JP2004111946A - Laser dicing equipment and dicing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dicing equipment which is capable of carving two lines efficiently at the same time or a single line twice without causing chipping to a wafer, and to provide a dicing method. <P>SOLUTION: The laser dicing equipment 10 is equipped with a plurality of laser heads 31 which are separately moved in a Y direction perpendicular to an X direction as a processing direction, and the condensing points of laser beams L emitted from the laser heads 31 can be positioned on the same line in the X direction. The dicing method is carried out in such a manner wherein the two laser heads 31 are index-moved from both the ends to center of the wafer W or from the center to both ends of the wafer W or the laser heads 31 are arranged as they are kept separate from each other by a prescribed number of lines and index-moved in the same direction, and two lines are carved in the wafer W throughout its surface. Alternatively, the single line is irradiated twice with the laser beam L emitted from the laser heads 31 separated from each other by a prescribed distance or a prescribed number of lines. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a dicing apparatus and a dicing method for manufacturing chips such as semiconductor devices and electronic components, and more particularly to a dicing apparatus and a dicing method using laser light.

Conventionally, in order to divide a wafer having a semiconductor device or electronic component formed on its surface into individual chips, a dicing apparatus called a dicing blade that cuts the wafer by inserting a grinding groove into the wafer has been used. The dicing blade is obtained by electrodepositing fine diamond abrasive grains with Ni, and an extremely thin one having a thickness of about 30 μm is used.

The dicing blade was rotated at a high speed of 30,000 to 60,000 rpm and cut into the wafer, and the wafer was completely cut (full cut) or incompletely cut (half cut or semi full cut). Half-cut is a method of cutting about half the thickness of the wafer, and semi-full cut is a case where a grinding groove is formed leaving a thickness of about 10 μm.

In order to efficiently perform dicing with this dicing blade, two spindles each having a dicing blade attached to the tip are opposed to the same straight line in the Y direction perpendicular to the X direction when the grinding groove processing direction is the X direction. A dicing apparatus has been proposed in which two lines can be simultaneously processed with the same processing stroke as when a single spindle is used (see, for example, Patent Document 1).

Further, in the dicing apparatus described in Patent Document 1, one of the two spindles can be moved in the X direction with respect to the other spindle, and the two dicing blades are arranged on the same straight line in the X direction. It is configured to be able to.

In the case of grinding with this dicing blade, since the wafer is a highly brittle material, it becomes brittle mode processing, and chipping occurs on the front and back surfaces of the wafer, and this chipping is a factor that degrades the performance of the divided chips. It was. As a means to solve this chipping problem in the dicing process, instead of cutting with a conventional dicing blade, a laser beam having a focused point is incident on the inside of the wafer, and a modified region by multiphoton absorption is formed inside the wafer. Techniques relating to laser processing methods of forming and dividing into individual chips have been proposed (see, for example, Patent Documents 2 to 7).
Japanese Patent Laid-Open No. 10-064853 JP 2002-192367 A JP 2002-192368 A JP 2002-192369 A JP 2002-192370 A JP 2002-192371 A JP 2002-205180 A

However, in the case of the dicing apparatus described in Patent Document 1, when the two spindles are arranged opposite to each other on the same straight line in the Y direction, Since the holding mechanism and cover of the dicing blade interfere with each other, two lines cannot be processed at the same time in the center of the wafer, and the remaining processing must be processed with a single dicing blade. The processing efficiency has been reduced.

In addition, if the remaining part of the machining is moved to a position where the two spindles move relative to each other in the X direction so as not to interfere with each other, and the two lines are to be machined simultaneously, the machining stroke increases. It was not right.

Further, the techniques proposed in the above Patent Documents 2 to 7 are based on the cleaving technique using a laser beam, and the chipping problem is solved. However, there is only one processing head, and each line has one. However, there was a problem that the processing efficiency was poor because it could only be processed.

The present invention has been made in view of such circumstances, and can simultaneously process two lines efficiently, or can perform two processes efficiently on one line, and can perform chipping. An object of the present invention is to provide a dicing apparatus and a dicing method that do not occur.

In order to achieve the above object, the present invention provides a dicing apparatus for dividing a wafer into individual chips, wherein a laser beam is incident from the surface of the wafer to enter the inside of the wafer. In a laser dicing apparatus for forming a modified region, a plurality of laser heads that irradiate the laser beam toward the wafer, and a processing direction relative to the plurality of laser heads mounted on the wafer. And a chuck table that moves in the X direction, and the plurality of laser heads are configured to be independently movable in the Y direction perpendicular to the X direction.

The laser dicing apparatus according to the first aspect of the present invention has a plurality of laser heads, and the plurality of laser heads can move independently in the Y direction, so that a plurality of lines are provided for wafers having various processing pitches. Can be processed at the same time, and the processing efficiency is high.

According to a second aspect of the present invention, in the laser dicing apparatus according to the first aspect, the plurality of laser heads are configured such that the condensing points of the laser beams emitted from the respective laser heads are on the same straight line in the X direction. It is characterized by being arranged.

According to the invention of claim 2, the plurality of laser heads can move independently in the Y direction, and the condensing points of the laser light emitted from each laser head can be arranged on the same straight line in the X direction. Therefore, the laser heads do not interfere with each other, and a plurality of lines can be processed simultaneously even in the central portion of the wafer.

According to a third aspect of the present invention, in the laser dicing apparatus according to the first or second aspect, the plurality of laser heads are provided so as to be independently movable in the Z direction orthogonal to the X direction and the Y direction. It is characterized by having.

According to the invention of claim 3, since the plurality of laser heads can be moved independently in the Z direction, the Z direction positions of the condensing points of the laser beams irradiated from the respective laser heads are set to different positions. Can be set. Therefore, a plurality of modified region layers can be formed inside the wafer within one processing stroke, and even a thick wafer can be easily cleaved.

According to a fourth aspect of the present invention, there is provided a dicing method for dividing a wafer into individual chips using the laser dicing apparatus according to the first to third aspects, wherein the first laser of the plurality of laser heads is used. A head and a second laser head are positioned above both ends in the Y direction of the wafer placed on the chuck table, and the first laser head and the second laser head are placed at a predetermined pitch on the wafer. Indexing and feeding in the direction approaching each other toward the upper center, and moving the chuck table in the X direction relative to the first laser head and the second laser head, the wafer is moved to the laser. It is characterized by dicing.

According to the invention of claim 4, two laser heads are positioned above both ends of the wafer, two lines are processed simultaneously, and the two laser heads are indexed from both ends of the wafer toward the center. Since two lines are processed simultaneously, two lines can be processed simultaneously over the entire surface of the wafer with almost the same processing stroke as when one laser head is used, and the processing efficiency is high.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the first laser head and the second laser head are indexed and fed in a direction approaching each other to the vicinity of the center of the wafer, and the center of the wafer is measured. In the vicinity of the portion, the first laser head and the second laser head are indexed and fed in the same direction in the Y direction.

According to the invention of claim 5, the first laser head and the second laser head are indexed and fed in directions approaching each other, and in the vicinity of the center portion of the wafer, the interference between both heads is avoided, and both heads are set to Y. Since indexing and feeding are performed in the same direction, even a wafer having a small feeding pitch can be diced efficiently.

A sixth aspect of the present invention is a dicing method for dividing a wafer into individual chips using the laser dicing apparatus according to any one of the first to third aspects, wherein the first laser head of the plurality of laser heads and A second laser head is positioned above the central portion of the wafer placed on the chuck table, and the first laser head and the second laser head are positioned at a predetermined pitch from above the central portion of the wafer. Indexing and feeding in directions away from each other toward the upper end of each direction, and moving the chuck table in the X direction relative to the first laser head and the second laser head. Is characterized by laser dicing.

According to the invention of claim 6, the two laser heads are positioned above the central portion of the wafer, the two lines are processed simultaneously, and the two laser heads are indexed from the central portion upward toward the upper ends. Since the two lines are fed and processed at the same time, two lines can be processed simultaneously over the entire surface of the wafer with almost the same processing stroke as when one laser head is used, and the processing efficiency is high.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the first laser head and the second laser head are indexed and fed in the same direction in the Y direction in the vicinity of the center of the wafer, and then the The first laser head and the second laser head are indexed and fed in directions away from each other.

According to the invention of claim 7, in the vicinity of the center portion of the wafer, the interference between the first laser head and the second laser head is avoided, the both heads are indexed and fed in the same direction in the Y direction, and then both heads are mutually connected. Since indexing and feeding are performed in the direction of separation, dicing can be efficiently performed even for a wafer having a small feeding pitch.

The invention described in claim 8 is a dicing method for dividing a wafer into individual chips using the laser dicing apparatus according to any one of claims 1 to 3, wherein the first laser head of the plurality of laser heads and Positioning the second laser head at a position separated by one pitch or a plurality of pitches in the Y direction, indexing and feeding the first laser head and the second laser head at a predetermined pitch in the same direction of the Y direction, The wafer is laser-diced by moving the chuck table in the X direction relative to the first laser head and the second laser head.

According to a ninth aspect of the present invention, in the eighth aspect of the invention, the first laser head is positioned above the end in the Y direction of the wafer placed on the chuck table, and the second laser head A laser head is positioned above the center of the wafer, and the first laser head and the second laser head are indexed and fed at a predetermined pitch in the same direction in the Y direction.

According to the inventions of claims 8 and 9, two lines are simultaneously processed by two laser heads positioned at a predetermined pitch in the Y direction, and the two laser heads are indexed in the same direction. Since the two lines are fed and processed at the same time, the two lines can be processed simultaneously over the entire surface of the wafer with a constant processing stroke, and no complicated control is required. This is particularly effective for square wafers.

According to a tenth aspect of the present invention, there is provided a dicing method for dividing a wafer into individual chips using the laser dicing apparatus according to the first to third aspects, wherein the first laser head of the plurality of laser heads is used. On the other hand, in the second laser head of the plurality of laser heads, the irradiation point of the laser light emitted from each laser head is located at a position separated by one pitch or a plurality of pitches rearward in the feed direction in the Y direction. The first laser head and the second laser head are indexed and fed one pitch at a time in the same direction of the Y direction, and the chuck table is moved with respect to the first laser head and the second laser head. By moving relatively in the X direction, the laser beam from the first laser head of the wafer is irradiated. The lines, by irradiating a laser beam from the second laser head 1 pitch or more pitch lag, is characterized in that laser dicing the wafer.

An eleventh aspect of the present invention is a dicing method for dividing a wafer into individual chips using the laser dicing apparatus according to the first to third aspects, wherein the first laser of the plurality of laser heads is used. The head and the second laser head are positioned such that the irradiation points of the laser beams emitted from the respective laser heads are located at a predetermined distance apart on the same straight line in the X direction, Indexing and feeding the second laser head at a predetermined pitch in the same direction of the Y direction, and moving the chuck table in the X direction relative to the first laser head and the second laser head The second laser is delayed by a predetermined distance to the line irradiated with the laser light from the first laser head of the wafer. By irradiating a laser beam from the head, it is characterized in that laser dicing the wafer.

According to the invention of claim 10 or claim 11, the second laser is delayed by one pitch or a plurality of pitches or by a predetermined distance delay on the line irradiated with the laser light from the first laser head of the wafer. Since the laser beam from the head is irradiated, a modified layer is formed inside the wafer with the laser beam from the first laser head, and the line is cleaved with the laser beam from the second laser head. In addition, it is possible to efficiently perform a process of forming two modified layers.

A twelfth aspect of the invention is characterized in that, in the tenth aspect of the invention, the first laser head and the second laser head irradiate the wafer with different types of laser beams. .

According to the twelfth aspect of the present invention, since two types of laser light can be efficiently irradiated to one line, a wide variety of processing can be dealt with.

A thirteenth aspect of the present invention is the laser dicing method according to any one of the tenth, eleventh and twelfth aspects of the present invention, wherein the position of the condensing point of the laser light irradiated from the plurality of laser heads is the Z It is characterized by different directions.

According to the invention of claim 13, since the Z-direction positions of the condensing points of the laser beams irradiated from the plurality of laser heads are different from each other, a plurality of stages of reforming are performed inside the wafer within one processing stroke. A region layer can be formed, and even a thick wafer can be easily cleaved.

As described above, the laser dicing apparatus of the present invention has a plurality of laser heads, and the plurality of laser heads can move independently in the Y direction perpendicular to the processing direction, so that the wafer having various processing pitches can be used. On the other hand, a plurality of lines can be processed simultaneously, and the processing efficiency is high.

In addition, since the plurality of laser heads can move independently in the Y direction, and the condensing points of the laser light emitted from the respective laser heads can be arranged on the same straight line in the X direction as the processing direction, Even if the distance between the dicing lines is extremely small, the laser heads do not interfere with each other, and a plurality of lines can be processed simultaneously even in the central portion of the wafer.

Furthermore, since the plurality of laser heads can move independently in the Z direction, the Z direction position of the condensing point of the laser light emitted from each laser head can be set to a different position. Therefore, a plurality of modified region layers can be formed inside the wafer within one processing stroke, and even a thick wafer can be easily cleaved.

In the dicing method of the present invention, the two laser heads are positioned above both ends of the wafer and indexed and fed from both ends of the wafer toward the center, or the two laser heads are positioned above the center of the wafer. The two laser heads are positioned at one or more pitches in the Y direction, and the two laser heads are in the Y direction. Since two dicing lines are processed at the same pitch in the same direction, the two lines are simultaneously processed over the entire surface of the wafer with almost the same processing stroke as when one laser head is used. And the processing efficiency is remarkably improved.

Also, two laser heads are positioned at a position separated by one pitch or a plurality of pitches in the Y direction and indexed and fed by one pitch in the same direction, or the two laser heads are separated by a predetermined distance on the same straight line in the X direction. Thus, the wafer is indexed and fed at a predetermined pitch, and one line is delayed by one pitch or a plurality of pitches or delayed by a predetermined distance, so that the wafer can be surely diced.

Hereinafter, preferred embodiments of a laser dicing apparatus and a dicing method according to the present invention will be described in detail with reference to the accompanying drawings. In each figure, the same number or symbol is attached to the same member.

FIG. 1 is a perspective view showing an internal configuration of a dicing apparatus according to the present invention. The dicing apparatus 10 includes a chuck table 12 that sucks and places a wafer on a main body base (not shown) and is moved in the Xθ direction by a driving mechanism (not shown). The chuck table 12 includes an X table 12A, a θ table 12B, and a suction table 12C. The suction table 12C is rotated by θ while a wafer is sucked thereon, and is processed and fed in the X direction.

A Y guide base 41 is provided above the chuck table 12. The Y guide base 41 is guided by Y guide rails 42, 42 and is moved in the Y direction by a drive mechanism (not shown). Is provided. Each Y table 43 is provided with two Z tables 52, 52 that are guided by Z guide rails 51, 51 and moved in the Z direction by a drive mechanism (not shown).

A laser head 31 is attached to each Z table 52 via a holder 32, and the two laser heads 31 and 31 are independently moved in the Z direction and independently indexed in the Y direction. It is supposed to be sent.

In addition, the dicing apparatus 10 includes a wafer cassette elevator (not shown), a wafer transfer means, an operation plate, a television monitor, an indicator lamp, a controller 40, and the like.

The wafer cassette elevator moves the cassette containing the wafer up and down and positions it at the transfer position. The conveying means conveys the wafer between the cassette and the chuck table 12.

A switch and a display device for operating each part of the dicing device 10 are attached to the operation plate. The television monitor displays a wafer image captured by a CCD camera (not shown), displays program contents, various messages, and the like. The indicator lamp displays an operation status such as processing end, emergency stop, etc. during processing of the dicing apparatus 10. The controller housed inside the dicing apparatus main body includes a CPU, a memory, an input / output circuit unit, and the like, and controls the operation of each unit of the dicing apparatus 10.

FIG. 2 is a side view for explaining the configuration of the laser head 31. The laser head 31 is positioned above the wafer W so as to irradiate the wafer W placed on the chuck table 12 provided on the base 11 of the dicing apparatus 10 with the laser light L.

The laser head 31 includes a laser oscillator 31A, a collimating lens 31B, a mirror 31C, a condensation lens 31D, and the like. As shown in FIG. 2, the laser light L oscillated from the laser oscillator 31A is parallel to the horizontal direction by the collimating lens 31B. The reflected light is reflected by the mirror 31C in the vertical direction and condensed by the condensation lens 31D.

When the condensing point of the laser beam L is set inside the thickness direction of the wafer W placed on the chuck table 12, the energy of the laser beam L transmitted through the surface of the wafer W is concentrated at the condensing point, and the inside of the wafer In the vicinity of the light condensing point, a modified region such as a crack region due to multiphoton absorption, a melting region, a refractive index change region, or the like is formed.

Further, the laser head 31 has a tilting mechanism (not shown) so that the laser beam L can be irradiated at an arbitrary angle with respect to the wafer surface.

FIG. 3 is a conceptual diagram illustrating a modified region formed in the vicinity of a light condensing point inside the wafer. FIG. 3A shows a state in which the modified region P is formed at the condensing point of the laser light L incident inside the wafer W, and FIG. 3B shows that the wafer W is moved in the horizontal direction and modified. This represents a state in which the quality regions P are formed side by side. In this state, the wafer W is naturally cleaved starting from the reforming region P, or is cleaved starting from the reforming region P by applying a slight external force. In this case, the wafer W is easily divided into chips without causing chipping on the front and back surfaces.

When the wafer W is diced by the laser dicing apparatus 10 of the present invention, as shown in FIG. 4, the wafer W is mounted on a dicing frame F via a dicing tape T having an adhesive on one side, and a dicing process is performed. The inside is conveyed in this state. As described above, since the wafer W has the dicing tape T attached to the back surface, even if the wafer W is divided into individual chips, the wafer W does not fall apart one by one.

Next, the operation of the laser dicing apparatus 10 according to the present invention will be described. In dicing, the wafer W initially placed on the chuck table 12 is photographed on the surface circuit pattern and alignment mark by a CCD camera (not shown), and is aligned by an alignment means having an image processing means.

Next, the two laser heads 31, 31 are sent by the Y tables 43, 43 and positioned on the dicing line of the wafer W. Here, the laser light L, L is irradiated onto the wafer W from the laser heads 31, 31 adjusted in height in the Z direction by the Z tables 52, 52 so that the condensing point is located inside the wafer W. The wafer W is processed and fed in the X direction by the X table 12A. As a result, a modified region is formed inside the wafer of the two dicing lines.

Next, the two laser heads 31 and 31 are indexed and sent to the next dicing line by the Y tables 43 and 43, and the wafer W is processed and fed in the X direction under the laser light L and L irradiation, and the next two In the dicing line, a modified region is formed inside the wafer. When the laser irradiation to all the dicing lines is completed, the wafer W is rotated by 90 ° by the θ table 12B, and the dicing line perpendicular to the previous dicing line is irradiated with the laser light L. As for the dicing line on this side, the X-direction processing feed of the wafer W and the Y-direction indexing feed of the laser heads 31 and 31 are repeated, and when the laser irradiation of all the lines is completed, the laser dicing of one wafer W is completed.

Next, the dicing method according to the present invention will be described. FIG. 5 is a side view for explaining the first embodiment. FIG. 8 is a conceptual plan view thereof. In the dicing method of the present invention, as shown in FIGS. 5 and 8, first, the laser beam irradiation point L1 of the first laser head 31-1 and the laser beam irradiation point L2 of the second laser head 31-2 are the wafer. Two dicing lines at both ends of the wafer W are laser-diced simultaneously by the X-direction processing feed of the chuck table 12 positioned on dicing lines (S1, S22 in FIG. 8) at both ends of W.

Next, the first laser head 31-1 and the second laser head 31-2 are indexed and fed in a direction approaching each other, and the laser light irradiation point L1 is positioned at S2 and the laser light irradiation point L2 is positioned at S21. The next two dicing lines of the wafer W are sequentially laser-diced simultaneously by the X-direction processing feed of the chuck table 12. In this way, laser dicing is performed on all dicing lines in this direction (hereinafter referred to as CH-2).

The X-direction machining feed stroke at this time is the shortest at the end of the wafer W and becomes longer as it goes toward the center of the wafer W. That is, the stroke is set along the outer shape of the wafer W by the stroke of the wafer W plus alpha. The plus alpha is a value in consideration of the center distance of the tip portions of the first laser head 31-1 and the second laser head 31-2 and the stroke margin.

When the CH-2 laser dicing is completed, the wafer W is rotated by 90 °, and the process moves to a line in a direction perpendicular to the CH-2 dicing line (hereinafter referred to as CH-1). At the end of laser dicing of CH-2, the first laser head 31-1 and the second laser head 31-2 are on the same line at the center of the wafer W, as shown in the plan view of FIG. As shown in FIG. 9, since it is on the line next to the center part, when starting CH-1, it starts from the line next to the center part and away from each other toward both ends of the wafer W. It is indexed. In this way, all the dicing lines of the wafer W are laser-diced.

The first direction of dicing is referred to as CH-2. In the alignment of the wafer before dicing, CH-1 is first aligned, and then CH-2 is rotated by 90 °. It is because it is diced from.

At the start of CH-1, the first laser head 31-1 and the second laser head 31-2 return to both ends of the wafer W shown in FIGS. 5 and 8, and index from there toward the center. May be sent.

Further, in the laser dicing of CH-2, the first laser head 31-1 and the second laser head 31-2 are indexed and fed in directions approaching each other, and interfere with each other when approaching the center of the wafer W. In such a case, the index is sent out as shown in the conceptual diagram of FIG.

That is, the laser beam irradiation point L1 of the first laser head 31-1 and the laser beam irradiation point L2 of the second laser head 31-2 are first positioned on the dicing lines S1 and S22 at both ends of the wafer W, The laser beam irradiation point L1 is indexed and sent to the dicing line S8, and the laser beam irradiation point L2 is sequentially indexed and sent to the dicing line S15 (step 1 in FIG. 10).

Next, the laser beam irradiation point L1 is sent to the dicing line S9, and the laser beam irradiation point L2 is sent to the dicing line S12. From there, the laser beam irradiation point L1 is indexed and sent to the dicing lines S10 and S11, and the laser beam irradiation point L2 is indexed and sent to the dicing lines S13 and S14 (step 2 in FIG. 10), and all the lines are diced. And rotated to CH-1.

In CH-1, as shown in FIG. 11, the laser beam irradiation point L1 is positioned on the dicing line S11 and the laser beam irradiation point L2 is positioned on the dicing line S14, and from there both in the same direction, that is, the laser beam irradiation point L1. Is indexed to the dicing lines S10 and S9, and the laser beam irradiation point L2 is indexed and sent to the dicing lines S13 and S12 (step 1 in FIG. 11).

Next, the laser beam irradiation point L1 is sent to the dicing line S8, the laser beam irradiation point L2 is sent to the dicing line S15, and from there to the dicing line S1 and the dicing line S22 at both ends of the wafer W are indexed in directions away from each other. It is fed (step 2 in FIG. 11) and all lines are diced.

By indexing and feeding the laser beam irradiation point L1 of the first laser head 31-1 and the laser beam irradiation point L2 of the second laser head 31-2 as shown in FIG. 10 and FIG. Even in the case where the first laser head 31-1 and the second laser head 31-2 interfere with each other at the center, dicing can be efficiently performed by two lines.

According to the first embodiment described above, since the widths of the tip portions of the laser head 31-1 and the second laser head 31-2 are narrow, the wafer W is laser-diced by one laser head 31. Since every two dicing lines are processed simultaneously with almost the same X-direction machining stroke, the dicing time is almost halved.

Next, a second embodiment of the dicing method of the present invention will be described. First, as shown in the plan view of FIG. 6, the first laser head 31-1 and the second laser head 31-2 are moved to the center of the wafer W and positioned on the two dicing lines at the center. It is done.

From this state, the machining feed in the X direction and the index feed in the direction in which the first laser head 31-1 and the second laser head 31-2 move away from each other toward the both ends of the wafer W are repeated. -2 laser dicing is performed. At the end of CH-2 dicing, the first laser head 31-1 and the second laser head 31-2 are positioned at both ends of the wafer W as shown in FIG. Further, the CH-1 dicing is performed while the first laser head 31-1 and the second laser head 31-2 are indexed and fed from both ends of the wafer W toward the center.

Also in the case of the second embodiment, the X-direction machining feed stroke is shortest at the end of the wafer W and becomes longer toward the center of the wafer W, and the stroke of the wafer W plus alpha along the outer shape of the wafer W. Set by. Since the widths of the tips of the laser head 31-1 and the second laser head 31-2 are narrow, the wafer W has two X-direction machining strokes that are almost the same as when laser dicing is performed with one laser head 31. Since each dicing line is processed simultaneously, the dicing time is almost halved.

FIG. 7 is a side view showing a third embodiment of the dicing method according to the present invention. FIG. 12 is a conceptual plan view thereof. In the third embodiment, first, in the laser dicing of CH-2, the first laser head 31-1 is positioned on the dicing line in the center of the wafer W, and the second laser head 31-2 is the wafer dicing of the wafer W. Positioned at the end dicing line.

That is, the laser beam irradiation point L1 of the first laser head 31-1 is positioned on the dicing line S12, and the laser beam irradiation point L2 of the second laser head 31-2 is positioned on the dicing line S1.

From here, the first laser head 31-1 and the second laser head 31-2 are indexed and fed in the same direction by a predetermined pitch. That is, the first laser head 31-1 is indexed and fed toward the end portion of the wafer W, and the second laser head 31-2 is indexed and fed toward the center portion of the wafer W. In CH-1 dicing rotated 90 °, the first laser head 31-1 is now indexed and fed toward the center of the wafer W, and the second laser head 31-2 is the end of the wafer W. It is indexed and sent to.

Also in the case of the third embodiment, the widths of the tip portions of the laser head 31-1 and the second laser head 31-2 are narrow, so the wafer W is almost the same as when laser dicing is performed with one laser head 31. Since two dicing lines are simultaneously processed with the same X-direction processing stroke, the dicing time can be almost halved. In the case of the third embodiment, the machining stroke in the X direction is constant at the diameter of the wafer W plus alpha. Further, the first laser head 31-1 and the second laser head 31-2 are indexed in the same direction, and the feed control in the X direction and the Y direction is simplified.

FIG. 13 shows a modification of the above-described third embodiment in which the first laser head 31-1 and the second laser head 31-2 are indexed and fed in the same direction. In this modification, in CH-2, first, the laser beam irradiation point L1 of the first laser head 31-1 is on the dicing line S1, and the laser beam irradiation point L2 of the second laser head 31-2 is first. Positioned on the dicing line S2, the dicing lines S1 and S2 are diced simultaneously.

Next, the first laser head 31-1 and the second laser head 31-2 are divided and sent out by two pitches in the same direction. That is, the laser beam irradiation point L1 of the first laser head 31-1 is positioned on the dicing line S3, and the laser beam irradiation point L2 of the second laser head 31-2 is positioned on the dicing line S4. And S4 are diced simultaneously. In the same manner, dicing lines S21 and S22 are processed.

The same process is performed on the CH-1 side where the wafer W is rotated by 90 °, and all lines are diced.

FIG. 14 shows another modification of the third embodiment. This another modification is a method for dealing with the case where the first laser head 31-1 and the second laser head 31-2 interfere with each other when they are very close to each other.

In this other modification, the laser beam irradiation point L1 of the first laser head 31-1 is on the dicing line S1, and the laser beam irradiation point L2 of the second laser head 31-2 is several pitches away from the dicing line S1. Is positioned on the dicing line (S4 in the case of FIG. 14), from which the laser beam irradiation point L1 is sequentially indexed and fed to the dicing lines S2 and S3, and the laser beam irradiation point L2 is sequentially indexed to the dicing lines S5 and S6. Is done.

Next, the laser beam irradiation points L1 and L2 are respectively sent by a distance twice as long as the distance from each other. That is, in the case of FIG. 14, the laser beam irradiation point L1 is indexed and sent to the dicing line S7, and the laser beam irradiation point L2 is indexed and sent to the dicing line S10.

As described above, the first laser head 31-1 and the second laser head 31-2 are sent twice by one pitch and then once by four pitches, and this operation is repeated.

Thus, even if the first laser head 31-1 and the second laser head 31-2 interfere with each other when indexing and feeding as shown in FIG. 14 are performed, Dicing can be performed efficiently without greatly increasing the X-direction machining feed stroke.

FIG. 15 is a conceptual diagram showing a fourth embodiment of the dicing method according to the present invention. The fourth embodiment shows a processing method in which one dicing line is irradiated twice with the laser light of the first laser head 31-1 and the laser light of the second laser head 31-2. .

As shown in FIG. 15, the laser beam irradiation point L1 of the first laser head 31-1 and the laser beam irradiation point L2 of the second laser head 31-2 are separated by a predetermined distance on the same dicing line S1. The dicing line S1 is first irradiated with the laser beam of the first laser head 31-1 by the left feed of the chuck table 12 in the X direction, and then the laser beam of the second laser head 31-2 is emitted with a predetermined distance delay. Irradiated.

Next, the first laser head 31-1 and the second laser head 31-2 are indexed and fed by one pitch and positioned on the dicing line S <b> 2. -2 is preceded by the laser beam of the first laser head 31-1, and this operation is repeated.

Further, as shown in FIG. 16, the laser beam irradiation point L1 of the first laser head 31-1 and the laser beam irradiation point L2 of the second laser head 31-2 are separated by one pitch or several pitches in the Y direction. Alternatively, the laser beam of the first laser head 31-1 may be irradiated in advance, and the laser beam of the second laser head 31-2 may be irradiated with a delay of one line or several lines.

In the fourth embodiment, the wafer is formed with a modified layer inside W by the first laser beam irradiation, and the modified layer is cleaved from the starting point by the second laser beam irradiation or Efficient processing is possible, for example, when two modified layers are formed inside.

In the case of FIG. 16, the laser light of the first laser head 31-1 and the laser light of the second laser head 31-2 are different types of laser light, and different processing is performed with each laser light. You can also.

For example, in the case of a wafer W having a die attach tape attached to the back surface, the wafer W is diced with the laser beam of the first laser head 31-1, and the wafer W is irradiated with the laser beam of the second laser head 31-2. It can be used for processing such as fusing the die attach tape affixed to the back of the tape.

The perspective view showing the internal structure of the laser dicing apparatus based on this invention Side view showing the configuration of the laser head Conceptual diagram explaining the reformed area formed inside the wafer Perspective view showing wafer mounted on frame The side view showing 1st Embodiment of the dicing method concerning this invention The top view showing 2nd Embodiment of the dicing method concerning this invention. Side view showing the third embodiment of the dicing method according to the present invention. 1 is a conceptual plan view showing a first embodiment of a dicing method according to the present invention. Conceptual plan view 2 representing the first embodiment Conceptual plan view 3 representing the first embodiment 4 is a conceptual plan view showing the first embodiment. Conceptual plan view showing a third embodiment of the dicing method according to the present invention. Conceptual plan view showing a modification of the third embodiment The conceptual top view showing another modification of 3rd Embodiment Conceptual plan view showing a fourth embodiment of the dicing method according to the present invention. Conceptual plan view showing a modification of the fourth embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Laser dicing apparatus, 12 ... Chuck table, 12A ... X table, 12B ... θ table, 12C ... Suction table, 31 ... Laser head, 31A ... Laser oscillator, 31B ... Collimating lens, 31C ... Mirror, 31D ... Condensation lens, 43 ... Y table, 52 ... Z table, F ... frame, L ... laser light, L1, L2 ... laser light irradiation point, P ... modified region, T ... dicing tape, W ... wafer

Claims (13)

A dicing apparatus for dividing a wafer into individual chips, wherein a laser beam is incident from the surface of the wafer to form a modified region inside the wafer.
A plurality of laser heads that irradiate the laser beam toward the wafer;
A chuck table on which the wafer is placed and moved in the X direction which is a processing direction relative to the plurality of laser heads;
The laser dicing apparatus, wherein the plurality of laser heads are configured to be independently movable in a Y direction orthogonal to the X direction. 2. The laser according to claim 1, wherein the plurality of laser heads are provided such that condensing points of laser beams emitted from the respective laser heads can be arranged on the same straight line in the X direction. Dicing equipment. 3. The laser dicing apparatus according to claim 1, wherein the plurality of laser heads are provided so as to be independently movable in a Z direction orthogonal to the X direction and the Y direction. A dicing method for dividing a wafer into individual chips using the laser dicing apparatus according to claim 1,
A first laser head and a second laser head of the plurality of laser heads are positioned above both ends in the Y direction of the wafer placed on the chuck table,
Indexing and feeding the first laser head and the second laser head at a predetermined pitch toward the upper part of the center of the wafer toward each other;
A dicing method, wherein the wafer is laser-diced by moving the chuck table in the X direction relative to the first laser head and the second laser head. The first laser head and the second laser head are indexed and fed in directions approaching each other up to the vicinity of the center of the wafer, and the first laser head and the second laser head near the center of the wafer. The dicing method according to claim 4, wherein indexing and feeding are performed in the same direction in the Y direction. A dicing method for dividing a wafer into individual chips using the laser dicing apparatus according to claim 1,
The first laser head and the second laser head among the plurality of laser heads are positioned above the center portion of the wafer placed on the chuck table,
The first laser head and the second laser head are indexed and fed at a predetermined pitch from the upper part of the wafer toward the upper part of both ends in the Y direction so as to be separated from each other. A dicing method comprising: laser dicing the wafer by moving in the X direction relative to the laser head and the second laser head. Near the center of the wafer, the first laser head and the second laser head are indexed and fed in the same direction in the Y direction, and then the first laser head and the second laser head are separated from each other. The dicing method according to claim 6, wherein indexing is performed in a direction. A dicing method for dividing a wafer into individual chips using the laser dicing apparatus according to claim 1,
Of the plurality of laser heads, the first laser head and the second laser head are positioned at a position separated by one pitch or a plurality of pitches in the Y direction,
Indexing and feeding the first laser head and the second laser head at a predetermined pitch in the same direction of the Y direction,
A dicing method, wherein the wafer is laser-diced by moving the chuck table in the X direction relative to the first laser head and the second laser head. The first laser head is positioned above the Y-direction end of the wafer placed on the chuck table, and the second laser head is positioned above the central portion of the wafer. 9. The dicing method according to claim 8, wherein the head and the second laser head are indexed and fed at a predetermined pitch in the same direction in the Y direction. A dicing method for dividing a wafer into individual chips using the laser dicing apparatus according to claim 1,
The second laser head of the plurality of laser heads is sent to the first laser head of the plurality of laser heads, and the irradiation point of the laser light emitted from each laser head is sent in the Y direction. Positioned to be one pitch or a plurality of pitches away in the rear direction,
Indexing and feeding the first laser head and the second laser head by one pitch in the same direction of the Y direction,
By moving the chuck table in the X direction relative to the first laser head and the second laser head, the wafer is irradiated with the laser beam from the first laser head. A dicing method comprising irradiating a laser beam from the second laser head with a delay of one pitch or a plurality of pitches and laser dicing the wafer. A dicing method for dividing a wafer into individual chips using the laser dicing apparatus according to claim 1,
Of the plurality of laser heads, the first laser head and the second laser head are located at positions where the irradiation points of the laser beams emitted from the respective laser heads are separated by a predetermined distance on the same straight line in the X direction. Positioned as
Indexing and feeding the first laser head and the second laser head by a predetermined pitch in the same direction of the Y direction,
By moving the chuck table in the X direction relative to the first laser head and the second laser head, the wafer is irradiated on the line irradiated with the laser light from the first laser head. A dicing method comprising irradiating a laser beam from the second laser head with a predetermined distance delay and laser dicing the wafer. 11. The dicing method according to claim 10, wherein the first laser head and the second laser head irradiate different types of laser beams to the wafer. 13. The laser dicing method according to claim 10, wherein positions of condensing points of laser beams irradiated from the plurality of laser heads are different from each other in the Z direction.

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