JPS5919466B2 - How to align chip bonding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chip bonding alignment method for directly bonding a chip to a pad or lead of a substrate in order to manufacture a semiconductor device.

In general, chip bonding is performed by directly bonding bumps 2a of a chip 2 to pads or leads 1a of a substrate 1 by overlapping them, as shown in FIG.

In such chip bonding, the pad 1a of the substrate 1
To align the bumps 2a of the chip 2 and the bumps 2a of the chip 2, as shown in FIG.
is temporarily clamped, and the image of the chip 2 reflected by the half mirror 4 is reflected on the image of the substrate 1 observed through the half mirror 4, which is placed at a position deviating from the straight line connecting the substrate 1 and the chip 2 and perpendicular to the straight line. Observe them by superimposing them, and adjust the orientation of the two by rotating the rotary table 3.
The deviation in direction is adjusted by driving an XY table (not shown) on which a collet 5 for picking up the chip 2 is attached. Conventionally, the rotating operation of the rotary table 3 for adjusting the orientation of the substrate 1 with respect to the chip 2 is performed by manually operating the rotary table 3 directly, or by equipping the rotary table 3 with a pulse motor without an encoder. A switch is used to send pulses to the pulse motor one pulse at a time to operate the rotary table 3 for matching.

However, in the former method of direct manual operation, it is not possible to automate the conveyance path, a high degree of skill is required for operation, and it is difficult to operate the rotary table 3 and the XY table at the same time. It has its drawbacks. Furthermore, the latter method of operating one pulse at a time has the disadvantage that it takes a considerable amount of time, about 6 to 10 seconds, to align the substrate 1 and the chip 2. Therefore, conventionally, measures have been taken to minimize the amount of rotation of the rotary table 3, such as providing a chip position correction station on the tray to which the chip 2 is attached or between the wafering position and the bonding position. ing. The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a chip bonding alignment method that can easily, accurately and quickly align a chip and a substrate.

Hereinafter, the present invention will be explained with reference to illustrated embodiments. Figure 3a
shows the positional relationship between the substrate 1 and the chip 2 immediately after being transported, and it is assumed that the chip 2 is shifted from the substrate 1 as shown by the solid line. Therefore, as shown in FIG. 3a and FIG.
Set l, Q, and define this coordinate as P, (X,,,yl),
If the straight line passing through P1 and Q1 is parallel to the X axis, then y1=Y2. Also here, P1
Let the length of and Q be 2. In addition, the two bumps of chip 2 bonded to the leads Pl and Ql points are P2 and Q2.
shall be. The method of the invention will now be explained according to FIG. 3 with reference to FIG. First, as shown in FIG. 3b, the chip 2 is moved on a plane using an XY table to align the first point. That is, the bump P2 is aligned with the lead P. Next, as shown in FIG. 3C, alignment is performed at the second point. That is, the bump Q2 is aligned with the lead Q1. At this time, the amount by which point Q2 moves from state b to state C in the same diagram is △X
, Δy, the inclination of the chip 2 with respect to the substrate 1, that is, the inclination ★θ of P7F (P2 with respect to Q1) is expressed by the following formula.Equation (1) is for the case where PV, is parallel to the As shown in FIG. 5, when PV is parallel to the Y axis, the following equation is obtained.

ΔX Further, when P7L has an arbitrary slope r with respect to the X axis as shown in FIG. 6, the following equation is obtained.

In the above formula (1×2X3), 2, IXl−X2l.
yl-Y2l is determined by detecting the lengths of the two points on the X and Y axes of the lead, and △X and △y are determined by operating the manipulator to set the first point of the chip to the first point of the lead. This is the amount of movement of the second point of the chip when the XY table is driven and aligned, and from this state the second point of the chip is aligned with the second point of the lead in the same manner as described above. Easily detectable. Therefore, by detecting these values, the rotation angle θ for rotating the reed is easily and automatically calculated by the computer according to the above (1X2X3), and by rotating the rotation table 3 by the θ angle, As shown in FIG. 2, all bonding points between substrate 1 and chip 2 coincide. FIG. 7 shows a flowchart of the method described above. As is clear from the above description, according to the chip bonding alignment method of the present invention, the first bump on the chip corresponding to the first lead on the board is aligned with the first lead on the board, and then All you have to do is match the second point lead with the corresponding second point bump, and this will detect the amount of movement of the second point bump and calculate the rotation angle of the lead with respect to the chip. , its operation is easy and requires no skill,
It can also be done quickly and accurately.

It is also possible to pick up the chips directly from the tray or wafer ring and transport them to the bonding position, and a chip position correction station can be omitted.
As described above, the angle of the rotary table 3 that holds the substrate 1 is calculated, and thereby the angular deviation between the substrate 1 and the chip 2 is corrected.

In this case, the center of rotation of the turntable 3 is the second point Q1 of the lead.
When they match, all the bonding points between the substrate 1 and the chip 2 are perfectly matched just by rotating the rotary table. However, when the center of the rotary table does not coincide with the second point Q1 of the lead, it is necessary to drive the XY table to move the chip 2 in the XY direction so that the center coincides with the second point Q1 of the lead. Next, a method of adjusting the amount of pellet movement after θ correction using the rotary table described above will be explained.

Now, the case where Gtl is parallel to the X axis as shown in FIG. 4 will be explained. As shown in Figure 8, the center of rotation of the turntable is set to O.
point, and the coordinates P1(
Suppose that Xl, yl) and Q1 (X2, y2) are determined. PJ, Q2' is the first point P2 of the chip when the second point Q2 of the chip is matched with the second point Q1 of the lead.
and the position of the second point Q2. In this state, if the rotary table is rotated by the angle θ calculated as above,
Lead P,,Ql point is P/,Q parallel to P2',Q2'
/become. Therefore, Q/ and Q2' (or P/ and P2')
When the chip is moved by the amount of deviation △Xl, △y1, Q
/ will match QJ, and P/ will match P2'. now,
Let θ1 be the angle between the angle and the X axis, and r be the length of the angle, then σ
Since Q1=0Q/-r, ΔXl and Δy1 are expressed by the following equations.

Here, since RcOsθ1:X2, rsinθ1=Y2, the above equation (4×5) becomes as follows.

As is clear from these equations (6X7), if the coordinates of any point on the substrate or chip are determined with the center of rotation of the rotating table as a reference, the deviation between the chip and the substrate when the rotating table is rotated by θ can be calculated. The quantities ΔXl and Δy1 are calculated.

With this, after aligning the second point with the manipulator as described above, the rotary table is set at θ angle and the XY table is set at △X.
By moving the substrate 1 and the chip 2 by 1 and Δy1, the substrate 1 and the chip 2 are brought into bonding compatible positions.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the state before bonding, Figure 2 is an explanatory diagram showing how to observe the substrate and chip, and Figures 3A and b.
, c, d are explanatory diagrams showing one embodiment of the method of the present invention;
5 and 6 are diagrams for explaining the angle calculation method used in the method of the present invention, FIG. 7 is a flowchart diagram of the method of the present invention, and FIG. FIG. 3 is a diagram for explaining a positional deviation calculation method showing an example. 1... Board, 1a... Lead, 2...
...Tip, 2a...Bump, 3...
・・Rotary table, 5・・Collection, P1・・・・
・1st point of lead, P2...1st point of bump, Q1...2nd point of lead, Q2...
...Second point of bump, θ...Rotation angle.

Claims (1)

[Scope of Claims] 1. The image of the substrate positioned on the rotating table and the chip that is attracted to the collet and transported by the collet driven by the In a chip bonding method in which the inclination of the substrate and chip is adjusted by rotating the board and the chip is bonded, an XY table is driven to attach a bump at the first point of the chip corresponding to an arbitrary first point lead on the substrate. Then, drive the XY table to match the corresponding second point bump to the lead of any second point in the same way as above,
By detecting the amount of movement of the XY table from the first point to the second point and inputting it into the computer, the inclination of the pellet with respect to the substrate is calculated, and the rotating table is rotated by the calculated rotation angle. A chip bonding alignment method characterized by matching the inclination of the board to the inclination of the chip. 2 The rotating table is rotated using the superimposed images of the substrate positioned on the rotating table and the chips that are attracted and transported by the collet driven by the XY table above the substrate. In a chip bonding method in which bonding is performed by adjusting the inclination between the substrate and the chip and the deviation between the substrate and the chip by driving an XY table,
Drive the XY table to align the first point bump of the chip corresponding to the first point lead on the board,
Next, drive the XY table in the same manner as above to match the second point bump corresponding to the lead of any second point,
By detecting the amount of movement of the XY table from the first point to the second point and inputting it into the computer, the inclination of the pellet with respect to the substrate is calculated, and the rotating table is rotated by the calculated rotation angle. By adjusting the inclination of the substrate to the inclination of the chip, and using the rotation angle of the rotary table and the coordinates of an arbitrary point on the substrate with the rotation center of the rotary table as the origin, the computer calculates the parallel relationship between the substrate and the chip. Calculate the amount of deviation,
A chip bonding alignment method characterized by aligning a substrate and a chip by driving an XY table to correct the amount of deviation.