JPH0231786Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention is a die bonding process for bonding a semiconductor piece to a lead frame, for example, an LED that forms the segments of a 7-segment display element.
The present invention relates to a heat block used to heat a lead frame in the process of bonding a chip to the lead frame, and more particularly to a heat block that has been improved so that the surface temperature distribution of the block body is uniform.

[Conventional technology]

Generally, in the process of bonding a semiconductor chip to a lead frame formed by connecting the chip bonding parts, wire bonding parts, or leads of a large number of electronic devices with a diver, the lead frame is It is done in a heated state. This heating is
Usually, this is done by placing the lead frame in contact with a heat block whose shape matches the lead frame shape. As shown in FIG. 2, the conventional heat block has a heater insertion hole 12 in the heat block body 11.
A sheathed heater 13 is inserted into this heater insertion hole 12. Heat block body 11
It is preferable that the material is corrosion resistant, has high surface hardness, and is made of a material that exhibits little temperature fluctuation due to external disturbances. Stainless steel, which has a relatively low thermal conductivity, satisfies these conditions most often, so
It is known to be the most suitable material for the block body 11. By the way, since the heater insertion hole 12 is normally formed to have a slightly larger diameter than the outer diameter of the sheathed heater 13, if the sheathed heater 13 is an ideal straight line, the circumference of the sheathed heater 13 and the heater insertion hole 12 will be It will be in linear contact with the surface over its entire length. However, in reality, the sheathed heater 13 is curved, and the heater insertion hole 12
It is often inserted at an angle.
In such a case, there may be a portion where the circumferential surfaces of the sheathed heater 13 and the sheathed heater insertion hole 12 do not come into contact, or there may be a spiral line contact between the sheathed heater 13 and the circumferential surface of the sheathed heater insertion hole 12. , the temperature distribution on the surface of the block body 11, which has relatively low thermal conductivity, becomes uneven. If the temperature distribution of the block body 11 becomes uneven in this way, the bonding state between the lead frame and the semiconductor chip, which are bonded at the same time, will become uneven depending on the longitudinal position of the heat block, resulting in a higher rate of defective products. This results in disadvantages such as increased product reliability and reduced product reliability.

[Problems that the idea should solve]

The present invention was devised under these circumstances, and the technical problem to be solved is to provide a heat block with a uniform surface temperature distribution, thereby reducing the incidence of defective products. , to increase the reliability of the product.

[Means to solve the problem]

In order to achieve the above-mentioned problems, the present invention takes the following technical measures. That is, the heat block of the present invention includes a block main body in which a sheathed heater is inserted into a heater insertion hole formed through the entire length in the longitudinal direction.
In addition, in a heat block in which a part of the surface of the block body is used as a heating surface over its entire length, the inner peripheral surface of the heater insertion hole is made of a good thermal conductor and has a length corresponding to the length of the block body. The heat exchanger is characterized by inserting a conduction tube having a heat exchanger in a tight-fitting manner, and inserting the sheathed heater into the heat exchanger tube.

[Functions and effects of the idea]

The sheathed heater contacts the inner peripheral surface of the heat exchanger tube and transfers heat to the heat exchanger tube. Since the heat exchanger tube is made of a good thermal conductor, even if there is a part where the sheathed heater and the heat exchanger tube are not in contact, or even if there is a line contact between the sheathed heater and the heat exchanger tube in a spiral or arc shape. However, the temperature on the outer circumferential surface of the heat exchanger tube becomes uniform at each part in the longitudinal direction. As a result, the circumferential surface of the sheathed heater insertion hole is heated uniformly, and the surface temperature of the block body becomes uniform throughout its longitudinal direction. In this way, the heat block according to the present invention is
The surface temperature is uniform, and the bonding condition between all the semiconductor chips or wires that are bonded simultaneously on the heating surface over almost the entire length of the lead frame can be made uniform, which reduces the incidence of defective products and improves product quality. can be made homogeneous, increasing the reliability of the product.

[Explanation of Examples]

Embodiments of the present invention will be specifically described below with reference to the drawings. As shown in Fig. 1, the heat block according to the present invention has a block main body 1 made of stainless steel.
has. This block main body is formed into a square prism shape so that a lead frame having a U-shaped cross section can be conveniently placed thereon, and almost the entire length of its upper surface is formed so as to be used as a heating surface. A heater insertion hole 2, which is a circular hole, is formed along its longitudinal axis. This heater insertion hole 2 is preferably formed over the entire length of the block body 1. A heat exchanger tube 3 made of a good thermal conductor such as an aluminum alloy is tightly fitted into the heater insertion hole 2, and a sheathed heater 4 is inserted into the inner space of the heat exchanger tube 3. In the heat block configured in this way, the sheathed heater 4 contacts the inner circumferential surface of the heat exchanger tube 3, and the heat of the sheathed heater 4 is transmitted to the heat exchanger tube 3. Since the heat exchanger tube 3 is made of a good thermal conductor, heat transferred to a portion thereof is rapidly diffused throughout. Therefore, even if there is a part where the sheathed heater 4 and the heat exchanger tube 3 are not in contact, or even if the sheathed heater 4 and the heat exchanger tube 3 are in line contact in a spiral or arc shape, the heat exchanger tube 3 The temperature of the outer circumferential surface of the tube becomes uniform throughout its length. As a result, the peripheral surface of the sheathed heater insertion hole 2 is uniformly heated by the sheathed heater 3 via the heat transfer tube 3, and the surface temperature of the block body 1 becomes uniform over the entire length of the heating surface. By making the surface temperature of the heat block main body 1 uniform in this manner, the processing conditions for bonding treatments that are performed simultaneously using the same heat block can be made uniform over the entire length of the heat block. Therefore, the bonding state between all the semiconductor pieces and the lead frame that are simultaneously bonded on the heating surface extending over the entire length of the same heat block in the longitudinal direction can be made uniform. As a result, the incidence of defective products can be reduced, the quality of the products can be made uniform, and the reliability of the products can be increased. Of course, the present invention is not limited to the above-described embodiment; for example, the heat exchanger tube 3 may be made of a copper tube, an iron tube, or a steel tube. Further, the cross-sectional shape of the heat block main body can be changed depending on the form of the lead frame to be heated.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional example. 1...Block body, 2...Heater insertion hole, 3
...Heat transfer tube, 4...Sheathed heater.

Claims (1)

[Claims for Utility Model Registration] A block main body in which a sheathed heater is inserted into a heater insertion hole formed through the entire length in the longitudinal direction, and a part of the surface of the block main body extends over the entire length thereof. In a heat block used as a heating surface, a heat transfer tube made of a good thermal conductor and having a length corresponding to the length of the block body is inserted into the inner peripheral surface of the heater insertion hole in a tight-fitting manner. A heat block characterized in that the sheathed heater described above is inserted into a pipe.