JP4034085B2 - Electronic component crimping head load detection device and load detection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a load detection device and a load detection method for a crimping head of an electronic component.
[0002]
[Prior art]
As a method for bonding an electronic component to a substrate, a method by thermocompression bonding is known. In this method, an electronic component is pressed against a substrate by a crimping head, and the electronic component is heated by a heater and bonded to the substrate by soldering or a resin adhesive. Here, in order to obtain a good thermocompression bonding quality, it is necessary to control the crimping load in the thermocompression bonding process according to a predetermined control target value. For this reason, the thermocompression bonding apparatus is provided with a mechanism for controlling the load value at which the pressure bonding head presses the electronic component to a predetermined load.
[0003]
This load control is based on the load value detected by the load detecting means interposed between the crimping head and the lifting part. It is performed by controlling based on. Accordingly, the control accuracy (resolution) of the crimping load depends on the resolution of the lifting operation, and the smaller the amount of change in the pressing load per displacement of the unit lifting operation, the higher the precision load control is realized.
[0004]
[Problems to be solved by the invention]
However, since the load cell used as the load detecting means in the conventional thermocompression bonding apparatus for electronic parts has a small absolute value of the displacement amount of the load point, the load value greatly fluctuates due to slight displacement of the lifting operation. That is, the control accuracy (resolution) of the crimping load is restricted by the absolute value of the displacement amount of the load cell and is very low, and it is difficult to improve the accuracy of controlling the crimping load.
[0005]
Therefore, an object of the present invention is to provide a load detection device and a load detection method for a crimping head of an electronic component that can improve the control accuracy of the crimping load.
[0006]
[Means for Solving the Problems]
The load detection device for a crimping head of an electronic component according to the present invention includes a load detection unit that detects a load acting on the crimping head that presses the electronic component against a substrate, an elevating unit that moves the crimping head up and down, and an overhanging unit. comprising a crimping block which is fixed the above bonding head at the bottom, and a cylinder for pressing downward at a constant pressing force to the load detecting means overhang of the crimping block is provided in the lifting unit, the load detection It means, and the load sensor consists of a spring which have a linear load-displacement characteristics, provided on the elevating unit, and has a configuration which is interposed between the bonding head and the lifting unit, the spring Thus, the amount of displacement of the load detecting means at the time of loading is amplified .
[0007]
Further, the present invention is a method for detecting a load of a crimping head for crimping an electronic component to a substrate, and between a crimping head fixed to a lower part of a crimping block having an overhang portion and an elevating unit that moves the crimping head up and down. and the load sensor comprises a load detecting means composed of a spring that have a linear load-displacement characteristics, a projecting portion of the crimping block provided in the elevator portion against a load detecting means provided in the lifting unit A load acting on the pressure-bonding head is detected by using a load detecting device that is pressed downward by a cylinder with a constant pressing force and amplifies the amount of displacement of the load detecting means when a load is applied by the spring.
[0008]
According to the present invention, as a load detecting means of the crimping head, and the load sensor, so using a spring to have a linear load-displacement characteristics, a pressing load per unit vertical movement by the displacement amount larger load detection means The amount of change can be reduced, and the control accuracy of the crimping load can be improved.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of an electronic component thermocompression bonding apparatus according to an embodiment of the present invention, and FIGS. 2A and 2B are partial side views of the electronic component thermocompression bonding apparatus according to an embodiment of the present invention. FIG. 3 is a graph showing the relationship between the load of the electronic component thermocompression bonding apparatus and the amount of vertical movement displacement in one embodiment of the present invention.
[0010]
First, the structure of an electronic component thermocompression bonding apparatus will be described with reference to FIG. In FIG. 1, a positioning table 2 is disposed on a base 1. A substrate 3 is placed on the positioning table 2. By driving the positioning table 2, the substrate 3 moves in the horizontal direction and positions the substrate 3. A frame 4 is erected on the base 1. A guide rail 5 is vertically disposed on the front surface of the frame 4, and a slider 6 is mounted on the guide rail 5 so as to be movable up and down.
[0011]
An elevating part 7 is fixed to the slider 6. A motor 8 is disposed on the frame 4, and the rotation shaft of the motor 8 is connected to a vertical feed screw 9. The feed screw 9 is screwed into a nut 10 coupled to the elevating unit 7, and therefore the elevating unit 7 is moved up and down when the motor 8 rotates forward and backward. That is, the motor 8, the feed screw 9 and the nut 10 serve as elevating means for elevating the elevating unit 7. As shown in FIG. 1, the elevating part 7 has a U-shaped cross-sectional shape, and is composed of an upper protruding part 7a, a recessed part 7b, and a lower protruding part 7c.
[0012]
A guide rail 12 is vertically disposed on the protruding portion 7c. A slider 13 is fitted to the guide rail 12 so as to be movable up and down, and a crimping block 11 is fixed to the slider 13. The crimping block 11 has an inverted L shape, and the upper projecting portion 11 a is located in the recess 7 b of the elevating unit 7. A cylinder 14 is suspended from the lower surface of the protruding portion 7a of the elevating unit 7, and the rod 14a of the cylinder 14 is in contact with the upper surface of the overhanging portion 11a.
[0013]
A load cell 15 that is a load sensor elastically supported by a spring 16 having a linear load / displacement characteristic is mounted on the upper surface of the projecting portion 7c of the elevating / lowering portion 7, and the load point of the load cell 15 is an overhang of the crimping block 11. It is in contact with the lower surface of the portion 11a. A crimping head 17 is fixed to the lower part of the crimping block 11. Therefore, the crimping head 17 is supported by the elevating part 7 so as to be movable up and down, and the load cell 15 and the spring 16 as load detecting means are disposed between the elevating part 7 and the crimping head 17. A load caused by the weight of the crimping block 11 and a pressing force of the cylinder 14 act on the load point of the load cell 15. The load signal detected by the load cell 15 is sent to the control unit 30, and the control unit 30 controls the motor 8 that is the lifting means based on this load signal.
[0014]
A thermocompression bonding tool 18 is attached to the lower end portion of the pressure bonding head 17. The thermocompression bonding tool 18 holds the electronic component 19, heats the electronic component 19, and press-bonds the substrate to the substrate 3 with a predetermined load.
[0015]
Here, functions of the cylinder 14 and the load cell 15 will be described with reference to FIGS. 2 (a) and 2 (b). FIG. 2A shows the force of each part in a state in which the elevating part 7 is raised, and FIG. 2B shows the force of each part in the state in which the elevating part 7 is lowered and the electronic component 17 is thermocompression bonded to the substrate 3. Showing balance. The cylinder 14 is supplied with air pressure of a predetermined pressure from an air source and a regulator. Therefore, the cylinder 14 presses the crimping block 11 downward with a predetermined pressing force Fo. In the state shown in FIG. 2A, the sum Fo + W of the pressing force Fo and the load W corresponding to the weight of the crimping block 11 and the like is balanced with the load f applied to the load cell 15. That is, in the state where the elevating unit 7 is in the raised position, the detected load value of the load cell 15 is equal to the sum of the pressing force Fo of the cylinder 14 and the dead weight W of the crimping block 11 or the like.
[0016]
On the other hand, in the state shown in FIG. 2B, the crimping head 17 receives a reaction force F equal to the crimping load from the electronic component 19, and the sum Fo + W of the aforementioned force is the reaction force F of the crimping load and the load cell. 15 is balanced with the sum F + f of the load f applied to 15. That is, the reaction force F of the crimping load is expressed as Fo + W−f. Therefore, in order to control the crimping load F, Fo + W is a constant value. Therefore, while the detected load value f of the load cell 15 is monitored by the control unit 30, the drive of the motor 8 is controlled to move the lifting unit 7 up and down. Can be controlled.
[0017]
Next, the function of the spring 16 will be described with reference to FIG. FIG. 3 is a graph showing the relationship between the horizontal axis with the vertical displacement amount ΔZ of the elevating unit 7 and the vertical axis with the increase / decrease value Δf of the detected load of the load cell 15. Graph a shows the case where only the load cell 15 is used as in the conventional method, and graph b shows the case where the load cell 15 is supported by the spring 16 as in the present embodiment. As shown in FIG. 3, when only the load cell 15 is used, the amount of increase / decrease indicated by ΔZ1 corresponds to a certain load increase / decrease value Δf1. On the other hand, when the load cell 15 is supported by the spring 16, the displacement amount of the spring 16 is added to the displacement amount ΔZ1 of only the load cell 15, so that the up / down motion much larger than ΔZ1 with respect to the similar increase / decrease value Δf1. Corresponding to the displacement amount (indicated by ΔZ2).
[0018]
In other words, the relationship between the minimum unit displacement amount (resolution) and the load increase / decrease value of the lifting operation and the load increase / decrease value are smaller in the case of graph b, in other words, For example, more precise load detection can be performed using a lifting mechanism with the same resolution. In particular, in the case of a light load, the displacement amount of the load cell 15 is very small, and it is difficult to detect a load with high accuracy by the conventional load detection method using only the load cell 15. On the other hand, in the present embodiment, by adding the spring 16 and amplifying the amount of displacement when a load is applied, it is possible to detect a load with high accuracy using an elevating mechanism with the same resolution.
[0019]
This electronic component thermocompression bonding apparatus has the above-described configuration, and the operation will be described next. First, in FIG. 1, the substrate 3 is placed on the positioning table 2, and the substrate 3 is positioned with respect to the pressure bonding head 7 by driving the positioning table 2. Next, the electronic component 19 is supplied from the supply part (not shown) of the electronic component 19 and is held by the thermocompression bonding tool 18. Next, when the elevating part 7 is lowered, the electronic component 19 held by the thermocompression bonding tool 18 comes into contact with the substrate 3.
[0020]
Thereafter, the electronic component 19 is heated at a predetermined temperature by the thermocompression bonding tool 18, and the electronic component 19 is pressed against the substrate 3 with a predetermined load. At this time, the load cell 15 as load detecting means is elastically supported by a spring 16 having a linear load / displacement characteristic, and the amount of displacement of the lifting operation corresponding to the pressing load is amplified. It can be carried out. Therefore, since the pressure bonding load at the time of thermocompression bonding can be controlled with high accuracy, good thermocompression bonding quality can be obtained.
[0021]
【The invention's effect】
According to the present invention, the load detection means for detecting the load acting on the crimping head is increased to decrease the increase / decrease value of the detected load per unit lifting operation displacement amount, thereby performing more precise load detection. it can. Thereby, the crimping load can be controlled with high accuracy.
[Brief description of the drawings]
FIG. 1 is a side view of an electronic component thermocompression bonding apparatus according to an embodiment of the present invention. FIG. 2 (a) is a partial side view of an electronic component thermocompression bonding apparatus according to an embodiment of the present invention. FIG. 3 is a partial side view of an electronic component thermocompression bonding apparatus according to an embodiment of the present invention. FIG. 3 is a graph showing the relationship between the load and the vertical movement displacement amount of the electronic component thermocompression bonding apparatus according to an embodiment of the present invention. Explanation of]
DESCRIPTION OF SYMBOLS 1 Base 2 Positioning table 3 Board | substrate 7 Lifting / lowering part 8 Motor 9 Feed screw 11 Crimp block 15 Load cell 16 Spring 17 Crimp head 18 Thermo-compression tool 19 Electronic component

Claims (2)

A load detecting means for detecting a load acting on the bonding head to press the electronic component to the substrate, and a lifting unit for vertically moving said crimping head, the crimping block which is fixed to the bonding head to the bottom has a projecting portion, said A cylinder that is provided in the elevating part and presses the protruding portion of the crimping block downward with a constant pressing force against the load detecting means. The load detecting means has a load sensor and linear load / displacement characteristics. It consists of a perforated springs, provided in the elevating section, and has a configuration which is interposed between the bonding head and the lifting unit, for amplifying the displacement of the load detecting means at the time of load application by the spring A load detecting device for a crimping head of an electronic component, characterized in that it is configured as described above . A method of detecting a load of a crimping head for crimping an electronic component to a substrate, wherein a load sensor and a linear are arranged between a crimping head fixed to a lower part of a crimping block having an overhanging portion and an elevating unit that moves the crimping head up and down. a load, comprising a load detecting means comprising a displacement characteristics and a spring for chromatic, certain press overhanging portion of the crimping block cylinder provided on the elevating unit with respect to the load detecting means provided in the lifting unit An electronic component that detects a load acting on the pressure-bonding head by using a load detection device that is pressed downward by pressure and amplifies a displacement amount of a load detection means when a load is applied by the spring. Of detecting the load of the crimping head.

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