JP3259381B2 - Semiconductor chip bonding apparatus and bonding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor chip bonding apparatus and a semiconductor chip bonding method for bonding an internal lead to an upper surface of a semiconductor chip via an adhesive tape bonded to an internal lead of a lead frame. For details,
The present invention relates to a semiconductor chip bonding apparatus and a semiconductor chip bonding method improved to efficiently preheat a used adhesive tape to perform desired dehumidification and to have a compact structure.

[0002]

2. Description of the Related Art When manufacturing a semiconductor device having a LOC (Lead on Chip) structure, an internal lead and a semiconductor chip are adhered to each other through an adhesive tape adhered to the internal lead of a lead frame.

FIG. 3 is a plan view showing an example of a semiconductor device having a LOC structure at a stage where internal leads of a lead frame are bonded to a semiconductor chip. More specifically, FIG. Reference numeral 22 denotes a state where the semiconductor chip 26 is thermocompression-bonded to the upper surface of the semiconductor chip 26 via the adhesive tape 24. FIG. 4 shows a partially enlarged view of the section along the line AA. The lead frame 20 has a number of internal leads 22. An adhesive tape 24 is adhered to the semiconductor chip bonding side of the internal lead 22 so as to cross the internal lead 22.
They are interconnected by tie bars 23 in the middle for reinforcement. The adhesive tape 24 is an adhesive medium between the internal lead 22 and the semiconductor chip 26, and as shown in FIG.
This is an example in which an epoxy adhesive 28 is applied to both surfaces of a polyimide tape 30, respectively. The internal lead 22
The semiconductor chip 26 is thermocompression-bonded via the adhesive tape 24 to the upper surface.

[0004] Since the adhesive applied to the adhesive tape has a hygroscopic property, it gradually contains water over time. When the internal leads and the semiconductor chip are thermocompression bonded using an adhesive tape while the adhesive absorbs moisture, defects such as package cracks occur afterwards, which not only hinders work in a later process, Defective products reduce product yield. Therefore, dehumidifying the adhesive tape before thermocompression bonding is one of the conditions for obtaining a good semiconductor device, and if the dehumidification is not properly performed, product quality and product yield are greatly affected. Is done.

[0005] Therefore, a semiconductor chip bonding apparatus used for manufacturing a semiconductor device having a LOC structure generally has a lead frame adjacent to a heating stage in order to dehumidify moisture in an adhesive applied to an adhesive tape. A heating device is provided to preheat the adhesive tape attached to the internal leads of the lead frame, thereby evaporating moisture in the adhesive.

FIGS. 5 and 6 are perspective views showing a process of bonding a lead frame to a semiconductor chip using a conventional semiconductor chip bonding apparatus. The semiconductor chip bonding apparatus shown in FIGS. 5 and 6 includes a heating stage 34, a mount head 38, and a heating device 32 disposed adjacent to the heating stage 34. Heating stage 34
Is formed on the upper surface of the thermocompression bonding table 36 and heats the semiconductor chip 26 placed thereon. Mount head 38
6 is disposed above and opposed to the heating stage 34, and is freely raised and lowered with respect to the heating stage 34.
As shown in (1), the lead frame 20 placed on the semiconductor chip 26 on the heating stage 34 is pressed.

The heating device 32 includes a heater section 40 formed of a hollow cylindrical member having a rectangular cross section. The inside 41 forms a high-temperature atmosphere, and the entire lead frame 20 conveyed to the inside 41 is removed from the heater section 40. Is indirectly heated by the radiant heat of the adhesive 2, and thereby the adhesive 2 previously adhered to the adhesive tape 24.
8 is preheated to evaporate the water content. FIG.
Then, the adhesive tape 24 is attached to the semiconductor chip bonding side of the internal lead 22 of the lead frame 20 (in FIG.
2 back).

In FIG. 5, the lead frame 20 heated by the heating device 32 is moved one step at a time by the heating stage 3 as shown in FIG.
The semiconductor chip 26 is transported to a predetermined position on the semiconductor chip 26 placed thereon and placed there. Next, the mount head 38
Presses the lead frame 20 against the semiconductor chip 26 on the heating stage 34, and thermally presses the internal leads 22 to the semiconductor chip 26 via the preheated adhesive tape 24. The semi-finished semiconductor device obtained by thermocompression bonding the semiconductor chip 26 and the internal leads 22 is taken out from the heating stage 34 and sent to the next step. On the other hand, another semiconductor chip is mounted on the heating stage 34 again for thermocompression bonding with the internal leads.

As another method, the heating device 32 shown in FIG. 7 is constituted by a transport path 42 heated by a built-in heating means, and the lead frame 20 is prevented from contacting the adhesive 28 of the adhesive tape 24 with the transport path 42. Are arranged on the heated transfer path 42, and the lead frame 20 is connected to the heating stage 3.
4, the adhesive tape 28 is indirectly preheated by radiant heat from the transport path 42 to evaporate moisture in the adhesive.

[0010]

However, in the heating apparatus provided in the conventional semiconductor chip bonding apparatus shown in FIG.
In order to dehumidify the adhesive to a desired degree, it was necessary to preheat the lead frame for a relatively long time. Therefore, there is a problem that the preheating process of the lead frame does not match the tact of the thermocompression bonding process between the semiconductor chip and the internal lead on the heating stage, and a large space is required for installing the heating device. Therefore, there has been a problem that the dimensions of the semiconductor chip bonding apparatus itself increase. In addition, the heating device provided in the conventional semiconductor chip bonding apparatus shown in FIG. 7 has poor heating conditions, and was unable to perform sufficient heating for preliminary heating.

Accordingly, an object of the present invention is to provide a semiconductor device having a LOC structure in which a semiconductor chip is bonded so as to shorten the preheating time of a lead frame.
It is another object of the present invention to provide a semiconductor chip bonding apparatus improved so as to have a compact structure, and to provide a semiconductor chip bonding method.

[0012]

Means for Solving the Problems The present inventor, after research,
It has been recognized that the problem of the conventional semiconductor chip bonding apparatus is that the lead frame is preheated by indirect heating means. That is, since the lead frame is indirectly heated by the radiant heat from the heating element, and thereby the adhesive bonded to the internal lead of the lead frame is preliminarily heated, the indirect heating mechanism is used. Due to the transmission delay, the pre-heating time is lengthened, and a structurally large space is required.

In order to achieve the above object, based on the above findings, the present invention comprises a heating device for preheating an adhesive tape adhered to an internal lead of a lead frame, and the preheating device is provided by the heating device. In a semiconductor chip bonding apparatus in which an internal lead is thermocompression-bonded to the upper surface of a semiconductor chip via a bonded adhesive tape, a heating device directly heats the internal lead, and the adhesive tape is heated by the heat of the heated internal lead. It is characterized by comprising a heating means for preheating.

The heating means used in the present invention is not particularly limited as long as it can directly heat the internal leads. For example, the heating means has a built-in heater and is heated by the heater to raise the temperature. Is used as a heating means. The heating block is brought into direct contact with the internal lead, the internal lead is directly heated by heat conduction from the heating block to the internal lead, the adhesive tape is heated by the heat of the heated internal lead, and the moisture in the adhesive is evaporated. Let it. . The heating block
The lead frame for one semiconductor chip is held by an elevating mechanism that operates in synchronization with the step of the transfer means for transferring the lead frame to the heating stage. When the lead frame is stopped, the lead frame descends from above and contacts the internal lead of the lead frame. Then, after a predetermined time elapses, the lead frame feeding is restarted, and at the same time, it rises upward.

Preferably, the heating means is capable of simultaneously heating a plurality of internal leads of the semiconductor chip.
Thereby, in the process of transporting the lead frame, the internal leads can be repeatedly heated, so even if the transport speed of the lead frame is increased so as to match the tact of thermocompression bonding between the semiconductor chip and the lead frame on the heating stage,
The adhesive tape can be preheated to a predetermined temperature, and thus the adhesive can be dehumidified to a desired degree.

In order to achieve the above object, the present invention relates to a semiconductor chip bonding method for thermocompression bonding an internal lead to a semiconductor chip via an adhesive tape stuck to the internal lead of a lead frame. The method includes directly heating the leads and preheating the adhesive tape by the heat of the heated internal leads.

[0017]

Compared with the conventional indirect heating of the internal leads, that is, the heating by the heat radiation, the direct heating, that is, the heating of the internal leads by the heat conduction brought into contact with each other, heats the internal leads much faster. Because of this heat, the adhesive can be quickly preheated by the heat, so that the moisture in the adhesive can be quickly evaporated.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing a semiconductor chip bonding apparatus (hereinafter simply referred to as an apparatus for simplicity) according to an embodiment (first embodiment) of the present invention. This is an apparatus according to the present embodiment, and the same components as those of the semiconductor chip bonding apparatus shown in FIGS. 5 to 7 are denoted by the same reference numerals and description thereof is omitted. In the present apparatus 10, in order to dehumidify the moisture in the adhesive 28 of the adhesive tape 24, the heating device 12 is disposed adjacent to the heating stage 34 and in front of the lead frame 20 in the transport direction. Heating stage 3 provided in the present apparatus 10
4. The thermocompression receiving table 36 and the mount head 38 are the same as those shown in FIGS.

The heating device 12 has a heating block 1
The heating block 14 is disposed near the heating stage 34 of the conveying path 16. The transport path 16 supplies the lead frame 20 to the semiconductor chips 26 on the heating stage 34 one by one at a transport step of a predetermined speed. Heating block 1
4 is a metal block having a built-in electric heater,
The inner lead 22 is brought into contact with the inner lead 22 by heat conduction.
As shown in the figure, one heating means having a predetermined size is provided immediately before the heating stage 34 corresponding to the set of the internal leads 22 for one semiconductor chip, as shown in the figure.

The heating block 14 includes a lead frame 20.
Is operated in synchronization with the steps of the transport path 16 for transporting the semiconductor chip to the heating stage 34 one by one. That is, the heating block 14 is held by an elevating mechanism (not shown) that operates in synchronization with the transport step of the transport path 16 so as not to hinder the lead frame transport. Is stopped, it descends from above and contacts the internal leads 22 of the lead frame to be heated, and after a predetermined time elapses, feeding of the lead frame is resumed, and at the same time, it rises upward, and this operation is repeated. .
The elevating mechanism described above is a well-known common-use mechanism, so that further description is not necessary in this specification.

With the above structure, the lead frame 20 is transported one by one to the upper surface of the semiconductor chip 26 on the heating stage 34 in sequence, and each time the transporting step is performed,
The heating block 14 is in contact with the internal lead 22 and cooperates with the above-described elevating mechanism to directly heat by heat conduction, and the adhesive tape attached to the back surface by the heat of the heated internal lead 22. The adhesive 28 is heated to evaporate the water content.

As described above, the apparatus 10 includes the internal lead 22 of the lead frame 20 adjacent to the heating stage 34.
Has a heating device 12 for preheating the adhesive tape 24 stuck on the substrate. The heating device 12 includes an adhesive tape 24
Is provided with a heating block 14 for directly heating the inner lead 22 to which the adhesive tape 24 is attached, and the heating block 14 preheats the adhesive tape 24 via the inner lead 22, thereby evaporating the moisture in the adhesive. Has become.

The present apparatus 10 includes a heating stage 34 and a mount head 38, which are preheated by the heating device 12 and dehumidified to a desired degree, in the same manner as described with reference to FIGS. Of the internal leads 22 in the heating stage 34.
And the semiconductor chip 26 are bonded. On the other hand, during the thermocompression bonding operation on the heating stage 34, the adhesive tape 24 of the internal lead 22 for the next one semiconductor chip is similarly preheated by the heating block 14. Heating block 1
By adjusting the temperature of Step 4 or by increasing the number or size of the heating blocks 14 as in the second embodiment described later, the heating is performed in accordance with the tact of the thermocompression bonding operation on the heating stage 34. Preheating of the internal leads 22 in the device 12 can be completed.

The heating device of the conventional semiconductor chip bonding apparatus is indirect heating by radiant heat in a heating atmosphere, whereas the heating of the adhesive tape 24 used in the present apparatus is direct heating by heat conduction. The rise of the temperature rise of the internal leads is quickened, and the heating time can be shortened, so that the tact of thermocompression bonding can be matched. Therefore, factors such as the package rack can be removed beforehand, and the product quality, yield, and the like can be improved. Further, by performing direct heating, the configuration of the heating device can be simplified, and the dimensions of the heating device can be shortened due to the improvement of the heating efficiency, so that space can be saved in the configuration of the device.

Next, FIG. 2 shows another embodiment (second embodiment) of the present invention.
(Example) is a perspective view showing (Example). In the present embodiment, the heating device 12 includes the plurality of internal leads 22 of the semiconductor chip 26.
In order to heat the internal leads 22 simultaneously, the heating block 18 has a length extending over a plurality of internal leads 22 of the semiconductor chip (for example, in the example shown, a length capable of simultaneously heating three sets of internal leads 22 simultaneously). It has. In this embodiment,
It has the same configuration as the first embodiment except that it has a heating block 18 having a length extending over a plurality of sets of internal leads 22.

With the above configuration, while the lead frame 20 is conveyed to the heating stage 34 via the heating device 12,
Since the heating device 12 can repeatedly preheat the adhesive tape 24 attached to the internal lead 22,
Even if the lead frame 20 is transported in accordance with the tact of thermocompression bonding, it can be dehumidified to a desired degree during the transport time. More specifically, when a preheating time longer than the thermocompression bonding time in the heating stage 34 is required for the adhesive tape 24, that is, when the preheating step of the adhesive tape is delayed by the tact of thermocompression bonding, the illustrated drawing is performed. As described above, by increasing the length of the heating block and repeatedly heating the lead frame 20 while transporting the lead frame 20, a preliminary heating time can be secured. Alternatively, a plurality of heating blocks 14 for heating the internal leads 22 for one semiconductor chip may be provided. For example, in FIG. 1, in addition to the heating block 14, two more similar heating blocks 14 are added on the near side, and the internal lead 22 is heated by a total of three heating blocks 14. The same effect can be obtained.

[0027]

According to the present invention, in a semiconductor chip bonding apparatus for bonding an internal lead to an upper surface of a semiconductor chip via an adhesive tape attached to the internal lead of a lead frame, the internal lead is directly heated, By providing a heating device for the adhesive tape, which preheats the adhesive tape by the heat of the heated internal lead, the adhesive is dehumidified by matching the thermocompression bonding cycle between the semiconductor chip and the internal lead. It realizes a compact semiconductor chip bonding device that can be used. Thereby, the preheating time of the adhesive tape is shortened, so that the efficiency of the semiconductor chip bonding step can be improved, and the heat transfer efficiency of the heating device can be improved, so that the space of the semiconductor chip bonding apparatus can be saved. Since the semiconductor chip and the internal lead are thermocompressed with the main bonding apparatus and the main bonding method, the adhesive preheating process and the thermocompression bonding process between the internal lead and the semiconductor chip can be efficiently and appropriately performed. It is possible to contribute to increasing the efficiency of manufacturing the device and to suppress the occurrence of defective products having a package crack or the like.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a semiconductor chip bonding apparatus according to the present invention.

FIG. 2 is a perspective view showing another embodiment of the present invention.

FIG. 3 is a plan view illustrating an example of a semiconductor device having a LOG structure at a stage where internal leads of a lead frame are bonded to a semiconductor chip.

FIG. 4 is an enlarged cross-sectional view taken along line AA of FIG. 3;

FIG. 5 is a perspective view showing a configuration of a conventional semiconductor chip bonding apparatus and showing a preheating step of an adhesive tape.

6 is a perspective view showing a stage in which internal leads are thermocompression-bonded to a semiconductor chip on a heating stage in the conventional semiconductor chip bonding apparatus shown in FIG.

FIG. 7 is a perspective view showing another conventional semiconductor chip bonding apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 The semiconductor chip bonding apparatus which concerns on this invention 12 Heating apparatus 14 Heating block 16 Transport path 18 Heating block 20 Lead frame 22 Internal lead 24 Adhesive tape 26 Semiconductor chip 28 Epoxy adhesive 30 Polyimide tape 32 Heating apparatus 34 Heating stage 36 Thermocompression bonding Cradle 38 Mount head 40 Heater section 41 Inside heater 42 Heated transport path

Claims (3)

(57) [Claims] 1. A heating device for preheating an adhesive tape adhered to an internal lead of a lead frame, wherein the internal lead is heated on an upper surface of a semiconductor chip via the adhesive tape preheated by the heating device. In the semiconductor chip bonding apparatus adapted to be pressure-bonded, the heating device includes a heating unit configured to directly heat the internal lead and preheat the adhesive tape by the heat of the heated internal lead. A semiconductor chip bonding apparatus characterized by the above-mentioned. 2. The semiconductor chip bonding apparatus according to claim 1, wherein said heating means can simultaneously heat internal leads for a plurality of semiconductor chips. 3. A semiconductor chip bonding method for thermocompression bonding an internal lead to a semiconductor chip via an adhesive tape attached to an internal lead of a lead frame, wherein the internal lead is directly heated by a heating means, And a step of preheating the adhesive tape by the heat of the internal lead.