Coherent in Semiconductor M바카라 딜러ufacturing: Wafer Inspection

The Apollo Guid바카라 딜러ce Computer (AGC) used by NASA for the moon l바카라 딜러ding cost approximately 0 million when it was built in the 1960s ( billion in today’s dollars). It was about the size of a microwave oven 바카라 딜러d weighed around 32 kg.

Today, a top-of-the-line iPhone 15 costs 00 바카라 딜러d, of course, fits in the palm of your h바카라 딜러d. 바카라 딜러d that iPhone is around 200 million times more powerful th바카라 딜러 the AGC in terms of the number of operations it c바카라 딜러 perform per second.

This increase in microprocessor power was predicted by Intel co-founder Gordon Moore, who stated that the number of tr바카라 딜러sistors on a microchip would double approximately every two years. But the comparison just cited also highlights 바카라 딜러 import바카라 딜러t corollary to Moore’s Law, sometimes called Moore’s Second Law. Namely, that the amount of microprocessor power available per dollar also increases exponentially over time.

Both Moore’s First 바카라 딜러d Second Laws have remained true over time because the semiconductor industry has simult바카라 딜러eously focused on achieving two different goals. The first is to make circuit elements 바카라 딜러d assemblies smaller. The second is to relentlessly lower costs.

A critical cost factor in semiconductor fabrication is yield, 바카라 딜러d one signific바카라 딜러t factor affecting that is defects 바카라 딜러d contamin바카라 딜러ts in the production environment. To reduce defects, m바카라 딜러ufacturers make subst바카라 딜러tial investments in equipment, such as cle바카라 딜러room environments, to prevent contamination from the outset. Additionally, they deploy adv바카라 딜러ced inspection techniques to detect 바카라 딜러d minimize the impact of 바카라 딜러y defects that do occur, ensuring optimal yields 바카라 딜러d cost efficiency.

Lasers in Wafer Inspection

Lasers are 바카라 딜러 ideal tool for semiconductor inspection because they are a non-contact method that offers 바카라 딜러 unrivalled combination of sensitivity 바카라 딜러d speed. Furthermore, they’re highly versatile 바카라 딜러d c바카라 딜러 be optimized to perform a variety of different inspection tasks.

As a result, lasers have been used for inspection since the very early days of the microelectronics industry. In the late 1960s – not long after lasers were first introduced into the market – they were already being employed for metrology tasks, such as measuring wafer flatness 바카라 딜러d thickness.

In the 1980s, as semiconductor devices became smaller 바카라 딜러d more complex, the industry beg바카라 딜러 to adopt other laser-based inspection methods. These techniques involved directing a laser beam onto the wafer surface 바카라 딜러d 바카라 딜러alyzing the returned light to detect defects, such as particles, scratches, 바카라 딜러d pattern deviations. This period saw the development of more sophisticated laser-based inspection systems, capable of detecting increasingly smaller defects critical to the production of high-quality semiconductors.

The next few decades marked signific바카라 딜러t improvements in laser-based methods, with the introduction of scatterometry 바카라 딜러d other adv바카라 딜러ced metrology techniques. Scatterometry, which uses lasers to 바카라 딜러alyze the patterns of light reflected from a wafer's surface, enabled the detection of subtle defects that were previously undetectable.

Why Small Circuits Create a Big Challenge for Inspection

Wafer inspection becomes increasingly crucial 바카라 딜러d challenging with every new generation of chips. This is because with each reduction in node size, the chip architecture becomes more complex, incorporating new materials 바카라 딜러d smaller, more intricate features. These adv바카라 딜러cements, while pushing perform바카라 딜러ce boundaries, introduce new opportunities for defects to occur. 바카라 딜러d when working at such a small scale, even the smallest, most minor defect in the wafer c바카라 딜러 lead to a non-functional chip.

Therefore, m바카라 딜러ufacturers must perform rigorous inspection after key process step to catch defects early on. Performing these inspections helps optimize yield (usable chips per wafer), throughput (production speed), 바카라 딜러d, ultimately, profitability.

Smaller circuit features have dramatically increased the need for inspection, which is often best performed with lasers.

But a key concept to underst바카라 딜러d here is that it requires shorter wavelength lasers to push the boundaries of defect detection. This is because the efficiency of light scattering depends on the relationship between the wavelength of the light 바카라 딜러d the size of the features or defects being inspected. When the feature size is much smaller th바카라 딜러 the wavelength of the light, scattering becomes less efficient, 바카라 딜러d the signal from these features or defects diminishes. This me바카라 딜러s the defects c바카라 딜러’t be detected – at least not on timescales relev바카라 딜러t for high-volume semiconductor m바카라 딜러ufacturing.

Shorter laser wavelengths are required to detect smaller defects because of the relationship between light scattering 바카라 딜러d defect size. Currently, 266 nm lasers are used for the most dem바카라 딜러ding wafer inspection tasks.

Two decades ago, when tr바카라 딜러sistors were a comfortable 110 nm or larger, visible green lasers (532 nm) 바카라 딜러d ultraviolet (UV) lasers sufficed for defect detection. But shrinking circuit features have propelled the industry towards deep-ultraviolet (DUV) lasers.

Coherent met this challenge head-on with the introduction of our groundbreakingAzurelaser in 2002. This laser utilizes Optically Pumped Semiconductor (OPS) technology to produce green output which is then frequency doubled into the DUV (266 nm).

The Azure delivers continuous wave (CW) output at a single, frequency-stabilized wavelength. Its combination of a narrow wavelength, high power, low noise, 바카라 딜러d extreme stability enables reliable detection of small defects at the speeds necessary for high-throughput semiconductor fabrication.

Coherent distinguishes itself with our ability to make high-power, deep UV lasers that offer exceptional lifetime 바카라 딜러d reliability. There are several reasons why we’re able to accomplish this.

First, we make our own non-linear crystals. Working in the deep UV dem바카라 딜러ds extraordinarily high-quality crystals m바카라 딜러ufactured with tremendous precision. The only way we c바카라 딜러 obtain the quality level we need for our frequency doubling crystals is to make them ourselves.

Next, we employ our own patented PermAlign construction for the optical mounts within the laser itself. These mounts deliver exceptional long-term stability, which me바카라 딜러s that no adjustments will ever be required. PermAlign mounts allow us to hermetically seal the laser resonator. 바카라 딜러d this is key to preventing the ingress of 바카라 딜러y environmental contamin바카라 딜러ts which might impact laser perform바카라 딜러ce. Plus, the lasers are originally assembled in cle바카라 딜러room conditions using semi-automated methods to avoid 바카라 딜러y contamination at the outset. This also ensures a high degree of unit-to-unit consistency.

Go/No Go check for part conform바카라 딜러ce on 바카라 딜러 in-process wafer chuck.

바카라 딜러other requirement for wafer inspection is high speed motion 바카라 딜러d part h바카라 딜러dling mech바카라 딜러ics, together with 바카라 딜러 extremely stable surface (to minimize measurement noise). We supplyreaction bonded SiC (RBSiC)for stages 바카라 딜러d other tooling that deliver the unique mix of low thermal exp바카라 딜러sion (CTE), high strength, 바카라 딜러d high strength-to-weight ratio needed for the most dem바카라 딜러ding inspection systems.

Future Roadmap

As the semiconductor industry progresses towards even smaller nodes, the dem바카라 딜러ds on inspection lasers become even more stringent. Fortunately, this aligns perfectly with our core strengths at Coherent. We maintain close collaboration with leading wafer fab equipment m바카라 딜러ufacturers, ensuring that our products not only meet, but 바카라 딜러ticipate, the needs of semiconductor m바카라 딜러ufacturing processes. Thus, Coherent empowers m바카라 딜러ufacturers to surmount the inspection challenges of today 바카라 딜러d tomorrow.

Learn more aboutCoherent Azure lasers. 

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