JP2000269244A - Method and apparatus for pellet bonding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately place a pellet in a bonding position on a board at high speed, before bonding it by correcting a displacement of the board on a bonding stage in the direction of rotation through the rotation of the bonding stage. SOLUTION: A bonding stage 15 is placed between a board feeding portion 26 and a board housing portion 27 and a motor 31 is installed, which makes the guide rails 29 rotatable on the bonding stage 15 about the center of rotation. In addition a camera 32 is installed for detecting the position in the direction of rotation and the position in the X and Y directions of the board 1 on the bonding stage 15. Using the camera 32, the center of rotation of the bonding stage 15 is calculated by a processor. Any displacement of the board 1 in the direction of rotation relative to a reference position is corrected through the rotation of the bonding stage 15, and thus the position of the substrate 1 in the direction of rotation is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for pellet bonding.

[0002]

2. Description of the Related Art For electronic components such as ICs and LSIs,
The position of the pellet taken out from the wafer stage is corrected by the precisor stage, and the pellet is sucked by the suction nozzle of the bonding head and bonded to the mounting portion (bonding point) of the substrate on the bonding stage (guide rail of the pellet transfer device). You are going to. At this time, the pellets must be bonded to the mounting portion of the substrate so that the positions in the X and Y directions and the position in the rotation direction are matched without any deviation.

For this reason, in the prior art, the deviation of the rotational position of the pellet sucked by the bonding head from the reference position is corrected by rotation of the precisor stage, and the position of the pellet sucked by the bonding head in the X and Y directions is corrected. Is corrected by the movement of the bonding head in the X and Y directions when the bonding head sucks the pellet. The displacement of the substrate in the rotational direction relative to the reference position is corrected by rotating the pellet by the rotating part of the suction nozzle mounted on the bonding head. The displacement of the substrate in the X and Y directions relative to the reference position is corrected by the bonding head. Discloses that the correction is made by moving the bonding head when bonding the pellet to the substrate. As a result, the pellet is bonded to the mounting portion of the substrate at a correct bonding position where there is no relative displacement in all directions of the X, Y and rotation directions.

[0004]

However, in the prior art, the displacement of the substrate in the rotational direction is corrected by rotating the pellet by the rotating portion of the suction nozzle mounted on the bonding head. For this reason, the weight of the bonding head is increased due to the presence of the rotating portion, which impairs the high-speed and high-accuracy positioning of the pellet at the bonding position.

An object of the present invention is to position and bond a pellet with respect to a bonding position of a substrate at high speed and with high accuracy without increasing the weight of a bonding head.

[0006]

According to a first aspect of the present invention, there is provided a pellet bonding method for bonding a pellet to a substrate on a bonding stage. The correction is made by rotation.

According to a second aspect of the present invention, there is provided a pellet bonding apparatus for bonding pellets to a substrate on a bonding stage, wherein a rotational device for rotating the bonding stage is shifted from a rotational position of the substrate on the bonding stage. And a processing unit that obtains the detection result of the detection device, controls the rotation device, and corrects the displacement of the position of the substrate on the bonding stage in the rotation direction by the rotation of the bonding stage. It is like that.

[0008]

According to the first aspect of the present invention, the following operations are provided.
The displacement of the rotational position of the substrate on the bonding stage is corrected by the rotation of the bonding stage.
Therefore, the weight of the bonding head can be reduced as compared with a method in which the displacement of the substrate in the rotational direction is corrected by rotating the suction nozzle of the bonding head, and the positioning of the pellet on the substrate (bonding position) by the bonding head can be performed at a high speed. High accuracy can be realized.

[0009]

FIG. 1 is a schematic view showing an example of a pellet bonding apparatus according to the present invention, FIG. 2 is a front view showing a bonding stage of the pellet bonding apparatus shown in FIG. 1, and FIG. 3 is a pellet bonding apparatus shown in FIG. FIG. 4 is a schematic diagram illustrating the principle of calculating the rotation center of the bonding stage, FIG. 5 is a schematic diagram illustrating the principle of calculating the amount of displacement of the substrate on the bonding stage, and FIG. 6 is a diagram illustrating the substrate caused by the rotation of the bonding stage. FIG. 3 is a schematic diagram showing the principle of calculating the amount of displacement in the X and Y directions.

As shown in FIG. 1, a pellet bonding apparatus 10 mounts and bonds a pellet 3 on a mounting section 2 of a substrate (lead frame) 1. A wafer stage 11, a pellet take-out apparatus 12, a precisor stage 13, a bonding head 14, and a bonding stage 15.

The wafer stage 11 is mounted on an XY table, and has a wafer ring unit 4 mounted thereon.
The wafering unit 4 holds a wafer sheet 6 to which a wafer 5 divided for each pellet 3 is attached.

At this time, the wafer stage 11 is provided with a camera 20 (image processing device 20A).
As a result, while detecting the rotational direction position of the wafer 5,
The X and Y directions of each pellet 3 are detected. Then, based on these detection results, the wafer stage 11 corrects the displacement of the rotational position of the wafer 5 with respect to the reference position, and moves each of the pellets 3 to a pellet extracting position of the pellet extracting device 12 by a suction nozzle 22 described later. Position.

The pellet unloading device 12 includes a pellet transfer 21 that moves relatively to the wafer stage 11.
Thus, the pellets 3 on the wafer sheet 6 are sequentially sucked and taken out, and the pellets 3 are transferred to the precisor stage 13.

The precisor stage 13 includes a rotary table 23 on which the pellets 3 taken out by the pellet transfer 21 are placed, and a camera 24 for detecting the position of the pellet 3 on the rotary table 23 in the rotational direction and the X and Y directions.
(Image processing device 24A) and the precisor stage 1
The deviation of the rotational position of the pellet 3 from the reference position on the rotary table 23 is corrected by the rotation of the pellet 3 due to the rotation of the rotary table 23, and the rotational position of the pellet 3 is corrected.

The bonding head 14 is mounted on an XY table, and has a suction nozzle 25 for sucking the pellet 3 whose rotational position has been corrected by the precisor stage 13.
5 is mounted on the mounting portion 2 of the substrate 1 and bonded using an adhesive or the like. When the suction head 25 sucks the pellet 3 on the precisor stage 13, the bonding head 14 shifts the X and Y directions of the pellet 3 on the rotary table 23 of the precisor stage 13 with respect to the reference position. X, Y of the bonding head 14
The correction is made by moving in the direction to correct the position of the pellet 3 in the X and Y directions.

The bonding stage 15 is constituted by a guide rail 29 of a pellet transfer device 28 installed between the substrate supply section 26 and the substrate storage section 27, and is arranged in the longitudinal direction of the substrate position (the transfer direction of the pellet transfer device 28). Each of the plurality of mounting sections 2 provided at a constant interval (pitch) is positioned at a bonding work position by the bonding head 14 and clamped by intermittent feeding of the pellet conveying device 28. At this time, the bonding stage 15 includes a motor 31 (rotating device) that enables the guide rail 29 to rotate around the rotation center O (FIGS. 1 and 2), and the rotational position of the substrate 1 on the bonding stage 15. And a camera 32 (image processing device 32A) (detection device) for detecting the positions in the X and Y directions, and the displacement of the rotational direction position of the substrate 1 from the reference position is corrected by the rotation of the bonding stage 15 as described later. The position of the substrate 1 in the rotational direction is corrected, and the displacement of the substrate 1 in the X and Y directions with respect to the reference position will be described later. , Y direction movement to correct the position of the substrate 1 in the X and Y directions.

As shown in FIG. 3, the pellet bonding apparatus 10 has cameras 20, 24,
Based on the 32 detection results, the above-described wafer stage 11, pellet extracting device 12, precisor stage 13, bonding head 14, and bonding stage 15 are controlled. At this time, the arithmetic processing unit 16 performs the detection of the displacement of the substrate 1 and the correcting operation thereof as follows (A) to (D).

(A) Teaching of the center of rotation O of the bonding stage 15 (FIG. 4) The arithmetic processor 16 calculates the center of rotation O (X _S , Y _S ) of the bonding stage 15 using the camera 32 and stores it. Keep it. That is, as shown in FIG.
The position a = (ax, ay) of the target T provided above is detected using the camera 32. Next, the guide rail 29 is rotated by a predetermined angle, for example, 30 ° clockwise. Then, the camera 32 detects the position b = (bx, by) of the target T after the movement.

Here, the rotation center O of the bonding stage 15 can be obtained from the target positions a and b obtained above and the rotation angle of the bonding stage 15.

That is, the rotation center O of the bonding stage 15 passes through the middle point c of the points a and b and is orthogonal to the straight line connecting the points a and b, and the straight line K1 passes through the point a. It is located at an intersection with a straight line K2 having a tilt of 1/2 of the rotation angle of the bonding stage 15 in a direction opposite to the rotation direction of the stage 15 (counterclockwise direction).
Now, the bonding stage 15 is moved clockwise by 30 degrees.
°, the center of rotation O is the midpoint c between points a and b.
And a straight line K1 passing through the point a and orthogonal to a straight line connecting the points a and b, and a straight line K2 passing through the point a and having a tilt of 15 ° in a counterclockwise direction with respect to the straight line K1. The coordinates can be obtained as (X _S , Y _S ).

(B) Position Detection of the Substrate 1 (FIG. 5) Guide Rail 29 Constituting Bonding Stage 15
The position of the substrate 1 (X, Y-direction position and rotation direction position) which is conveyed above and positioned at the bonding operation position and clamped is at two distant points on the surface of the substrate 1, for example, the substrate 1
Position recognition marks (hereinafter, marks) are provided at two points on a diagonal line passing through the bonding center of the mounting portion 2 and equidistant from the bonding center, and the position recognition marks provided at these two points are provided. Is detected by the camera 32, the image processing device 32A recognizes the position of the mark based on the captured image, and compares this position with the reference position of the mark (previously stored in the storage unit of the image processing device). , The displacements ΔX and ΔY of the substrate 1 in the X and Y directions and the displacement Δθ in the rotation direction (θ) are calculated. This ΔX, ΔY,
The calculation of Δθ is performed as follows.

The reference positions of the marks are defined as A = (X _{0
1, Y 0 1), B} = (X 0 2, Y 0 2), respectively the real position of the _{mark, C = (X 1 1,} Y 1 1), D = (X 1 2, Y 1
2), and, A, the slope of a straight line connecting ^{_{B, θ 0 = tan -1 (}} Y 0 1-Y 0 2) / (X 0 1-X 0 2) C, the gradient of the straight line connecting the D, theta ^{_{1 = tan -1 (Y 1 1}} -Y 1 2) / (X 1 1-X 1 2) and the time, X, positional deviation amount ΔX in the Y-direction, [Delta] Y is
Reference position P of bonding center, which is the midpoint between A and B
₀ (X ₀ , Y ₀ ) coordinates (X ₀ = (X ₀ 1 + X ₀ 2) / 2, Y
₀ = (Y ₀ 1 + Y ₀ 2) / 2) and coordinates (X ₁ = Y ₁ ) of the actual position P ₁ (X ₁ , Y ₁ ) of the bonding center, which is the middle point between C and D.
_{(X 1 1 + X 1 2} ) / 2, Y 1 = (Y 1 1 + Y 1 2) / 2)
And the amount of displacement Δθ in the rotational direction is θ ₀ and θ ₁
From the difference between

The _{ΔX = (X 1 1 + X} 1 2) / 2- (X 0 1 + X 0 2) / 2 ΔY = (Y 1 1 + Y 1 2) / 2- (Y 0 1 + Y 0 2 ) / 2 Δθ = θ ₁ -θ ₀

(C) Correction of Rotational Position of Substrate 1 Rotation (rotation) of the bonding stage 15 by controlling the motor 31 is based on the deviation Δθ of the rotational position of the substrate 1 on the bonding stage 15 calculated in the above (B). Angle Δ
θ).

(D) Correction of the position of substrate 1 in the X and Y directions (FIG. 6) (D-1) The amount of displacement (Δθ) of the position of the substrate 1 in the rotational direction is determined by the bonding stage 15. According to the corrected by the rotation of, X in the substrate 1, in consideration of the new displacement in the Y direction, the deviation amount ΔXf for X of the substrate 1, the reference position in the Y direction (reference bonding point P _0), calculates the DerutaYf.

As the calculation conditions for ΔXf and ΔYf, the coordinates O of the center of rotation of the bonding stage 15 are represented by (X _S , Y _S ),
The coordinates of the reference bonding point P ₀ are (X ₀ , Y ₀ )
Deviation amount relative to the reference bonding point P ₀ of the actual bonding point P ₁ above (ΔX, ΔY), and Δθ the deviation amount in the rotational direction of the substrate 1. These ΔX, ΔY, Δθ are as described in (B) above.
Has already been calculated.

First, the coordinates (X ₁ , Y ₁ ) of the bonding point P ₁ are obtained by the following equation. X ₁ = X ₀ + ΔX Y ₁ = Y ₀ + ΔY

Next, the bonding stage 15 is adjusted by the above-mentioned (C) by ΔC around the coordinate O (X _S , Y _S ) of the rotation center of the bonding stage 15 which has been taught in (A).
The coordinates P ₂ (X ₂ , Y ₂ ) of the point P ₁ after the θ rotation are obtained by the following equation.

X ₂ = X _S + R cos (Δθ + α) Y ₂ = Y _S + R sin (Δθ + α)

[0030]

(Equation 1) alpha: the point O, the angle alpha = tan ^-1 of the straight line parallel to the straight line and the X axis connecting the point P ₁ is made _{(Y 1 -Y S) / (} X 1 -X S) Next, with respect to the bonding point P ₀ The deviation amount of the point P ₂ (ΔX
f, ΔYf).

ΔXf = X ₀ −X ₂ ΔYf = Y ₀ −Y ₂

(D-2) The final displacement amounts ΔXf and ΔYf of the substrate 1 on the bonding stage 15 in the X and Y directions calculated in the above (D-1) are determined by the bonding head The correction is made by the movement of the bonding head 14 when bonding to. That is, the bonding head 14 is moved in the X and Y directions from the bonding point P ₀ so as to eliminate ΔXf and ΔYf, and the center of the pellet 3 that the suction nozzle 25 of the bonding head 14 is sucking is placed on the substrate 1. The bonding is performed so as to match the bonding center (P ₂ ) of the mounting portion 2 of the mounting portion 2, and the position of the substrate 1 in the X and Y directions is corrected.

Therefore, according to the present embodiment, the following operations are provided. The displacement of the rotational position of the substrate 1 on the bonding stage 15 is corrected by the rotation of the bonding stage 15. Therefore, compared to a method in which the positional deviation of the substrate 1 in the rotation direction is corrected by rotating the suction nozzle 25 of the bonding head 14, the bonding head 14
And a high-speed and high-accuracy positioning of the pellet 3 on the substrate (bonding point) by the bonding head 14 can be realized.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and the design can be changed without departing from the scope of the present invention. The present invention is also included in the present invention. For example, in the embodiment of the present invention, the relative displacement between the rotational position of the pellet on the precisor stage and the rotational position of the substrate on the bonding stage is calculated, and this relative displacement is calculated as The correction may be made at once by rotating the substrate.

[0035]

As described above, according to the present invention, the pellet can be positioned and bonded to the bonding position of the substrate with high speed and high accuracy without increasing the weight of the bonding head.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a pellet bonding apparatus according to the present invention.

FIG. 2 is a front view showing a bonding stage of the pellet bonding apparatus of FIG. 1;

FIG. 3 is a block diagram of the pellet bonding apparatus shown in FIG.

FIG. 4 is a schematic diagram illustrating a principle of calculating a rotation center of a bonding stage.

FIG. 5 is a schematic diagram illustrating a principle of calculating a displacement amount of a substrate on a bonding stage.

FIG. 6 is a schematic diagram showing a principle of calculating a displacement amount of a substrate in X and Y directions due to rotation of a bonding stage.

[Explanation of symbols]

 Reference Signs List 1 substrate 3 pellet 10 pellet bonding device 15 bonding stage 16 arithmetic processing unit 31 motor (rotating device) 32 camera (detection device)

Claims (2)

[Claims] 1. A pellet bonding method for bonding a pellet to a substrate on a bonding stage, wherein the displacement of the rotational position of the substrate on the bonding stage is corrected by the rotation of the bonding stage. 2. A pellet bonding apparatus for bonding pellets to a substrate on a bonding stage, comprising: a rotating device for rotating the bonding stage; a detecting device for detecting a shift in the rotational direction of the substrate on the bonding stage; A pellet processing apparatus, comprising: an arithmetic processing unit that obtains a detection result of the apparatus, controls the rotation apparatus, and corrects a shift in the rotational position of the substrate on the bonding stage by rotation of the bonding stage. .