OTFT (Organic Thin Film Transistor) technology operates at low temperatures, allowing direct processing on Micro LED displays. This eliminates the need for the large-scale transfer and laser bonding processes required by traditional methods in Micro LED display manufacturing.
UK-based company Smartkem has developed a six-layer transistor stack design and process using its Truflex semiconductor and dielectric inks (or electronic polymers). Smartkem’s core chemical process involves processing its electronic polymers at 80°C and then depositing them onto low-cost plastic or glass substrates.
Smartkem claims this will enable the introduction of a “Chip First” display architecture. Moreover, it allows the processing of OTFT on plastic substrates, not just glass, which opens up opportunities for the production of low-cost, thin, transparent, flexible, and lightweight Micro LED displays.
In collaboration with AU Optronics, Smartkem aims to commercialize this technology, with the industrialization project expected to begin on January 1, 2025. The project has received funding from UK and Taiwan research and development cooperation programs.
While the specific funding amount has not been disclosed, Smartkem revealed that the UK-Taiwan R&D cooperation program has invested over £10 million ($12.5 million) in nine projects in 2024 to promote bilateral industrial technology development, with each project valued at about £1 million ($1.25 million).
Recently, Smartkem published its financial results, indicating a strong need for this partnership and corresponding funding. The company reported a revenue of $40,000 for the first nine months of 2024, with a net loss of $7.6 million. As of September 30, 2024, the company’s cash reserves were $1.8 million, which is insufficient to cover operational and capital expenditures for the next 12 months. The company requires additional capital funding to continue operations and R&D activities.
Current Challenges in Micro LED Display Manufacturing: Mass Transfer Process
The most significant challenge in manufacturing Micro LED displays is the mass transfer process.
Mass Transfer is the critical step where Micro LED chips are transferred from the growth substrate to the target substrate. Given the high density and small size of Micro LED chips, traditional transfer methods struggle to meet the high precision required for accurate chip placement. To create a display array that combines Micro LED chips with driving circuits, multiple mass transfer steps are required, each transferring a large number of chips. This process demands high stability and precision to ensure each chip is placed with micron-level accuracy. Below are the main mass transfer technologies currently in use:
- Laser Mass Transfer:
- First, Laser Lift-Off (LLO) is used to separate chips from the native sapphire substrate.
- Next, ablation is applied to the target substrate, where the chips are transferred onto a substrate with adhesive materials (e.g., PDMS).
- Finally, the chips are transferred from the PDM substrate to the TFT backplane using metal bonding forces on the TFT backplane.
- The technology requires precise laser removal of the GaN epitaxial layer from the sapphire substrate. The laser energy excites the GaN material, causing thermal decomposition, which leads to chip separation.
- A key challenge is that the yield of laser lift-off directly impacts the overall mass transfer yield. Furthermore, high precision is needed to control the positioning of each chip within a micron range.
- Electrostatic Transfer:
- This technique involves using a transfer head with a dual-stage structure. Electrostatic forces are applied to the chips, enabling their transfer by using positive and negative voltages for attraction and release.
- Van der Waals Force Transfer:
- This method uses an elastic stamp and high-precision motion control printhead to transfer chips via Van der Waals forces.
- Selective Release:
- This method involves transferring the Micro LED chips directly from the original substrate. The most commonly used approach is Patterned Laser Lift-Off (p-LLO).
- Self-Assembly:
- In this method, physical forces like magnetic fields or fluid dynamics are used to automatically arrange the Micro LED chips into predetermined positions.
- Transfer Printing:
- This involves using techniques like roller transfer or fluid assembly to transfer Micro LED chips onto target substrates.
Disclaimer: The views and opinions expressed in this article are those of the original authors and do not necessarily reflect the official policy or position of MiniMicroLED Insights . While we strive to ensure the accuracy and reliability of the information provided, the content on this website may include translations, re-edited versions of second-hand information, or information derived from unverifiable sources. MiniMicroLED Insights makes no representations or warranties, express or implied, regarding the completeness, accuracy, or timeliness of such content. The information in this article is for informational purposes only and should not be construed as professional advice. Any reliance you place on such information is strictly at your own risk. To the fullest extent permitted by law, MiniMicroLED Insights disclaims all liability for any direct, indirect, incidental, consequential, or punitive damages arising out of your use of, or reliance on, the information contained in this article.
Copyright Notice: This article may include translated and re-edited content derived from various online sources, including websites and social media platforms. While we strive to credit the original authors and sources to the best of our ability, we may not always be able to verify the original source of the content. All rights to the original content remain with the original author or source publication. Where applicable, this content is reproduced for educational and informational purposes under the fair use doctrine. If you believe any content on this site infringes upon your intellectual property rights, or if you are the copyright owner and believe we have not credited you correctly, please contact us at minimicroled.business@gmail.com. We will investigate and take corrective action, including removing or properly crediting the content if necessary.
Content sourced and adapted by MiniMicroLED Insights (Doris).
