JPH11145209A - Thermocompression-bonding equipment of electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermocompression-bonding equipment of an electronic component, where load detection can be made with high precision in a wide range from low load to high load. SOLUTION: In a thermocompression-bonding equipment of an electronic component where bonding to a board is performed by heating and pressing an electronic component 30 against the board with a thermocompression-bonding tool 29, a thermal insulating member cutting off heat transfer from the thermocompression-bonding tool 29, a load cell 22 of a piezoelectric type which is interposed between an elevating part 7 and the thermocompression-bonding tool 29 and detects a pressing load, and a spring 25 as a preliminary means for applying preliminary pressure to the load cell 22 are arranged on a thermocompression-bonding head 20 attached on the elevating part 7 as a pressing means. Since the rigidity of the load cell 22 of a piezoelectric type is high, a vertically moving guide for preventing deformation becomes unnecessary, so that sliding resistance of the vertically moving guide is not contained in a detecting value of the load cell 22, and load detection of high precision which has little error can be made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component thermocompression bonding apparatus for thermocompression bonding an electronic component to a substrate.

[0002]

2. Description of the Related Art As a method for bonding an electronic component to a substrate, a method using thermocompression bonding is known. In this method, an electronic component is pressed against a substrate by a thermocompression bonding tool, 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 good thermocompression bonding quality, it is necessary to control the crimping load in the thermocompression bonding process according to a predetermined control target value. Conventionally, as load detection means for this load control,
There has been used a method of detecting a pressing load by interposing a strain gauge type load cell in series between a thermocompression bonding tool and a pressing means for generating a pressing force.

[0003]

A strain gauge type load cell measures a load by electrically measuring, using a strain gauge, an elastic strain generated in a measurement body of the load cell by the load. Therefore, when a strain gauge type load cell is used, it is inevitable that the load point of the load cell is deformed. However, when performing thermocompression bonding of electronic components, the posture of the thermocompression tool that transmits a force to the load cell must be strictly maintained.

For this reason, in order to maintain a strict posture of the thermocompression bonding tool while applying a load by interposing a load cell between the pressing means and the thermocompression bonding tool, conventionally, the vertical movement of the thermocompression bonding tool is guided. A linear guide was required.
However, the linear motion guide has a sliding resistance, and the sliding resistance is also included in the pressure load value and detected by the load cell, so that the accuracy of detecting the pressure load is adversely affected. In particular, when performing pressure bonding with a low load, the relative ratio of the sliding resistance to the pressure load value is large, so that the error due to the sliding resistance cannot be ignored.

As described above, in the conventional thermocompression bonding apparatus, since a strain gauge type load cell is used for load detection, it is necessary to use a linear motion guide, and it is possible to eliminate an error caused by sliding resistance of the linear motion guide. However, there is a problem that it is difficult to detect the load with high accuracy.

Accordingly, an object of the present invention is to provide a thermocompression bonding apparatus for electronic components capable of detecting a load with high accuracy.

[0007]

According to the present invention, there is provided a thermocompression bonding apparatus for an electronic component, comprising: a thermocompression bonding tool for heating and pressing the electronic component;
A heat insulating member that blocks heat transfer from the thermocompression bonding tool and insulates the heat; a pressing unit that presses the electronic component via the thermocompression tool; and a pressing load interposed between the pressing unit and the thermocompression tool to detect the pressing load. The piezoelectric load cell includes a piezoelectric load cell and a preload means for applying a preload to the piezoelectric load cell.

According to the present invention, a high-rigidity piezoelectric load cell is interposed between a pressing means for pressing an electronic component through a thermocompression tool and the thermocompression tool, thereby preventing deformation of a load point of the load cell. No need for a linear motion guide
Therefore, the load can be detected with high accuracy while excluding the influence of the sliding resistance of the linear motion guide.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a front view of a thermocompression bonding apparatus for electronic components according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a crimping head of the thermocompression bonding apparatus for electronic components.

First, the structure of a thermocompression bonding apparatus for electronic components will be described with reference to FIG. In FIG. 1, a positioning table 2 is provided on a base 1. The substrate 3 is placed on the positioning table 2. By driving the positioning table 2, the substrate 3 moves in the horizontal direction and is positioned. A gate-shaped frame 4 is provided on the base 1. A guide rail 5 is vertically disposed on the front surface of the two side pillars of the frame 4, and a slider 6 is mounted on the guide rail 5 so as to be vertically movable. Two sliders 6
The elevating unit 7 is installed in the cradle. A motor 8 is provided in the center of the upper part of the frame 4, and the rotation axis of the motor 8 is connected to a vertical feed screw 9. The feed screw 9 is screwed into a nut 10 connected to the elevating unit 7.
Is mounted on the center line. Therefore, when the motor 8 rotates forward and backward, the lifting unit 7 moves up and down together with the pressure bonding head 20.

Next, the pressure bonding head 20 will be described with reference to FIG. In FIG. 2, the base 21 of the pressure bonding head 20 is fixed to the lower surface of the elevating unit 7. A through-hole 21 a is provided in a concave portion on the upper surface of the base 21.
A bolt 24 is inserted therein. A spring 25 is mounted on the bolt 24, and a screw portion at the tip of the bolt 24 is screwed into the nut block 23. A piezoelectric load cell 22 is interposed between the lower surface of the base 21 and the nut block 23. When a compressive load acts on the load cell 22, the load cell 22 outputs a load signal proportional to the magnitude of the load.

Further, by fastening the bolt 24,
The load cell 22 includes the lower surface of the base 21 and the nut block 23.
, And the load cell 22 is compressed. That is, the bolt 24, the spring 25, and the nut block 23 are preload means for preloading the load cell 22. Adjust the bolt 24 to load cell 2
By adjusting the preload of No. 2, the load cell 22 can be used in a load range where the load detection characteristic is the best.

On the lower surface of the nut block 23, a heat insulating material 2 is provided.
6, a heat block 27 is fixed. The heat block 27 has a built-in heater 28.
By driving 8, the electronic component 30 is heated via the thermocompression bonding tool 29 mounted on the lower surface of the heater block 27. That is, the heater 28 serves as heating means for heating the electronic component 30. The heat insulating material 26 is a heat insulating means for blocking heat from the heater 28 as a heating means from being transmitted upward.

Electronic component 3 held by thermocompression bonding tool 29
0 is pressed against the substrate 3 by the lowering of the elevating unit 7 to which the pressure bonding head 20 is attached. That is, the lifting unit 7, the motor 8, the feed screw 9 and the nut 10 shown in FIG.
Is pressing means for pressing the electronic component 30 against the substrate 3 via the thermocompression bonding tool 29. The load cell 22 is interposed between the pressing unit and the thermocompression bonding tool 29, feeds back a load signal from the load cell 22 to a control unit (not shown), and drives the motor 8 based on the feedback, thereby pressing the load. Is controlled.

This thermocompression bonding apparatus for electronic components has the above-described configuration, and the operation will be described next. In FIG. 1, a substrate 3 is placed on a positioning table 2, and by driving the positioning table 2, the substrate 3
Is positioned with respect to Next, the electronic component 30 is supplied by a supply unit (not shown) of the electronic component 30, and is held by the thermocompression bonding tool 29. Then, the electronic component 30 held by the thermocompression bonding tool 29 is brought into contact with the substrate 3 by lowering the elevating unit 7. Thereafter, the electronic component 30 is heated at a predetermined temperature by the thermocompression bonding tool 29, and the electronic component 3 is heated.
0 is pressed against the substrate 3 with a predetermined load.

The control of the load at this time will be described.
When the electronic component 30 is pressed against the substrate 3, a pressing force also acts on the load cells 22 that are interposed in series in the pressure bonding head 20. This pressing force is applied to the load cell 22
The electronic component 30 is pressed against the substrate 3 with a predetermined load by controlling the driving of the motor 8 by feeding back the load signal.

Here, the load cell 22 is of a piezoelectric type,
High rigidity and almost no deformation. Therefore, the thermocompression bonding tool 29 integrally provided below the load cell 22 and supported by the load cell 22 always keeps a correct posture. For this reason, there is no need to separately provide a linear motion guide for holding the posture of the pressure bonding head 20 during the vertical movement.

As a result, there is no additional sliding resistance due to the provision of the vertical movement guide mechanism. Therefore, the load value detected by the load cell 22 is the pressure load value of the electronic component 30 itself, and the pressure load is detected very accurately. can do. As described above, as the load detecting means for detecting the pressing load at the time of thermocompression bonding, the piezoelectric type load cells 22 are mounted in series in the pressure bonding head 20 so that the load cells can be extremely accurately over a wide range from a low load range to a high load range. Pressing charge can be detected.

[0019]

According to the present invention, a high-rigidity piezoelectric load cell is arranged in series between a pressing means for pressing an electronic component via a thermocompression bonding tool and a thermocompression bonding tool to detect a pressing load. Therefore, the linear motion guide in the portion below the load cell becomes unnecessary, and therefore, the load resistance detected by the load cell includes the sliding resistance value of the linear motion guide included in the detected load value in the conventional thermocompression bonding apparatus. It is not included, and the pressing load value itself is detected. As a result, the pressing load at the time of thermocompression bonding can be detected very accurately, and the accuracy of the pressing load control can be improved to obtain good thermocompression bonding quality.

[Brief description of the drawings]

FIG. 1 is a front view of a thermocompression bonding apparatus for electronic components according to an embodiment of the present invention.

FIG. 2 is a sectional view of a crimping head of the thermocompression bonding apparatus for electronic components according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Positioning table 3 Substrate 7 Elevating part 8 Motor 9 Feed screw 20 Crimping head 22 Load cell 24 Bolt 25 Spring 26 Insulation material 28 Heater 29 Thermocompression tool

Claims (1)

[Claims] 1. A thermocompression tool for heating and pressing an electronic component, a heat insulating member for interrupting heat transfer from the thermocompression tool to insulate the electronic component, pressing means for pressing the electronic component via the thermocompression tool, and A thermocompression bonding apparatus for electronic parts, comprising: a piezoelectric load cell interposed between a pressing means and a thermocompression tool to detect a pressing load; and a preload means for preloading the piezoelectric load cell.