English

The Key Role of Laser Pointing Stability in the Application of Lithography Systems

404
2024-07-02 14:24:25
See translation

Lithography is one of the core processes in semiconductor manufacturing, and extreme ultraviolet lithography technology, as a new generation lithography technology, is also in a rapid development stage. The basic principle is to use photoresist (also known as photoresist) to form corrosion resistance due to photochemical reactions after being photosensitive, and to engrave the patterns on the mask onto the processed surface. The main steps of photolithography of silicon dioxide in semiconductor chips include coating photoresist, aligning the mask and exposing it, dissolving the photosensitive photoresist layer with developer, dissolving the unprotected silicon dioxide layer with etchant, and removing the photosensitive photoresist layer.

In lithography systems, stable laser pointing is crucial as it directly affects the accuracy and consistency of the lithography pattern. There are three main factors that affect the stability of beam pointing, namely the displacement of the laser itself, the vibration differences between lasers and lighting systems on different bases, and the disturbances of the optical system during transmission. These disturbances will have a serious impact on the quality of lithography.

Firstly, the stability of laser pointing is crucial for ensuring precise etching of the pattern. During the lithography process, the laser beam needs to be precisely irradiated onto a specific area on the silicon wafer to achieve accurate transfer of patterns. If the laser pointing is unstable, it can cause problems such as displacement of the graphic position and size changes, seriously affecting the quality and performance of the product.

Secondly, the stability of laser pointing is also related to the repeatability and consistency of lithography. In semiconductor manufacturing, it is often necessary to perform photolithography on a large number of silicon wafers, which requires a high degree of repeatability and consistency in the photolithography process. If the laser pointing is unstable, the results of each photolithography will vary, resulting in inconsistent performance between product batches, increasing manufacturing difficulty and cost.

Therefore, the stability of laser pointing is particularly important under the constantly improving accuracy requirements.


We can achieve relative stability of the beam by reducing vibration and temperature changes, but this is only a passive compensation method and cannot completely avoid these interferences. In this regard, an active compensation system can be used to adjust the optical path and turn the beam back when it deviates, making the environmental requirements less stringent.

The Aligna laser beam pointing stabilization system from TEM company can effectively solve and achieve the above functions. The system consists of two Fast Reflecting Mirrors (FSMs), a Position Detector (PSD), and a Control Cabinet. The deflection of FSM can be achieved by combining electric motors and piezoelectric ceramics, ensuring both wide range and high accuracy of the fast reflector. Coupled with a high-resolution position detector (PSD), the total accuracy of the system can reach the sub micron level. In addition, response time is also crucial for systems that require real-time stability of laser beams, and excellent algorithms can limit it to the range of 0.2ms with a closed-loop bandwidth exceeding 5KHZ.

The following diagram is a schematic diagram of the beam detection and stabilization system. After passing through two fast reflection mirrors R1 and R2, the laser is incident on the beam splitter BS1. The transmitted light is used for subsequent experiments and normal use, and a small amount of reflected light will enter the PSD for beam detection. PSD is a photoelectric device based on the transverse photoelectric response of a semiconductor PN junction. According to the output voltage of the centroid of the incident light spot, two PSDs are used to detect the position deviation and angle deviation of the beam, respectively. After the controller detects the deviation information, it passes the feedback information to the FSM through an algorithm, controls the rotation of the FSM, and realizes the pointing correction of the main beam.

The following figure shows the displacement of the spot position before and after using the system. It can be clearly seen that the spot position is unstable and has a significant displacement before the system works; After the system starts working, the position of the spot is basically controlled near the origin, and the stability of the position is significantly improved.

Source: Yangtze River Delta Laser Alliance

Related Recommendations
  • This perovskite solar cell laser equipment company has received another round of financing

    Recently, Lecheng Intelligent Technology (Suzhou) Co., Ltd. (hereinafter referred to as "Lecheng Intelligent") completed a strategic financing round of tens of millions of yuan, which is exclusively invested by Dongfang Fenghai Capital. The financing funds will mainly be used for technology research and development, laboratory construction, and talent recruitment.This is the second round of financ...

    2023-10-10
    See translation
  • Overview of Residual Stress in Metal Additive Manufacturing: Detection Techniques, Numerical Simulation, and Mitigation Strategies

    Researchers from Shantou University have reported a review of residual stresses in metal additive manufacturing: detection techniques, numerical simulations, and mitigation strategies. The relevant paper titled "A comprehensive review of residual stress in metal additive manufacturing: detection techniques, numerical simulations, and mitigation strategies" was published in the Journal of the Brazi...

    2024-12-20
    See translation
  • Panasonic has announced the launch of two new laser projectors

    Panasonic announced the launch of two new 1-Chip 4K DL laser projectors, the PT-REQ15 projector offering 15,000 lumens of brightness, while its counterpart, the PT-REZ15, offers 15,000 lumens of WUXGA resolution.The REQ15 uses Panasonic's Quad Pixel Drive, a two-axis pixel shift technology, to reproduce 4K images. It is capable of projecting 2K/240Hz content on multiple edge hybrid screens with a ...

    2023-09-07
    See translation
  • New Progress: III-V Laser and Silicon Optics Technology Achieve Single Chip High Integration

    Recently, Scientific Photonics, a supplier of silicon photonic integrated circuits (PICs) headquartered in Grenoble, announced that it has successfully integrated III-V-DFB lasers and amplifiers with standard silicon photonic technology into the production process of Tower Semiconductor.By utilizing proprietary technology and standard silicon photonics, Scientific Photonics has achieved full inte...

    2024-03-01
    See translation
  • Netherlands Integrated Photonics Ecological Platform Raises € 60 million to Support European Photonics Startups

    PhotonVentures, based in Eindhoven, the Netherlands, has announced the launch of a venture capital fund designed to help early-stage photonic chip startups and scale-up businesses.In the first round of funding, PhotonDelta, a Dutch photonic integrated circuit (PIC) pioneer, raised €60 million as the lead investor and numerous private investors. PhotonVentures said it plans to raise a total of...

    2023-09-02
    See translation