JPS6246979B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire bonding method, which is one of the manufacturing processes of semiconductor devices, and an apparatus therefor.

Generally, in a glass-sealed semiconductor device, as shown in FIG. 1, a lead frame 3 is welded with glass 4 to a ceramic base 2 to which a semiconductor element (pellet) 1 is fixed, and then the pellet 1 and lead frame 3 are bonded together. A wire 5 is connected between each inner lead 3a.
The cap 6 is then welded onto the cap 6 to complete the package. However, in this type of semiconductor device, each inner lead 3a is formed to have a narrow width in order to achieve high density, so its rigidity is low. Each inner lead 3a is fixed in a different bent state only by a slight difference in the molten state of the glass. Therefore, as shown in FIG. 2, each inner lead 3a comes to have variations in its upper surface height position.

If there are variations in the height position of each inner lead 3a in this way, each inner lead 3a
In order to perform ultrasonic wire bonding that is suitable for each, the operating characteristics of the wire bonder tool in the Z direction (vertical direction) must have sufficient margin to allow for these height variations. be. That is, the downward movement speed of the tool is made low at an early stage, and the tool is configured so that within the above-mentioned variation range, the tool gradually comes into contact with the inner lead no matter what height position the inner lead is at. Therefore, by providing such a margin, the overall downward movement speed of the tool is reduced and the operating cycle time of the tool is lengthened, resulting in a problem that the wire bonding time becomes longer and this becomes a hindrance to increasing the speed. There is.

Therefore, an object of the present invention is to control the Z-direction operating characteristics of the tool according to the height position of each inner lead, minimize the wire bonding time for each inner lead, and speed up wire bonding as a whole. An object of the present invention is to provide a wire bonding method and an apparatus therefor.

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 shows a wire bonding apparatus for carrying out the method of the present invention, which is composed of a lead height measuring section 7, a wire bonder section 8, and a control section 9. As shown in FIG.
A plurality of conductive pins 13 are arranged in parallel on a support 12 that can be moved up and down with respect to 1 while maintaining mutual insulation, and each pin 13 is urged downward by a spring 14. are doing. The pins 13 are arranged side by side at intervals equal to the interval between the inner leads 3a of the semiconductor device 11, and their tips are sharp so that they can contact the inner leads, and the respective lead wires 15 are connected to the rear ends for control. It is connected to part 8. 16 is a stopper for restricting the downward movement position of the tip of the pin 13.

On the other hand, the wire bonder section 9 is provided with a horn 19 movable in the vertical Z-axis direction by a Z cam 18 on a base 17 movable in the horizontal X and Y-axis directions,
A wedge (tool) 21 is attached to the tip of an arm 20 that is continuous with the horn 19. A wire 22 is hung on the wedge 21, and this wire 22
are bonded between the inner leads 3a and the element pellets 1 of the semiconductor device 11, respectively. The drive system of the Z cam 18 is connected to the control section 8, and the rotation speed of the Z cam 18 can be varied and controlled by the control section 8.

Further, the semiconductor device 11 is mounted on a predetermined base 23.
The common 24 connected to the control section 8 can be connected to the integrated lead 3.

Therefore, according to the wire bonding apparatus having the above configuration, the height of each inner lead 3a is measured by moving the measuring section 7 downward with respect to the semiconductor device 11 prior to the wire bonding action by the wire bonder section 9. That is, by moving the support body 12 downward, the plurality of pins 13 . The contacted pin forms a closed circuit with the lead wire 15, pin 13, inner lead (lead) 3a, and common 24 and outputs a predetermined signal to the control unit 8, so that the signal changes over time in the control unit 8. By sequentially recording the downward movement positions of the measuring section 7, the height positions of the rotary leads 3a can be measured independently based on the signals input from time to time.

In this way, the height position of each lead 3a is measured and stored in the control unit 8, and then when wire bonding is performed by the wire bonder unit 9, control is performed according to the height position of each lead 3a to be wire bonded. Section 8 controls the rotational speed of Z cam 18. That is, as shown in FIG. 5, which shows the stroke characteristics of the wedge 21, when the lead height is lower than the reference height H ₀ , the lowering speed _{V 1 is} set slightly higher and the lead height is lower than the reference height H 1 . When it is high, the speed is reduced to _H2 . By controlling in this manner, stable wire bonding can be performed by keeping the lead contact speed V ₂ and the contact timing t ₀ of the wedge constant regardless of the difference in lead height. Therefore, there is no need to provide a low-speed margin in the wedge's downward movement characteristics, which can reduce the wire bonding time. Also, when the lead height is high, the wedge and lead Collisions can be prevented and damage to the wedge tip and lead can be prevented.

As described above, according to the wire bonding method and apparatus of the present invention, the heights of a plurality of leads are measured prior to wire bonding, and the vertical movement of the tool is performed during wire bonding of each corresponding lead based on the measured values. Since it is controlled appropriately, it is possible to perform the wire bonding action of each lead appropriately and in a short time, thereby increasing the reliability and speeding up the wire bonding of the entire semiconductor device. It has the effect of being able to

[Brief explanation of the drawing]

Fig. 1 is a broken perspective view of the semiconductor device, Fig. 2 is an enlarged sectional view of a part thereof, Fig. 3 is an overall configuration diagram of the device of the present invention, Fig. 4 is a sectional view of the measuring section, and Fig. 5 is the characteristics. It is a diagram. DESCRIPTION OF SYMBOLS 1...Element pellet, 2...Ceramic base, 3...Lead frame, 3a...Inner lead, 4...Glass, 5...Wire, 7...(Height) measurement unit, 8...Control unit, 9... Wire bonder part, 11... Semiconductor device, 12... Support body, 13
... Pin, 14 ... Spring, 18 ... Z cam, 19 ... Horn, 21 ... Wedge (tool), 22 ... Wire, 24 ... Common.

Claims (1)

[Scope of Claims] 1. When wire bonding is performed on a plurality of inner leads whose heights vary, wire bonding is performed using a height measuring section having a plurality of measurement pins provided corresponding to each inner lead. The height position of each inner lead is measured in advance, and while this measurement value is stored, the tool vertical movement mechanism in the wire bonder section is controlled based on this memory, thereby controlling the tool operating characteristics of the wire bonder. Characteristic wire bonding method. 2. A measurement unit that measures the height of each lead of a semiconductor device to which wire bonding is performed, a wire bonder unit that moves a tool up and down to bond the wire to each of the leads, and a lead height measurement signal of the measurement unit. a control section that controls a vertical movement speed of a tool of the wire bonder section based on the above. 3 The measurement unit supports a plurality of conductive pins corresponding to the leads on a support that can be moved up and down while maintaining insulation from each other, and each pin outputs a measurement signal when it is moved down and comes into contact with the lead. A wire bonding apparatus according to claim 2, which comprises: