Mechanical Dicing Research Articles

Influence of diamond abrasives on material removal of single crystal SiC in mechanical dicing

Mechanical dicing is a critical step in producing electronic chips and devices. Single crystal silicon carbide (SiC) is a vital wafer material in modern electronic chips because of its exceptional physical properties, such as wide bandgap and high breakdown voltage. However, the high hardness of SiC makes it extremely challenging to achieve the dicing quality required for the reliable functioning of electronic chips. The removal characteristics of single crystal SiC in mechanical dicing process remains largely unclear. This work aims to systematically investigate the influences of diamond abrasives in ultrathin blades on the dicing force, chipping size, surface roughness, and material removal of single crystal SiC in mechanical dicing. Experimental results indicate the diamond abrasives considerably affect the chipping formation and the material removal of SiC workpieces by changing the undeformed chip thickness. Theoretical analysis based on the classic brittle-ductile transition model reveals that single crystal SiC can be removed in a ductile-like mode using relatively large abrasive size and low concentration, as long as the undeformed chip thickness is sufficiently smaller than the calculated critical depth of cutting. In addition, the mounting method of single crystal SiC workpieces and the wear characteristics of diamond blades play a crucial role in the removal behaviours and, therefore, the dicing quality. An example was given to demonstrate the feasibility of simultaneously improving the dicing quality and the removal rate via appropriately increasing concentration and reducing sizes of abrasives in ultrathin blades. Ultimately, the findings in this research provide a guideline for further optimization of the dicing tools and parameters for other hard-and-brittle solids.

Mechanical dicing of optical quality facets and waveguides in a silicon nitride platform

AbstractThe authors report a ductile dicing process for manufacturing optical‐quality facets in a multi‐layered silicon nitride platform without the need for polishing. A surface roughness (Sa) of 1.5 nm was achieved. This technique was extended to fabricate ridge waveguides, and the results and characterization are reported.

Bias-Magnet-Free Optical Isolating Ridge Waveguide Operating at 780 nm

The fabrication and isolation characteristics of bias-magnet-free optical isolating waveguides with optimal wavelength operations of 780 nm are outlined in this report. Bismuth-substituted iron garnet thin films grown by liquid phase epitaxy on gadolinium gallium garnet substrates were used as the starting material to form the waveguides. Slab optical waveguides were produced using mechanical dicing and precision polishing. Single mode ridge waveguides were produced in the slabs using focused ion beam lithographic techniques. Commercially available polarizing fibers were implemented for the Faraday isolation function in place of polarizing films. Fiber-to-fiber isolation performance was measured to be up to 25 dB at 790 nm and fiber-to-fiber loss was as low as 11 dB at 765 nm, with the bulk of the loss being attributed to fiber coupling and connector losses. Intrinsic loss for the Faraday waveguide was estimated to be on order of 1 dB.

Development and post-dicing wet release of MEMS magnetometer: an approach

PurposeSi-based micro electro mechanical systems (MEMS) magnetometer does not require specialized magnetic materials avoiding magnetic hysteresis, ease in fabrication and low power consumption. It can be fabricated using the same processes used for gyroscope and accelerometer fabrication. The paper reports the dicing mechanism for the released MEMS xylophone magnetic sensor fabricated using wafer bonding technology and its characterization in ambient pressure and under vacuum conditions. The purpose of this paper is to dice the wafer bonded Si-magnetometer in a cost-effective way without the use of laser dicing and test it for Lorentz force transduction.Design/methodology/approachA xylophone bar MEMS magnetometer using Lorentz force transduction is developed. The fabricated MEMS-based xylophone bars in literature are approximately 500 µm. The present work shows the released structure (L = 592 µm) fabricated by anodic bonding technique using conducting Si as the structural layer and tested for Lorentz force transduction. The microstructures fabricated at the wafer level are released. Dicing these released structures using conventional diamond blade dicing may damage the structures and reduce the yield. To avoid the problem, positive photoresist S1813 was filled before dicing. The dicing of the wafer, filled with photoresist and later removal of photoresist post dicing, is proposed.FindingsThe devices realized are stiction free and straight. The dynamic measurements are done using laser Doppler vibrometer to verify the released structure and test its functionality for Lorentz force transduction. The magnetic field is applied using a permanent magnet and Helmholtz coil. Two sensors with quality factors 70 and 238 are tested with resonant frequency 112.38 kHz and 114.38 kHz, respectively. The sensor D2, with Q as 238, shows a mechanical sensitivity of 500 pm/Gauss and theoretical Brownian noise-limited resolution of 53 nT/vHz.Originality/valueThe methodology and the study will help develop Lorentz force–based MEMS magnetometers such that stiction-free structures are released using wet etch after the mechanical dicing.

Dicing of composite substrate for thin film AlGaInP power LEDs by wet etching

In this paper, thin film AlGaInP LED chips with a 50 μm thick composite metal substrate (Copper-Invar-Copper; CIC) were obtained by the wet etching process. The pattern of the substrate was done by the backside of the AlGaInP LED/CIC. There was no delamination or cracking phenomenon of the LED epilayer which often occurs by laser or mechanical dicing. The chip area was 1140 μm × 1140 μm and the channel length was 360 μm. The structure of the CIC substrate was a sandwich structure and consisted of Cu as the top and bottom layers, with a thickness of 10 μm, respectively. The middle layer was Invar with a 30% to 70% ratio of Ni and Fe and a total thickness of 30 μm. The chip pattern was successfully obtained by the wet etching process. Concerning the device performance after etching, high-performance LED/CIC chips were obtained. They had a low leakage current, high output power and a low red shift phenomenon as operated at a high injected current. After the development and fabrication of the copper-based composite substrate for N-side up thin-film AlGaInP LED/CIC chips could be diced by wet etching. The superiority of wet etching process for the AlGaInP LED/CIC chips is over that of chips obtained by mechanical or laser dicing.

Backside Chippings Improvement through Wafer Dicing Parameter Optimization and Understanding the Anistropic Silicon Properties

Semiconductor Companies and Industries soar high as the trend for electronic gadgets and devices increases. Transition from “manual” to “fully automatic” application is one of the advantages why consumer adapt to changes and prefer electronic devices as one of daily answers. Individuals who admire these electronic devices often ask how they are made.
 As we look inside each device, we can notice interconnected microchips commonly called IC (Integrated Circuit). These are specially prepared silicon wafers where integrated circuit are developed. Commonly, each device is composed of numerous microchips depending on the design and functionality
 IC production is processed from “front-end” to “back-end” assembly. Front-end assembly includes wafer fabrication where electrical circuitry is prepared and integrated to every single silicon wafers. Back-end assembly covers processing the wafer by cutting into smaller individual and independent components called “dice”. Each dice will be placed into Leadframe, bonded with wires prior encapsulating with mold compounds. After molding, each IC will be cut through a process called singulation. Afterwards, all molded units are subjected for functional testing.
 Dice is central to each IC; it is where miniature transistor, resistor and capacitor are integrated to form complex small circuitry in microchips.
 Pre-assembly (Pre-assy) stations have the first hand prior to all succeeding stations. Live wafers are primary direct materials processed in these stations. Robust work instruction and parameter must be practiced during handling and processing to avoid gross rejection and possible work-related defects.
 The paper is all about the challenges to resolve and improved the backside chippings in 280um wafer thickness in mechanical dicing saw. The conventional Mechanical dicing process induce a lot of mechanical stress and vibration during the cutting process which oftentimes lead to backside chipping and die crack issues. However, backside chippings can mitigate with proper selection of parameter settings and understand the silicon wafer properties.

Introduction of Laser Pi-Grooving as Breakthrough Solution to Enhance die Strength of 40 nm ulow-k CMOS Silicon Technology during Wafer Saw Process

Nowadays, semiconductors and electronics are becoming part of our everyday activities. As the Integrated circuits become more useful to people, it also requires more function, which contain more complex and compact components. Aligned to this package requirement, the more challenging it become to package development as Silicon technology becomes more critical and complex from bare silicon to conventional MOS technology to Ultra Low-K, which requires a different strategy. The new process development in the Semiconductor industry is a necessity to cope up with these new technologies. Low-k devices always pose a big challenge in achieving good dicing quality. This is because of the weak mechanical properties of the low-k dielectric material used. Mechanical Sawing is the most popular cutting method for silicon, but with Ultra low-K technology, using mechanical sawing will lead to various sawing defects such as chippings and delamination [1,2]. These leads to the introduction of Laser Grooving to get rid of these dilemmas. Laser grooving uses heat to eradicate metals on this very thin metal wafer dicing saw streets in preparation for wafer saw process to prevent topside chippings and delamination/metal peel off [3]. These defects are not acceptable especially since the product application is a chip card. Since chip cards must be flexible and durable, they require higher die and package strength to serve its purpose. To achieve such package requirement, different method was evaluated such as standard mechanical dicing, standard Laser Grooving and the PI laser groove. 
 The paper will discuss how we were able to achieve the quality requirement for Ultra Low-K and at the same time eliminating top reject contributor during startup of this device.

Use of a Novel Sanitizer To Inactivate Salmonella Typhimurium and Spoilage Microorganisms during Flume Washing of Diced Tomatoes

As demand for fresh-cut produce increases, minimizing the risk of salmonellosis becomes critical for the produce industry. Sanitizers are routinely used during commercial flume washing of fresh-cut produce to minimize cross-contamination from the wash water. This study assessed the efficacy of a novel sanitizer blend consisting of peracetic acid (PAA; OxypHresh 15) with a sulfuric acid-surfactant (SS) antimicrobial (PAA-SS; ProduceShield Plus) against Salmonella during simulated commercial washing of diced tomatoes. Triplicate 9.1-kg batches of Roma tomatoes were dip inoculated in a two-strain avirulent Salmonella cocktail (Salmonella Typhimurium LT2 and MHM112) to achieve 5 to 6 log CFU per tomato and air dried for 2 h. After mechanical dicing, the tomatoes were washed in a pilot-scale processing line for 60 s with or without an added organic load in 90 ppm of PAA-SS (pH 1.8), SS at pH 1.8, 90 ppm of PAA, 5 or 10 ppm of free chlorine or sanitizer-free water as the control. Overall, PAA-SS (1.75 ± 0.75 log CFU/g) was significantly (P ≤ 0.05) more effective than water (0.69 ± 0.42 log CFU/g), chlorine (0.35 ± 0.36 log CFU/g), or SS (0.36 ± 0.19 log CFU/g) in reducing Salmonella. After washing for 20 s, PAA-SS was the only sanitizer to show a significant (P ≤ 0.05) reduction (1.93 ±0.59 log CFU/g) in Salmonella. All wash water samples were negative for Salmonella, except for 5 and 10 ppm of chlorine and the water control. Using PAA-SS with an organic load, yeast and mold populations were below the limit of detection (1.40 log CFU/g) and significantly (P ≤ 0.05) lower on diced tomatoes after 14 days of refrigerated storage compared with the other treatments (8.37 ± 0.08 log CFU/g), with SS at pH 1.8 (3.91 ± 0.93 log CFU/g) most effective against yeast and mold in the absence of an organic load. On the basis of these findings, the safety and shelf life of commercially washed diced tomatoes can be improved with PAA-SS.

Dicing before Grinding: A Robust Wafer Thinning and Dicing Technology

The never-ending trend for package miniaturization has been driving the semiconductor industry to the brink of technology. Hence, development of new technologies is necessary to cope up with the demand for advance and aggressive process capabilities.
 The paper is all about the challenges in developing and installing a robust 50 µm wafer thinning and dicing capability in ST Calamba. As silicon wafers are grinded thinner, the more it becomes sensitive to mechanical stress and vibration. The conventional mechanical dicing process induce a lot of mechanical stress and vibration during the cutting process which oftentimes lead to backside chipping and die crack issues. Backside chippings serves as fracture points at the back of the dice, which significantly reduce its die strength. This dilemma was addressed with the use of a breakthrough technology known as Dicing Before Grinding (DBG).

Mechanism study of SiO2 layer formation and separation at the Si die sidewall during nanosecond laser dicing of ultrathin Si wafers with Cu backside layer

Laser dicing of ultrathin dies is promising and is gaining importance because of its cost and quality advantages over mechanical and plasma dicing. However, the effects of laser dicing on the mechanical strength and microstructure of ultrathin Si dies need to be further understood, especially when dicing through Si wafers with backside Cu layer. A critical phenomenon effecting the Si die sidewall strength after nanosecond laser dicing of Si wafers with backside Cu is the formation and separation of a SiO2 layer at the sidewall. The mechanisms behind the SiO2 layer formation and separation were studied in this work. Si wafer samples without and with backside Cu layer were prepared by dicing with nanosecond laser using standard production parameters. The microstructure and phases formed were investigated by energy dispersive spectroscopy and nanobeam diffraction in a transmission electron microscope. In die samples without backside Cu, the sidewall consists of a thin surface layer of amorphous Si, followed by a polycrystalline Si layer, and finally an epitaxial Si layer. In die samples with backside Cu, the sidewall microstructure was observed to be vastly different. At the upper region of the sidewall, a surface layer of polycrystalline Cu was found, followed by a polycrystalline Cu3Si layer, a SiO2 layer mixed with Cu3Si, and finally a thick SiO2 layer. The Cu3Si catalyzes the growth of the SiO2 through an oxidation step of the Cu3Si on the sidewall surface as well as at the SiO2/Si interface. In the lower region of the sidewall, the microstructure is similar to the upper region, but there is a separation of the SiO2 layer from the crystalline Si. The SiO2 undergoes a decomposition reaction at the SiO2/Si interface, releasing volatile SiO which causes microvoids to form and grow laterally at the interface. The growth and coalescence of the microvoids eventually lead to the separation of the SiO2 layer from the crystalline Si, leaving behind a clean and rough crystalline Si surface with a peak-to-peak roughness of 100–200 nm. In the areas where the SiO2 layer has separated from the Si die sidewall, the fracture strength of the sidewall is dependent on the material property and surface roughness of the crystalline Si, and not on the SiO2 layer. In the sidewall region near the die frontside, the SiO2 thickness is more than regions near the die backside, and no microvoiding and separation at the SiO2/Si interface were detected. This is hypothesized to be due to a higher O2 pressure at the upper region of the narrow dicing trench which is open to the atmosphere compared to the lower regions where there could be O2 deprivation and lower O2 pressure.

Quantitative transfer and sanitizer inactivation of Salmonella during simulated commercial dicing and conveying of tomatoes

Diced tomatoes have been linked to outbreaks of salmonellosis in the United States. Compared to slicing, commercial production of diced tomatoes is more complex and includes mechanical dicing as well as washing, dewatering, conveying, and packing. Consequently, this study aimed to 1) quantify Salmonella transfer during pilot-scale dicing of tomatoes, 2) assess the efficacy of three sanitizer treatments against Salmonella during flume tank washing, and 3) assess the efficacy of four sanitizers against Salmonella during conveyance of diced tomatoes. One 0.9 kg batch of Salmonella Typhimurium LT2-inoculated Roma tomatoes (∼5 log CFU/g) was mechanically diced, followed by ten batches of uninoculated tomatoes. All uninoculated tomatoes yielded Salmonella with populations decreasing from 3.3 to 1.1 log CFU/g during dicing. Flume tank washing in sanitizer-free water or water containing 80 ppm of peroxyacetic acid, mixed peracid, or total chlorine decreased Salmonella populations in diced tomatoes 1.3 ± 0.2, 2.3 ± 0.4, 2.35 ± 0.4, and 2.4 ± 0.1 log CFU/g, respectively. After processing, Salmonella populations in flume water containing a sanitizer were always below the limit of detection (−1.0 log CFU/ml) and were significantly lower (P ≤ 0.05) than for the sanitizer-free control (1.5 ± 0.3 log CFU/ml). When the same three sanitizer treatments as well as electrolyzed water (80 ppm chlorine) were applied to smooth and interlocking belts on a dual track conveyor, Salmonella reductions were greater using mixed peracid (6.49 and 6.76 log) and peroxyacetic acid (5.95 and 6.10 log) as compared to chlorine (3.72 and 5.70 log) and electrolyzed water (3.50 and 4.53 log), respectively. All four sanitizer treatments were more effective than water alone in reducing Salmonella on conveyor belt surfaces. These findings should help provide some practical guidelines for the industry and aide in the development of improved risk assessments.

Fracture strength and microstructural study of ultrathin Si die with Cu backside layer diced with picosecond laser

Mechanical and plasma dicing of Si wafers with a backside metal layer poses serious challenges in quality and manufacturing cost. Mechanical dicing through the metal layer causes blade clogging and damage, which results in severe Si die chipping and cracks. The cost of plasma dicing is high as additional photolithography steps are required for etching the metal layer, in addition to the extremely slow metal etch rate. Laser dicing is promising and is currently used to singulate thin Si wafers. In this paper, picosecond laser dicing of 20 μm Si dies with 0–30 μm backside Cu was found to be feasible. Utilizing an improved three-point bending test method, the frontside and backside characteristic fracture strengths of ultrathin Si dies with varying backside Cu thickness were measured. The die types with backside Cu show an average of 17% higher frontside characteristic fracture strength, and an average of 13% higher backside characteristic fracture strength, compared to the die type without backside Cu. The die sidewall microstructures, defects, and compositions have been characterized in detail by transmission electron microscopy, and their effect on mechanical strength is discussed.

Characterization of the Flexural Strength and Fatigue Life of Ultrathin Glass After Dicing

Ultrathin glass (UTG) exhibits a great potential for use as a substrate for emerging consumer electronics for weight and profile reduction and flexibility or bendability enhancement. However, the brittle nature of UTG poses critical challenges during fabrication and operation. This study aims at investigating the cut edge/sidewall quality, ultimate flexural strength, and flexural fatigue life of UTG after dicing through finite-element analysis (FEA) and experiments. The focus is placed on the effects of dicing techniques, i.e., mechanical dicing, picosecond laser dicing, and wet etching. The ultimate flexural strengths of these diced UTGs are characterized using two-point bending (2PB) and three-point bending tests. In addition, their dependence on the UTG thickness and loading rate is also addressed. Furthermore, a surface treatment process is applied in an attempt to improve the cut edge/sidewall quality and even the ultimate flexural strength of the diced UTGs. At last, the maximum bending stress and flexural fatigue life of the diced UTGs at different bending curvatures, cyclic loading frequencies, and temperatures are assessed via FEA and cyclic 2PB fatigue test, respectively, by which the stress–fatigue life relationships are established.

Ultrafast-laser dicing of thin silicon wafers: strategies to improve front- and backside breaking strength

Thin 50-µm silicon wafers are used to improve heat dissipation of chips with high power densities. However, mechanical dicing methods cause chipping at the edges of the separated dies that reduce the mechanical stability. Thermal load changes may then lead to sudden chip failure. Recent investigations showed that the mechanical stability of the cut chips could be increased using ultrashort-pulsed lasers, but only at the laser entrance (front) side and not at the exit (back) side. The goal of this study was to find strategies to improve both front- and backside breaking strength of chips that were cut out of an 8″ wafer with power metallization using an ultrafast laser. In a first experiment, chips were cut by scanning the laser beam in single lines across the wafer using varying fluencies and scan speeds. Three-point bending tests of the cut chips were performed to measure front and backside breaking strengths. The results showed that the breaking strength of both sides increased with decreasing accumulated fluence per scan. Maximum breaking strengths of about 1100 MPa were achieved at the front side, but only below 600 MPa were measured for the backside. A second experiment was carried out to optimize the backside breaking strength. Here, parallel line scans to increase the distance between separated dies and step cuts to minimize the effect of decreasing fluence during scribing were performed. Bending tests revealed that breaking strengths of about 1100 MPa could be achieved also on the backside using the step cut. A reason for the superior performance could be found by calculating the fluence absorbed by the sidewalls. The calculations suggested that an optimal fluence level to minimize thermal side effects and periodic surface structures was achieved due to the step cut. Remarkably, the best breaking strengths values achieved in this study were even higher than the values obtained on state of the art ns-laser and mechanical dicing machines. This is the first study to the knowledge of the authors, which demonstrates that ultrafast-laser dicing improves the mechanical stability of thin silicon chips.

A hybrid method of ultrafast laser dicing and high density plasma etching with water soluble mask for thin silicon wafer cutting

Future silicon wafers are getting thinner in semiconductor industry to satisfy the requirement of miniaturizing package size in mobile device applications. Development of thin wafers is the mutual goal of current semiconductor researches. In this paper, a novel method incorporating the convenience of laser ablation and speed of plasma etching is proposed to replace traditional mechanical dicing saw for thin wafer cutting. The main idea is to use laser to create patterns on the silicon wafer coated with water soluble protection material and the unprotected area is exposed to the high-density plasma which is later etched through. This study includes development of the water-soluble protecting mask material, design of inductively coupled plasma (ICP) and microwave plasma sources, pattern scribing utilizing ultrafast laser, and trial of an etching (Bosch) process associated with the high-density plasma chamber to create high aspect ratio trench. The polyvinyl alcohol (PVA) based protecting material has excellent solubility and is extremely easy to be rinsed by water. With appropriately added chemicals, optical absorption is improved for laser ablation. A 532nm 10 pico-second laser is used to perform surface scribing with minimal recast and heat affected zone (HAZ) at the edges. Good plasma homogeneity is demonstrated in the designed 12″ microwave and ICP chambers. With the protection coating the silicon wafer can be etched at 7.2µm/min rate and 10.11 etch selectivity by the microwave and ICP sources in the chamber. Finally, etching process trials are performed, and the results show that deep and high aspect ratio trenches (~15µm wide, ~95µm deep) can be achieved which is fully acceptable for wafers under 100µm thickness.

Optimizing the dicing saw parameters of 60 μm wafer dicing street

Wafer surface dicing chipping can expand to impact chip circuits, which may cause serious defects during the IC assembly process, potentially resulting in IC circuit function failure. Throughout the semiconductor wafer process, the street design of wafer dicing is gradually narrowed, that raising the importance of controlling chipping performance. To obtain the key factor of dicing parameters, this paper studies and evaluates the dicing of a wafer with a street width of 60 µm and thickness of 200 µm using mechanical dicing saw and diamond dicing blade. In this design of experiment, experimental data were analyzed using analysis of variance to obtain key parameters for surface chipping. The results show that high cutting spindle speed of 50,000 rpm with shallow cutting depth of 50 µm provides better surface chipping performance, and improves chipping of abnormal base with a blade dicing saw.

Performance of active edge pixel sensors

To cope with the High Luminosity LHC harsh conditions, the ATLAS inner tracker has to be upgraded to meet requirements in terms of radiation hardness, pile up and geometrical acceptance. The active edge technology allows to reduce the insensitive area at the border of the sensor thanks to an ion etched trench which avoids the crystal damage produced by the standard mechanical dicing process. Thin planar n-on-p pixel sensors with active edge have been designed and produced by LPNHE and FBK foundry. Two detector module prototypes, consisting of pixel sensors connected to FE-I4B readout chips, have been tested with beams at CERN and DESY. In this paper the performance of these modules are reported. In particular the lateral extension of the detection volume, beyond the pixel region, is investigated and the results show high hit efficiency also at the detector edge, even in presence of guard rings.

Electron microscopic analysis of surface damaged layer in Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystal

Single crystals of lead magnesium niobate–lead titanate, Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT), have superior dielectric and piezoelectric properties suitable for medical ultrasound imaging. Imaging devices with superior performance can be manufactured from thinner PMN–PT single crystals by mechanical dicing and/or polishing. Although it is often a concern that a damaged layer may form during the mechanical dicing and/or thinning process, the microscopic characteristics of the damaged layer have not yet been investigated in detail. In this study, the microstructural characterization of a damaged layer was investigated by transmission electron microscopy. It was found that mechanical polishing introduced dislocation near the surface of the crystal. It was also found that the domain structure was affected by the introduction of dislocation.

Dependence of Chipping Damage on the Crystallographic Orientation During the Mechanical Dicing of Silicon Wafers

Dependence of Chipping Damage on the Crystallographic Orientation During the Mechanical Dicing of Silicon Wafers

Ultrashort pulse laser dicing of thin Si wafers: the influence of laser-induced periodic surface structures on the backside breaking strength

High power electronic chips are usually fabricated on about 50 µm thin Si wafers to improve heat dissipation. At these chip thicknesses mechanical dicing becomes challenging. Chippings may occur at the cutting edges, which reduce the mechanical stability of the die. Thermal load changes could then lead to sudden chip failure. Ultrashort pulsed lasers are a promising tool to improve the cutting quality, because thermal side effects can be reduced to a minimum. However, laser-induced periodic surface structures occur at the sidewalls and at the trench bottom during scribing. The goal of this study was to investigate the influence of these periodic structures on the backside breaking strength of the die. An ultrafast laser with a pulse duration of 380 fs and a wavelength of 1040 nm was used to cut a wafer into single chips. The pulse energy and the number of scans was varied. The cuts in the wafer were investigated using transmitted light microscopy, the sidewalls of the cut chips were investigated using scanning electron and confocal microscopy, and the breaking strength was evaluated using the 3-point bending test. The results indicated that periodic holes with a distance of about 20–30 µm were formed at the bottom of the trench, if the number of scans was set too low to completely cut the wafer; the wafer was only perforated. Mechanical breaking of the bridges caused 5 µm deep kerfs in the sidewall. These kerfs reduced the breaking strength at the backside of the chip to about 300 MPa. As the number of scans was increased, the bridges were ablated and the wafer was cut completely. Periodic structures were observed on the sidewall; the roughness was below 1 µm. The surface roughness remained on a constant level even when the number of scans was doubled. However, the periodic structures on the sidewall seemed to vanish and the probability to remove local flaws increases with the number of scans. As a consequence, the breaking strength was increased to about 700 MPa.