JPH04299542A - Die bonding device - Google Patents

Abstract

PURPOSE:To eliminate the variation in positional accuracy between a plurality of lots so as to reduce the occurrence of defective die bonding by automating the position adjustment between a pellet and pellet fitting section after fitting the pellet. CONSTITUTION:This die bonding device is provided with a discriminating camera 5b which takes the positional data of a pellet fitting section 11 and pellet 3 after the pellet 3 is fitted to the section 11, discriminating section 6b which calculates the deviation of the central positions between the section 11 and pellet 3, and motor control section 7b which corrects the moving position of a bonding arm from the data calculated by the section 6b.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die bonding apparatus for attaching a semiconductor element (hereinafter referred to as a pellet) to a pellet mounting portion of a lead frame or a ceramic substrate (hereinafter collectively referred to as a substrate).

0002

[Prior Art] A conventional die bonding apparatus has an x-axis for moving a bonding arm in the substrate transport direction,
The bonding arm is driven by a combination of servo motor control for a total of three axes: the y-axis, which moves in the left-right (back-and-forth) direction with respect to the transport direction, and the z-axis, which moves up and down with respect to the transport direction. The pellets positioned from the pellet supply mechanism are adsorbed and held using a collet, and then transported to the pellet attachment part of the board held by the conveyance mechanism, where they are attached using a resin adhesive such as silver paste. Do this.

[0003] Here, the repeatability of movement of the bonding arm is ±10 μm in the x-axis and y-axis directions, and ±20 μm in the z-axis direction, the pellet positioning accuracy of the pellet supply mechanism is ±20 to 50 μm, and the repeatability of the conveyance mechanism is ±10 μm. Accuracy is ±20 μm, substrate conveyance accuracy (transfer direction in the case of lead frame) is ±40 to 80 μm, and recognition accuracy when recognizing the substrate position is ±10 to 20 μm, so pellet installation accuracy ±90 to 160 μm without substrate position recognition, ±90 to 160 μm with substrate position recognition
It is 40 to 80 μm.

[0004] Furthermore, when determining the mounting position of the pellet in the pellet mounting section, the operator visually checks the amount of positional deviation using a monitor screen or a microscope, and changes the movement coordinates of the bonding arm or changes the relative position between the transport mechanism and the bonding arm. Perform position adjustment by position adjustment.

[0005]

[Problems to be Solved by the Invention] In this conventional die bonding apparatus, the position between the pellet and the pellet attachment part of the substrate is adjusted by the operator, so even if the repeat position accuracy of the pellet is ±40 μm, The positional accuracy of the internal leads of the board and the pellet is ±10 between multiple lots.
There was a problem that the thickness was 0 to 150 μm.

[0006] To explain this in detail, with the recent increase in the density of pellets, the pellet size has increased to 15 mm x 15 mm.
However, advances in wire bonding technology have led to smaller bonding pads and smaller pitches, resulting in an increase in the number of wires that can be bonded with the same pellet size, that is, the number of bonding wires required to wire one pellet. (for example, about 500 pellets of 15 mm x 15 mm). In addition, the package size of semiconductor devices is becoming smaller in order to reduce the occupancy rate on printed circuit boards and achieve high-density packaging. Therefore, the proportion of pellets in semiconductor devices has increased (for example, about 17 m
m x 7.5 mm package, conventional approx. 11.5 mm x
Approximately 15.5 mm x 6 mm pellets for 4.5 mm pellets). As a result, wire bonding may not be possible due to misalignment or inclination of the pellet, or the shape (loop shape) of the bonding wire after bonding may become uneven, resulting in defects such as edge touching or short circuits, or the distance between the bonding wires may become narrow. Due to problems such as becoming more likely to become defective,
Positional accuracy (±100 μm or less) between the internal lead and the pellet is now required.

[0007] Therefore, even when recognizing the position of the board and improving the repeating position accuracy of the pellet, only the amount of positional deviation between the board recognition camera and the board is obtained, so the final step is to determine the pellet attachment position. Since the adjustment and determination are made by the person responsible for the adjustment, variations occur between multiple lots, making it impossible to satisfy the required tolerance of ±100 μm or less.

[0008]

[Means for Solving the Problems] The die bonding apparatus of the present invention recognizes the respective positions of the pellet and the substrate after the pellet is attached, calculates the amount of deviation between the center positions of the two, and corrects the bonding arm movement position. have the means.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic diagram of a first embodiment of the present invention, and FIG. 2 is an explanatory diagram of position recognition in the first embodiment of the present invention. Pellets 3 are pasted on a wafer sheet 2 and attached to a pellet supply mechanism 1. Pellet supply mechanism 1
A recognition camera 5a is used to position the pellet 3.
The recognition unit 6a determines the position data of the pellet 3 taken in from the pellet, and the pellet 3 is moved in the x, y, and θ directions by the x-y-θ drive unit 4 controlled by the motor control unit 7a.

The collet 8 is attached to the tip of a bonding arm (not shown), and is driven by an xyz drive section 9 controlled by a motor control section 7b. The recognition unit 6b receives from the recognition camera 5b the position data of the pellet attachment part 11 of the lead frame 10 transported and held by a transport mechanism (not shown), and the position data of the pellet 3 and the pellet attachment part 11 after the pellet is attached. The correction data is sent to the motor control unit 7b.

[0012] Next, the operation will be explained. First, when the operator has adjusted the condition to the point where bonding is possible, one pellet is picked up and attached to the pellet attachment part of the lead frame whose position has been recognized. . After that, the position data of the pellet and the pellet attachment part are taken in, and the deviation amounts X and Y are calculated. By using this amount of deviation and correcting X and Y when bonding the next pellet, the deviation between the camera and the bonding arm will be corrected, so the camera coordinates and the collet coordinates at the tip of the bonding arm will match. Become. In other words, the center positions of the pellet and the pellet attachment portion can be substantially aligned.

[0013] Here, it is not necessary to perform this position correction every time, and after performing it several times at the start of work, the pellet 100
Is it done at regular intervals, such as for each piece or lot?
Or you don't have to do it. By performing this position correction, variations in the pellet mounting position will not occur between lots, that is, it will not depend on the operator, so pellets can be mounted with high positional accuracy.

[0014] Here, the positions of the pellet and the pellet mounting part are recognized and corrected, but other positions within the lead frame or within the pellet may be corrected, such as recognizing the position of the internal lead and the bonding pad of the pellet. Similar effects can be obtained using other positions.

FIG. 3 is a schematic diagram of a second embodiment of the invention. In this embodiment, a position recognition camera is attached to the bonding arm. In addition, a pellet tray is shown as the pellet feeding mechanism. Pellet tray 12
is pitch-fed in the x-y direction by the x-y drive section 13 controlled by the motor control section 7c. A bonding arm (not shown) to which the collet 8 and the recognition camera 5c are attached is moved in the xyz direction by an xyz-θ drive section controlled by a motor control section 7d. Further, only the collet 8 is rotatable in the θ direction.

In this embodiment, after the pellet is attached to the pellet attachment portion of the lead frame, deviations in the x, y, and θ directions can be calculated and corrected. Further, by using the x, y, and θ deviation amounts obtained by position recognition on the lead frame side, the pellets in the pellet tray can be recognized and corrected and picked up when picking up the pellets. In other words, by attaching the camera to the bonding arm, the camera and recognition unit can be combined into one pair.
Since the pickup side can also be corrected using the data obtained on the lead frame side, high positional accuracy can be easily obtained at low cost. Furthermore, in this embodiment, since the θ direction can also be corrected, pellets can be attached with higher precision.

[0017]

[Effects of the Invention] As explained above, the present invention provides a means for recognizing the respective positions of the pellet and the substrate after the pellet is attached, calculating the deviation of the center positions of the two, and correcting the movement position of the bonding arm. Therefore, there is no need for position adjustment by the operator, and good positional accuracy can be obtained even between multiple lots. That is, it has the effect of improving yield by reducing die bonding defects.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a first embodiment of the invention.

FIG. 2 is an explanatory diagram of position recognition in the first embodiment of the present invention.

FIG. 3 is a schematic diagram of a second embodiment of the invention.

[Explanation of symbols]

1 Pellet supply mechanism 2 Wafer sheet 3 Pellets 4
Collet 9 x-y-z drive section 10 Lead frame 11 Pellet attachment section 12 x-y-z-θ drive section

Claims (1)

[Claims] Claim 1: Positioning at least a semiconductor element;
A semiconductor element feeding mechanism for supplying semiconductor elements, a transport mechanism for transporting and holding a lead frame or ceramic substrate on which a semiconductor element is attached, and a semiconductor element mounting position recognition device for recognizing the position of the lead frame or ceramic substrate transported by the transport mechanism. , a bonding arm that transfers and attaches a semiconductor element from the semiconductor element supply mechanism to a semiconductor element attachment part of a lead frame or ceramic substrate that is transported and held by the transfer mechanism; and position data obtained by the semiconductor element attachment position recognition device. In a die bonding device equipped with a control mechanism that calculates the movement position of the bonding arm and controls the moving position of the bonding arm, after the semiconductor element is attached to the semiconductor element attachment part, the position data of the semiconductor element attachment part and the semiconductor element are captured. A die characterized in that it has a recognition camera, a recognition unit that calculates the amount of deviation between the center positions of the semiconductor element mounting part and the semiconductor element, and a motor control unit that corrects the bonding arm movement position based on the calculated data. bonding equipment.