JP4294165B2 - Electronic component mounting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component mounting apparatus for mounting a predetermined electronic component on a circuit board.
[0002]
[Prior art]
In recent years, flip-chip mounting in which electronic components such as semiconductor chips are directly mounted on a circuit board, which is a mounting target, has been used in order to reduce the size and weight of electronic devices. In this method, generally, bumps are formed on the electrode parts of the electronic component, and heat is applied to bond the bumps to the electrodes on the circuit board. Recently, an electronic component mounting apparatus that employs such a construction method has a mainstream having a bonding head that is mounted on a circuit board by applying heat while vacuum-adsorbing and handling the electronic component.
[0003]
In this regard, FIGS. 6 and 7 show an example of a bonding head in a conventionally known electronic component mounting apparatus. 6 and 7 are an explanatory cross-sectional view showing the configuration of the bonding head and an explanatory view showing the lower end surface of the bonding head, respectively. The bonding head 50 applies heat to the electronic component 51 while adsorbing and holding the electronic component 51 at the lower end side, and bonds the electronic component 51 to a predetermined position on the circuit board 54. At the lower end side, the electronic component 51 is bonded to the circuit board 54. A bonding tool 58 to be directly performed is held by suction. The bonding head 50 includes an elevating mechanism 66 and a horizontal movement mechanism 67, and can move up and down over the circuit board 54 or move in the horizontal direction. In the bonding head 50, an air path 60 (path at the center in the drawing) for sucking the electronic component 51 on the lower surface side of the bonding tool 58 to be sucked and held, and the bonding tool 58 to be sucked and held. Air path 61 (path on the left side in the figure). Further, a gas supply path 62 (path on the right side in the drawing) communicating with a plurality of outlets 62 a formed at the peripheral edge of the lower end surface of the head 50 is provided inside the head 50.
[0004]
In the bonding head 50, the electronic component 51 attracted and held by the bonding tool 58 is positioned so that the bumps 64 formed on the lower surface side thereof are in contact with the electrodes 65 formed on the circuit board 54 ( In FIG. 6), the bumps 64 are melted by being heated by a predetermined heating source (not shown), so that bonding is performed so as to be bonded to the circuit board 54. During such bonding, in order to prevent oxidation of the joint portion 63 between the bump 64 and the electrode 65, an inert gas such as nitrogen N ₂ is supplied through the gas supply path 62, and the joint portion is supplied from the outlet 62a. 63 is sprayed. The inert gas is supplied from a gas supply source 68 that communicates with the gas supply path 62.
The inert gas outlet 62a is formed on the lower end side of the bonding head 50 and in the vicinity of the outside of the portion to which the bonding tool 58 is adsorbed. As can be seen from FIG. 7, the bonding tool 58 is adsorbed and held. In this state, it is located along the outer periphery of the tool 58. The inert gas is blown out in an equal amount from each outlet 62a.
[0005]
[Problems to be solved by the invention]
However, in the conventional bonding head 50, the inert gas outlet 62 a is provided on the lower end side of the head 50, and therefore when the various electronic components 51 of different sizes are targeted, the position of the outlet 62 a is determined. May be greatly separated from the joint 63 between the electronic circuit 51 and the circuit board 54. In this case, the concentration of the inert gas that reaches the joint 63 is reduced by mixing with the surrounding air, and the oxidation of the joint 63 cannot be sufficiently prevented, and the joint quality may be lowered. .
In any case, since the height from the outlet 62a to the substrate surface is the same, a pressure difference is unlikely to occur, and the inert gas blown to the circuit board 54 In some cases, the flow path cannot be secured during this period, and the inert gas may not reach the joint 63. As a result, the oxidation of the joint 63 cannot be sufficiently prevented, and stable joint quality cannot be obtained.
[0006]
The present invention has been made in view of the above technical problems, and constitutes an inert gas blowout port that can cope with various component shapes, and prevents oxidation at the joint between the circuit board and the electronic component. An object is to provide an electronic component mounting apparatus that stabilizes quality.
[0007]
[Means for Solving the Problems]
In the invention according to claim 1 of the present application, a bonding tool attached to the front end side of the bonding head is brought into contact with the back surface of the electronic component and heated using a predetermined heating source, whereby the electronic component and the circuit board are heated. In an electronic component mounting apparatus that performs bonding by thermally bonding electrodes to each other, a blowout port that blows an inert gas to the bonded portion at the time of thermal bonding between the electrodes is in the vicinity of a portion that contacts the electronic component of the bonding tool. The bonding tool is characterized in that a part of the blowout port is provided farther from a portion in contact with the electronic component than the other blowout ports .
[0008]
The invention according to claim 2 of the present application is characterized in that, in the invention according to claim 1, the heating source is a ceramic heater .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view showing an internal structure of an electronic component mounting apparatus according to an embodiment of the present invention. The electronic component mounting apparatus 1 performs bonding by sequentially positioning the electronic component 3 at a predetermined position on the circuit board 5, applying heat to the electronic component 3, and thermally bonding the electronic component 3 to the circuit board 5. The basic configuration includes a bonding head 10 that applies heat while holding the electronic component 3 and a bonding stage 21 on which the circuit board 5 is placed. The bonding head 10 is placed in the horizontal direction (X direction in the figure) by the horizontal direction moving mechanism 19 and the lifting mechanism 18 (see FIG. 2) above the circuit board 5 that is held and arranged on the bonding stage 21 by suction. ) And the vertical direction (Z direction in the figure). In the electronic component mounting apparatus 1, a plurality of electronic components 3 to be mounted on the circuit board 5 are stored in a tray 20, and the bonding head 10 sequentially takes out each electronic component 3 and puts it at a predetermined position on the circuit board 5. It comes to be installed.
[0011]
The bonding stage 21 and the tray 20 are fixed on a slide base 22 that is movable in the horizontal direction (Y direction orthogonal to the X direction in the figure). Can be moved to. In addition, the electronic component mounting apparatus 1 is equipped with an image recognition optical system 25 as means for recognizing the positions of the electronic component 3 and the circuit board 5 when mounting the electronic component 3. It is movable in both the X and Y directions in the figure, and moves with the operation of the bonding stage 22 on which the circuit board 5 is placed. This image recognition optical system 25 recognizes the position of the circuit board 5 positioned below and the electronic component 3 positioned above it by switching the visual field.
[0012]
In the mounting operation of the electronic component 3, when the image recognition optical system 25 recognizes the positions of the electronic component 3 and the circuit board 5, the bonding head 10 handles the electronic component 3 while adsorbing and holding based on the position information. The electronic component 3 is positioned at a predetermined position on the circuit board 5. With the electronic component 3 positioned as described above, heat is applied to the electronic component 3 and the bumps 4 (see FIG. 2) formed on the lower end surface of the electronic component 3 are melted. 5 is thermally bonded.
[0013]
FIG. 2 is a longitudinal sectional explanatory view schematically showing the configuration of the bonding head. The bonding head 10 is formed by combining a bonding head body 9, a water jacket 15, a heating source 14, and a bonding tool 2 in this order from the top. An air path 11 (path in the center in the figure) that opens to the lower end surface of the bonding tool 2 on the other end side while communicating with (not shown), and a decompression device (not shown) from the bonding head body 9 on one end side. ) And an air path 12 (path on the left side in the drawing) that opens at the lower end surface of the heating source 14 on the other end side. In the bonding head 10, the bonding tool 2 is attracted and held on the lower surface side of the heating source 14 by the pressure reducing action in the air path 12, and the pressure reducing action in the air path 11 is applied to the lower surface side of the bonding tool 2. The circuit board 3 is abutted and held on the back surface thereof.
Further, the bonding head 10 has an inert gas supply path 13 (in the drawing) that communicates with the gas supply source 17 from the bonding head main body 9 at one end and opens at the lower end surface of the heating source 14 at the other end. On the right side of). The inert gas supply path 13 is provided with an electromagnetic valve 16 that can control on / off of the inert gas supply.
[0014]
In the bonding head 10, the bonding tool 2 receives heat from the heating source 14 disposed on the upper surface side thereof, and heats and melts the bumps 4 formed on the lower end surface of the electronic component 3, so that the circuit board 5 is heated. Bonding is performed by bonding to the electrode 6. In this embodiment, a ceramic heater is used as the heating source 14. During bonding of the electronic component 3, cooling water is circulated inside the water jacket 15 disposed on the upper surface side of the heating source 14, thereby interrupting heat transfer from the heating source 14 to the upper side of the head. Thus, a decrease in machine accuracy due to thermal expansion of the bonding head 10 is prevented.
[0015]
In the bonding head 10, the gas supply source is used to prevent oxidation of the joint 7 between the bump 4 on the electronic component 3 side and the electrode 6 on the circuit board 5 side during bonding of the electronic component 3. An inert gas such as nitrogen supplied from 17 through the inert gas supply path 13 is blown against the joint 7. In the present embodiment, in order to realize the blowing of the inert gas to the joint portion 7, the groove portion 2 c having a predetermined depth is formed along the periphery on the upper surface side of the bonding tool 2 in contact with the heating source 14. Furthermore, a plurality of gas flow paths 2b extending downward from the bottom surface of the groove 2c and opening at the lower end surface of the bonding tool 2 are provided at a predetermined interval. As can be seen from FIG. 2, the width of the groove 2 c is the same as that described above when the bonding tool 2 is held by suction on the lower end surface of the heating source 14 so as to form an air path 11 for sucking electronic components together with other components. It is set so as not to communicate with the air path 12 but to communicate only with the inert gas supply path 13. The gas flow path 2b opens on the lower surface side of the tool 2 as a gas outlet 2a.
According to the bonding tool 2 having such a structure, the inert gas supplied from the gas supply source 17 through the inert gas supply path 13 flows into the groove 2c from the portion communicating with the air path 13, and the bonding tool 2 It spreads over the whole groove part 2c along a peripheral edge, and is blown out uniformly from the said blowing outlet 2a through each gas flow path 2b.
[0016]
FIG. 3 is an explanatory view showing the lower end surface of the bonding tool 2. In this bonding tool 2, the gas outlet 2 a on the lower end surface of the bonding tool 2 is in the vicinity of the periphery of the electronic component 3 while the electronic component 3 (indicated by a one-dot chain line) is adsorbed and held by the pressure reducing action in the air path 11 Will be located. As a result, the inert gas supplied through the gas flow path 2b is reliably blown from the outlets 2a to the joint 7 between the electronic component 3 and the circuit board 5.
In this way, the inert gas is reliably blown to the joint 7 from the vicinity of the periphery of the electronic component 3 that is relatively close to the joint 7 between the electronic component 3 and the circuit board 5, thereby reaching the joint 7. The concentration of the inert gas does not decrease so much depending on the atmosphere, and the joining portion 7 or the solder material can be sufficiently prevented from being oxidized during the thermal joining. As a result, high quality bonding can be realized.
[0017]
In this embodiment, since the blowout port 2a is provided on the bonding tool 2 side, a bonding tool having a different position of the blowout port 2a is prepared in advance and is sucked and held at the lower end side of the bonding head 10. By appropriately selecting the bonding tool 2 whose blowout port 2a is located in the vicinity of the periphery of the electronic component 3 according to the shape and size of the electronic component 3, a good inert gas can be blown to the bonding portion 7. This can be realized only by the tool 2 type support.
In the embodiment described above, the bonding tool 2 has a large number of outlets 2a. However, the present invention is not limited to this. Instead of the plurality of outlets 2a, a slit-like opening or a continuous annular shape is provided. You may have a slit.
[0018]
Next, another embodiment of the present invention will be described in detail. In the following description, the same components as those in the above-described embodiment are denoted by the same reference numerals, and further description is omitted.
4 and 5 are an explanatory sectional view schematically showing a bonding head according to another embodiment of the present invention and an explanatory view showing a lower end surface of the bonding tool, respectively. The bonding head 30 has the same configuration as that of the above-described embodiment. In this embodiment, the gas flow path 33b extending downward from the bottom surface of the groove 32c having a predetermined depth on one side of the bonding tool 32. Is set so that the lower surface 33 of the tool 32 becomes higher. That is, a blowout port 33 a in which the gas flow path 33 b is opened at the lower end surface of the bonding tool 32 is formed at a position higher than the other blowout ports 32 a in the tool 32 and contacts the electronic component 3 on the lower surface side of the tool 32. It is far from the part that touches.
[0019]
When the bonding tool 32 having such a structure is used, when the inert gas supplied through the inert gas supply path 13 in the bonding head 30 is blown out from the blowing ports 32a and 33a having different heights, the bonding tool 32 is high. The pressure applied to the joint portion 7 by the inert gas blown from the blowout port 33 a at the position is smaller than that of the blowout port 32 a located in the vicinity of the joint portion 7. Due to the pressure difference of the inert gas, the electronic component 3 and the circuit board 5 are moved from the high pressure side where the blowout port 32a is located in the vicinity of the portion in contact with the electronic component 3 to the low pressure side where the blowout port 33a is formed. An inert gas stream that passes through the gap is generated (indicated by an arrow). As a result, the concentration of the inert gas that has reached the joint portion 7 is stably ensured, and oxidation of the joint portion 7 or the solder material or the like can be sufficiently prevented during thermal joining, thereby achieving high-quality bonding. be able to.
[0020]
Note that the present invention is not limited to the illustrated embodiments, and it goes without saying that various improvements and design changes are possible without departing from the scope of the present invention.
[0021]
【The invention's effect】
As is clear from the above description, according to the present invention, when the electrodes are thermally bonded to each other, the blowout port for blowing the inert gas to the bonded portion is provided in the vicinity of the portion that contacts the electronic component of the bonding tool. As a result, the inert gas can be reliably blown to the joint and the concentration of the inert gas in the vicinity of the joint can be stably secured. Thereby, at the time of thermal bonding, oxidation of the bonding portion or the solder material can be sufficiently prevented, and high-quality bonding can be achieved. Further, according to the present invention, a bonding tool having a different outlet position is prepared in advance, and the bonding tool is located near the periphery of the electronic component while being sucked and held at the lower end side of the bonding head. By appropriately selecting according to the shape and size of the electronic component, it is possible to realize a good inert gas blowout to the joint only by dealing with the types of bonding tools.
[0022]
Further, according to the present invention, in the bonding tool, a part of the inert gas blowout port is provided farther from the portion in contact with the electronic component than the other blowout ports. The pressure to the joint due to the inert gas blown out from the air is smaller than that at the outlet located near the joint, and the pressure difference of the inert gas passes through the gap between the electronic component and the circuit board. An inert gas stream can be generated. As a result, the concentration of the inert gas that reaches the joint is stably ensured, and oxidation of the joint or solder material or the like can be sufficiently prevented during thermal joining, thereby realizing high-quality bonding. it can.
[Brief description of the drawings]
FIG. 1 is an overall perspective view showing an internal structure of an electronic component mounting apparatus according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view schematically showing the bonding head according to the embodiment.
FIG. 3 is an explanatory view showing a lower end surface of the bonding tool according to the embodiment.
FIG. 4 is a longitudinal sectional explanatory view schematically showing a bonding head according to another embodiment of the present invention.
FIG. 5 is an explanatory view showing a lower end surface of a bonding tool according to another embodiment.
FIG. 6 is a longitudinal sectional view schematically showing a conventional bonding head.
FIG. 7 is an explanatory view showing a lower end surface of a conventional bonding head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electronic component mounting apparatus 2 ... Bonding tool 2a ... Inert gas outlet 3 ... Electronic component 4 ... Bump 5 ... Circuit board 6 ... Circuit board side electrode 7 ... Bonding part 10 ... Bonding head

Claims (2)

A bonding tool attached to the front end side of the bonding head is brought into contact with the back surface of the electronic component and heated by using a predetermined heating source, whereby the electrodes of the electronic component and the circuit board are thermally bonded to perform bonding. In electronic component mounting equipment,
A blowing port for blowing an inert gas to the bonding portion and the vicinity thereof at the time of thermal bonding between the electrodes is provided in the vicinity of a portion in contact with the electronic component of the bonding tool, and a part of the blowing port in the bonding tool Is provided apart from the portion that contacts the electronic component as compared with the other outlets . 2. The electronic component mounting apparatus according to claim 1 , wherein the heating source is a ceramic heater .

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