JPH08172115A - Bonding device and bonding - Google Patents

Abstract

PURPOSE: To prevent damage to a lead due to adhesion of a bonding tool to the lead and reduction in junction strength between the lead and an electrode of a semiconductor element, and to prevent reduction in reliability of junction due to adhesion of Sn formed on the surface of the lead to the surface of the bonding tool. CONSTITUTION: A semiconductor element 1 having an electrode 5 is held by a bonding tool 40 having heating means 41. The bonding tool 40 holding the semiconductor element 1 is moved toward a lead 4 set on a device 43 located at a position facing the bonding tool 40. Thus, the lead 4 and the electrode 5 are pressurized in contact with each other, and the pressurized portion is heated by the heating means 41 so as to join the lead 4 with the electrode 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for connecting a lead and a semiconductor element.

[0002]

2. Description of the Related Art A so-called film carrier system in which a film-like lead and an aluminum electrode on a semiconductor element are connected via a metal projection is utilized as a mounting method suitable for thinning or miniaturization. FIG. 2 shows a conventional method of joining a film lead of a film carrier type to an electrode on a semiconductor element.

The electrode 2 of the semiconductor element 1 and the lead 4 obtained by etching the Cu foil of the film carrier 3 and performing Sn plating are aligned with each other. At this time, the metal protrusion 5 is formed on the electrode 2 of the semiconductor element 1 as a multilayer metal film (barrier metal).
It is also possible to form it on the lead side by a transfer bump method. FIG. 2 shows a metal bump formed on the lead side by the transfer bump method. The semiconductor element 1 is placed on a stage 24, and a bonding tool 20 having a heater 21 pressurizes and heats 23 the leads 4. Next, when the pressurization and heating 23 are removed, if the metal protrusion 5 is made of Au, the metal protrusion 5 and the aluminum electrode 2 on the semiconductor element 1 are separated by A.
It is joined with an alloy of u and Al. Further, the temperature of the bonding tool 20 reaches 350 to 550 ° C.

[0004]

In such bonding, since the temperature of the bonding tool is relatively high, the bottom surface of the bonding tool 20 and the lead 4 adhere to each other, and the lead 4 may be damaged or the metal projection 5 may be damaged. Electrode 2 of semiconductor element 1
Also, the bonding strength with the resin was reduced.

At the time of bonding, Sn which has been surface-treated on the leads 4 adheres to the bottom surface of the bonding tool 20, which is oxidized due to high temperature and forms a layer having poor heat conduction. The heat conduction to the leads is poor, and the temperature at the junction becomes unstable. For this reason, the reliability of the bonding strength is reduced.

[0006]

In order to eliminate the problems of the prior art, the present invention provides a mechanism for pressurizing and heating the back surface of the semiconductor element.

[0007]

[Function] The bonding tool does not directly contact the lead,
Since the structure is in contact with only the back surface of the semiconductor element, it is possible to prevent adhesion of the lead to the bonding tool and deterioration of heat conduction on the bottom surface of the bonding tool due to an adhered matter.

[0008]

FIG. 1 shows an embodiment of the present invention. The metal projections 5 are joined to the leads 4 of the film carrier 3 by the transfer bump method, and the semiconductor element 1 is placed on the bonding tool 6 for applying pressure and heating. On the other hand, a jig 9 having a heat-resistant glass 10 is provided above the lead 4 at a position facing the semiconductor element 1.

In this state, if the bonding tool 6 is raised and the jig 9 is lowered, the metal protrusion 5 and the electrode 2 of the semiconductor element 1 can be joined. That is, the heat of the heater 7 of the bonding tool 6 is transmitted to the semiconductor element 1 to heat the joint. Alternatively, the bonding tool 6 may be fixed in the configuration of FIG. 1 and only the jig 9 having the heat-resistant glass 10 may be lowered and raised 12 to apply pressure. The bonding tool 8 may be of a constant heating type, but a so-called pulse heating method of heating only at the time of bonding may be used. The heat-resistant insulating material 10 of the jig 9 may be made of quartz, heat-resistant glass or ceramic. If the jig 9 is provided with a heater and the heat-resistant insulating material 10 is heated at a certain temperature, the temperature of the bonding tool can be reduced.

Next, another embodiment will be described with reference to FIG. At the time of bonding, the leads 4 of the film carrier 3 are set on a jig 43 made of a heat-resistant insulating material such as heat-resistant glass or ceramic, and the semiconductor element 1 is connected to a bonding tool 40 for pressing and heating the back surface thereof. Is held. When the alignment between the metal projection 5 on the lead 4 and the electrode of the semiconductor element 1 is completed, the bonding tool 40 is lowered.
2. Bonding is performed. According to the present embodiment, since the bonding tool has both the heating means and the means for holding the semiconductor element 1, the semiconductor element 1
Can be heated before being transported onto the lead 4, so that pressurization and heating of the electrode 2 of the semiconductor element and the lead 4 can be performed efficiently in a short time.

In the embodiment shown in FIGS. 1 and 3, the metal protrusion 5 is used.
Has shown the example formed on the lead 4. However, a structure in which a metal projection is formed on the electrode of the semiconductor element via a multilayer metal film may be used.

With this structure, the high temperature bonding tool does not directly contact the leads.

[0013]

Next, the effects of the present invention will be described.

(1) Since the bonding tool and the lead do not come into direct contact with each other and heating is performed from the back surface of the semiconductor element, there is no adhesion between the bonding tool and the lead, the lead is not damaged, and the reliability of the joint portion is high. Remarkably improved.

(2) Contamination with Sn, which is the deposit from the lead, does not adhere to the bonding tool, so that a stable temperature can be supplied to the bonding portion, reliable bonding can be obtained, and the bottom surface of the bonding tool can be cleaned. A cleaning process for removing the bonding tool is unnecessary, and the wear of the bonding tool is extremely small.

(3) Conventionally, since the lead is pressed and heated from the opening of the film carrier, the dimension of the bonding tool may depend on the dimension of the opening. However, since the present invention has a structure in which the back surface of the semiconductor element is heated and pressed, the bonding tool has the following dimensions:
Since the shape can be freely designed, a bonding tool with a stable temperature distribution can be obtained, and stable and highly reliable bonding can be obtained.

(4) Further, conventionally, an expensive material such as diamond was required as the material of the bonding tool, but since the problem of adhesion or the like does not occur in the structure of the present invention, a normal rope material is used. Therefore, the cost of the bonding tool can be significantly reduced.

(5) Since the film carrier tape is not directly exposed to the high temperature bonding tool, the film carrier tape is not bent and the lead pitch is not shifted by heat.

(6) Further, when quartz or heat-resistant glass is provided on the lead side during bonding, the heat applied from the back surface of the semiconductor element remains in the quartz or heat-resistant glass contacting the lead and the back surface of the semiconductor element. Since it will be higher than the temperature of, the temperature of the bonding tool can be lowered accordingly.
It is not necessary to apply excessive temperature to the semiconductor element, and the semiconductor element can be protected from heat.

[Brief description of drawings]

FIG. 1 is a sectional structural view at the time of bonding according to an embodiment of the present invention.

FIG. 2 is a cross-sectional structural view at the time of bonding of a conventional example.

FIG. 3 is a sectional structural view at the time of bonding according to another embodiment of the present invention.

[Explanation of symbols]

 1 semiconductor element 2 electrode 3 film carrier 4 lead 5 metal protrusion 6 bonding tool

Claims (2)

[Claims] 1. A first jig for holding a semiconductor element having a heating means and having an electrode on a main surface from a surface opposite to the main surface, and a first jig installed at a position facing the first jig. A second jig, and the first jig holding the semiconductor element is brought close to a lead placed on the second jig to move the lead and the electrode to the first jig. A bonding apparatus for contact-pressing with the jig of No. 1 and heating the contact-pressurizing portion with the heating means to bond the lead and the electrode. 2. A step of holding a semiconductor element having an electrode on a main surface from a surface opposite to the main surface by a first jig having a heating means, and a step of installing the semiconductor element at a position facing the first jig. The first jig holding the semiconductor element is brought close to the lead placed on the second jig, and the lead and the electrode are contact-pressed by the first jig and A bonding method comprising a step of heating the contact pressurizing section with a heating means to bond the lead and the electrode.