JP2683697B2 - Pellet bonding equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pellet bonding apparatus.

[Prior Art] A semiconductor pellet 1 has one wafer 2 as shown in FIG. 6 (A).
6A and 6B, the adhesive sheet 3 is attached to the adhesive sheet 3 and diced together, and then the periphery of the adhesive sheet 3 is pulled in the radial direction to be separated from each other as shown in FIG. 6B. Then, of the separated pellets, only non-defective products are picked up and bonded on a substrate such as a lead frame with or without a gauging table.

At the time of bonding the pellets, the pellets must be bonded to a predetermined position on the substrate in a correct posture.

However, the individual pellets picked up for bonding are disturbed in the inclination as shown in FIG. 6 (B) under the separated state on the adhesive sheet 3.

Therefore, conventionally, in order to adjust the inclination of the pellets to a reference state, as a pellet bonding device, an XY table that moves in the XY direction with respect to a gantry, and is rotatably mounted on the XY table and holds a large number of pellets. The rotary table, the pellet recognition unit that detects the pellet on the rotary table and recognizes the tilt of the detected pellet with respect to the reference position, and the above-described tilt of the pellet by rotating the rotary table based on the recognition result of the pellet recognition unit Some are configured to have a control unit for correction.

[Problems to be Solved by the Invention] However, in the above-described conventional pellet bonding apparatus, the tilt-corrected pellets deviate from the detection area (for example, the visual field of the television camera) of the pellet recognition unit due to the movement due to the correction. It does not consider the possibility that it will be lost. This is not a problem if the detection area of the pellet recognition unit is sufficiently wide, but in the pellet recognition unit having only a limited detection area, the pellet after the tilt correction is lost from the detection area, and then The position of the pellet cannot be controlled, and the re-correction operation or the pickup operation to be applied to the pellet is disabled.

Therefore, the present inventor has considered to control the position of the pellet by tracking the moving state of the pellet when correcting the inclination (θ) of the pellet at the pellet recognition position by rotating the rotary table. However, when correcting the tilt of the pellet by the rotation of the rotary table, the pellet is rotated about the rotation center of the rotary table by an angle (θ) from the position before the tilt correction, and the tilt (θ) is corrected. It will move to the position after tilt correction. Therefore, it is essential to know the rotation center coordinates (Tx, Ty) of the rotary table in the coordinate system of the XY table as a precondition for executing the position management of the above-described tilt-corrected pellets.

It is an object of the present invention to reliably and accurately find the coordinates of the center of rotation of a rotary table mounted on an XY table.

[Means for Solving the Problems] The present invention according to claim 1 is an XY table that moves in the XY direction with respect to a mount, and a rotary table that is rotatably mounted on the XY table and holds a large number of pellets. And a pellet recognition unit that detects the pellet on the rotary table and recognizes the tilt of the detected pellet with respect to the reference position, and corrects the tilt of the pellet by rotating the rotary table based on the recognition result of the pellet recognition unit. In a pellet bonding apparatus configured to have a control unit and a pickup device for picking up the pellet whose inclination has been corrected by the control unit, a feature point that is fixedly positioned on the rotary table is determined, and a rotary table Rotation of the rotation table in the coordinate system of the XY table based on the change in the position of the above feature points in the XY direction due to rotation. It is obtained so as to determine the heart coordinates (Tx, Ty).

According to a second aspect of the present invention, at least three points located on the movement locus of the characteristic points due to the rotation of the rotary table are obtained, and at least a string formed by connecting two of these three points is formed. Two lines are obtained, and the coordinates of the intersection of the perpendicular bisectors of each string are obtained as the rotation center coordinates (Tx, Ty) of the turntable.

According to a third aspect of the present invention, the rotary table is rotated by a certain amount of rotation (θ), the start point and the end point of the movement locus of the characteristic points associated with the rotation are obtained, and the coordinates of the start point and the end point, and The rotation center coordinates (Tx, Ty) of the rotary table are obtained from the rotation amount (θ).

[Operation] According to the present invention described in each of claims 1 to 3, for example, in the manufacturing stage of the pellet bonding apparatus, the XY table is obtained based on the data obtained by actually rotating the rotary table for each actual machine. It is possible to obtain the coordinates of the center of rotation of the rotary table in the coordinate system. Therefore, the rotation center coordinates can be obtained reliably and accurately.

In the present invention, the "characteristic point located in a fixed state on the rotary table" is defined, for example, in the orientation flat corner portion of the wafer held by the wafer ring set on the rotary table or the rotary table itself. Any feature can be used.

[Embodiment] FIG. 1 is a schematic view showing an essential part of an example of a pellet bonding apparatus of the present invention, FIG. 2 is a block diagram showing an example of a control system in the pellet bonding apparatus of the present invention, and FIG. FIG. 4 is a schematic diagram showing a moving state, FIG. 4 is a schematic diagram showing a pellet detection region, and FIG. 5 is a schematic diagram showing an example of a process of determining the rotation center coordinates of the rotary table according to the present invention.

The pellet bonding apparatus 10 is, as shown in FIG.
It has an XY table 12 that moves in the XY directions with respect to the gantry 11, and a rotary table 13 rotatably mounted on the XY table 12. The XY table 12 is driven by the XY table drive motor 14, and the rotary table 13 is a rotary table drive motor.
Driven at 15.

A wafer ring 16 can be attached to and detached from the rotary table 13, and the wafer ring 16 holds an adhesive sheet to which a large number of pellets 18 are attached as shown in FIG. 5 (A). The pellets 18 are separated from each other as shown in FIG. 5 (B).

The pellet bonding apparatus 10 has a pellet recognition unit 19 arranged at a fixed position. The pellet recognition unit 19
The pellet 18 is composed of a television camera, detects the pellet 18 on the rotary table 13 at the center of the visual field in the detection area (V ₀ ), and detects the inclination of one side AB of the detected pellet 18 with respect to the reference position of the pellet 18. Recognize (θ) (Fig. 3 (A))
(See FIG. 4).

The pellet bonding apparatus 10 has a control unit 20 including a microcomputer. The control unit 20 obtains the tilt (θ) of the pellet 18 which is the recognition result of the pellet recognition unit 19 and controls the rotary table drive motor 15 to rotate the rotary table 13 by the angle (θ). To correct the inclination (θ) of the pellet 18 (3rd
(See FIG. (B), see FIG. 4).

The pellet bonding device 10 includes a pickup device 21.
have. The pickup device 21 has a collet 22 and a needle 23 that sandwich the pellet 18 from above and below at the pickup position, and the pellet 18 pushed up on the adhesive sheet by the needle 23 can be adsorbed by the collet 22 and picked up. As a result, the pickup device 21 picks up the pellet 18 after the tilt correction, and then transfers the pellet 18 to the gauging table or transfers the pellet 18 to the substrate without the gauging table and performs bonding.

At this time, the pellet 18 picked up by the pickup device 21 is adsorbed and transferred to the collet 22 in a state where the inclination (θ) is corrected as described above. Bonded in the correct posture.

Therefore, the controller 20 controls the position of the pellet 18 before the pickup by the pickup device 21 after the inclination correction by the rotary table 13 as described below. In addition, FIG. 4 shows XY
In the coordinate system of the table 12, the XY table 12 is moved from its origin position (0,0) to x _{0 in} the X direction and y _{0 in} the Y direction. Further, the coordinates of the center of rotation of the rotary table 13 when the XY table 12 is at the origin position are (x ₁ , y ₁ ).

(1) The control unit 20 first obtains the rotation center coordinates (T _X , T _Y ) of the turntable 13 by the following equation.

T _X = x ₀ + x ₁ (1) T _Y = y ₀ + y ₁ (2) Next, image processing is performed on the pellet image before tilt correction captured by the pellet recognition unit 19 to detect the detection area 19A. A shift amount between the center of the visual field and a specific point on the pellet 18, that is, point A in this example, is calculated. Now, let us say that the X direction of this shift amount is a and the Y direction is b.

By the way, since the pellet recognition unit 19 is arranged at a fixed position, the visual field center coordinates (Xs, Ys) of the detection area 19A have a fixed value, and therefore, the coordinates (X ₁ , Y ₁ )
Is determined by the following equation.

X ₁ = Xs + a (3) Y ₁ = Ys + b (4) Next, the coordinates of the point A after tilt correction, that is, the coordinates (X) rotated by an angle (θ) around the point (T _X , T _Y ). ₂ , Y ₂ ) is calculated by the following equation.

X ₂ = T _X + Rcos (θ + α) (5) Y ₂ = T _Y + Rsin (θ + α) (6) In addition, α is a line connecting the point A before tilt correction and the rotation center coordinates (Tx, Ty) of the rotary table 13 parallel to the X axis of the coordinate system of the XY table 12 and the point (Tx, Ty). It means the angle formed by the passing straight line, and in Fig. 4, the coordinates (Tx, Ty)
If the clockwise direction to the point is the positive direction, then α = -θ,
Equations (5) and (6) are as follows.

X ₂ = T _X + R (5 ′) Y ₂ = T _Y (6 ′) Then, the XY table operation amount (Xa, Ya) for setting the tilt-corrected pellet 18 to the pellet recognition position again is calculated by the following equation. Ask by.

Xa = Xm−X ₂ (7) Ya = Ym−Y ₂ (8) Here, Xm and Ym are placed at the position (Xs, Ys) where the pellet 18 has a zero tilt. It is a theoretical coordinate value corresponding to the point A when it is assumed that it can be calculated if the coordinates (Xs, Ys) and the size of the pellet 18 are known.

(2) The control unit 20 controls XY based on the calculation result of (1) above.
By driving the table 12, the pellet 18 after the tilt correction is reset to the pellet recognition position, and the pellet 18 is reset.
Of the inclination (θ ') is recognized again, and this inclination (θ') is corrected again by rotating the rotary table 13 by the angle (θ ') in the same manner as described above (see FIG. 3B). (See FIG. 4).

(3) The control unit 20 performs the re-correction operation of (2) as appropriate, and then calculates the XY table operation amount (Xb, Yb) for setting the tilt-corrected pellet 18 at the pickup position by the following equation. Ask by.

Xb = Xp−X ₂ ′ (9) Yb = Yp−Y ₂ ′ (10) where Xp and Yp correspond to point A when the pellet is positioned at the pickup position with zero tilt. X,
It is a theoretical coordinate value in the Y direction and can be calculated if the pickup position coordinate, which is a fixed value, and the size of the pellet 18 are known. Further, X ₂ ′ and Y ₂ ′ are coordinates of point A when the pellet 18 is rotated by an angle (θ ′), respectively, and are expressed by the formula (5),
If (6) is used, it can be obtained in the same manner as when the inclination (θ) is corrected.

(4) The control unit 20, based on the calculation result of (3) above,
By driving the XY table 12, the tilt-corrected pellet 18 is set at the pickup position by the pickup device 21 described above.

In FIG. 4, P1 is the pellet 18 before inclination correction,
P2 is the pellet 18 after tilt correction, and P3 is the pellet 18 reset at the pellet recognition position.

However, in the present invention, the coordinates of the rotation center (Tx, T) of the rotary table 13 in the coordinate system of the XY table 12 described above.
y) is calculated as follows.

The orientation flat corner portion of the wafer 17 held by the wafer ring 16 fixedly set on the rotary table 13 is defined as a characteristic point (A).

The feature point A is aligned with the visual field center of the detection region (V ₀ ) of the pellet recognition unit 19, and the coordinates A ₀ (XA ₀ , YA ₀ ) of the feature point A recognized by the pellet recognition unit 19 are controlled by the control unit 20. (See FIG. 5 (A)).

The rotary table 13 is rotated by a certain rotation angle (θ ₁ ), for example, 60 degrees. At this time, the characteristic point A moves to the coordinate A ₁ . The feature point A located at this coordinate A ₁ is re-aligned with the center of the visual field of the detection region (V ₀ ) of the pellet recognition unit 19, and the pellets obtained from the movement amounts ΔX ₁ and ΔY ₁ of the XY table 12 at this time Coordinates A ₁ (XA ₀ ΔX ₁ , YA ₀ + of this feature point A recognized by the recognition unit 19
ΔY ₁ ) is stored in the control unit 20 (see FIG. 5 (B)).
In the Figure, [Delta] X ₁ to the feature point A ₁ towards the detection region V _0,
ΔY ₁ is shown in a moved state.

The rotary table 13 is further rotated by a certain rotation angle (θ ₂ ), for example,
Rotate 60 degrees. At this time, the characteristic point A moves to the coordinate A ₂ .
The feature point A located at this coordinate A ₂ is aligned with the center of the visual field of the detection area (V ₀ ) of the pellet recognition unit 19, and the pellet recognition obtained from the movement amounts ΔX ₂ and ΔY ₂ of the XY table 12 at this time. The coordinates A ₂ (XA ₀ ΔX ₁ + ΔX ₂ ,
YA ₀ + ΔY ₁ + ΔY ₂ ) is stored in the control unit 20 (see FIG. 5 (C)).

From the above, the control unit 20 obtains three points A ₀ , A ₁ , and A ₂ located on the movement locus of the characteristic point A with the rotation of the rotary table 13 with respect to the XY table 12, and then, FIG. )
As shown in, the two points A ₀ and A ₁ are connected A ₀ / A ₁ and the two points A ₁ and A ₁ .
Determine the A ₁ / A ₂ that connects the _2. Further, the control unit 20 controls each string A ₀ / A
The coordinates of the intersection of the vertical bisectors of ₁ , A ₁ and A ₂ are obtained, and these coordinates are determined as the rotation center coordinates (Tx, Ty) of the rotary table 13.

The control unit 20 obtains the starting point A 0 and the ending point A ₁ of the moving locus of the characteristic point A by the rotation of the rotation angle (θ ₁ ) of the rotary table 13 by the above, and then changes the coordinate values of both points. The rotation center direction of the rotary table 13 is detected with respect to the straight line connecting the additional points A ₀ and A ₁ , and the start point A ₀ and the end point are detected.
From the coordinates of A _{1 and} the rotation angle (θ ₁ ) above, those 2
Assume an isosceles triangle whose base is the chord A ₀ / A ₁ connecting points A ₀ and A ₁ and whose angle is the apex angle θ ₁ , and the coordinates of its vertices are the coordinates of the center of rotation (Tx, Ty) of the rotary table 13. Can also be determined as

 Next, the operation of the above embodiment will be described.

According to the above-described embodiment, for example, at the manufacturing stage of the pellet bonding apparatus 10, for each actual machine, the rotary table 13 is actually used.
Based on the data obtained by rotating, the coordinates of the center of rotation (Tx, T
y) can be obtained. Therefore, the rotation center coordinates can be obtained reliably and accurately. Thus, when the tilt of the pellet 18 is corrected by the rotation of the rotary table 13, the tilt-corrected pellet 18 will be the pellet recognition unit 19
Even if it deviates from the detection area (V ₀ ) of (1),
As shown in (4) to (4), the position of the pellet 18 is controlled so that the inclination of the pellet 18 can be re-corrected and the correction accuracy can be improved by using the rotation center coordinates.
The position of the pellet 18 can be controlled so that the pellet 18 can be picked up reliably.

[Effects of the Invention] As described above, according to the present invention, the coordinates of the center of rotation of the rotary table mounted on the XY table can be determined reliably and accurately.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an essential part of an example of the pellet bonding apparatus of the present invention, and FIG. 2 is a block diagram showing an example of a control system in the pellet bonding apparatus of the present invention.
FIG. 4 is a schematic diagram showing a moving state of a pellet, FIG. 4 is a schematic diagram showing a detection region of a pellet, and FIG.
FIG. 6 is a schematic view showing an array state of pellets. 10 …… Pellet bonding machine, 11 …… Stand, 12 …… XY table, 13 …… Rotary table, 18 …… Pellet, 19 …… Pellet recognition section, 20 …… Control section, 21 …… Pickup unit.

Claims (3)

(57) [Claims] 1. An XY table that moves in XY directions relative to a gantry, a rotary table that is rotatably mounted on the XY table, and holds a large number of pellets, and pellets that are detected on the rotary table and are detected. Of the pellet recognition unit for recognizing the tilt with respect to the reference position, a control unit that corrects the tilt of the pellet by rotating the rotary table based on the recognition result of the pellet recognition unit, and the tilt is corrected by the control unit. In a pellet bonding apparatus configured to have a pickup device for picking up pellets, a characteristic point located in a fixed state on a rotary table is determined, and a change in the position of the characteristic point in the XY direction due to rotation of the rotary table is performed. Based on the coordinate system of the XY table, the rotation center coordinates (Tx, Ty) of the rotary table are obtained. Door bonding apparatus. 2. Obtaining at least three points located on the movement locus of the characteristic points due to the rotation of the turntable, and obtaining at least two strings formed by connecting two of these three points, The coordinate of the intersection of the vertical bisectors of the chord is obtained as the rotation center coordinate (Tx, Ty) of the rotary table.
The described pellet bonding apparatus. 3. The rotation table is rotated by a certain amount of rotation (θ), the starting point and the end point of the movement locus of the characteristic points associated with the rotation are obtained, the coordinates of these starting point and the end point, and the amount of rotation (θ). ) To the rotation center coordinates (Tx, T
The pellet bonding apparatus according to claim 1, wherein y) is obtained.