JP2021109183A - Condenser lens unit and laser processing device - Google Patents

Abstract

To provide a condenser lens unit that prevents debris from adhering to a condenser lens, and to provide a laser processing device.SOLUTION: A condenser lens unit includes: a condenser lens for condensing laser light; and a nozzle having a bottomed shape in which a laser passage port through which condensed laser light passes is disposed in the bottom and a suction port for communicating an internal space of the nozzle to the outside is disposed therein other than the bottom. A laser processing device includes: a laser light source for emitting laser light; and an air suction device connected to the suction port outside the nozzle.SELECTED DRAWING: Figure 6

Description

The present invention relates to a condenser lens unit and a laser processing apparatus, and particularly relates to a technique for removing debris generated by laser processing.

Prior to the blade dicing process that divides a wafer on which semiconductor devices and electronic components are formed into individual chips, laser processing is performed to remove various films and metal patterns in advance by irradiating the workpiece with laser light. ..

In this laser processing, processing debris called debris is generated. If the scattered debris adheres to the condenser lens, the transmittance of the condenser lens is lowered, which may cause processing defects or damage to the coating of the condenser lens. In addition, scattered debris may adhere to the wafer surface and remain after cleaning, which may reduce the yield.

In order to prevent debris from adhering to the condenser lens, air is blown from a position about 10 mm away from the condenser lens. However, there is a problem that it is difficult to sufficiently remove debris.

On the other hand, Patent Document 1 and Patent Document 2 disclose a technique for sucking debris and suppressing the scattering of debris.

Japanese Unexamined Patent Publication No. 2014-136239 International Publication No. 2003/0951040

However, even with the techniques described in Patent Document 1 and Patent Document 2, there is a problem that debris scattering is not sufficiently suppressed and debris may adhere to the condenser lens.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a condenser lens unit and a laser processing apparatus for preventing debris from adhering to the condenser lens.

One aspect of the condensing lens unit for achieving the above object is a bottomed shape in which a condensing lens that condenses the laser light and a laser passage port through which the condensed laser light passes are arranged at the bottom. It is a condenser lens unit including a nozzle in which a suction port for communicating the space inside the nozzle and the outside is arranged other than the bottom.

According to this aspect, since the laser passage port is provided at the bottom of the bottomed nozzle, it is possible to reduce the probability that debris generated from the workpiece irradiated with the laser beam is scattered on the condenser lens. In addition, since the air inside the nozzle can be sucked from the suction port, the flow velocity of the air between the workpiece and the bottom of the nozzle is increased, and debris is appropriately sucked from the suction port through the laser passage port. can do. Therefore, it is possible to prevent debris from adhering to the condenser lens.

A condenser lens holder for storing a condenser lens in an internal space, the condenser lens holder is provided with a condenser lens holder in which the space inside the condenser lens holder communicates with the space inside the nozzle, and the condenser lens holder is a condenser lens holder. It is preferable that a supply port for supplying air for cooling the lens is provided. As a result, the condenser lens can be cooled by the air from the supply port. In addition, it is possible to suppress debris scattered on the condenser lens and prevent debris from adhering to the condenser lens.

It is preferable to provide a condenser lens protective plate which is arranged between the condenser lens and the laser passage port and allows the condensed laser light to pass therethrough. Even if the debris is scattered on the condenser lens side, it is possible to prevent the debris from adhering to the condenser lens by blocking the debris with the condenser lens protective plate.

One aspect of the laser processing device for achieving the above object is a laser light source that emits laser light, a condenser lens that concentrates the laser light, and a laser passage port through which the focused laser light passes. A bottomed-shaped nozzle arranged in a laser, a nozzle in which a suction port that communicates the space inside the nozzle and the outside is arranged outside the bottom, and an air suction device connected to the suction port outside the nozzle. It is a laser processing apparatus provided with.

According to this aspect, since the laser passage port is provided at the bottom of the bottomed nozzle, the probability that debris is scattered on the condenser lens can be reduced. In addition, by sucking the internal air from the suction port with the air suction device, the flow velocity of the air between the workpiece and the bottom of the nozzle can be increased, so debris from the suction port via the laser passage port. Can be properly sucked. Therefore, it is possible to prevent debris from adhering to the condenser lens.

A condenser lens holder for storing a condenser lens in an internal space, the condenser lens holder is provided with a condenser lens holder in which the space inside the condenser lens holder communicates with the space inside the nozzle, and the condenser lens holder is a condenser lens holder. It is preferable that a supply port for supplying air for cooling the lens is arranged, and further, an air supply device connected to the supply port outside the condenser lens holder is provided. The condenser lens can be cooled by supplying air from the supply port toward the condenser lens inside by the air supply device. In addition, debris scattered on the condenser lens can be suppressed, and debris can be prevented from adhering to the condenser lens.

It is preferable to provide a control device that controls the amount of air sucked by the air suction device to a value larger than the amount of air supplied by the air supply device. By making the suction amount of air relatively larger than the supply amount, debris can be appropriately sucked from the suction port through the laser passage port.

It is preferable to provide a condenser lens protective plate which is arranged between the condenser lens and the laser passage port and allows the condensed laser light to pass therethrough. Even if the debris is scattered on the condenser lens side, it is possible to prevent the debris from adhering to the condenser lens by blocking the debris with the condenser lens protective plate.

According to the present invention, it is possible to prevent debris from adhering to the condenser lens.

FIG. 1 is a block diagram showing a configuration of a laser processing apparatus. FIG. 2 is a perspective view of the condenser lens unit as viewed from the upper surface side. FIG. 3 is a perspective view of the condenser lens unit as viewed from the lower surface side. FIG. 4 is an exploded perspective view of the condenser lens unit as viewed from the upper surface side. FIG. 5 is an exploded perspective view of the condenser lens unit as viewed from the lower surface side. FIG. 6 is a diagram for explaining the operation of the laser processing apparatus. FIG. 7 is a bottom view of the condenser lens unit according to the modified example.

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

<Laser processing equipment>
FIG. 1 is a block diagram showing a configuration of a laser processing apparatus 10. The laser processing apparatus 10 is a wafer processing apparatus that performs laser processing along a scheduled division line of a wafer W, which is a workpiece on which a laminated film including a metal film is formed on the surface. The laser processing device 10 includes a laser source 12, a safety shutter 14, a condenser lens 16, a dust collector 18, an air supply device 50, an air suction device 52, and a control device 54.

The laser source 12 is a laser light source including a laser oscillator (not shown) that oscillates a laser beam under the control of a control device 54. The laser source 12 emits the laser beam L oscillated by the laser oscillator.

The safety shutter 14 includes a light-shielding member capable of blocking laser light. The safety shutter 14 is in a blocking state in which a light-shielding member is inserted into the optical path of the laser light L emitted from the laser source 12 to block the laser light, and the light-shielding member is retracted from the optical path of the laser light L to pass the laser light L. It has a passing state. The safety shutter 14 is controlled by the control device 54 in either a shutoff state or a passing state.

The condensing lens 16 includes a condensing optical system (not shown) that condenses laser light. The condensing lens 16 condenses the laser beam L emitted from the laser source 12 and passing through the safety shutter 14 onto the wafer W to be processed.

The dust collecting unit 18 collects debris generated by irradiating the wafer W with the laser beam L collected by the collecting lens 16. The condensing lens unit 20 is composed of the condensing lens 16 and the dust collecting unit 18. The air supply device 50 and the air suction device 52 are connected to the dust collector 18.

The air supply device 50 is a blower such as a fan or a blower that supplies air with a predetermined supply amount. The air suction device 52 is a vacuum pump that sucks air with a predetermined suction amount.

The control device 54 is realized by a general-purpose computer such as a personal computer or a microcomputer. The control device 54 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, and the like. In the control device 54, various programs such as a control program stored in the ROM are expanded in the RAM, and the programs expanded in the RAM are executed by the CPU to realize the functions of each part in the laser processing apparatus 10. , Various arithmetic processing and control processing are executed via the input / output interface. The control device 54 controls to irradiate the laser beam L along the scheduled division line of the wafer W. Further, the control device 54 controls the supply of air by the air supply device 50 and the suction of air by the air suction device 52.

<Structure of condenser lens unit>
FIG. 2 is a perspective view of the condenser lens unit 20 as viewed from the upper surface side, and FIG. 3 is a perspective view of the condenser lens unit 20 as viewed from the lower surface side. Further, FIG. 4 is an exploded perspective view of the condenser lens unit 20 viewed from the upper surface side, and FIG. 5 is an exploded perspective view of the condenser lens unit 20 viewed from the lower surface side.

The condenser lens unit 20 mainly includes a condenser lens 16, an adapter 22, an upper plate 24, a condenser lens holder 28, a condenser lens protection plate support member 32, a condenser lens protection plate 34, and a nozzle 36. And are configured with.

The adapter 22 is a member for optically connecting a laser generator (not shown) including a laser source 12 and a safety shutter 14 (see FIG. 1) and a condenser lens unit 20. The adapter 22 has a circular through hole 22A in the center.

The upper plate 24 is a plate-shaped member having a circular through hole 24A in the central portion. The through hole 22A and the through hole 24A serve as an optical path for the laser light for incident the laser light generated by the laser generator on the condenser lens 16.

The condenser lens 16 has a cylindrical housing having a predetermined diameter. The condenser lens 16 includes a cylindrical connecting portion 16A extending upward (Z direction) on the upper surface. The connection portion 16A of the condenser lens 16 fits into the through hole 22A of the adapter 22 via the through hole 24A of the upper plate 24.

The condenser lens holder 28 has a cylindrical through hole 28A that penetrates the inside in the Z direction. The condenser lens 16 is housed in the through hole 28A of the condenser lens holder 28. The upper plate 24 sandwiched between the condenser lens 16 and the adapter 22 is fixed to the condenser lens holder 28 by four screws 26.

Two cooling air supply ports 28B are arranged along the Z direction on the side surface of the condenser lens holder 28. The two cooling air supply ports 28B are located at positions where the tangent line of the housing of the condenser lens 16 and the side surface of the condenser lens holder 28 intersect each other in the top view (XY plane view). It is placed toward the tangent line of. The two cooling air supply ports 28B communicate with the through hole 28A corresponding to the space inside the condenser lens holder 28 and the outside of the condenser lens holder 28, respectively, and air is supplied toward the condenser lens 16. .. A supply connector 30 having a through hole is connected to each of the two cooling air supply ports 28B. The number of cooling air supply ports 28B is not limited to two and can be appropriately determined.

The condenser lens protection plate support member 32 supports the condenser lens protection plate 34. The condenser lens protection plate support member 32 has a mounting portion 32A, a recess 32B, a through hole 32C, and a light guide portion 32D.

The mounting portion 32A is arranged on the upper surface of the condenser lens protection plate support member 32. The mounting portion 32A is a rectangular recess corresponding to the shape of the condenser lens protective plate 34. The mounting portion 32A is surrounded by an outer peripheral edge in three lateral directions and does not have an outer peripheral edge in one direction. The mounting portion 32A has a cylindrical recess 32B on the bottom surface. Further, in the center of the recess 32B, there is a through hole 32C that penetrates the inside in the Z direction.

The light guide unit 32D is arranged on the lower surface of the condenser lens protection plate support member 32. The light guide portion 32D has a cylindrical shape and has a through hole 32C inside. The through hole 32C has a tapered shape that narrows downward (as it moves away from the recess 32B).

The condenser lens protective plate 34 is a thin plate-like member made of glass. The condenser lens protection plate 34 is mounted on the upper surface of the mounting portion 32A of the condenser lens protection plate support member 32.

The nozzle 36 has a bottomed rectangular parallelepiped shape (an example of a bottomed shape). The nozzle 36 has a circular recess 36A in the center of the upper surface corresponding to the size of the light guide portion 32D of the condenser lens protection plate support member 32. The nozzle 36 has a flat nozzle bottom 36B on the lower surface. The nozzle bottom 36B has a rectangular shape with a side of 50 mm to 60 mm. At the center of the nozzle bottom 36B, a laser passage port 36C that communicates the recess 36A and the nozzle bottom 36B is arranged.

The light guide portion 32D of the condenser lens protection plate support member 32 is housed in the recess 36A of the nozzle 36. The condenser lens holder 28, the condenser lens protection plate support member 32, and the nozzle 36 are each fixed by four screws 40 inserted from the nozzle bottom 36B of the nozzle 36.

The condenser lens protection plate 34 is not surrounded by the outer peripheral edge of the mounting portion 32A in a state where the condenser lens holder 28, the condenser lens protection plate support member 32, and the nozzle 36 are fixed by the screw 40. A part protrudes from the direction. The user can remove the condenser lens protection plate 34 from the condenser lens unit 20 and insert it into the condenser lens unit 20 by grasping the protruding portion of the condenser lens protection plate 34. Therefore, the condenser lens protective plate 34 can be easily cleaned and replaced.

Further, with the condenser lens holder 28, the condenser lens protection plate support member 32, and the nozzle 36 fixed by the screw 40, the through hole 28A of the condenser lens holder 28 and the condenser lens protection plate support member 32 There is a gap between the lens and the mounting portion 32A. As a result, the space inside the condenser lens holder 28 and the space inside the nozzle 36 communicate with each other.

Two debris suction ports 36D are arranged along the Z direction on the side surface of the nozzle 36 (an example other than the bottom). The two debris suction ports 36D communicate with the recess 36A corresponding to the space inside the nozzle 36 and the outside of the nozzle 36, respectively. A suction connector 38 having a through hole is connected to each of the two debris suction ports 36D. The number of debris suction ports 36D is not limited to two and can be appropriately determined.

<Operation of laser processing equipment>
FIG. 6 is a diagram for explaining the operation of the laser processing apparatus 10. In FIG. 6, the condenser lens unit 20 is shown in cross section. As shown in FIG. 6, an air supply device 50 is connected to the supply connector 30 of the condenser lens unit 20. Further, an air suction device 52 is connected to the suction connector 38 of the condenser lens unit 20.

The control device 54 (not shown in FIG. 6) makes the nozzle bottom 36B of the nozzle 36 face the wafer W at a distance d. Further, the control device 54 emits the laser beam L to the laser source 12 (not shown in FIG. 6) to pass the safety shutter 14.

The laser beam L incident on the condenser lens 16 from the laser source 12 is condensed by the condenser lens 16. The laser beam L focused by the condenser lens 16 passes through the condenser lens protective plate 34. The laser beam L transmitted through the condenser lens protection plate 34 passes through the through hole 32C of the condenser lens protection plate support member 32 and the laser passage port 36C of the nozzle 36, and is incident on the wafer W.

The control device 54 moves the condensing lens unit 20 and the wafer W relative to each other, and irradiates the laser beam L along the planned division line of the wafer W. Debris D is generated by irradiating the processing point of the wafer W with the laser beam L. Here, by making the diameter of the laser passage port 36C as small as possible, the probability that the scattered debris is scattered on the condenser lens 16 side can be reduced.

Further, the control device 54 supplies air by the air supply device 50 and sucks air by the air suction device 52.

When air is supplied by the air supply device 50, the supplied air is supplied to the through hole 28A of the condenser lens holder 28 via the two cooling air supply ports 28B. The air supplied to the through hole 28A is supplied toward the condenser lens 16 and spirally circulates around the condenser lens 16 to cool the condenser lens 16. The air that has cooled the condenser lens 16 further reaches the condenser lens protection plate 34 to cool the condenser lens protection plate 34. The air that has cooled the condenser lens protection plate 34 passes through the gap between the through hole 28A of the condenser lens holder 28 and the mounting portion 32A of the condenser lens protection plate support member 32, and then the condenser lens protection plate. It passes through the through hole 32C of the support member 32 and the laser passage port 36C of the nozzle 36, and is guided to the machining point. The line A shown in FIG. 6 shows the flow of air supplied by the air supply device 50. In this way, the air supplied by the air supply device 50 evenly cools the condenser lens 16 and is supplied from the laser passage port 36C coaxially with the laser beam L.

When air is sucked by the air suction device 52, air is sucked from the laser passage port 36C through the two debris suction ports 36D. The air supplied by the air supply device 50 and guided to the processing point also joins the air sucked from the laser passage port 36C and is sucked into the air suction device 52 via the two debris suction ports 36D.

Further, the debris D generated by irradiating the wafer W with the laser beam L is also sucked from the laser passage port 36C and penetrates into the recess 36A of the nozzle 36. The debris D that has entered the recess 36A is sucked into the air suction device 52 via the two debris suction ports 36D and collected dust. The line B shown in FIG. 6 shows the flow of air sucked by the air suction device 52.

Here, the control device 54 controls the amount of air sucked by the air suction device 52 to a value larger than the amount of air supplied by the air supply device 50. As a result, air can be sucked from the laser passage port 36C, so that the movement of the debris D to the wafer W side can be suppressed.

Further, by making the distance d between the nozzle bottom 36B of the nozzle 36 and the wafer W as narrow as possible, the flow velocity of air between the nozzle bottom 36B and the wafer W can be increased. The distance d can be, for example, 1 mm to 2 mm.

As described above, according to the laser processing apparatus 10, it is possible to prevent debris from adhering to the condenser lens 16.

Further, when the condensing lens 16 and the condensing lens protective plate 34 thermally expand during processing of the wafer W, the height at which the laser light is focused and the spot shape of the laser light change, so that the condensing state is changed. It may change and the processing quality may become abnormal. According to the condensing lens unit 20 of the laser processing device 10, the air supplied by the air supply device 50 spirally circulates around the condensing lens 16 and reaches the condensing lens protection plate 34 to collect the air. The optical lens 16 and the condenser lens protective plate 34 can be appropriately cooled.

<Modification example>
In the above example, debris is sucked from the laser passage port 36C arranged at the nozzle bottom 36B of the nozzle 36, but debris may be sucked from other than the laser passage port 36C.

FIG. 7 is a bottom view of the condenser lens unit 20 according to the modified example. As shown in FIG. 7, a circular suction groove 36E is arranged around the laser passage port 36C at the nozzle bottom 36B of the nozzle 36 of the condenser lens unit 20 according to the modified example.

The suction groove 36E communicates with the recess 36A of the nozzle 36. When air is sucked by the air suction device 52, debris is sucked together with the air from the laser passage port 36C and the suction groove 36E, and is sucked into the air suction device 52 via the recess 36A of the nozzle 36 and the two debris suction ports 36D. It is sucked and dust is collected.

<Others>
The technical scope of the present invention is not limited to the scope described in the above embodiments. The configurations and the like in each embodiment can be appropriately combined between the respective embodiments without departing from the spirit of the present invention.

10 ... Laser processing device 12 ... Laser source 14 ... Safety shutter 16 ... Condensing lens 16A ... Connection part 18 ... Dust collecting unit 20 ... Condensing lens unit 22 ... Adapter 22A ... Through hole 24 ... Top plate 24A ... Through hole 28 ... Condensing lens holder 28A ... Through hole 28B ... Cooling air supply port 30 ... Supply connector 32 ... Condensing lens protection plate support member 32A ... Mounting part 32B ... Recessed portion 32C ... Through hole 32D ... Light guide part 34 ... Condensing lens protection Plate 36 ... Nozzle 36A ... Recessed 36B ... Nozzle bottom 36C ... Laser passage port 36D ... Debris suction port 36E ... Suction groove 38 ... Suction connector 50 ... Air supply device 52 ... Air suction device 54 ... Control device A ... Line B ... Line D ... Debris L ... Laser beam

Claims (7)

A condenser lens that collects laser light and
A bottomed nozzle in which a laser passage port through which the focused laser light passes is arranged at the bottom, and a suction port for communicating the space inside the nozzle with the outside is arranged in a place other than the bottom. Nozzle and
Condensing lens unit equipped with. A condenser lens holder for storing the condenser lens in an internal space, comprising a condenser lens holder in which the space inside the condenser lens holder communicates with the space inside the nozzle.
The condenser lens unit according to claim 1, wherein the condenser lens holder is provided with a supply port for supplying air for cooling the condenser lens. The condenser lens unit according to claim 1 or 2, which is arranged between the condenser lens and the laser passage port and includes a condenser lens protective plate through which the condensed laser light is transmitted. A laser light source that emits laser light and
A condensing lens that condenses the laser beam and
A bottomed nozzle in which a laser passage port through which the focused laser light passes is arranged at the bottom, and a suction port for communicating the space inside the nozzle with the outside is arranged in a place other than the bottom. Nozzle and
An air suction device connected to the suction port outside the nozzle,
Laser processing equipment equipped with. A condenser lens holder for storing the condenser lens in an internal space, comprising a condenser lens holder in which the space inside the condenser lens holder communicates with the space inside the nozzle.
The condenser lens holder is provided with a supply port for supplying air for cooling the condenser lens.
The laser processing device according to claim 4, further comprising an air supply device connected to the supply port outside the condenser lens holder. The laser processing device according to claim 5, further comprising a control device for controlling the amount of air sucked by the air suction device to a value larger than the amount of air supplied by the air supply device. The laser processing apparatus according to any one of claims 4 to 6, which is arranged between the condenser lens and the laser passage port and includes a condenser lens protective plate through which the condensed laser light is transmitted.

Images