is connected to a solder portion forming a pad on a circuit board in a face-down manner, In the flip-chip mounting method of melting and bonding the two, before the bump portion of the bare chip contacts the solder portion on the circuit board, the solder portion does not melt, and the bump portion of the bare chip After contacting the solder part on the circuit board, the solder part is melted, and while the molten state of the solder part is maintained, the bare chip is released from the suction action by the heating tool. The second embodiment according to the present invention relates to a flip chip connecting method, wherein a bare chip is sucked and heated by a heating tool, Driving means for lowering or raising the heating tool in a flip-chip connection device for connecting the bump portion of the bare chip to a solder portion forming a pad on a circuit board in a flip-chip manner, melting the solder portion and joining the two. The driving means is interlocked with the descent drive mode of the heating tool, while the heating tool continues to descend, raises the temperature of the heating tool,
The temperature of the heating tool is controlled such that the temperature of the heating tool reaches a temperature equal to or higher than the melting point of the solder portion at or immediately before the bump portion of the bare chip and the solder portion on the circuit board contact. Temperature control means, the bump portion of the bare chip and the solder portion on the circuit board are brought into contact with each other, and while the solder portion is in a molten state, means for releasing the bare chip from restraint by the heating tool, and Means for raising the heating tool after the bare chip has been released from the restraint of the heating tool.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The flip-chip connection method and the flip-chip connection device according to the present invention employ the above-described technical configuration. In the flip-chip mounting method, there are provided a means for melting the solder portion after both electrodes of the bare chip and the circuit board are in contact with each other, and a means for obtaining a self-alignment effect by releasing the suction while heating the bare chip. And a flip-chip connection method is performed by using such a device.

In other words, in the flip chip connection method according to the present invention, for example, since the solder portion is melted after the electrodes of both the bare chip and the circuit board are in contact with each other, the time required to heat the solder above the melting point of the solder is minimized. Thus, the oxidation of the solder portion and the thermal expansion of the circuit board can be reduced. In addition, since the suction is released while heating the bare chip, a self-alignment effect can be obtained by the action of the surface tension when the solder portion is melted.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of one embodiment of the flip-chip connection method and flip-chip connection device according to the present invention will be described below in detail with reference to the drawings. 1 (A) to 1 (F)
FIG. 4 is a cross-sectional view showing a process procedure of one specific example of the flip chip connection method according to the present invention. In the drawing, a bare chip 3 is sucked and heated by a heating tool 4 and the bump 2 Is connected to a solder portion 7 constituting a pad on the circuit board 5, and the solder portion 7 is melted to join the two.
Before the bump 2 of the bare chip 3 contacts the solder 7 on the circuit board 5, the solder 7 does not melt, and the bump 2 of the bare chip 3 After the solder portion 7 is contacted with the solder portion 7, the solder portion 7 is melted, and the bare chip 3 is released from the suction action by the heating tool 4 while the molten state of the solder portion 7 is maintained. The illustrated flip-chip connection method is shown.

Here, the above-mentioned embodiment of the present invention will be described in more detail. FIGS. 1A to 1F show a mounting flow of the flip-chip connection method in the above-mentioned embodiment of the present invention. Are described in order for each step. That is, as shown in FIG. 1A, first, a bare chip 3 having a bump portion 2 formed in advance on an electrode 1 is suctioned face down with a heating tool 4, and then the positional displacement between the bare chip 3 and the circuit board 5 is corrected. This is performed by performing image processing using known image processing means.

Next, as shown in FIG.
The heating tool 4 that has absorbed the heat is lowered, and is brought into contact with the solder portion 7 previously mounted on the pad portion 6 on the circuit board 5. The heating conditions of the heating tool 4 at this time are as shown in FIG.
As shown in (B), the temperature on the circuit board 5 side is maintained while all the steps of the flip-chip connection method are performed.
The temperature is desirably set to a temperature equal to or lower than the melting point of the solder portion 7, and it is preferable that the temperature be maintained at a substantially constant temperature throughout the flip chip connection method.

On the other hand, the temperature condition of the heating tool 4 is shown in FIG.
As shown in (B), it is configured to change with the progress of the process. That is, as an example of the heating condition, the bump 2 of the bare chip 3
Before the contact with the bump portion 2 of the bare chip 3
Is maintained at a temperature equal to or lower than the melting point of the solder constituting the solder portion, and at least immediately before or when the bump portion 2 comes into contact with the solder portion 7, the bump portion 2
The configuration is such that the temperature of the bump section 2 is set to be equal to or higher than the melting point of the solder section 7 while the solder section 7 and the solder section 7 are in contact with each other.

Therefore, in the above embodiment of the present invention, before the bump 2 and the solder 7 come into contact with each other (FIG. 1B), the solder of the solder 7 does not melt, FIG.
As shown in (C), the feature is that the solder portion 7 is brought into a molten state only after the two come into contact with each other. In the present invention, when the solder of the solder portion 7 melts, the molten solder rises along the surface of the bump portion 2 as shown in FIG. Occurs.

When the wetting state occurs and the operation of the solder rising along the surface of the bump portion 2 stops, it is considered that the wetting has been completed, and at that time, FIG. As shown in E), the suction of the bare chip 3 by the heating tool 4 is stopped, the vacuum is broken by air blow, and then the heating tool 4 is slightly raised. As a result, a minute gap is generated between the heating tool 4 and the bare chip 3, the behavior of the bare chip 3 becomes free, and the state in which the solder of the solder portion 7 is melted by the radiant heat of the heating tool 4 is maintained. As a result, a self-alignment effect is obtained as shown in FIG. Next, the heating tool 4 is raised to complete the joining.

FIG. 2A is a timing chart showing the relationship between the vertical movement and the suction operation of the heating tool 4 in the embodiment of the present invention shown in FIG. That is, FIG.
As shown in (A), from time t1 to time t2, the heating tool 4 is lowered from a predetermined position a to a position b while adsorbing the bare chip 3, and the pads 6 on the circuit board 5 are removed. The covering solder part 7 and the bump part 2 on the bare chip 3 are brought into contact with each other. After that, until the time t3, the lowering operation is stopped while being lowered to the position c substantially the same as the position b. During this time, the solder portion 7 is melted. To instantaneously (time between times t3 and t4) to separate the bare chip 3 from the heating tool 4, and then stop the suction operation after time t4.

During that time, the heating tool 4 is kept lowered to a position d substantially the same as the position b. Next, between the time t4 and the time t5, the heating tool is slightly raised from the position d to the position e, and the heating tool is held at the position f substantially the same as the position e until the time t6.

Thereafter, the heating tool is raised to the initial position g to complete one cycle of the joining operation. On the other hand, FIG. 2B shows an example of an algorithm of a temperature change of the heating tool 4 synchronized with the vertical movement operation and the suction operation of the heating tool 4. That is, the heating temperature of the heating tool 4 reaches time t2 at which the heating tool 4 drops from the predetermined position a and the solder portion 7 covering the pads on the circuit board 5 comes into contact with the bare chip 3. Until the solder part 7
Is controlled so as to be equal to or lower than the melting point temperature of the solder constituting the above.

Specifically, the temperature of the heating tool 4 is
The heating of the heating tool 4 is started from the time when the heating tool 4 starts lowering or an appropriate time thereafter, and immediately before or immediately after the temperature of the heating tool 4 reaches the time t2, or after that. The temperature is set so as to be equal to or higher than the melting point of the solder constituting the solder portion 7.

After the solder is melted, the solder is wetted to the bumps, and the self-alignment effect is obtained by the surface tension of the molten solder. It is desirable to keep the temperature at or above the solder melting temperature until time t6, which is immediately after. At time t6 when the solder wetting and the self-alignment action are completed, the heating tool 4 is raised and the heating tool 4
Is returned to the initial state.

On the other hand, in the present invention, the circuit board 5
Generally, the temperature condition of the circuit board 5 is set to a temperature equal to or lower than the melting point of the solder. Furthermore, in the flip chip connection method according to the present invention, Au, Cu, the high melting point solder portion 7 and the like are made of a metal material as the material of the bump 2 and are formed on bare chip electrodes or circuit board pads. Or you may form in both. In some cases, bonding is performed without using bumps.

The solder used as the brazing material may be supplied on the electrodes of the bare chip, on the pads of the circuit board, or on both. As a heating method of the heating tool, a constant heating method, a pulse heating method, or the like is used.In the case of the constant heating method, in a mode in which the solder portion is supplied to the bare chip side, as a means for melting the solder portion only at the time of joining, a heat source is used. A method in which the heating tool is separated and the temperature of the heating tool is instantaneously increased by heat conduction from a heat source, a method in which a heating gas is injected into the heating tool, and the heating temperature is varied stepwise are used.

That is, in the present invention, the heating tool 4
The temperature of the bare chip 3 is raised during the lowering process by the face-down method while sucking the bare chip 3, so that at least the bump 2 of the bare chip 3 is in contact with the solder 7 on the circuit board 5. It is desirable that the temperature of the heating tool 4 be controlled so as to be equal to or higher than the melting temperature of the solder portion 7 near the point of contact.

Further, in the present invention, the bare chip 3 is sucked and heated by the heating tool 4, and the bump portion 2 of the bare chip 3 is connected to the solder portion 7 for covering the pad 6 on the circuit board 5 in a face-down manner. In the flip-chip mounting method of connecting and melting the solder portion 7 to join them together, for example, (1) a step of adsorbing and holding a bare chip on a heating tool, (2) a circuit of a bump portion of the bare chip by a face-down method Lowering the heating tool to make contact with the solder portion on the board; (3) raising the temperature of the heating tool while the heating tool continues to lower, so that the bump portion of the bare chip and the bump on the circuit board The heating tool is heated so that the temperature of the heating tool reaches a temperature equal to or higher than the melting point of the soldering part at or immediately before the soldering part contacts. A step of controlling the temperature, (4) a step of bringing the bump portion of the bare chip and a solder portion on the circuit board into contact with each other to melt the solder portion, and (5) while the solder portion is in a molten state. Releasing the bare chip from the restraint by the heating tool; and (6)
Elevating the heating tool after the bare chip is released from the restraint of the heating tool, and a flip chip connection method is provided.

More specifically, in the above embodiment according to the present invention, once the heating temperature of the heating tool 4 reaches a temperature equal to or higher than the melting temperature of the solder portion 7,
The bump portion of the bare chip 3 and the solder portion 7 on the circuit board
Until the connection with the solder is completed, the temperature is maintained at a temperature equal to or higher than the melting temperature of the solder portion, and then lowered to a predetermined temperature.

Further, as described above, in the present invention,
It is preferable that the temperature of the circuit board 5 is fixedly set to a predetermined temperature equal to or lower than a predetermined melting temperature of the solder portion during the flip-chip mounting process. In addition, in the present invention, particularly important, the determination of the time to release the bare chip from the suction of the heating tool,
Although not particularly specified, it is desirable to control the suction releasing operation by grasping the point in time when the solder of the solder portion 7 has completed the wetting of the bump portion 2.

More specific control methods include, for example, the type of solder used, the amount of solder used to form one bump, the heating temperature, the heating method, the substrate temperature, the pump material, the contact pressure, and the contact pressure. Since the timing of completion of the wetting state varies depending on the area, the shape of the pump, and the like, appropriate experiments are performed in advance, and a specific control table is used to combine each of the environmental conditions as described above, or a combination thereof. For each of the environmental conditions, an optimum value of the time from the start of the heating operation on the heating tool 4 to the occurrence of the wetting completion point is determined, and the optimum value is stored as a function, and stored in the control table. The above-described opening operation is executed by using the stored data.

FIG. 3A is a plan view showing an example of the structure of a bare chip used in an embodiment of the present invention.
The bare chip 3 has a pad pitch of 120 μm, an outer dimension of 10 mm in length and width, and a thickness of 0.3 mm. A ball bump 9 having a diameter of 80 to 90 μm is formed on an aluminum pad 8 with an Au wire.

FIG. 3B is a plan view showing an example of the structure of a circuit board used in an embodiment of the present invention. The circuit board 10 uses a printed wiring board laminated with a build-up resin on a glass epoxy board. On the printed wiring board 10, a solder resist treatment 11 having an opening with a width of 200 to 300 μm is performed, and a solder portion 7 made of a composition of Sn-3.5Ag having a thickness of 25 to 30 μm is formed on the exposed pad 6. Supplied by plating.

FIGS. 4 and 5 are cross-sectional flow charts showing a flip-chip mounting process in another example of the flip-chip connection method according to the present invention. 4 (A) to 4 (D) correspond to the steps of FIGS. 6 (A) to 6 (D) for explaining the conventional example, and FIGS. 5 (E) to 5 (D).
FIGS. 7 (E) to 7 (E) illustrate a conventional example.
This corresponds to each step of (G).

That is, the flip chip connecting apparatus according to the present invention uses a constant heating type, the substrate side heating stage 12 is set at 60 to 100 ° C., and the heating tool 4 side is set at 240 to 100
Heat to 260 ° C. The bare chip 3 on which the ball bumps 9 are formed and the printed wiring board 10 on which the solder portion 7 is formed are installed at predetermined positions of a flip chip connecting device, and the bare chip 3 is taken out of the tray 14 by the pickup head 13 and inverted by 180 °. Transfer to heating tool 4.
(FIGS. 4A and 4B) Next, an image of the circuit surface of the bare chip 3 is captured by the camera 15 and the illumination 16 installed below, and the recognition pattern taught in advance is displayed on any position on the screen. Is obtained by the image processing apparatus, and the suction posture of the bare chip 3 is calculated. Similarly, the holding posture of the printed wiring board 10 is calculated by capturing an image using the camera 15 and the illumination 16 provided above. (FIG. 4 (C) ~
(D) Next, the X, Y, and Θ axes are operated so that the positions of the ball bumps 9 and the pads 6 coincide with each other, thereby correcting the positional deviation of both. (FIG. 5 (E)) In this embodiment, in order to confirm the self-alignment effect, the offset is adjusted so that the center of the ball bump 9 and the center of the pad 6 are in contact with each other while being shifted by 30 to 40 μm.

Thereafter, the heating tool 4 is lowered to bring the solder portion 7 and the ball bump 9 into contact. When both touch, 2
The solder portion 7 is melted by heat conduction from the ball bump 9 heated to 40 to 260 ° C., and causes the ball bump 9 to wet. (FIG. 5 (F)) Thereafter, after maintaining the state for several seconds until the solder portions 7 on all the pads are melted, the suction of the bare chip 3 is stopped and blowing is performed to break the vacuum. (FIG. 5G) Next, the heating tool 4 is raised by about 100 μm to form a minute gap (FIG. 5G). Accordingly, the state in which the solder portion 7 is melted by the radiant heat of the heating tool 4 is maintained, and the behavior of the bare chip 3 becomes free.
The displacement of μm is repaired. After maintaining this state for several seconds, the heating tool 4 is raised. As a result, radiant heat from the heating tool is not applied, so that the solder portion 7 is solidified and the joining is completed.

The bonding atmosphere is an oxygen concentration of 1 to 4%.
Bonding can be performed even at a relatively high oxygen concentration. As understood from the above description of the specific example, the flip chip connection device according to the present invention suctions and heats a bare chip with a heating tool, and forms a bump portion of the bare chip into a pad on a circuit board in a face-down manner. In a flip-chip connection device that connects to a solder portion to be heated, melts the solder portion, and joins the two, a driving unit 50 that lowers or raises the heating tool, a lowering unit 53 of the heating tool 4 of the driving unit 50, In conjunction with this, while the heating tool continues to descend, the temperature of the heating tool is increased, and at or immediately before the bump portion of the bare chip and the solder portion on the circuit board are in contact, the temperature of the heating tool is Temperature control means 51 for controlling the temperature of the heating tool so as to reach a temperature equal to or higher than the melting point of the solder portion; Means 52 for releasing the bare chip from the restraint by the heating tool while the solder portion on the circuit board is brought into contact with each other and the solder portion is in a molten state; and Means 54 for raising the heating tool after it has been opened.

Further, in the flip chip connecting apparatus according to the present invention, the means 52 for releasing the bare chip from the restraint by the heating tool is driven in response to a predetermined control condition. Desirably,
Furthermore, it is preferable that the control condition be a function of at least temperature or time. In particular, in the present invention, the control condition is such that the time when the wetting of the solder portion to the bump portion is completed is grasped by appropriate means, and the heating tool of the bare chip 3 is determined by the presence or absence of the time when the wetting is completed. 4 is configured to execute an opening operation.

It is desirable that the control of each of the above-described units is configured to be comprehensively controlled by an appropriate central processing control unit 55.

[0037]

The flip-chip connection method and the flip-chip connection device according to the present invention employ the above-described configuration, so that when the solder is completely wetted to the bumps, the suction of the bare chip is released, By raising the heating tool slightly, a small gap is created between the bare chip and the heating tool, which releases the behavior of the bare chip and keeps the molten state of the solder by the radiant heat of the heating tool, and the surface of the molten solder The self-alignment effect can be obtained by the tension. As a result, even if the guaranteed accuracy of the flip-chip mounting machine is poor to some extent, high-precision flip-chip mounting becomes possible. Oxidation of solder can be suppressed to the minimum necessary compared to similar technologies in the past,
In addition, high-quality and highly reliable bonding can be performed even on a circuit board having relatively low heat resistance, such as a resin-based printed wiring board.

That is, since the flip-chip connection method and the flip-chip connection device according to the present invention employ the above-described configuration, by obtaining a self-alignment effect, the positioning accuracy of the flip-chip mounting machine can be improved.
It does not require a high level of accuracy. The reason is that since the suction by the heating tool is released while the bare chip is being heated, the self-alignment effect can be obtained by the action of the surface tension when the solder portion is melted.

Another effect is that, compared with the conventional method in which the solder portion is melted in advance, the solder portion is less oxidized, and the fluxless joining can be performed in a relatively high oxygen concentration region. . In addition, even in a mode in which a resin-based circuit board is used and the solder portion is supplied on the pads of the circuit board, the influence of the thermal expansion on the joint can be reduced. The reason is that the solder portion is melted after the electrodes of both the bare chip and the circuit board are in contact with each other, so that the time required to heat the solder portion to the melting point or more can be minimized.

[Brief description of the drawings]

FIGS. 1A to 1F are flowcharts showing cross-sectional views of respective steps of a flip-chip mounting method in a specific example of a flip-chip connection method according to the present invention.

FIG. 2A is a timing chart showing a timing relationship between a heating tool used in the specific example of the present invention shown in FIG. 1 and a suction operation, and FIG. It is a graph which shows a change state.

FIG. 3A is a plan view showing a structure of a bare chip according to one embodiment of the present invention, and FIG. 3B is a plan view showing a structure of a circuit board according to one embodiment of the present invention; It is the top view shown.

FIGS. 4A to 4D are flow charts showing cross-sectional views of each step of a flip-chip mounting method in another specific example of the flip-chip connection method according to the present invention. .

FIGS. 5 (E) to 5 (G) are flow diagrams showing steps of a flip chip mounting method in another specific example of the flip chip connection method according to the present invention in a sectional view. .

6 (A) to 6 (D) are flowcharts showing cross-sectional views of respective steps of a flip-chip mounting method in a conventional flip-chip connection method.

FIGS. 7 (E) to 7 (G) are flow diagrams showing steps of a flip-chip mounting method in a conventional flip-chip connection method in a cross-sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electrode 2 ... Bump part 3 ... Bare chip 4 ... Heating tool 5 ... Circuit board 6 ... Pad 7 ... Solder part 8 ... Aluminum pad 9 ... Ball Bump 10 ... Printed wiring board 11 ... Solder resist 12 ... Board side heating stage 13 ... Pickup head 14 ... Tray 15 ... Camera 16 ... Lighting

Claims (10)

[Claims] 1. A bare chip is attracted and heated by a heating tool, a bump portion of the bare chip is connected to a solder portion forming a pad on a circuit board by a face-down method, and the solder portion is melted and joined. In the flip-chip mounting method, before the bump portion of the bare chip comes into contact with the solder portion on the circuit board, the solder portion does not melt, and the bump portion of the bare chip changes the solder portion on the circuit board. After the contact, the solder portion is melted, and while the molten state of the solder portion is maintained, the bare chip is configured to be released from the suction action by the heating tool, Flip chip connection method. 2. The temperature of the heating tool is raised during a step of descending by a face-down method while adsorbing the bare chip, so that at least a bump portion of the bare chip is mounted on the circuit board. 2. The method according to claim 1, wherein the temperature is controlled so as to be equal to or higher than the melting temperature of the solder portion in the vicinity of the point of contact with the solder portion. 3. The bare chip is attracted and heated by a heating tool, and the bump portion of the bare chip is connected to a solder portion forming a pad on a circuit board by a face-down method, and the solder portion is melted and joined. In the flip chip mounting method, a step of attracting and holding the bare chip on a heating tool, a step of lowering the heating tool to bring a bump portion of the bare chip into contact with a solder portion on a circuit board by a face-down method, While the descent is continuing, the temperature of the heating tool is raised, and at or immediately before the bump portion of the bare chip and the solder portion on the circuit board come into contact with each other, the temperature of the heating tool is equal to or higher than the melting point temperature of the solder portion. Controlling the temperature of the heating tool so as to reach the temperature of the bumps of the bare chip and the circuit board. A step of melting the solder part by contacting the solder part with each other, and a step of releasing the bare chip from the restraint by the heating tool while the solder part is in a molten state; and Raising the heating tool after being released from the constraint, and a method of connecting a flip chip. 4. After the heating temperature of the heating tool once reaches a temperature equal to or higher than the melting temperature of the solder portion, the heating tool is heated until the connection between the bump portion of the bare chip and the solder portion on the circuit board is completed. 4. The method according to claim 3, wherein the temperature is maintained at a temperature equal to or higher than the melting temperature of the solder portion, and thereafter, the temperature is lowered to a predetermined temperature. 5. The temperature of the circuit board is fixedly set to a predetermined temperature equal to or lower than a predetermined melting temperature of the solder portion during a flip-chip mounting process. The flip chip connection method according to claim 3, wherein: 6. The method according to claim 1, wherein the time when the bare chip is released from the suction of the heating tool is a time when the wetting of the solder portion to the bump portion is completed. Flip chip connection method. 7. The bare chip is attracted and heated by a heating tool, and the bump portion of the bare chip is connected to a solder portion forming a pad on a circuit board in a face-down manner, and the solder portion is melted and joined. In the flip-chip connection device, the driving means for lowering or raising the heating tool, in conjunction with the lowering driving mode of the heating tool of the driving means, while the heating tool continues to lower, raise the temperature of the heating tool, The temperature of the heating tool is controlled such that the temperature of the heating tool reaches a temperature equal to or higher than the melting point of the solder portion at or immediately before the bump portion of the bare chip and the solder portion on the circuit board contact. Temperature control means, the bump portion of the bare chip and the solder portion on the circuit board are brought into contact with each other, and the solder portion is in a molten state. Meanwhile, means for releasing the bare chip from the restraint by the heating tool, and means for raising the heating tool after the bare chip is released from the restraint of the heating tool. Flip chip connection device. 8. The flip chip connection device according to claim 7, wherein the means for releasing the bare chip from the restraint by the heating tool is driven in response to a predetermined control condition. 9. The flip-chip connection device according to claim 8, wherein the control condition is a function of at least temperature or time. 10. The flip-chip connection device according to claim 8, wherein the control condition is based on whether or not wetting of the solder portion to the bump portion is completed.