KR101410171B1 - Wafer bumping apparatus and bumping method using the same - Google Patents

Abstract

Disclosed are a wafer bumping apparatus and a bumping method using the same. The wafer bumping apparatus according to the present invention includes: a chuck unit including a chuck on which a wafer is put and a chuck driver to move the chuck; an alignment table including a penetration portion in which the chuck elevates and a first alignment means formed around the penetration portion; a guide rail horizontally disposed around the chuck; a flux mask unit including a flux mask, a flux mask frame having a second alignment means supporting an edge of the flux mask and coupled to the first alignment means, and a first driver to move the flux mask frame along the guide rail; a ball mask unit including a ball mask, a ball mask frame having a third alignment means supporting an edge of the ball mask and coupled to the first alignment means, and a second driver to move the ball mask frame along the guide rail; and a plurality of vision cameras installed at an upper portion of the chuck, to acquire each position value of a plurality of reference marks formed on a wafer. According to the present invention, a position of the wafer may be accurately aligned by confirming an alignment state of a wafer bumping region and a mask hole using the vision cameras in a state that the wafer is close to the flux mask or the ball mask, and accordingly the work accuracy is improved so that a failure rate may be significantly reduced.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer bumping apparatus and a bumping method using the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer bumping apparatus, and more particularly, to a wafer bumping apparatus and method capable of significantly improving work accuracy by more accurately aligning a wafer and a mask.

Generally, in order to manufacture a semiconductor package, a predetermined thin film is first deposited on a wafer, and the deposited thin film is subjected to photolithography and etching to form a circuit pattern.

In addition, a packaging process must be performed in which the wafer on which the circuit pattern is formed is again sawed into individual dies (or chips), and individual die segments are attached to the PCB substrate and molded.

Thus, conventionally, it has been common to divide the wafer into individual dies and then proceed with the packaging process for each die. Recently, however, a wafer bumping method has been widely used in which a ball bumping technique is sophisticated and a plurality of solder balls are attached to a plurality of dies formed on a wafer at one time by using a mask before cutting the wafer.

In this wafer bumping, alignment of the wafer and the mask is very important because the bumping operation is performed simultaneously on the plurality of dies. In general, the position of the mask and the position of the wafer are checked through the vision camera and the positions of the wafer and the wafer are aligned.

However, with such a conventional method, there is a limit to precisely align the positions of the mask holes and the wafer die, which become finer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a bumping apparatus and method capable of more accurately aligning positions of dice and mask holes of a wafer in a wafer bumping process.

According to the present invention, there is provided a wafer bumping method for attaching a solder ball to a wafer including an edible bore having a shape different from that of the remaining ones of the plurality of bores, the method comprising the steps of: Obtaining a position value, and adjusting a position of the wafer using a chuck driving unit when there is a position error; Moving a flux mask over the chuck; Confirming the alignment state of the position-recognizing bolt and the mask hole formed in the flux mask using the vision camera, and adjusting the position of the wafer using the chuck driver when there is an alignment error; Performing a flux squeezing process on top of the flux mask; Moving the ball mask to an upper portion of the chuck; Confirming the alignment state of the position-recognizing bolt and the mask hole formed in the ball mask using the vision camera, and adjusting the position of the wafer using the chuck driving unit when there is an alignment error; And performing a ball quenching process at an upper portion of the ball mask.

The apparatus includes an aligning table having a through portion through which the chuck ascends and retreats at a central portion and a first aligning means at a peripheral portion. In the wafer bumping method according to the present invention, the step of moving the flux mask to an upper portion of the chuck And subsequently fixing said flux mask to said alignment table by raising said alignment table and combining said first alignment means with second alignment means formed in a flux mask frame supporting said flux mask, After the step of moving the mask to the top of the chuck, the alignment table is elevated to engage the first alignment means with third alignment means formed on the ball mask frame supporting the ball mask, And fixing the light emitting diode to the light emitting diode.

In addition, in the step of performing a ball quenching process on the ball mask, a solder ball is supplied to an upper portion of the ball mask, then a solder ball is squirted using a brush or a blade, The step of horizontally moving the ball mask may be performed.

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Further, in the bumping method according to the present invention, after performing the flux squeezing process on the flux mask, the chuck on which the wafer is placed may be lowered while spraying air at the top of the flux mask.

The present invention also provides a chuck unit comprising: a chuck on which a wafer is placed; and a chuck driver for moving the chuck; An aligning table having a penetrating portion on which the chuck moves up and a first aligning means formed on the periphery of the penetrating portion; A guide rail disposed horizontally around the chuck; A flux mask frame including a flux mask and second alignment means for supporting the rim of the flux mask and engaging with the first alignment means; and first mask drive means for moving the flux mask frame along the guide rail A flux mask unit; A ball mask frame having a ball mask and a third aligning means for supporting the rim of the ball mask and engaging with the first aligning means and a second mask driving means for moving the ball mask frame along the guide rails A ball mask unit; And a plurality of vision cameras mounted on the chuck to acquire positional values of a plurality of reference marks formed on the wafer, respectively.

The bumping device according to the present invention includes: an elevating table provided apart from the alignment table; A first vertical driving means for lifting the elevating table; A second vertical driving means, one end of which is connected to the elevating table to elevate the chuck driving portion; And air spraying means for spraying air at an upper portion of the flux mask.

According to the present invention, the position of the wafer can be more accurately aligned by confirming the alignment state between the wafer bumping area and the mask hole using a vision camera in the state where the wafer is in close proximity to the flux mask or the ball mask, Can be greatly reduced. Further, since the wafer is lowered while jetting the air after the flux squeezing process, it is possible to prevent the shape of flux dipped in the bumping area from being deformed or the position error being generated.

1 is a front view of a wafer bumping apparatus according to an embodiment of the present invention;
2 is a top view of a wafer bumping apparatus according to an embodiment of the present invention.
3 is a plan view illustrating a flux mask (ball mask)
Figures 4A-4N are flow charts illustrating the operation of the wafer bumping equipment in accordance with an embodiment of the present invention.
5 is a plan view illustrating a wafer
6 is a view showing a reference mark of a wafer
7 is a detailed view showing a flux mask process
8 is a detailed view showing the ball mask process

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

A wafer bumping apparatus 100 according to an embodiment of the present invention includes a chuck unit 110 for supporting a wafer w to be processed, a flux mask unit 130, A ball mask unit 140, vision cameras 170a and 170b for acquiring position data for alignment of the wafer and the mask, and the like.

The chuck unit 110 includes a chuck 112 having a vacuum adsorption hole as a part on which the wafer w is placed and a lower chuck 112 for moving up, down, and / And a connected chuck driver 114.

Further, in the embodiment of the present invention, an alignment table 120 for aligning the flux mask or the ball mask is provided on the periphery of the chuck 112 on the wafer w.

The alignment table 120 has a through hole through which the chuck 112 ascends or descends at the center of the alignment table 120. Alignment protrusions 122 and 122, which are inserted into the alignment holes 134 and 144 formed in the flux mask frame 131 or the ball mask frame 141, Is protruded upward.

The alignment table 120 is fixed to the elevation table 124 at a predetermined distance from the upper portion of the elevation table 124 and the elevation table 124 is fixed to the main frame 102 by a first vertical driving means 126 ). Therefore, the alignment table 120 can be moved up and down by driving the first vertical driving means 126. [

The chuck drive unit 114 includes a second vertical drive unit 118 for lifting and lowering the chuck 112, a horizontal drive unit for moving in the horizontal direction, and a rotation drive unit for rotating motion. Particularly, the second vertical driving means 118 has one end connected to the lifting table 124 to move the entire chuck driving unit 114 up and down.

Although not shown in the drawing, the chuck driving unit 114 may be provided with an interval measuring unit for measuring the interval between the wafer w and the flux mask / ball mask.

The flux mask unit 130 includes a positive mask 132 having a plurality of mask holes corresponding to the bumping area of the wafer and a flux mask frame 131 supporting the edge of the flux mask 132. The flux mask frame 131 has a plurality of alignment holes 134 into which a plurality of alignment protrusions 122 of the alignment table 120 are inserted, respectively.

Further, the flux mask frame 131 may be provided with a first squeegee end 161 for moving a blade (see 191 in FIG. 7) at an upper portion of the flux mask 132. The first squeegee end 161 may be installed separately from the flux mask frame 131.

4H) for moving the air on the upper portion of the flux mask 132 and a transfer means (not shown) for moving the air injection means 198 to the upper portion of the flux mask 132, Can be mounted. The air jetting means serves to provide the air pressure so that the flux passing through the mask hole is separated from the flux mask 132 when the wafer w is lowered after the flux squeezing process so as to stably be dotted to the bumping region of the wafer w . Although the jetting area of the air jetting means 198 is preferably similar to that of the wafer w, the jetting area of the air jetting means 198 may be long. On the other hand, the air injecting means 198 and the conveying means for the air injecting means 198 are not necessarily mounted on the flux mask frame 131, but may be mounted on the main frame 102 of the apparatus so as to be capable of vertical movement and / or horizontal movement.

The lower end of the flux mask unit 130 is fixed to the main frame 102 and is coupled to the guide rails 106 arranged in the x-axis direction of the equipment. The flux mask unit 130 is connected to the first mask drive means 136 And reciprocates horizontally along the guide rails 106. [

The ball mask unit 140 includes a ball mask 142 having a plurality of mask holes corresponding to the bumping area of the wafer and a ball mask frame 141 for supporting the rim of the ball mask 142. The ball mask frame 141 has a plurality of alignment holes 144 into which the alignment protrusions 122 of the alignment table 120 are inserted, respectively. The ball mask frame 141 may be provided with a second squeegeeing end 162 for moving a brush (see 192 in FIG. 8) at an upper portion of the ball mask 142. The second squeegee end 162 may be installed separately from the ball mask frame 141.

The lower end of the ball mask unit 140 is also coupled to the guide rails 106 and the ball mask unit 140 is horizontally reciprocated along the guide rails 106 by the second mask drive means 146.

A stencil may be used for the flux mask 132 and / or the ball mask 142, or a metal plate having a plurality of mask holes may be used. 3 illustrates a pattern of a mask hole formed in the flux mask 132 or the ball mask 142. Each rectangular unit corresponds to each die of the wafer and corresponds to a bumping region of the wafer A plurality of mask holes are formed.

In the embodiment of the present invention, it is described that the alignment holes 134 and 144 are formed in the flux mask frame 131 and the ball mask frame 141, respectively, and the alignment protrusion 122 protruded upwardly from the alignment table 120 But it could be the opposite. That is, the flux mask frame 131 and the ball mask frame 141 may have a plurality of alignment protrusions protruded downward and a plurality of alignment holes corresponding to the alignment protrusions may be formed on the alignment table 120, respectively.

The vision cameras 170a and 170b are used to acquire the position value of the wafer w placed on the chuck 112 or obtain the position value of the flux mask 132 and the ball mask 142, And serves to check the alignment state of the flux mask 132 or the ball mask 142 in a state where the flux mask 132 or the ball mask 142 is placed. Or may be used to determine whether or not a defect has occurred after the bumping process. In the embodiment of the present invention, two vision cameras 170a and 170b are used. Thereby obtaining a position value for at least two points of the wafer (w), the flux mask (132), and the ball mask (142), thereby enabling more accurate alignment.

The images photographed by the first and second vision cameras 170a and 170b are displayed through the first and second monitors 180a and 180b so that the operator can confirm the alignment state of the wafer w and the like .

The wafer bumping apparatus 100 according to the embodiment of the present invention may have a height that can monitor the height error of the wafer 112 or the masks 132 and 142 with respect to the reference height in addition to the vision cameras 170a and 170b Detection means (e. G., Laser probes, etc.). Also, it is possible to separately include an inspection means capable of measuring the height or position error of the solder ball after the bumping process is completed.

Hereinafter, a wafer bumping method according to an embodiment of the present invention will be described with reference to the flowcharts of FIGS. 4A to 4N and FIGS. 1 and 2. FIG.

Before the start of the process, the alignment table 120 must be positioned below the horizontal movement plane of the flux mask 132 and the ball mask 142, and the chuck 112 must be in a lowered state with respect to the alignment table 120 do. (See FIG. 4A)

In this state, the wafer w on which the circuit pattern is formed is placed on the chuck 112 using a wafer transfer robot or manually. At this time, the wafer W must be positioned so that the bumping area is exposed upward.

The position of the wafer W is obtained by using the first and second vision cameras 170a and 170b and the chuck driving part 114 is operated in the presence of an error in comparison with the reference position to determine the position of the wafer w Adjust.

5, a reference die A for obtaining a position value is provided on each side of the wafer w, and each reference die A is provided with first, A recognition mark that can be confirmed by the second vision cameras 170a and 170b is displayed.

In the embodiment of the present invention, the edible bore 12, which is a position formed at a specific position (e.g., the lower right corner) of each reference die A, is used as a recognition mark. Accordingly, when the first and second vision cameras 170a and 170b acquire the positional values of the edible bolts 12 at respective positions, it is possible to confirm the positional error of the wafer w with respect to the reference value.

In the embodiment of the present invention, the position detecting bolt 12 is formed into an octagon so as to be distinguished from the remaining bolts 11, but the shape is not limited thereto. The borings 11 and 12 mean a pattern formed in the bumping region of the wafer w. (See FIG. 4B)

After adjusting the position of the wafer W in the above process, the first mask driving means 136 is operated to position the flux mask 132 on the upper portion of the chuck 112, that is, above the wafer W. (See FIG. 4C)

Then, the first vertical driving means 126 is operated to raise the chuck 112 and the alignment table 120 at the same time. When the alignment table 120 is lifted up, the alignment protrusions 122 are inserted into the alignment holes 134 of the flux mask frame 131, The mask 132 is fixed to the alignment table 120. (See Figure 4d)

Next, the second vertical driving means 118 of the chuck driving unit 114 is operated to lift the chuck 112. The chuck 112 rises until the gap between the wafer W and the flux mask 132 reaches a set interval and thus controls the operation of the second vertical driving means 118 using the interval measuring means described above . (See FIG. 4E)

In this embodiment of the present invention, the first and second vision cameras 170a and 170b may be disposed in the vicinity of the wafer (w) and the flux mask 132, To confirm the alignment status again.

Since the respective borings 11 and 12 of the wafer W are positioned below the respective mask holes of the flux mask 132, the first and second vision cameras 170a and 170b, The alignment state of the wafer W and the flux mask 132 can be confirmed by checking whether or not the center of the mask (12 in FIG. 6) and the center of the mask hole of the flux mask 132 located at the upper portion coincide with each other.

Alternatively, the alignment state of the mask hole of the flux mask 132 and the wafer (w) borland below the mask hole may be photographed by the first and second vision cameras 170a and 170b, and based on the images displayed on the monitors 180a and 180b, Can visually confirm the alignment state or automatically check the alignment state in comparison with the previously registered image and the photographed image.

If there is no misalignment as a result of the check, the next process is performed. If there is an alignment error, the chuck driving unit 114 is operated to adjust the position of the wafer w again. (See FIG. 4F)

If it is determined that the wafer W and the flux mask 132 are correctly aligned in the above process, the flux F is squeezed onto the flux mask 132 using the first squeegee stage 161. 7, when the blade 191 is moved above the flux mask 132, the flux F passing through the mask hole of the flux mask 132 is transferred to the respective bumping areas of the wafer w . (See Fig. 4G)

When flux squeezing is complete. The second vertical driving means 118 is operated to lower the chuck 112 on which the wafer w is placed. In order to prevent such a phenomenon, the flux spraying means 198 may be attached to the flux mask 132 in order to prevent the flux mask 132 from being deformed or a positional error occurring due to the flux applied to the wafer (w) And the chuck 112 on which the wafer W is placed may be lowered while jetting air. When the wafer W is lowered and air is jetted from the upper portion of the flux mask 132, the flux dipped in the wafer w due to the air pressure is buried in the flux mask 132, and the shape is deformed or a position error occurs Can be prevented. (See FIG. 4H)

After the wafer W is lowered by a predetermined distance, the first vertical driving means 126 is operated to lower the alignment table 120 and the chuck 112 together. (See Fig. 4i)

The first mask driving means 136 is operated to move the flux mask 132 and the air jetting means 198 to the standby position and the second mask driving means 146 is operated to move the ball mask 142 to the chuck 112). (See Fig. 4J)

The first vertical driving means 126 is operated to raise the alignment table 120 to fix the ball mask frame 141 and operate the second vertical driving means 118 to lift the chuck 112. (See Figure 4k)

The first and second vision cameras 170a and 170b may be used to move the wafer w and the ball mask 132 in the same manner as the flux process, It is preferable to confirm the alignment state of the wafer 132 again and adjust the position of the wafer w. (See FIG. 4I)

If it is determined that the wafer W and the ball mask 142 are correctly aligned in the above process, the solder ball B is poured and scoured onto the ball mask 142 using the second squeegee stage 162. 8, when the brush 192 is moved on the top of the ball mask 142, the solder ball B passing through the mask hole of the ball mask 142 contacts the respective bump areas of the wafer w Is adhered to the previously applied flux (F). Meanwhile, the solder ball squeegee process may be performed automatically by pouring the solder ball B onto the ball mask 142, using a brush, or manually by a worker. (See Figure 4m)

When the ball quiz is completed. The aligning table 120 and the chuck 112 are lowered together by operating the first vertical driving means 126 and the second mask driving means 146 is operated to move the ball mask 142 to the standby position. (See Figure 4n)

The solder balls B are adhered to the respective bumping areas of the wafer W by the flux F as described above. However, since this state is a bonding state, a reflow step for fusing the solder ball B to the wafer W in a high-temperature atmosphere must be performed.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course, fall within the scope of the present invention.

100: Wafer bumping device 102: Main frame
106: guide rail 110; Chuck unit
112: chuck 114: chuck driving part
118: second vertical driving means 120: alignment table
122: alignment protrusion 124: lift table
126: first vertical driving means 130: flux mask unit
131: flux mask frame 132: flux mask
134: Align hole 140: Ball mask unit
141; Ball mask frame 142: ball mask
144: alignment hole 161: first squeegee stage
162: Second squeegee stage 170a, 170b: First and second vision cameras
180a, 180b: first and second monitors 191: blade
192: Brush 198: Air injection means

Claims (6)

1. A wafer bumping method for attaching a solder ball to a wafer comprising a plurality of borings and an edible bore having a position different from the rest of the bores,
Obtaining a position value of the wafer placed on the chuck with a vision camera, and adjusting the position of the wafer using a chuck driving unit when there is a position error;
Moving a flux mask over the chuck;
Confirming the alignment state of the position-recognizing bolt and the mask hole formed in the flux mask using the vision camera, and adjusting the position of the wafer using the chuck driver when there is an alignment error;
Performing a flux squeezing process on top of the flux mask;
Moving the ball mask to an upper portion of the chuck;
Confirming the alignment state of the position-recognizing bolt and the mask hole formed in the ball mask using the vision camera, and adjusting the position of the wafer using the chuck driving unit when there is an alignment error;
Performing a ball quenching process at an upper portion of the ball mask
≪ / RTI > The method of claim 1, Wherein the chuck is lifted and lowered through a penetration formed in a central portion of the alignment table, and a first alignment means is provided at a peripheral portion of the alignment table,
After the step of moving the flux mask to the top of the chuck, raising the alignment table and coupling the first alignment means with second alignment means formed in the flux mask frame supporting the flux mask, And fixing to the table,
After the step of moving the ball mask to an upper portion of the chuck, raising the alignment table to engage the first alignment means with third alignment means formed on the ball mask frame supporting the ball mask, ≪ / RTI > characterized in that it comprises fixing to an alignment table delete The method according to claim 1,
Wherein after the step of performing flux squeezing at the top of the flux mask, the chuck on which the wafer is placed is lowered while spraying air at the top of the flux mask A chuck unit having a chuck on which the wafer is placed and a chuck driving part for moving the chuck;
An aligning table having a penetrating portion on which the chuck moves up and a first aligning means formed on the periphery of the penetrating portion;
A guide rail disposed horizontally around the chuck;
A flux mask frame including a flux mask and second alignment means for supporting the rim of the flux mask and engaging with the first alignment means; and first mask drive means for moving the flux mask frame along the guide rail A flux mask unit;
A ball mask frame having a ball mask and a third aligning means for supporting the rim of the ball mask and engaging with the first aligning means and a second mask driving means for moving the ball mask frame along the guide rails A ball mask unit;
A plurality of vision cameras installed on the chuck to acquire position values of a plurality of reference marks formed on the wafer,
A wafer bumping device 6. The method of claim 5,
An elevating table provided apart from the alignment table;
A first vertical driving means for lifting the elevating table;
And a second vertical driving means connected to the lifting table for lifting the chuck driving unit,
An air injection means for injecting air at an upper portion of the flux mask
Further comprising a wafer bumping device

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