JP2774614B2 - Bonding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention is to heat and press a gold bump formed on an electrode of an integrated circuit (IC chip) and a lead of a film carrier tape, for example. The present invention relates to a bonding apparatus for bonding by using a bonding method.

(Description of the Related Art) FIG. 5 shows a film carrier tape 1 in which IC chip bonding holes 2 are formed at predetermined intervals, and these IC chip bonding holes are formed. 2, lead (first electrodes) 3... Of copper plated with tin (Sn) are arranged around the periphery of the lead 2. FIG. 6 shows an IC chip 4 on which gold bumps (second electrodes) 5 to be connected to the respective lead wires 3 are formed. However, when the IC chip 4 is bonded to the film carrier tape 1, the IC chip 4 is placed on the chip stage 6 and the bonding tool 7 is arranged above the chip stage 6, as shown in FIG. And a film carrier tape 1 between the chip stage 6 and the bonding tool 7.
Is passed. In this state, the respective lead wires 3 of the film carrier tape 1 and the respective gold bumps 5 of the IC chip 4 are positioned. Thereafter, the bonding tool 7 is lowered to heat the respective lead wires 3 and the respective gold bumps 5. Pressed. Among the heating and pressurizing, the heating is related to the joining property of joining the gold bump 5 and the tin of the lead wire 3 by eutectic reaction, and the pressing is applied to each of the gold bumps 5 and each of the leads having a variation in height position. It is involved in the adhesion to the wire 3. Therefore, each gold bump 5 and each lead wire 3 are joined by this heating and pressing.

However, if the bonding is continued under the same conditions, for example, the heating temperature of the bonding tool 7 is controlled to be constant at any one of T ₁ , T ₂ , and T ₃ , the temperature of the bonding tool 7 becomes as shown in FIG. Decreases as the number of times of bonding increases. This is because tin oxide adheres to the surface of the bonding tool 7 as the number of times of bonding increases, and the thickness of the tin oxide becomes about 1 μm when the number of times of bonding is about 100, and the temperature of bonding at this time decreases. Is several tens of degrees Celsius. When the bonding temperature falls outside the appropriate temperature range Q for bonding,
The bonding strength between each of the gold bumps 5 and each of the lead wires 3 is reduced, and lead peeling frequently occurs. For this reason, the number of times of bonding is 50 to
At about 100 times, cleaning is performed on the bonding tool 7 to remove tin oxide.
Further, in order to secure the bonding stability, the bonding temperature is set in advance higher than the appropriate temperature by, for example, 50 ° C., or the number of times of cleaning the bonding tool 7 is increased.

However, if the number of times of cleaning of the bonding tool 7 increases, the life of the bonding tool 7 is shortened and the loss time in cleaning is increased.
Also, the IC chip has more pins and a narrower pitch (for example, 20 pins).
(0 or more, lead pitch 100 μm or less), the size of the gold bumps 5 of the IC chip 4 also becomes smaller. Therefore, when bonding is performed by setting the bonding temperature higher than an appropriate temperature in advance as described above, the IC electrode and the gold The reaction at the bonding interface of the bumps progresses, and the strength of this interface is reduced. As a result, the gold bumps 5 are easily peeled off from the gold bumps 5 and are easily deformed in relation to the pressing force. I do. Furthermore, since the IC chip 4 becomes larger with an increase in the number of pins, the yield due to the above-mentioned problems is not economical.

(Problems to be Solved by the Invention) As described above, the temperature of the bonding tool 7 decreases as the number of times of bonding increases, whereby the bonding strength between each of the gold bumps 5 and each of the lead wires 3 decreases and the lead peels off. Will occur frequently.

Accordingly, an object of the present invention is to provide a bonding apparatus capable of performing stable bonding while maintaining the temperature of a bonding tool at an appropriate temperature.

[Means for Solving the Problems] According to the present invention, in a bonding apparatus for bonding a first electrode and a second electrode by heating and pressing with a bonding tool, a bonding counter for counting the number of times of bonding by the bonding tool is provided. There is provided a bonding apparatus comprising: means for bonding; and bonding temperature control means for variably controlling the temperature of the bonding tool within an appropriate temperature range in accordance with the number of times of bonding counted by the bonding counting means.

Also, the present invention provides a bonding apparatus for bonding a first electrode and a second electrode by heating and pressurizing with a bonding tool, and a bonding counting means for counting the number of times of bonding by the bonding tool, and a bonding counted by the bonding counting means. A bonding apparatus that achieves the above object by providing a bonding load control unit that changes a load on a first electrode and a second electrode of a bonding tool according to the number of times.

Further, the present invention provides a bonding apparatus for bonding a first electrode and a second electrode by heating and pressurizing with a bonding tool, a bonding counting means for counting the number of times of bonding by the bonding tool, and a bonding counted by the bonding counting means. Bonding temperature control means for variably controlling the temperature of the bonding tool within an appropriate temperature range in accordance with the number of times; and a load applied to the first electrode and the second electrode of the bonding tool in accordance with the number of times of bonding counted by the bonding counting means. And a bonding load control means for achieving the above object.

(Operation) With the provision of such means, the number of times of bonding by the bonding tool is counted by the bonding counting means, and the temperature of the bonding tool is variably controlled within an appropriate temperature range by the bonding temperature control means according to the number of times of bonding. Is done.

Also, by providing the above means, the number of times of bonding by the bonding tool is counted by the bonding counting means, and the load on the first electrode and the second electrode of the bonding tool is varied by the bonding load control means in accordance with the number of times of bonding. You.

Further, by providing the above means, the number of times of bonding by the bonding tool is counted by the bonding counting means, and the temperature of the bonding tool is variably controlled within an appropriate temperature range by the bonding temperature control means in accordance with the number of times of bonding. The load on the first electrode and the second electrode of the bonding tool is varied by the bonding load control means according to the number of times.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a bonding apparatus. Above the chip stage 6, a bonding tool 10 is arranged. This bonding tool 10 is a tool vertical drive mechanism
The bonding head 10a is provided with a cartridge heater 12 that can be mounted and removed and a thermocouple 13 that detects the temperature of the bonding head 10a. ing. The thermoelectromotive force generated in the thermocouple 13 is sent to a temperature adjustment circuit 14.The temperature adjustment circuit 14 obtains the temperature of the head 10a of the bonding tool 10 from the thermoelectromotive force and receives the set temperature T _S to obtain the temperature. It has a function of supplying power for adjusting the temperature of the bonding head 10 to the set temperature T _S to the cartridge heater 12. The tool vertical drive mechanism 11 is provided in the XY moving mechanism 15 and can move on the XY plane.

On the other hand, the film carrier tape 1 is wound around a supply reel 16, and each guide roll 17, 1
Chip table 6 and bonding tool 10 through 8,19
After passing between the chip table 6 and the bonding tool 10, the paper is sent to the winding roll 23 through the guide rolls 20, 21, and 22.

Reference numeral 24 denotes a tool cleaning mechanism. The tool cleaning mechanism 24 has a grindstone 26 attached to a rotating shaft of a motor 25. The motor 25 is driven by being supplied with electric power from a motor drive circuit 27. It is supposed to.

The main control circuit 28 includes a bonding counter for counting the number of times of bonding performed by the bonding tool 10 by the vertical movement of the tool vertical drive mechanism 11, and a set temperature corresponding to the number of bondings counted by the bonding counter.
T _S , for example, a set temperature of 450 ° C. at the start, a set temperature of 470 ° C. for 25 or more bonding times, a set temperature of 490 ° C. for 50 or more bonding times, and a set temperature of 510 ° C. for 75 or more bonding times to the temperature adjustment circuit 14. Thus, it has a function as bonding temperature control means for variably controlling the temperature of the bonding tool 10 within an appropriate temperature range Q.
Further, the main control circuit 28 has a function of cleaning the bonding tool 10 by issuing a cleaning command to the motor drive circuit 27 when the number of times of bonding counted by the bonding counting means reaches a predetermined number of times, for example, 100 times.

Next, a description will be given of a bonding flowchart shown in FIG. The main control circuit 28 sets the total number of bonding times to N in step s1, sets the number of bonding operations n to “0” in the next step s2, further sets the set temperature T _S at the start in step s3 to 450 ° C. The number of times of bonding n ′ (= 100) necessary for cleaning of No. 10 is set to “0”. When the set temperature T _S is set to 450 ° C., the temperature adjustment circuit 14 supplies electric power corresponding to the set temperature T _S (450 ° C.) to the cartridge heater 12, whereby the bonding head 10a of the bonding tool 10 is set to 45 °. Heat to ° C.

In this state, the main control circuit 28 executes bonding in step s5. That is, the main control circuit 28 issues a command to the tool vertical drive circuit 11 and issues a command to the loader mechanism and the reel drive mechanism (not shown). This allows the IC
The chip 4 is placed on the chip stage 6 by the loader mechanism, and the supply reel 16 and the take-up reel 23
Rotates and each lead wire 3 of the film carrier tape 1
It is positioned with respect to each gold bump 5 of the IC chip 4. Then, the bonding tool 10 is lowered by the tool up / down driving mechanism 11, and each gold bump (second electrode) of the IC chip 4 is moved.
5 and the respective lead wires (first electrodes) 3 of the film carrier tape 1 are joined by being heated and pressed. Thereafter, the bonding tool 10 is raised by the tool up / down driving mechanism 11, and is in a standby state for the next bonding. Like this one
When the number of bonding operations has been completed, the main control circuit 28 adds the number of bonding operations n and the number of bonding operations n 'in step s6, and determines in step s7 whether the number of bonding operations n has reached the total number of bonding operations N. If the number n of bonding operations has not reached the total number N of bonding operations, the main control circuit 28 proceeds to step s8.
It is determined whether the number of bondings n 'has reached 100 times, and it is further determined in the next steps s9 to s12 whether the number of bondings n has reached 25 times or more, 50 times or more, and 75 times or more, respectively. . If the number of bondings n is 25 or less as a result of the above determination of the number of bondings, the main control circuit 28 returns to step s5 again and executes the next bonding. In this case, the next IC chip 4 is mounted on the chip stage 4 by the loader mechanism, and the film carrier tape 1 is moved so that each lead wire 3 at the next position is connected to each gold bump 5 of the IC chip 4. Positioned with respect to.

When the bonding is performed a plurality of times as described above, the tin Sn oxide adheres to the bonding tool 10, and the temperature of the bonding tool 10 gradually decreases as shown in FIG. Therefore, when the number of times of bonding becomes 25 or more, the main control circuit 28 moves from step s9 to step s11 through step s10, and changes the set temperature T _S to 470 ° C. As a result, the bonding head 10a of the bonding tool 10 is heated at 450 ° C., but the upper limit temperature of the appropriate temperature range Q is actually reached because the tin Sn oxide is attached. After the setting temperature T _S is thus changed to 450 ° C., the main control circuit 28 returns to step s5 again to execute the bonding. Then, when the number of bonding increases to 50 or more, the main control circuit 28 moves from step s10 through step s12 to step s13, and sets the set temperature T _S.
Change the setting to 490 ° C. Hereinafter, similarly, when the number of times of bonding becomes 75 or more, the main control circuit 28 changes the set temperature T _S to 510 ° C. in step s14. Even if the set temperature T _S is changed in this way and the overheating temperature is increased each time, the temperature of the bonding tool 10 is within the appropriate temperature range as shown in FIG.

Then, when the number of times of bonding reaches 100, the main control circuit 28 moves to step s15 according to the judgment in step s8 and performs cleaning of the bonding tool 10. That is, the main control circuit 28 issues a movement command to the XY movement mechanism 15 to position the bonding tool 10 above the cleaning member 26 of the cleaning mechanism 24, and then issues a lowering command to the tool vertical drive mechanism 11 and the motor drive circuit. A driving command is issued to 27 to remove the oxide of tin Sn adhering to the head 10a of the bonding tool 10. When this cleaning is completed, the main control circuit 28 returns to step s3 again, changes the set temperature T _S to 450 ° C., and resumes bonding.

As described above, in the above-described embodiment, the overheating temperature of the bonding tool 10 is changed stepwise to a higher value in accordance with the number of times of bonding by the bonding tool 10 and is controlled within the appropriate temperature range Q. Bonding tool 10 even if tin Sn oxide adheres
Temperature is always within the appropriate temperature range
The gold bumps 5 of the IC chip 4 and the respective lead wires 3 of the film carrier tape 1 can be joined. As a result, bonding can be continuously performed 100 times or more, the number of times of cleaning of the bonding tool 10 can be reduced, and the loss time due to cleaning can be reduced.

Next, a second embodiment of the present invention will be described. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, the main control circuit 28 has a bonding counting means for counting the number of times of bonding performed by the bonding tool 10, and the bonding tool 10 controls the IC chip 4 according to the number of times of bonding counted by the bonding counting means.
And a bonding load control means for sequentially changing the load of each gold bump 5 and each lead wire 3 of the film carrier tape 1 to a larger value.

With such a configuration, the main control circuit 28 performs steps f1 to f4.
, The total number of bondings is N, the number of bonding operations n is “0”, the set load G ₁ at the start, the number of bondings n ′ required for cleaning the bonding tool 10
(= 100) is set to “0”. The set temperature T _S is set to a constant value of, for example, 450 ° C., and the temperature adjustment circuit 14 supplies power corresponding to the set temperature T _S to the cartridge heater 12.

In this state, the main control circuit 28 executes bonding in step f5 in the same manner as described above. At this time, the bonding tool 10 is heated and pressed at a load G ₁ at a heating temperature of 450 ° C..
When the bonding is completed, the main control circuit 28 adds the number n of bonding operations and the number n 'of bondings in step f6, and determines whether the number n of bonding operations has reached the total number N of bondings in the next step f7. If the number n of bonding operations has not reached the total number N of bonding operations, the main control circuit 28
The process proceeds to f8, where it is determined whether the number of bondings n 'has reached 100. Further, in each of the following steps f9 to f12, it is determined whether the number of bondings n has reached a or more times, b or more times, and c or more times. I do. Note that a <b <c. If the number of bondings n is equal to or less than a as a result of the above determination of the number of bondings, the main control circuit 28 returns to step f5 again and executes the next bonding.

Further, when bonding is performed a plurality of times, the oxide of tin Sn adheres to the bonding tool 10, and the temperature of the bonding tool 10 gradually decreases. Therefore, when the number of times of bonding becomes a or more, the main control circuit 28 proceeds to step f11.
And change the set load to G ₂ (G ₂ > G ₁ ). Accordingly, the main control circuit 28 executes the bonding returns to step s5 again, this time the bonding tool 10 is heated and pressed with a load G ₂ at a heating temperature of 450 ° C.. Then, when the number of times of bonding increases to b times or more, the main control circuit
In step 28, the process proceeds to step f13 to change the set load to G ₃ (G ₃ > G ₂ ). Hereinafter, similarly, when the number of times of bonding becomes c or more, the main control circuit 28 changes the set load to G ₄ (G ₄ > G ₃ ) in step f14. However, even if the set load is changed and the load is increased each time,
The temperature of the bonding tool 10 falls within a proper temperature range as shown in FIG.

Then, when the number of times of bonding reaches 100, the main control circuit 28 proceeds to step f15 according to the judgment of step f8, and executes the cooling of the bonding tool 10.

As described above, in the second embodiment, the load of the bonding tool 10 is sequentially changed in accordance with the number of times of bonding by the bonding tool 10, so that the tin is added to the bonding tool 10 similarly to the first embodiment.
Even if Sn oxide adheres, the temperature of the bonding tool 10 can always be controlled within an appropriate temperature range, and the bonding tool 10
Cleaning time can be reduced, and the loss time due to cleaning can be reduced.

The present invention is not limited to the above embodiments, and may be modified without departing from the gist thereof. For example,
In each of the above embodiments, the heating temperature or the load of the bonding tool 10 is set and changed. However, the heating load time of the bonding tool 10 may be lengthened as the number of times of bonding increases. Further, the temperature of the bonding tool may be variably controlled within an appropriate temperature range according to the number of times of bonding, and the load on the first electrode and the second electrode of the bonding tool may be changed according to the number of times of bonding.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a bonding apparatus capable of performing stable bonding while maintaining the temperature of a bonding tool at an appropriate temperature.

[Brief description of the drawings]

1 to 3 are views for explaining a first embodiment of a bonding apparatus according to the present invention, wherein FIG. 1 is a configuration diagram, FIG. 2 is a bonding flowchart, and FIG. 3 is a bonding tool. FIG. 4 is a flow chart of a bonding apparatus according to a second embodiment of the present invention, FIG. 5 is an external view of a film carrier tape, FIG. 6 is an external view of an IC chip, FIG. 7 and FIG. FIG. 3 is a diagram for explaining a conventional technique. 10 bonding tool, 11 tool vertical drive mechanism, 12 cartridge heater, 13 thermocouple, 14
Temperature adjustment circuit, 15 XY moving mechanism, 16 Supply reel, 23 Rewind reel, 24 Cleaning mechanism, 25
... Motor, 26 ... Cleaning member, 27 ... Motor drive circuit, 28 ... Main control circuit.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/60 311

Claims (3)

(57) [Claims] 1. A bonding apparatus for bonding a first electrode and a second electrode by heating and pressurizing with a bonding tool, the bonding counting means for counting the number of times of bonding by the bonding tool, and the bonding counted by the bonding counting means. A bonding temperature control unit that variably controls the temperature of the bonding tool within an appropriate temperature range according to the number of times. 2. A bonding apparatus for bonding a first electrode and a second electrode by heating and pressurizing with a bonding tool, the bonding counting means for counting the number of times of bonding by the bonding tool, and the bonding counted by the bonding counting means. A bonding load control unit that changes a load on the first electrode and the second electrode of the bonding tool according to the number of times. 3. A bonding apparatus for bonding a first electrode and a second electrode by heating and pressurizing with a bonding tool, the bonding counting means for counting the number of times of bonding by the bonding tool, and the bonding counted by the bonding counting means. Bonding temperature control means for variably controlling the temperature of the bonding tool within an appropriate temperature range according to the number of times, and the first electrode and the second electrode of the bonding tool according to the number of times of bonding counted by the bonding counting means A bonding load control means for varying a load applied to the bonding device.