WO2015175268A1

WO2015175268A1 - Hybrid wafer dicing approach using an ultra-short pulsed laguerre gauss beam laser scribing process and plasma etch process

Info

Publication number: WO2015175268A1
Application number: PCT/US2015/029260
Authority: WO
Inventors: Wei-Sheng Lei; Brad Eaton; Ajay Kumar
Original assignee: Applied Materials, Inc.
Priority date: 2014-05-16
Filing date: 2015-05-05
Publication date: 2015-11-19
Also published as: TWI666729B; TW201603192A

Abstract

Methods of dicing semiconductor wafers, each wafer having a plurality of integrated circuits, are described. In an example, a method of dicing a semiconductor wafer having a plurality of integrated circuits involves forming a mask above the semiconductor wafer, the mask including a layer covering and protecting the integrated circuits. The method also involves patterning the mask with an ultra-short pulsed Laguerre Gauss laser beam laser scribing process to provide a patterned mask with gaps, exposing regions of the semiconductor wafer between the integrated circuits. The ultra-short pulsed Laguerre Gauss laser beam laser scribing process involves scribing with a laser beam having axially symmetrical polarization. The method also involves plasma etching the semiconductor wafer through the gaps in the patterned mask to singulate the integrated circuits.

Description

HYBRID WAFER DICING APPROACH USING AN ULTRA-SHORT PULSED LAGUERRE GAUSS BEAM LASER SCRIBING PROCESS AND PLASMA ETCH

PROCESS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.

61/994,385, filed on May 16, 2014, the entire contents of which are hereby incorporated by reference herein.

BACKGROUND

1) FIELD

[0002] Embodiments of the present invention pertain to the field of semiconductor processing and, in particular, to methods of dicing semiconductor wafers, each wafer having a plurality of integrated circuits thereon.

2) DESCRIPTION OF RELATED ART

[0003] In semiconductor wafer processing, integrated circuits are formed on a wafer (also referred to as a substrate) composed of silicon or other semiconductor material. In general, layers of various materials which are either semiconducting, conducting or insulating are utilized to form the integrated circuits. These materials are doped, deposited and etched using various well- known processes to form integrated circuits. Each wafer is processed to form a large number of individual regions containing integrated circuits known as dice.

[0004] Following the integrated circuit formation process, the wafer is "diced" to separate the individual die from one another for packaging or for use in an unpackaged form within larger circuits. The two main techniques that are used for wafer dicing are scribing and sawing. With scribing, a diamond tipped scribe is moved across the wafer surface along pre-formed scribe lines. These scribe lines extend along the spaces between the dice. These spaces are commonly referred to as "streets." The diamond scribe forms shallow scratches in the wafer surface along the streets. Upon the application of pressure, such as with a roller, the wafer separates along the scribe lines. The breaks in the wafer follow the crystal lattice structure of the wafer substrate. Scribing can be used for wafers that are about 10 mils (thousandths of an inch) or less in thickness. For thicker wafers, sawing is presently the preferred method for dicing.

[0005] With sawing, a diamond tipped saw rotating at high revolutions per minute contacts the wafer surface and saws the wafer along the streets. The wafer is mounted on a supporting member such as an adhesive film stretched across a film frame and the saw is repeatedly applied to both the vertical and horizontal streets. One problem with either scribing or sawing is that chips and gouges can form along the severed edges of the dice. In addition, cracks can form and propagate from the edges of the dice into the substrate and render the integrated circuit inoperative. Chipping and cracking are particularly a problem with scribing because only one side of a square or rectangular die can be scribed in the <110>direction of the crystalline structure. Consequently, cleaving of the other side of the die results in a jagged separation line. Because of chipping and cracking, additional spacing is required between the dice on the wafer to prevent damage to the integrated circuits, e.g., the chips and cracks are maintained at a distance from the actual integrated circuits. As a result of the spacing requirements, not as many dice can be formed on a standard sized wafer and wafer real estate that could otherwise be used for circuitry is wasted. The use of a saw exacerbates the waste of real estate on a semiconductor wafer. The blade of the saw is approximate 15 microns thick. As such, to insure that cracking and other damage surrounding the cut made by the saw does not harm the integrated circuits, three to five hundred microns often must separate the circuitry of each of the dice. Furthermore, after cutting, each die requires substantial cleaning to remove particles and other contaminants that result from the sawing process.

[0006] Plasma dicing has also been used, but may have limitations as well. For example, one limitation hampering implementation of plasma dicing may be cost. A standard lithography operation for patterning resist may render implementation cost prohibitive. Another limitation possibly hampering implementation of plasma dicing is that plasma processing of commonly encountered metals (e.g., copper) in dicing along streets can create production issues or throughput limits.

SUMMARY

[0007] Embodiments of the present invention include methods of, and apparatuses for, dicing semiconductor wafers.

[0008] In an embodiment, a method of dicing a semiconductor wafer having a plurality of integrated circuits involves forming a mask above the semiconductor wafer, the mask including a layer covering and protecting the integrated circuits. The method also involves patterning the mask with an ultra-short pulsed Laguerre Gauss laser beam laser scribing process to provide a patterned mask with gaps, exposing regions of the semiconductor wafer between the integrated circuits. The ultra-short pulsed Laguerre Gauss laser beam laser scribing process involves scribing with a laser beam having axially symmetrical polarization. The method also involves plasma etching the semiconductor wafer through the gaps in the patterned mask to singulate the integrated circuits.

[0009] In another embodiment, a system for dicing a semiconductor wafer having a plurality of integrated circuits includes a factory interface. A laser scribe apparatus is coupled with the factory interface and includes a laser assembly configured to provide an ultra-short pulsed Laguerre Gauss laser beam having axially symmetrical polarization. A plasma etch chamber is also coupled with the factory interface.

[0010] In another embodiment, a method of dicing a semiconductor wafer having a plurality of integrated circuits involves forming a mask above the semiconductor wafer, the mask comprising a layer covering and protecting the integrated circuits. The method also involves patterning the mask and singulating the integrated circuits with an ultra-short pulsed Laguerre Gauss laser beam laser scribing process. The ultra-short pulsed Laguerre Gauss laser beam laser scribing process involves scribing with a laser beam having axially symmetrical polarization.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a Flowchart representing operations in a method of dicing a semiconductor wafer including a plurality of integrated circuits, in accordance with an embodiment of the present invention.

[0012] Figure 2A illustrates a cross-sectional view of a semiconductor wafer including a plurality of integrated circuits during performing of a method of dicing the semiconductor wafer, corresponding to operation 102 of the Flowchart of Figure 1, in accordance with an embodiment of the present invention.

[0013] Figure 2B illustrates a cross-sectional view of a semiconductor wafer including a plurality of integrated circuits during performing of a method of dicing the semiconductor wafer, corresponding to operation 104 of the Flowchart of Figure 1, in accordance with an embodiment of the present invention.

[0014] Figure 2C illustrates a cross-sectional view of a semiconductor wafer including a plurality of integrated circuits during performing of a method of dicing the semiconductor wafer, corresponding to operation 108 of the Flowchart of Figure 1, in accordance with an embodiment of the present invention.

[0015] Figure 3A illustrates a plane of an electric component as a polarization plane.

[0016] Figure 3B illustrates the concept of P- and S- polarization of a laser beam.

[0017] Figure 3C illustrates different types of polarization for conventional and vector laser beams, as represented by the arrows, in accordance with an embodiment of the present invention. [0018] Figure 3D schematically illustrates the polarization effect on laser energy coupling into a material, in accordance with an embodiment of the present invention.

[0019] Figure 3E illustrates polarization direction versus laser scribing direction, in accordance with an embodiment of the present invention.

[0020] Figure 3F illustrates the effect of polarization direction versus laser scribing direction, in accordance with an embodiment of the present invention.

[0021] Figure 3G illustrates laser beams with conventional polarization having simple intensity structure.

[0022] Figure 3H illustrates laser beams with polarization having a complex intensity structure, in accordance with an embodiment of the present invention.

[0023] Figure 31 illustrates examples of laser beams with different intensity structure and examples of laser beams with cylindrically symmetric intensity structure, in accordance with an embodiment of the present invention.

[0024] Figure 3J illustrates laser beams with both complex polarization and complex intensity structure, in accordance with an embodiment of the present invention.

[0025] Figure 4 illustrates the formation of a TEM01* laser beam with radial and/or azimuthal polarization, in accordance with an embodiment of the present invention.

[0026] Figure 5 illustrates the effects of using a laser pulse width in the femtosecond range, picoseconds range, and nanosecond range, in accordance with an embodiment of the present invention.

[0027] Figure 6 illustrates a cross-sectional view of a stack of materials that may be used in a street region of a semiconductor wafer or substrate, in accordance with an embodiment of the present invention.

[0028] Figures 7A-7D illustrate cross-sectional views of various operations in a method of dicing a semiconductor wafer, in accordance with an embodiment of the present invention.

[0029] Figure 8 illustrates a block diagram of a tool layout for laser and plasma dicing of wafers or substrates, in accordance with an embodiment of the present invention.

[0030] Figure 9 illustrates a block diagram of an exemplary computer system, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

[0031] Methods of dicing semiconductor wafers, each wafer having a plurality of integrated circuits thereon, are described. In the following description, numerous specific details are set forth, such as ultra-short pulsed Laguerre Gauss laser scribing approaches and plasma etching conditions and material regimes, in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without these specific details. In other instances, well-known aspects, such as integrated circuit fabrication, are not described in detail in order to not unnecessarily obscure embodiments of the present invention. Furthermore, it is to be understood that the various embodiments shown in the Figures are illustrative representations and are not necessarily drawn to scale.

[0032] A hybrid wafer or substrate dicing process involving an initial laser scribe and subsequent plasma etch may be implemented for die singulation. The laser scribe process may be used to cleanly remove a mask layer, organic and inorganic dielectric layers, and device layers. The laser etch process may then be terminated upon exposure of, or partial etch of, the wafer or substrate. The plasma etch portion of the dicing process may then be employed to etch through the bulk of the wafer or substrate, such as through bulk single crystalline silicon, to yield die or chip singulation or dicing. More specifically, one or more embodiments are directed to implementing an ultra-short pulsed Laguerre Gauss laser beam laser scribing process for, e.g., dicing applications. In a specific such embodiment, the laser beam has axially symmetrical polarization.

[0033] To provide context, femtosecond laser scribing and subsequent plasma etching for wafer dicing has proven viable for wafer singulation. Depending on the specific application, the laser scribing depth can be limited to mask opening and device layer removal until an underlying silicon (Si) substrate is exposed, or it can extend into the Si substrate. At the extreme end of the spectrum, laser scribing is performed essentially through the entire wafer thickness, and plasma etching is used for repair of the singulated die sidewalls. Overlying mask layers may be thick or thin depending on bump height and wafer thickness. In the general regime, the following two aspects may require improvement: (1) there may be a need for reducing the surface roughness of the sidewall of the trench generated by laser scribing; (2) there may be a need for increasing the laser material removal rate in order to improve laser process throughput with a given laser power.

[0034] Conventionally, a circularly polarized Gaussian mode TEM00 laser beam is implemented to perform laser scribing or cutting in laser micromachining to avoid trench width variation otherwise associated with a linear polarization laser beam when laser scribing direction changes. However, adoption of a circular polarized beam may be realized at a cost of lowered laser absorption coefficiency, which can impact process throughput. In addition, although relatively lower sidewall roughness of a laser scribed trench may be achievable with application of proper laser spot overlap, e.g., by lowering scribing speed or increasing laser pulse frequency, it may be realized at a cost of lower scribing speed or a more expensive laser assembly. The increased cost may result since, at higher pulse frequency, the minimum laser pulse energy still has to be achieved. And, the sidewall surface roughness of a laser scribed trench may be improved in order to reduce the expense of a plasma etch based post-dicing sidewall

smoothening treatment effort.

[0035] In accordance with one or more embodiments described herein, an ultrashort pulsed Laguerre Gauss laser beam, such as a TEM01 * mode with axially symmetrical polarization, is implemented for laser scribing. A subsequent plasma etching operation may then be performed for wafer dicing. In one embodiment, the axially symmetrical polarization includes one or both of radial polarization and azimuthal polarization. The axially polarized laser beam with TEM01* mode can provide as much as two times a high laser absorption coefficiency as compared to that provided by a circularly polarized Gaussian beam (e.g., TEMOO mode).

Furthermore, the sidewall surface roughness on the trench generated by an axially polarized laser beam may be lower than that achieved by a circularly polarized laser beam. Both the axially and azimuthally polarized laser beams may provide a deeper penetration depth, and an azimuthally polarized beam may generate a sidewall with a steeper taper. In one embodiment, a donut shaped laser beam (e.g., TEM01* mode) with axially symmetrical polarization mode (e.g., radial or azimuthal, or both, polarization) can be converted from an initial linearly polarized Gaussian beam (TEMOO mode). In one or more embodiments described herein, laser beams having axially symmetrical polarization are implemented to improve the smoothness of a laser opened trench which can translate to a smoother plasma etch trench profile. In one or more embodiments described herein, the higher energy coupling efficiency associated with axial polarization improves the laser scribing throughput and/or enables thick mask opening, thick device layer removal, or wider kerf formation, any of which may otherwise be difficult to accomplish with a circular polarization beam at a same laser power level.

[0036] Thus, in an aspect of the present invention, a combination of an ultra-short pulsed

Laguerre Gauss laser beam laser scribing process with a plasma etching process may be used to dice a semiconductor wafer into singulated integrated circuits. Figure 1 is a Flowchart 100 representing operations in a method of dicing a semiconductor wafer including a plurality of integrated circuits, in accordance with an embodiment of the present invention. Figures 2A-2C illustrate cross-sectional views of a semiconductor wafer including a plurality of integrated circuits during performing of a method of dicing the semiconductor wafer, corresponding to operations of Flowchart 100, in accordance with an embodiment of the present invention.

[0037] Referring to operation 102 of Flowchart 100, and corresponding Figure 2A, a mask 202 is formed above a semiconductor wafer or substrate 204. The mask 202 is composed of a layer covering and protecting integrated circuits 206 formed on the surface of semiconductor wafer 204. The mask 202 also covers intervening streets 207 formed between each of the integrated circuits 206.

[0038] In accordance with an embodiment of the present invention, forming the mask

202 includes forming a layer such as, but not limited to, a photo-resist layer or an I-line patterning layer. For example, a polymer layer such as a photo-resist layer may be composed of a material otherwise suitable for use in a lithographic process. In one embodiment, the photo-resist layer is composed of a positive photo-resist material such as, but not limited to, a 248 nanometer (nm) resist, a 193 nm resist, a 157 nm resist, an extreme ultra-violet (EUV) resist, or a phenolic resin matrix with a diazonaphthoquinone sensitizer. In another embodiment, the photo-resist layer is composed of a negative photo-resist material such as, but not limited to, poly-cis- isoprene and poly-vinyl-cinnamate.

[0039] In another embodiment, forming the mask 202 involves forming a layer deposited in a plasma deposition process. For example, in one such embodiment, the mask 202 is composed of a plasma deposited Teflon or Teflon-like (polymeric CF₂) layer. In a specific embodiment, the polymeric CF₂ layer is deposited in a plasma deposition process involving the gas C₄F₈.

[0040] In another embodiment, forming the mask 202 involves forming a water-soluble mask layer. In an embodiment, the water-soluble mask layer is readily dissolvable in an aqueous media. For example, in one embodiment, the water-soluble mask layer is composed of a material that is soluble in one or more of an alkaline solution, an acidic solution, or in deionized water. In an embodiment, the water-soluble mask layer maintains its water solubility upon exposure to a heating process, such as heating approximately in the range of 50 - 160 degrees Celsius. For example, in one embodiment, the water-soluble mask layer is soluble in aqueous solutions following exposure to chamber conditions used in a laser and plasma etch singulation process. In one embodiment, the water-soluble mask layer is composed of a material such as, but not limited to, polyvinyl alcohol, polyacrylic acid, dextran, polymethacrylic acid, polyethylene imine, or polyethylene oxide. In a specific embodiment, the water-soluble mask layer has an etch rate in an aqueous solution approximately in the range of 1 - 15 microns per minute and, more particularly, approximately 1.3 microns per minute.

[0041] In another embodiment, forming the mask 202 involves forming a UV-curable mask layer. In an embodiment, the mask layer has a susceptibility to UV light that reduces an adhesiveness of the UV-curable layer by at least approximately 80%. In one such embodiment, the UV layer is composed of polyvinyl chloride or an acrylic -based material. In an embodiment, the UV-curable layer is composed of a material or stack of materials with an adhesive property that weakens upon exposure to UV light. In an embodiment, the UV-curable adhesive film is sensitive to approximately 365nm UV light. In one such embodiment, this sensitivity enables use of LED light to perform a cure.

[0042] In an embodiment, semiconductor wafer or substrate 204 is composed of a material suitable to withstand a fabrication process and upon which semiconductor processing layers may suitably be disposed. For example, in one embodiment, semiconductor wafer or substrate 204 is composed of a group IV-based material such as, but not limited to, crystalline silicon, germanium or silicon/germanium. In a specific embodiment, providing semiconductor wafer 204 includes providing a monocrystalline silicon substrate. In a particular embodiment, the monocrystalline silicon substrate is doped with impurity atoms. In another embodiment, semiconductor wafer or substrate 204 is composed of a ΠΙ-V material such as, e.g., a III-V material substrate used in the fabrication of light emitting diodes (LEDs).

[0043] In an embodiment, semiconductor wafer or substrate 204 has disposed thereon or therein, as a portion of the integrated circuits 206, an array of semiconductor devices. Examples of such semiconductor devices include, but are not limited to, memory devices or complimentary metal-oxide- semiconductor (CMOS) transistors fabricated in a silicon substrate and encased in a dielectric layer. A plurality of metal interconnects may be formed above the devices or transistors, and in surrounding dielectric layers, and may be used to electrically couple the devices or transistors to form the integrated circuits 206. Materials making up the streets 207 may be similar to or the same as those materials used to form the integrated circuits 206. For example, streets 207 may be composed of layers of dielectric materials, semiconductor materials, and metallization. In one embodiment, one or more of the streets 207 includes test devices similar to the actual devices of the integrated circuits 206.

[0044] Referring to operation 104 of Flowchart 100, and corresponding Figure 2B, the mask 202 is patterned with an ultra-short pulsed Laguerre Gauss laser beam laser scribing process to provide a patterned mask 208 with gaps 210, exposing regions of the semiconductor wafer or substrate 204 between the integrated circuits 206. As such, the laser scribing process is used to remove the material of the streets 207 originally formed between the integrated circuits 206. In accordance with an embodiment of the present invention, patterning the mask 202 with the ultra-short pulsed Laguerre Gauss laser beam laser scribing process includes forming trenches 212 partially into the regions of the semiconductor wafer 204 between the integrated circuits 206, as depicted in Figure 2B.

[0045] In accordance with an embodiment of the present invention, the ultra-short pulsed

Laguerre Gauss laser beam laser scribing process involves scribing with a laser beam having axially symmetrical polarization. In one embodiment, the laser beam has a radial polarization component. In another embodiment, the laser beam has an azimuthal polarization component. In another embodiment, the laser beam has both a radial polarization component and an azimuthal polarization component. In another embodiment, the laser beam has a TEMOl* mode. In another embodiment, the laser beam has a donut shape.

[0046] In order to provide further context, polarization of laser radiation is a fundamental optical property inherent in all laser beams. Laser light is a transverse electromagnetic wave containing both electric and magnetic components and the electric and magnetic field vectors point perpendicular to the direction of wave travel. The direction of polarization of an electromagnetic wave has traditionally been defined to lie along the direction of oscillation of the electric field vector. When light strikes an optical surface, such as a beam-splitter, at a non-perpendicular angle, the reflection and transmission characteristics depend upon

polarization. Light with a polarization vector lying in the plane containing the input and reflected beams is called P-polarized, and light which is polarized perpendicular to the plane containing the input and reflected beams is referred to as S-polarized. Any arbitrary state of input polarization can be expressed as a vector sum of the S and P components.

[0047] Figure 3A illustrates a plane of an electric component as a polarization plane.

Referring to portion 302 of Figure 3A, the orientation of electric and magnetic field vectors is shown relative to the direction of beam travel. Referring to portion 304 of Figure 3A, linearly polarized light propagating in the z-direction (or k-direction) is shown along with electric field amplitude, Y, and magnetic field amplitude, X. Referring to portion 306 of Figure 3A, direction of propagation and plane of polarization are shown along with the magnetic and electric filed vectors. Figure 3B illustrates the concept of P- and S- polarization of a laser beam. Referring to Figure 3B, portion 308 shows S-polarization and P-polarization for reflected beams and transmitted beams from a beam splitter relative to the laser beam propagation direction.

[0048] It is to be appreciated that there are different types of polarization. Conventional states of polarization include linear and circular polarization. In both cases, the direction of the electric vector does not depend on the spatial location in the beam cross-section. Linearly polarized lasers have a fixed electric vector that extends in a fixed direction. A laser with circular polarization has its electric vector rotating uniformly in a circular pattern.

Non-conventional states of polarization include radial polarization, where the direction of the electrical vector in the plane of the beam cross-section is parallel to the radial direction.

Non-conventional states of polarization also include azimuthal polarization, where the direction of the electrical vector in the plane of the beam cross-section is perpendicular to the radial direction. Within a laser beam, the electric vector (rather than the magnetic vector) contains the processing power. Therefore, the orientation of the electric vector, i.e., the polarization status/direction affects the laser-materials interaction and, hence, materials processing capability. In particular, in accordance with an embodiment of the present invention, polarization direction can have significant impact on the quality and throughput/efficiency of laser scribing/cutting processes.

[0049] Figure 3C illustrates different types of polarization for conventional and vector laser beams, as represented by the arrows, in accordance with an embodiment of the present invention. Referring to Figure 3C, for conventional states of polarization, such as linear or circular polarization 310, the direction of the electric vector does not depend on the spatial location in the beam cross-section. In vector beams, the state of polarization is spatially variant, such as for radial and azimuthal polarization 312.

[0050] Figure 3D schematically illustrates the polarization effect on laser energy coupling into a material, in accordance with an embodiment of the present invention. Referring to Figure 3D, schematic 314 demonstrates that the total energy of laser radiation as input (designated as 1 or 100%) can be partitioned into transmittance (T), reflectance (R), and absorbance (A), where A+R+T = 1 , or A= 1 -R-T. The energy coupling efficiency represented by A is affected by R and T. One known effect of polarization on laser radiation is that it can affect the reflectance of a laser beam on a material surface.

[0051] In accordance with an embodiment of the present invention, polarization effect on laser energy coupling into material can be attributed to the observation that polarization direction affects the laser energy coupling into a given material by affecting the laser reflectivity on the material surface. As an example, Figure 3E illustrates polarization direction versus laser scribing direction, in accordance with an embodiment of the present invention. Referring to Figure 3E, schematic 316 shows that polarization direction can vary and, thus, can impact quality and throughput/efficiency of laser scribing/cutting processes depends on the correlation between polarization direction and cutting/scribing (laser motion) direction. Relative sample and laser beam positions in the used coordinate system are depicted in Figure 3E.

[0052] Figure 3F illustrates the effect of polarization direction versus laser scribing direction, in accordance with an embodiment of the present invention. Referring to portion 318 of Figure 3F, in the case of linear polarization, the parameters of the beam interaction with the matter depend upon the direction of polarization. Referring to portion 320 of Figure 3F, kerf width variation can occur when changing laser scribing direction. The variation can be a result of laser power being absorbed differently when the polarization is in line and perpendicular to the laser beam traveling direction.

[0053] More generally, in accordance with an embodiment of the present invention, in the case of linear polarization, the parameters of the beam interaction with the matter depends upon the direction of polarization. Furthermore, scribing depth variation can occur when changing laser scribing direction, as a result of laser power being absorbed differently when the polarization is in line and perpendicular to the laser beam traveling direction. In certain cases, the energy efficiency is defined as the product of the cutting depth by cutting velocity. In the case of a circularly or randomly polarized beam, the electric vector rapidly changes over time. That is, the electric vector is oriented evenly in all cutting directions, so the effect of polarization on cutting quality is time-averaged and no effect on kerf width or cutting depth can be seen. However, in accordance with an embodiment of the present invention, from a laser energy coupling efficiency or cutting and associated cutting throughput viewpoint, the circular polarization is not optimal for minimum losses or maximum absorption.

[0054] Figure 3G illustrates laser beams with conventional polarization having simple intensity structure. Referring to Figure 3G, portion 322 shows circular and linear polarization modes for conventional Gaussian beams. Portion 324 shows a Gaussian intensity structure for a TEM00 beam. Portion 326 is a plot of power as a function of beam profile, with corresponding spot 328.

[0055] Figure 3H illustrates laser beams with polarization having a complex intensity structure, in accordance with an embodiment of the present invention. Referring to Figure 3H, portion 330 shows a linearly polarized Laguerre-Gaussian beam polarization mode as plotted as a function of time. Portion 332 shows a donut-shape intensity structure for a TEM01* beam. Portion 334 is a plot of power as a function of beam profile, with corresponding spot 336. To provide context, Figure 31 illustrates examples of laser beams with different intensity structure (338) and examples of laser beams with cylindrically symmetric intensity structure (340), in accordance with an embodiment of the present invention.

[0056] Figure 3J illustrates laser beams with both complex polarization and complex intensity structure, in accordance with an embodiment of the present invention. Referring to portion 342 of Figure 3J, (a) a radially polarized beam is shown, and (b) an azimuthally polarized beam is shown. Portion 344 shows a radially polarized Laguerre-Gaussian beam polarization mode as plotted as a function of time. Portion 346 shows a donut-shape intensity structure. Portion 348 is a plot of power as a function of beam profile, with corresponding spot 350. In an embodiment, the combination of an unconventional polarization and a unique intensity profile provides improved efficiency and precision in laser ablation.

[0057] In an embodiment, then, laser ablation is performed using a laser beam having both complex polarization and complex intensity structure. In one embodiment, a radially polarized beam is used. To compare, a radially polarized beam versus a circularly polarized beam, the effective absorption coefficient in the case of radial polarization is two times that of circular polarization. As a result, the product of cutting depth by cutting speed for radially polarized beam is approximately 1.5-2.0 times higher than that for circular polarized beam. In one embodiment, improved scribing/cutting quality in terms of roughness of laser machining is achieved. In a specific embodiment, a radially polarized beam generates a smoother sidewall as compared with a circular polarized beam. In a specific example, a radially polarized beam TEM01* compared to a circularly polarized Gaussian beam TEM00 shows approximately two times higher laser absorption, and lower sidewall surface roughness (Rz) through the cutting thickness (e.g., upper portion and lower portion).

[0058] Figure 4 illustrates the formation of a TEM01* laser beam with radial and/or azimuthal polarization, in accordance with an embodiment of the present invention. Referring to Figure 4, portion 402 shows pathway (a) where radial polarization is achieved to provide TME01*. Portion 404 shows pathway (b) where azimuthal polarization is achieved to provide TME01*. In one embodiment, the polarization is formed as a superposition of two plane polarized modes TEM01. In an embodiment, such linear to radial/azimuthal polarization conversion (LRAC) is based on segmented half -wave plates. As a comparison of a radially polarized beam TEM01* and azimuthally polarized beam TEM01*, with respect to cutting efficiency, the azimuthally polarized beam can achieve twice as deep a penetration compared to the radially polarized beam. With respect to kerf profile, the azimuthally polarized beam generates narrower cuts with larger taper than the radially polarized beam.

[0059] In an embodiment, a femtosecond-based laser is used as a source for an ultra-short pulsed Laguerre Gauss laser beam laser scribing process. For example, in an embodiment, a laser with a wavelength in the visible spectrum plus the ultra-violet (UV) and infra-red (IR) ranges (totaling a broadband optical spectrum) is used to provide a femtosecond-based laser, i.e., a laser with a pulse width on the order of the femtosecond (10 ^{~ 15} seconds). In one embodiment, ablation is not, or is essentially not, wavelength dependent and is thus suitable for complex films such as films of the mask 202, the streets 207 and, possibly, a portion of the semiconductor wafer or substrate 204.

[0060] Figure 5 illustrates the effects of using a laser pulse width in the femtosecond range, picosecond range, and nanosecond range, in accordance with an embodiment of the present invention. Referring to Figure 5, by using a laser beam profile with contributions from the femtosecond range, heat damage issues are mitigated or eliminated (e.g., minimal to no damage 502C with femtosecond processing of a via 500C) versus longer pulse widths (e.g., significant damage 502A with nanosecond processing of a via 500A). The elimination or mitigation of damage during formation of via 500C may be due to a lack of low energy recoupling (as is seen for picosecond-based laser ablation of 500B/502B) or thermal equilibrium (as is seen for nanosecond-based laser ablation), as depicted in Figure 5.

[0061] Laser parameters selection, such as beam profile, may be critical to developing a successful laser scribing and dicing process that minimizes chipping, microcracks and delamination in order to achieve clean laser scribe cuts. The cleaner the laser scribe cut, the smoother an etch process that may be performed for ultimate die singulation. In semiconductor device wafers, many functional layers of different material types (e.g., conductors, insulators, semiconductors) and thicknesses are typically disposed thereon. Such materials may include, but are not limited to, organic materials such as polymers, metals, or inorganic dielectrics such as silicon dioxide and silicon nitride.

[0062] A street between individual integrated circuits disposed on a wafer or substrate may include the similar or same layers as the integrated circuits themselves. For example, Figure 6 illustrates a cross-sectional view of a stack of materials that may be used in a street region of a semiconductor wafer or substrate, in accordance with an embodiment of the present invention.

[0063] Referring to Figure 6, a street region 600 includes the top portion 602 of a silicon substrate, a first silicon dioxide layer 604, a first etch stop layer 606, a first low K dielectric layer 608 (e.g., having a dielectric constant of less than the dielectric constant of 4.0 for silicon dioxide), a second etch stop layer 610, a second low K dielectric layer 612, a third etch stop layer 614, an undoped silica glass (USG) layer 616, a second silicon dioxide layer 618, and a layer of photo-resist 620, with relative thicknesses depicted. Copper metallization 622 is disposed between the first and third etch stop layers 606 and 614 and through the second etch stop layer 610. In a specific embodiment, the first, second and third etch stop layers 606, 610 and 614 are composed of silicon nitride, while low K dielectric layers 608 and 612 are composed of a carbon- doped silicon oxide material.

[0064] Under conventional laser irradiation (such as nanosecond-based irradiation), the materials of street 600 behave quite differently in terms of optical absorption and ablation mechanisms. For example, dielectrics layers such as silicon dioxide, is essentially transparent to all commercially available laser wavelengths under normal conditions. By contrast, metals, organics (e.g., low K materials) and silicon can couple photons very easily, particularly in response to nanosecond-based irradiation. In an embodiment, an ultra-short pulsed Laguerre Gauss laser beam laser scribing process is used to pattern a layer of silicon dioxide, a layer of low K material, and a layer of copper by ablating the layer of silicon dioxide prior to ablating the layer of low K material and the layer of copper.

[0065] The scribing process may be run in single pass only, or in multiple passes, but, in an embodiment, preferably 1-2 passes. In one embodiment, the scribing depth in the work piece is approximately in the range of 5 microns to 50 microns deep, preferably approximately in the range of 10 microns to 20 microns deep. In an embodiment, the kerf width of the laser beam generated is approximately in the range of 2 microns to 15 microns, although in silicon wafer scribing/dicing preferably approximately in the range of 6 microns to 10 microns, measured at the device/silicon interface.

[0066] Laser parameters may be selected with benefits and advantages such as providing sufficiently high laser intensity to achieve ionization of inorganic dielectrics (e.g., silicon dioxide) and to minimize delamination and chipping caused by underlayer damage prior to direct ablation of inorganic dielectrics. Also, parameters may be selected to provide meaningful process throughput for industrial applications with precisely controlled ablation width (e.g., kerf width) and depth. In an embodiment, an ultra-short pulsed Laguerre Gauss laser beam laser scribing process is suitable to provide such advantages.

[0067] It is to be appreciated that the dicing or singulation process could be stopped after the above described laser scribing in a case that the laser scribing is used to pattern the mask as well as to scribe fully through the wafer or substrate in order to singulate the dies. Accordingly, further singulation processing would not be required in such a case. However, the following embodiments may be considered in cases where laser scribing alone is not implemented for total singulation.

[0068] Referring now to optional operation 106 of Flowchart 100, an intermediate post mask-opening cleaning operation is performed. In an embodiment, the post mask-opening cleaning operation is a plasma-based cleaning process. In a first example, as described below, the plasma-based cleaning process is reactive to the regions of the substrate 204 exposed by the gaps 210. In the case of a reactive plasma-based cleaning process, the cleaning process itself may form or extend trenches 212 in the substrate 204 since the reactive plasma-based cleaning operation is at least somewhat of an etchant for the substrate 204. In a second, different, example, as is also described below, the plasma-based cleaning process is non-reactive to the regions of the substrate 204 exposed by the gaps 210.

[0069] In accordance with a first embodiment, the plasma-based cleaning process is reactive to exposed regions of the substrate 204 in that the exposed regions are partially etched during the cleaning process. In one such embodiment, Ar or another non-reactive gas (or the mix) is combined with SF₆ for a highly-biased plasma treatment for cleaning of scribed openings. The plasma treatment using mixed gases Ar +SF₆ under high-bias power is performed for bombarding mask-opened regions to achieve cleaning of the mask-opened regions. In the reactive breakthrough process, both physical bombardment from Ar and SF₆ along with chemical etching due to SF₆ and F-ions contribute to cleaning of mask-opened regions. The approach may be suitable for photoresist or plasma-deposited Teflon masks 202, where breakthrough treatment leads to fairly uniform mask thickness reduction and a gentle Si etch. Such a breakthrough etch process, however, may not be best suited for water soluble mask materials.

[0070] In accordance with a second embodiment, the plasma-based cleaning process is non-reactive to exposed regions of the substrate 204 in that the exposed regions are not or only negligible etched during the cleaning process. In one such embodiment, only non-reactive gas plasma cleaning is used. For example, Ar or another non-reactive gas (or the mix) is used to perform a highly-biased plasma treatment both for mask condensation and cleaning of scribed openings. The approach may be suitable for water-soluble masks or for thinner plasma-deposited Teflon 202. In another such embodiment, separate mask condensation and scribed trench cleaning operations are used, e.g., an Ar or non-reactive gas (or the mix) highly-biased plasma treatment for mask condensation is first performed, and then an Ar +SF₆ plasma cleaning of a laser scribed trench is performed. This embodiment may be suitable for cases where Ar-cleaning is not sufficient for trench cleaning due to too thick of a mask material. Cleaning efficiency is improved for thinner masks, but mask etch rate is much lower, with almost no consumption in a subsequent deep silicon etch process. In yet another such embodiment, three-operation cleaning is performed: (a) Ar or non-reactive gas (or the mix) highly-biased plasma treatment for mask condensation, (b) Ar +SF₆ highly-biased plasma cleaning of laser scribed trenches, and (c) Ar or non-reactive gas (or the mix) highly-biased plasma treatment for mask condensation. In accordance with another embodiment of the present invention, a plasma cleaning operation involves first use of a reactive plasma cleaning treatment, such as described above in the first aspect of operation 106. The reactive plasma cleaning treatment is then followed by a non- reactive plasma cleaning treatment such as described in association with the second aspect of operation 106.

[0071] Referring to operation 108 of Flowchart 100, and corresponding Figure 2C, the semiconductor wafer 204 is etched through the gaps 210 in the patterned mask 208 to singulate the integrated circuits 206. In accordance with an embodiment of the present invention, etching the semiconductor wafer 204 includes ultimately etching entirely through semiconductor wafer 204, as depicted in Figure 2C, by etching the trenches 212 initially formed with the ultra-short pulsed Laguerre Gauss laser beam laser scribing process.

[0072] In accordance with an embodiment of the present invention, the resulting roughness of mask opening from laser scribing can impact die sidewall quality resulting from the subsequent formation of a plasma etched trench. Lithographically opened masks often have smooth profiles, leading to smooth corresponding sidewalls of a plasma etched trench. By contrast, a conventional laser opened mask can have a very rough profile along a scribing direction if improper laser process parameters are selected (such as spot overlap, leading to rough sidewall of plasma etched trench horizontally). Although the surface roughness can be smoothened by additional plasma processes, there is a cost and throughput hit to remedying such issues. Accordingly, embodiments described herein may be advantageous in providing a smoother scribing process from the laser scribing portion of the singulation process.

[0073] In an embodiment, etching the semiconductor wafer 204 includes using a plasma etching process. In one embodiment, a through-silicon via type etch process is used. For example, in a specific embodiment, the etch rate of the material of semiconductor wafer 204 is greater than 25 microns per minute. An ultra-high-density plasma source may be used for the plasma etching portion of the die singulation process. An example of a process chamber suitable to perform such a plasma etch process is the Applied Centura® Silvia™ Etch system available from Applied Materials of Sunnyvale, CA, USA. The Applied Centura® Silvia™ Etch system combines the capacitive and inductive RF coupling ,which gives much more independent control of the ion density and ion energy than was possible with the capacitive coupling only, even with the improvements provided by magnetic enhancement. This combination enables effective decoupling of the ion density from ion energy, so as to achieve relatively high density plasmas without the high, potentially damaging, DC bias levels, even at very low pressures. This results in an exceptionally wide process window. However, any plasma etch chamber capable of etching silicon may be used. In an exemplary embodiment, a deep silicon etch is used to etch a single crystalline silicon substrate or wafer 204 at an etch rate greater than approximately 40% of conventional silicon etch rates while maintaining essentially precise profile control and virtually scallop-free sidewalls. In a specific embodiment, a through-silicon via type etch process is used. The etch process is based on a plasma generated from a reactive gas, which generally a fluorine- based gas such as SF₆, C₄ F₈, CHF₃, XeF₂, or any other reactant gas capable of etching silicon at a relatively fast etch rate. In an embodiment, the mask layer 208 is removed after the singulation process, as depicted in Figure 2C. In another embodiment, the plasma etching operation described in association with Figure 2C employs a conventional Bosch-type dep/etch/dep process to etch through the substrate 204. Generally, a Bosch-type process consists of three sub- operations: deposition, a directional bombardment etch, and isotropic chemical etch which is run through many iterations (cycles) until silicon is etched through.

[0074] Accordingly, referring again to Flowchart 100 and Figures 2A-2C, wafer dicing may be preformed by initial ablation using an ultra-short pulsed Laguerre Gauss laser beam laser scribing process to ablate through a mask layer, through wafer streets (including metallization), and partially into a silicon substrate. Die singulation may then be completed by subsequent through- silicon deep plasma etching. A specific example of a materials stack for dicing is described below in association with Figures 7A-7D, in accordance with an embodiment of the present invention.

[0075] Referring to Figure 7A, a materials stack for hybrid laser ablation and plasma etch dicing includes a mask layer 702, a device layer 704, and a substrate 706. The mask layer, device layer, and substrate are disposed above a die attach film 708 which is affixed to a backing tape 710. In an embodiment, the mask layer 702 is a water soluble layer such as the water soluble layers described above in association with mask 202. The device layer 704 includes an inorganic dielectric layer (such as silicon dioxide) disposed above one or more metal layers (such as copper layers) and one or more low K dielectric layers (such as carbon-doped oxide layers). The device layer 704 also includes streets arranged between integrated circuits, the streets including the same or similar layers to the integrated circuits. The substrate 706 is a bulk single-crystalline silicon substrate.

[0076] In an embodiment, the bulk single-crystalline silicon substrate 706 is thinned from the backside prior to being affixed to the die attach film 708. The thinning may be performed by a backside grind process. In one embodiment, the bulk single-crystalline silicon substrate 706 is thinned to a thickness approximately in the range of 50 - 100 microns. It is important to note that, in an embodiment, the thinning is performed prior to a laser ablation and plasma etch dicing process. In an embodiment, the photo-resist layer 702 has a thickness of approximately 5 microns and the device layer 704 has a thickness approximately in the range of 2 - 3 microns. In an embodiment, the die attach film 708 (or any suitable substitute capable of bonding a thinned or thin wafer or substrate to the backing tape 710) has a thickness of approximately 20 microns.

[0077] Referring to Figure 7B, the mask 702, the device layer 704 and a portion of the substrate 706 are patterned with an ultra-short pulsed Laguerre Gauss laser beam laser scribing process 712 to form trenches 714 in the substrate 706. Referring to Figure 7C, a through-silicon deep plasma etch process 716 is used to extend the trench 714 down to the die attach film 708, exposing the top portion of the die attach film 708 and singulating the silicon substrate 706. The device layer 704 is protected by the mask layer 702 during the through- silicon deep plasma etch process 716.

[0078] Referring to Figure 7D, the singulation process may further include patterning the die attach film 708, exposing the top portion of the backing tape 710 and singulating the die attach film 708. In an embodiment, the die attach film is singulated by a laser process or by an etch process. Further embodiments may include subsequently removing the singulated portions of substrate 706 (e.g., as individual integrated circuits) from the backing tape 710. In one embodiment, the singulated die attach film 708 is retained on the back sides of the singulated portions of substrate 706. Other embodiments may include removing the mask layer 702 from the device layer 704. In an alternative embodiment, in the case that substrate 706 is thinner than approximately 50 microns, the ultra-short pulsed Laguerre Gauss laser beam laser scribing process 712 is used to completely singulate substrate 706 without the use of an additional plasma process.

[0079] A single process tool may be configured to perform many or all of the operations in a hybrid laser train with ultra-short pulsed Laguerre Gauss laser beam ablation and plasma etch singulation process. For example, Figure 8 illustrates a block diagram of a tool layout for laser and plasma dicing of wafers or substrates, in accordance with an embodiment of the present invention.

[0080] Referring to Figure 8, a process tool 800 includes a factory interface 802 (FI) having a plurality of load locks 804 coupled therewith. A cluster tool 806 is coupled with the factory interface 802. The cluster tool 806 includes one or more plasma etch chambers, such as plasma etch chamber 808. A laser scribe apparatus 810 is also coupled to the factory interface 802. The overall footprint of the process tool 800 may be, in one embodiment, approximately 3500 millimeters (3.5 meters) by approximately 3800 millimeters (3.8 meters), as depicted in Figure 8.

[0081] In an embodiment, the laser scribe apparatus 810 houses a laser assembly configured to provide an ultra-short pulsed Laguerre Gauss laser beam. In one such embodiment, the laser beam has axially symmetrical polarization. In a specific embodiment, the laser assembly is configured to provide the laser beam having a radial polarization component. In another specific embodiment, the laser assembly is configured to provide the laser beam having an azimuthal polarization component. In another specific embodiment, the laser assembly is configured to provide the laser beam having both a radial polarization component and an azimuthal polarization component. In another specific embodiment, the laser assembly is configured to provide the laser beam having a TEM01 * mode. In another specific embodiment, the laser assembly is configured to provide the laser beam having a donut shape. In an embodiment, the laser scribe apparatus is configured to provide a linear to radial conversion, or linear to azimuthal conversion, or linear to both radial and azimuthal conversion, based on segmented half- wave plates.

[0082] In an embodiment, the laser is suitable for performing a laser ablation portion of a hybrid laser and etch singulation process, such as the laser ablation processes described above. In one embodiment, a moveable stage is also included in laser scribe apparatus 810, the moveable stage configured for moving a wafer or substrate (or a carrier thereof) relative to the laser. In a specific embodiment, the laser is also moveable. The overall footprint of the laser scribe apparatus 810 may be, in one embodiment, approximately 2240 millimeters by approximately 1270 millimeters, as depicted in Figure 8.

[0083] In an embodiment, the one or more plasma etch chambers 808 is configured for etching a wafer or substrate through the gaps in a patterned mask to singulate a plurality of integrated circuits. In one such embodiment, the one or more plasma etch chambers 808 is configured to perform a deep silicon etch process. In a specific embodiment, the one or more plasma etch chambers 808 is an Applied Centura® Silvia™ Etch system, available from Applied Materials of Sunnyvale, CA, USA. The etch chamber may be specifically designed for a deep silicon etch used to create singulate integrated circuits housed on or in single crystalline silicon substrates or wafers. In an embodiment, a high-density plasma source is included in the plasma etch chamber 808 to facilitate high silicon etch rates. In an embodiment, more than one etch chamber is included in the cluster tool 806 portion of process tool 800 to enable high manufacturing throughput of the singulation or dicing process.

[0084] The factory interface 802 may be a suitable atmospheric port to interface between an outside manufacturing facility with laser scribe apparatus 810 and cluster tool 806. The factory interface 802 may include robots with arms or blades for transferring wafers (or carriers thereof) from storage units (such as front opening unified pods) into either cluster tool 806 or laser scribe apparatus 810, or both.

[0085] Cluster tool 806 may include other chambers suitable for performing functions in a method of singulation. For example, in one embodiment, in place of an additional etch chamber, a deposition chamber 812 is included. The deposition chamber 812 may be configured for mask deposition on or above a device layer of a wafer or substrate prior to laser scribing of the wafer or substrate. In one such embodiment, the deposition chamber 812 is suitable for depositing a photo-resist layer. In another embodiment, in place of an additional etch chamber, a wet/dry station 814 is included. The wet/dry station may be suitable for cleaning residues and fragments, or for removing a mask, subsequent to a laser scribe and plasma etch singulation process of a substrate or wafer. In an embodiment, a metrology station is also included as a component of process tool 800.

[0086] Embodiments of the present invention may be provided as a computer program product, or software, that may include a machine-readable medium having stored thereon instructions, which may be used to program a computer system (or other electronic devices) to perform a process according to embodiments of the present invention. In one embodiment, the computer system is coupled with process tool 800 described in association with Figure 8. A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, a machine-readable (e.g., computer-readable) medium includes a machine (e.g., a computer) readable storage medium (e.g., read only memory ("ROM"), random access memory ("RAM"), magnetic disk storage media, optical storage media, flash memory devices, etc.), a machine (e.g., computer) readable transmission medium (electrical, optical, acoustical or other form of propagated signals (e.g., infrared signals, digital signals, etc.)), etc.

[0087] Figure 9 illustrates a diagrammatic representation of a machine in the exemplary form of a computer system 900 within which a set of instructions, for causing the machine to perform any one or more of the methodologies described herein, may be executed. In alternative embodiments, the machine may be connected (e.g., networked) to other machines in a Local Area Network (LAN), an intranet, an extranet, or the Internet. The machine may operate in the capacity of a server or a client machine in a client- server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine may be a personal computer (PC), a tablet PC, a set-top box (STB), a Personal Digital Assistant (PDA), a cellular telephone, a web appliance, a server, a network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while only a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines (e.g., computers) that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies described herein.

[0088] The exemplary computer system 900 includes a processor 902, a main memory

904 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM), etc.), a static memory 906 (e.g., flash memory, static random access memory (SRAM), etc.), and a secondary memory 918 (e.g., a data storage device), which communicate with each other via a bus 930.

[0089] Processor 902 represents one or more general-purpose processing devices such as a microprocessor, central processing unit, or the like. More particularly, the processor 902 may be a complex instruction set computing (CISC) microprocessor, reduced instruction set computing (RISC) microprocessor, very long instruction word (VLIW) microprocessor, processor implementing other instruction sets, or processors implementing a combination of instruction sets. Processor 902 may also be one or more special-purpose processing devices such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), network processor, or the like. Processor 902 is configured to execute the processing logic 926 for performing the operations described herein.

[0090] The computer system 900 may further include a network interface device 908.

The computer system 900 also may include a video display unit 910 (e.g., a liquid crystal display (LCD), a light emitting diode display (LED), or a cathode ray tube (CRT)), an alphanumeric input device 912 (e.g., a keyboard), a cursor control device 914 (e.g., a mouse), and a signal generation device 916 (e.g., a speaker).

[0091] The secondary memory 918 may include a machine-accessible storage medium

(or more specifically a computer-readable storage medium) 932 on which is stored one or more sets of instructions (e.g., software 922) embodying any one or more of the methodologies or functions described herein. The software 922 may also reside, completely or at least partially, within the main memory 904 and/or within the processor 902 during execution thereof by the computer system 900, the main memory 904 and the processor 902 also constituting machine- readable storage media. The software 922 may further be transmitted or received over a network 920 via the network interface device 908.

[0092] While the machine-accessible storage medium 932 is shown in an exemplary embodiment to be a single medium, the term "machine-readable storage medium" should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term "machine-readable storage medium" shall also be taken to include any medium that is capable of storing or encoding a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present invention. The term "machine- readable storage medium" shall accordingly be taken to include, but not be limited to, solid-state memories, and optical and magnetic media.

[0093] In accordance with an embodiment of the present invention, a machine-accessible storage medium has instructions stored thereon which cause a data processing system to perform a method of dicing a semiconductor wafer having a plurality of integrated circuits. The method includes forming a mask above the semiconductor wafer, the mask composed of a layer covering and protecting the integrated circuits. The mask is then patterned with an ultra-short pulsed Laguerre Gauss laser beam laser scribing process to provide a patterned mask with gaps, exposing regions of the semiconductor wafer between the integrated circuits. The ultra-short pulsed Laguerre Gauss laser beam laser scribing process involves scribing with a laser beam having axially symmetrical polarization. The semiconductor wafer is then plasma etched through the gaps in the patterned mask to singulate the integrated circuits.

[0094] Thus, hybrid wafer dicing approaches using an ultra-short pulsed Laguerre Gauss laser beam laser scribing process and plasma etch have been disclosed.

Claims

CLAIMS What is claimed is:

1. A method of dicing a semiconductor wafer comprising a plurality of integrated circuits, the method comprising:

forming a mask above the semiconductor wafer, the mask comprising a layer covering and protecting the integrated circuits;

patterning the mask with an ultra-short pulsed Laguerre Gauss laser beam laser scribing process to provide a patterned mask with gaps, exposing regions of the semiconductor wafer between the integrated circuits, wherein the ultra-short pulsed Laguerre Gauss laser beam laser scribing process comprises scribing with a laser beam having axially symmetrical polarization; and

plasma etching the semiconductor wafer through the gaps in the patterned mask to singulate the integrated circuits.

2. The method of claim 1 , wherein scribing with a laser beam having axially symmetrical polarization comprises scribing with a laser beam having a radial polarization component.

3. The method of claim 1, wherein scribing with a laser beam having axially symmetrical polarization comprises scribing with a laser beam having an azimuthal polarization component.

4. The method of claim 1 , wherein scribing with a laser beam having axially symmetrical polarization comprises scribing with a laser beam having both a radial polarization component and an azimuthal polarization component.

5. The method of claim 1, wherein scribing with a laser beam having axially symmetrical polarization comprises scribing with a laser beam having a TEM01* mode.

6. The method of claim 1 , wherein scribing with a laser beam having axially symmetrical polarization comprises scribing with a donut shape.

7. The method of claim 1, wherein patterning the mask with the laser scribing process comprises forming trenches in the regions of the semiconductor wafer between the integrated circuits, and wherein plasma etching the semiconductor wafer comprises extending the trenches to form corresponding trench extensions.

8. The method of claim 7, wherein each of the trenches has a width, and wherein each of the corresponding trench extensions has the width.

9. The method of claim 1, further comprising:

subsequent to patterning the mask with the ultra-short pulsed Laguerre Gauss laser beam laser scribing process and prior to plasma etching the semiconductor wafer through the gaps, cleaning the exposed regions of the semiconductor wafer with a plasma process.

10. A system for dicing a semiconductor wafer comprising a plurality of integrated circuits, the system comprising:

a factory interface;

a laser scribe apparatus coupled with the factory interface and comprising a laser assembly configured to provide an ultra-short pulsed Laguerre Gauss laser beam having axially symmetrical polarization; and

a plasma etch chamber coupled with the factory interface.

11. The system of claim 10, wherein the laser assembly is configured to provide the laser beam having a radial polarization component.

12. The system of claim 10, wherein the laser assembly is configured to provide the laser beam having an azimuthal polarization component.

13. The system of claim 10, wherein the laser assembly is configured to provide the laser beam having both a radial polarization component and an azimuthal polarization component.

14. The system of claim 10, wherein the laser assembly is configured to provide the laser beam having a TEM01* mode.

15. The system of claim 10, wherein the laser assembly is configured to provide the laser beam having a donut shape.