Laser scoring technology for LED wafer production

With the continuous growth of the market, the requirements of led manufacturing for production capacity and yield have become higher and higher. Laser processing technology has quickly become a common tool in the LED manufacturing industry, and even become the industry standard for high-brightness LED wafer processing.

Laser scribing LED scribing lines are much narrower than traditional mechanical scribing, so the material utilization rate is significantly improved, so the output efficiency is improved. In addition, laser processing is a non-contact process, and the scoring brings micro-cracks and other damage to the wafer, which makes the wafer particles closer, high output efficiency and high productivity, and the reliability of the finished LED device is also greatly improve.

Spectra-Physics industrial lasers have the advantages of high peak power and excellent beam quality. They are ideal tools for LED processing, bringing clean scribing lines, higher productivity and higher brightness of finished LEDs to the LED industry.

Advantages of laser scribing

-Hard and brittle materials can be scored cleanly and neatly

-Low operating cost of non-contact process

-Reduce the occurrence of defects such as chipping, micro cracks and delamination

-Narrow scribe lines increase the number of particles on a single wafer

-Reducing micro-cracks improves the long-term reliability of finished LED devices

-The wide range of processing tolerance makes the process controllable, which is a low-cost and highly reliable process.

2. Overview of LED laser scribing

Single crystal sapphire (Sapphire) and gallium nitride (GaN) are hard and brittle materials (tensile strength close to steel), so it is difficult to be cut into single LED devices. When cutting these materials with traditional mechanical saw blades, it is easy to cause damage such as wafer chipping, micro-cracks, and delamination. And LED devices, this greatly reduces the output efficiency of LED wafers.

Laser processing is a non-contact processing. As an alternative to traditional mechanical saw blade cutting, the laser dicing incision is very small, and the focused laser light spot quickly vaporizes the material on the wafer surface, making it very small between the LED active areas. To cut more LED cells on a wafer with a limited area. Laser scribing is especially good for gallium arsenide (GaAS) and other brittle compound semiconductor wafer materials. Laser processing LED wafers, the typical scoring depth is 1/3 to 1/2 of the thickness of the substrate so that the division can get a clean fracture surface, and manufacture narrow and deep laser scoring cracks while ensuring high-speed scoring speed. The laser is required to have excellent qualities such as narrow pulse width, high beam quality, high peak power, and high repetition frequency.

Not all lasers are suitable for LED scribing because the wafer material's transmittance to visible wavelength lasers. GaN is transmissive to light with a wavelength less than 365nm, while sapphire wafers are semi-transmissive to lasers with a wavelength greater than 177nm, so three- and four-frequency Q-switched all-solid-state lasers (DPSSL) with wavelengths of 355nm and 266nm are LED The best choice for circular laser scribing. Although the excimer laser can also achieve the wavelength required for LED scribing, the frequency-doubled all-solid-state Q-switched laser is smaller and much less maintenance than the excimer laser. The quality of the all-solid laser is very narrow and suitable For laser LED scribing.

Laser scribing greatly reduces wafer micro-cracks and micro-crack expansion, and the distance between LED monomers is closer, which improves both production efficiency and productivity. Generally speaking, 2 inch wafers can separate more than 20,000 LED single devices, so high density, so the cutting slit width will significantly affect the number of particles, reduce micro-cracks The long-term reliability of LED devices will also be significantly improved. Compared with the traditional blade cutting, laser scribing not only improves the output efficiency, but also improves the processing speed, avoids the processing defects and cost losses caused by blade wear. In short, the laser processing has high precision, large processing tolerance, and low cost.

Key market requirements for DPSS all solid-state lasers

-High reliability

-Long continuous running time

-One-click turn on laser LED scoring process with optimized parameters

--266nm all-solid laser for frontal scribing of LED wafers

--355nm for back side scoring

-Global service, technical support network

-Short pulse width and high peak power to achieve deep scribing and minimize thermal damage

-Excellent beam quality to achieve minimum scratch width

-Laser suppliers have strong application development strength and experience

3. Overview of Spectra-Physics lasers

For a long time, spectroscopy-physics has been the leader in serving global customers in the field of laser technology. 50 years of development history Spectroscopy-physical design, research and development, manufacturing a series of the world's first commercial lasers for the industrial market, including lasers for LED laser scribing.

In general, the advantages of laser scoring for LEDs are clear, but they also face many technical challenges, such as the differences caused by different materials, thicknesses, and scoring speeds in different cases. For this reason, Spectro-Physics provides multiple series of laser products for laser scribing and grading. It is a leader in this field of industrial processing, and has continuously introduced innovative high-precision lasers, such as Tristar TM, Navigator TM, HIPPOTM and other high-power series. Nanosecond laser products, and Vanguard TM series picosecond lasers. If you need a femtosecond laser, SolsTIce for Spectro-Physics? The laser can provide 100fs fully-automated femtosecond pulse laser. The product is designed for industrial applications and is rugged and reliable.

When the short pulse high peak power spectrum-physical laser acts on the LED substrate scoring, the effect is: the scribed line is clean, the material position moves little, and the thermal effect damage to the substrate is very small. Spectral-Physics provides you with deeper application knowledge and experience to help your process achieve the best results.

Our technology, experience and innovative spirit make us outstanding lasers. ProLite used in spectroscopy-physical all-solid-state lasers? The diode pump source has a leading position in the industry, and its life span is twice that of competitor products. In addition, the spectral-physical EternAlign TM optics assembly technology ensures good optical alignment inside and outside the laser throughout its lifetime.

Spectral-physical unique extra-cavity frequency doubling technology is the highest quality inside the all-solid Q laser. In addition, the laser key components such as pump diodes, optical fibers, shutters, output windows, etc. can be easily replaced in the field, which makes the continuous operation time of the spectrum-physical all-solid-state laser and the average maintenance time (MTTR) doubled. Your use and maintenance costs will be the lowest. Behind every spectral-physical laser you supply is the solid confidence and guarantee of the Newport global laser service technical support team.

Advantages of Spectra-Physics

-Long continuous working time-derived from the high reliability, excellent design and technical support of the product

-Pump diode lifetime-twice the average lifetime of industrial laser pump diodes

-Technical support--The global technical support after-sales service network provides quality services for large-scale installations

-Market verification-Thousands of installed spectrum-physical lasers have proven the excellent working performance of lasers in 24/7 industrial use.

-Short pulse width-means higher peak power and minimized heat affected area

-Nearly perfect beam quality-narrower scoring width

-Better quality of pulse-pulse energy stability-to achieve higher depth control of scoring