JP4860068B2 - Manufacturing method of semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a die bonding technique and a semiconductor device manufacturing technique, and more particularly to a technique effective when applied to a semiconductor device manufacturing process including a direct pickup die bonding process using a bonding tool such as a collet.
[0002]
[Prior art]
For example, in the assembly process of a semiconductor device, a wafer on which a plurality of semiconductor devices are collectively formed in a wafer process is divided into individual semiconductor devices (dies) and individually bonded to a lead frame or the like (packaging) There is an assembly process such as.
[0003]
As die bonding technology for bonding individual dies to lead frames, etc., each die is picked up from the adhesive tape on which the dies are arranged in a state of dividing the wafer with a collet and positioned on an intermediate stage, and then the lead frame, etc. There are known a method of bonding to each other and a direct pickup method of bonding individual dies picked up from an adhesive tape directly to a bonding object such as a lead frame.
[0004]
[Problems to be solved by the invention]
By the way, a high-hardness metal collet is used from the viewpoint of wear resistance, etc., but the collet and die position (x, y, θ) at the time of pickup is highly accurate (for example, x and y are ± 50 μm or less) Otherwise, die damage, pick-up mistakes, etc. will occur.
[0005]
For this reason, when attaching the collet to the bonding head, manually adjust the center of the shank hole of the bonding head with which the support shaft of the collet fits, using an adjustment jig or the like. However, it takes a lot of labor and a long time for the work, and it is very difficult to adjust the position accuracy to a high accuracy of, for example, about ± 50 μm or less, and it takes much time and labor. There was a technical problem.
[0006]
This adjustment work needs to be performed every time the collet is exchanged. For example, when the collet is frequently exchanged in correspondence with various types of dies, the throughput when the adjustment work is included is reduced.
[0007]
An object of the present invention is to reduce the time required for the bonding tool for performing a pickup operation and the position adjustment work of the pickup tool, to reduce the labor, and to improve the adjustment accuracy.
[0008]
Another object of the present invention is to realize an improvement in throughput in a die bonding process by exchanging bonding tools corresponding to various types of dies and improving the efficiency of adjustment work.
[0009]
Another object of the present invention is to improve yield by reducing die damage in the die bonding process.
[0010]
The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.
[0011]
[Means for Solving the Problems]
Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
[0012]
The present invention is a die bonding method in which a die held on an adhesive tape is collected by a bonding tool driven by a positioning mechanism and bonded to a bonding object, and the first position of a specific die on the adhesive tape A step of detecting information, a step of collecting a die from the adhesive tape into a bonding tool, a step of returning the collected die onto the adhesive tape, and a step of detecting second position information of the die returned on the adhesive tape And a step of detecting an attachment error of the bonding tool relative to the positioning mechanism based on the difference between the first position information and the second position information, and a step of correcting the position of the bonding tool during bonding based on the attachment error; Is included.
[0013]
The present invention also includes a wafer process for collectively forming a plurality of semiconductor devices on a semiconductor wafer, and an assembly process for assembling a die obtained by dividing the semiconductor wafer into individual semiconductor devices. An apparatus manufacturing method, in which the above-described die bonding method is used for die bonding in an assembly process.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a conceptual diagram illustrating an example of the action of a die bonding method in the method of manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 2 is a flowchart illustrating an example of the action. These are perspective views which show an example of a structure of the die-bonding apparatus which enforces the die-bonding method of this Embodiment.
[0016]
With reference to FIG. 3, an example of the structure of the die bonding apparatus of this Embodiment is demonstrated.
[0017]
The die bonding apparatus according to the present embodiment includes a wafer stage 10, a bonding stage 20, and a bonding head unit 30.
[0018]
The wafer stage 10 includes a wafer ring 12 that supports a peripheral portion of the adhesive tape 11 to which the back surfaces of a plurality of dies 51 obtained by dicing the wafer 50 (and extending the adhesive tape 11 as required) are attached. A positioning mechanism (not shown) that controls the position of the wafer ring 12 in the x, y, and θ directions, and a needle (not shown) that performs suction and fixing of the pickup portion from the back side of the adhesive tape 11 and pushing up the die 51 to be picked up. And the like.
[0019]
The bonding stage 20 is a heat that heats the bonding portion of the lead frame 60 at the bonding position from below to a predetermined bonding temperature from the rail 21 for intermittently conveying and positioning the lead frame 60 that is a bonding target. A block 22 and the like are provided.
[0020]
The bonding head unit 30 supports the bonding head 31 to which the support shaft 41 of the collet 40 is fixed, the θ control motor 32 that controls θ displacement around the z axis of the bonding head 31, and the θ control motor 32 to support the bonding head 31. The z-axis drive motor 33 and the z-axis rail 33a for controlling the displacement in the z-axis direction, and the y-axis drive motor 34 and the y-axis for supporting the z-axis rail 33a and controlling the displacement in the y-axis direction of the bonding head 31 An x-axis drive motor (not shown) that supports the drive rail 34a and the y-axis drive rail 34a to control the displacement of the bonding head 31 in the x-axis direction, and is fixed to the y-axis drive motor 34 in a downward attitude in the z-axis direction. By moving in the x and y directions together with the bonding head 31, the die 51 on the lower wafer stage 10 and the bonding x-coordinate of the lead frame 60 of the stage 20, and a y-coordinate, the position detecting optical system for detecting the θ coordinate 35, and the like.
[0021]
Although the collet 40 is not particularly illustrated, a recess having a tapered surface of a pyramid shape corresponding to the size of the die 51 is formed on the lower end surface, and the die 51 held in the recess is provided inside the support shaft 41. A suction path for adsorbing and fixing is formed.
[0022]
The position of the die 51 to be picked up on the wafer stage 10 and the position of the bonding part of the lead frame 60 on the bonding stage 20 are detected by the position detection optical system 35, and the bonding head 31 is detected according to the position detection result. By controlling the position of the collet 40 supported by, and controlling the movement of the collet 40 as in the pickup / bonding locus 100 shown in FIG. 3, the collet 40 picks up (collects) the die 51 from the wafer stage 10. Then, die bonding of the picked-up die 51 to the bonding portion of the lead frame 60 in the bonding stage 20 is executed.
[0023]
Accordingly, the mounting accuracy of the collet 40 with respect to the bonding head 31 is important from the viewpoint of preventing damage due to the pick-up mistake of the die 51 and contact with the collet 40. When replacing the collet 40, the same collet 40 is used. It is necessary to adjust the mounting accuracy of the collet 40 with respect to the bonding head 31 at any time even during maintenance work such as the start of work while it is attached. Conventionally, this has been done manually, which requires a great deal of man-hours and It took time and sometimes it was difficult to obtain the required accuracy.
[0024]
Therefore, in the present embodiment, adjustment of the accuracy of attaching the collet 40 to the bonding head 31 is automatically executed as follows.
[0025]
That is, as illustrated in the flowchart of FIG. 2, it is necessary when replacement of the collet 40 occurs due to change of the type of the die 51 or when adjustment of the mounting accuracy of the collet 40 is necessary for maintenance management work. Accordingly, after the collet 40 is mounted on the bonding head 31 (in the case of collet replacement) with rough accuracy (step 201), first, the position of any die 51 on the adhesive tape 11 of the wafer stage 10 (x1, y1, θ1). ) Is detected (step 202), the position of the detected die 51 is picked up from the adhesive tape 11 by the collet 40 (FIG. 1A) (step 203), and then returned to the original position of the adhesive tape 11 again. (Step 204), and the position (x2, y2, θ2) of the returned die 51 is detected again (step 205).
[0026]
Based on the difference between the position (x1, y1, θ1) of the die 51 before pickup and the position (x2, y2, θ2) when the die 51 is returned to the original position after pickup, the attachment error of the collet 40 to the bonding head 31 is determined. The correction value is set (step 206).
[0027]
That is, when the die 51 is picked up by the collet 40 attached to the bonding head 31 with a rough accuracy, the die 51 is stabilized according to the mounting error of the collet 40 so that the die 51 becomes stable following the pyramidal tapered surface of the collet 40. , Y, θ direction position is changed and when it is returned to the adhesive tape 11 again, as shown in FIG. 1C, the position before and after the pickup is reflected in the state reflecting the mounting error of the collet 40. Has changed.
[0028]
In the case of the present embodiment, using this, the correction value for the bonding head 31 of the collet 40 is determined, the correction values of x, y, and θ that cancel the error are determined, and the actual die This is reflected in the position control of the collet 40 (bonding head 31) in bonding.
[0029]
That is, in actual die bonding, first, the position (x3, y3, θ3) of the bonding portion of the lead frame 60 to be bonded is detected (step 207), and the target die 51 on the adhesive tape 11 is further detected. After the position (x1, y1, θ1) is detected (step 208), the correction value is set so that the position (x, y, θ1) of the collet 40 matches the position (x1, y1, θ1) of the die 51. Is used to position the collet 40 directly above the die 51 (step 209), and a pick-up operation is performed to hold the die 51 on the collet 40 by the pushing-up operation by the suction piece 13 (step 210). 51, bonding position (x3, y3, θ3) of the lead frame 60 of the bonding stage 20 using the correction value. (Step 211), the die 51 is pressed against the bonding portion of the lead frame 60 to execute die bonding (step 212), and the operation until the last die 51 is repeated (step 213).
[0030]
In the example of FIG. 1C, the die 51 before picking up is illustrated as an example in which θ1 is exactly 90 degrees with respect to the coordinate axes x and y of the position detection optical system 35, and there is no rotational deviation. When θ1 is not 90 degrees in the tape 11 stretching process or the like, a correction amount for the rotational displacement of the collet 40 is obtained by adding the rotational displacement amount of θ1 to the coordinate axes x and y to the difference between θ1 and θ2. . The same applies to the correction of the x and y coordinates of the collet 40 by the positions (x1, y1) and positions (x2, y2) before and after the pickup of the die 51.
[0031]
The lead frame 60 to which the die 51 is bonded in this way is subjected to a subsequent wire bonding process, a sealing process, a cutting process of the lead frame 60 for each individual die 51, a lead molding process, an inspection process, and the like as necessary. , Shipped as a product semiconductor device.
[0032]
As described above, according to the present embodiment, after the die 51 on the adhesive tape 11 is once picked up by the collet 40, the die 51 is returned to the original position, and the attachment error of the collet 40 to the bonding head 31 is reflected. Since the position correction of the collet 40 in the actual pickup and die bonding can be automatically performed based on the positional deviation of the die 51 before and after the pickup, the time required for the position adjustment work of the collet 40 for performing the pickup operation can be shortened. It becomes possible to reduce labor and improve adjustment accuracy.
[0033]
In particular, for example, when a plurality of types of collets 40 are frequently exchanged corresponding to various types of dies 51, the collet 40 can be exchanged and the efficiency of the adjustment work can be improved, and the throughput in the die bonding process can be improved. realizable.
[0034]
In addition, die damage due to misalignment or the like of the collet 40 in the die bonding process is reduced, and the yield in the semiconductor device manufacturing process can be improved.
[0035]
Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.
[0036]
For example, the present invention can also be applied to collet position adjustment as a die pick-up tool in an indirect pick-up method in which an intermediate stage for die positioning is provided between the pick-up portion and the bonding portion.
[0037]
【Effect of the invention】
Of the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.
[0038]
The effects of shortening the time required for the bonding tool for performing the pick-up operation and the position adjustment work of the pick-up tool, reducing the labor, and improving the adjustment accuracy can be obtained.
[0039]
In addition, it is possible to achieve an improvement in throughput in the die bonding process by exchanging bonding tools corresponding to various types of dies and improving the efficiency of adjustment work.
[0040]
In addition, the yield can be improved by reducing die damage in the die bonding process.
[Brief description of the drawings]
FIGS. 1A to 1C are conceptual diagrams illustrating an example of an operation of a die bonding method in a method for manufacturing a semiconductor device according to an embodiment of the present invention in order of steps.
FIG. 2 is a flowchart showing an example of an operation of a die bonding method in the method for manufacturing a semiconductor device according to an embodiment of the present invention.
FIG. 3 is a perspective view showing an example of a configuration of a die bonding apparatus that performs a die bonding method according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Wafer stage 11 Adhesive tape 12 Wafer ring 13 Adsorption piece 20 Bonding stage 21 Rail part 22 Heat block 30 Bonding head part 31 Bonding head 32 (theta) control motor 33 z-axis drive motor 33a z-axis rail 34 y-axis drive motor 34a y-axis drive Rail 35 Position detection optical system 40 Collet (bonding tool, pickup tool)
41 Support shaft 50 Wafer 51 Die 60 Lead frame (bonding object)
100 Pickup / bonding locus

Claims (4)

In a manufacturing method of a semiconductor device using a die bonding apparatus that collects a plurality of dies held on an adhesive tape into a bonding tool driven by a positioning mechanism and bonds them to a bonding object.
(A) disposing the plurality of dies held on the adhesive tape on a wafer stage of the die bonding apparatus;
(B) collecting an arbitrary die selected from the plurality of dies with the bonding tool, and picking up the arbitrary die from the adhesive tape;
(C) after the step (b), returning the picked-up arbitrary die onto the adhesive tape on the wafer stage without releasing the die;
(D) after the step (c), again picking up the arbitrary die from the adhesive tape, and bonding the arbitrary die to the bonding object,
After the arbitrary die is picked up from the adhesive tape in the step (b), it is returned to the adhesive tape in the step (c) without being released,
The die bonding apparatus is in a state where the first position information of the arbitrary die in a state of being arranged on the wafer stage in the step (a) and being returned on the wafer stage in the step (c). Second position information of the arbitrary die of
In the step (d), the arbitrary die is bonded to the bonding object based on position information obtained by correcting a difference between the first position information and the second position information. Production method. In the manufacturing method of the semiconductor device according to claim 1,
The bonding tool has a metal collet in which a concave portion having a pyramid tapered surface is formed on a lower surface thereof, and the first position information is obtained before the arbitrary die is picked up by the metal collet. And the second position information is position information after the arbitrary die has been picked up by the metal collet. The method of manufacturing a semiconductor device according to claim 2.
Wherein the first position information difference of the second position information, a method of manufacturing a semiconductor device, characterized in that the equivalent to the position displacement generated when mounting the metallic collet to said bonding tool. The method of manufacturing a semiconductor device according to claim 2.
In the step (b) and the step (c), the arbitrary die is stabilized following the tapered surface of the metal collet.

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