Application market of automotive display packaging solder
The rapid development of automotive display technology has driven the demand for high-performance packaging solders. The main growth drivers include:
◆ Popularization of new energy vehicles: The smart cockpit of electric vehicles has a higher demand for display screens, such as large-size central control screens, co-pilot entertainment screens, etc.
◆ Immersive driving experience: New technologies such as AR-HUD (augmented reality head-up display), 3D instrument panels, and multi-screen interaction rely on high-reliability packaging solders.
◆ 5G+AIoT technology integration: Internet of Vehicles and autonomous driving require display screens to have higher stability and anti-interference capabilities.
Main application scenarios
Packaging solder is widely used in the manufacture of automotive display modules, including:
◆ Display driver IC packaging (such as COF, COG process)
◆ Flexible OLED and Mini LED backlight module welding
◆ Lamination of touch sensor and cover glass
◆ Fixing of HUD (Head Up Display) optical components
As in-vehicle displays develop towards larger size, higher resolution and greater flexibility, the performance requirements for solders are also constantly increasing.
Typical solder paste types and characteristics of automotive display packaging solder
In the manufacturing of automotive displays, solder paste is one of the most commonly used welding materials, which can be divided into the following categories:
1． Lead-Free Solder Paste
Due to the requirements of environmental regulations (such as RoHS, REACH), lead-free solder paste has become the mainstream of the industry. The main ingredients include:
◆ SAC305 (Sn96.5Ag3.0Cu0.5): High reliability, suitable for high temperature environments in vehicles.
◆ SnAgCu : Improves thermal fatigue resistance.
Features:
◆ Comply with environmental regulations
◆ Good high temperature resistance (can withstand automotive grade -40°C~125°C temperature cycle)
◆ The soldering temperature is high (about 230-250°C), which may affect the flexible substrate
2． Low-Temperature Solder Paste (LTS)
Mainly used for flexible OLED and Mini LED packaging, typical ingredients:
◆ SnBi58 (Sn42Bi58): Melting point is about 138°C, suitable for heat-sensitive materials.
◆ SnBiAg : Silver (Ag) is added to improve mechanical strength.
Features:
◆ Reduce thermal stress and avoid deformation of flexible substrate
◆ Suitable for high-precision welding (such as Micro LED packaging)
◆ Low mechanical strength, requires underfill to enhance reliability
Challenges of Solder in Automotive Display Packaging
Despite the continuous advancement of solder technology, the following challenges still exist in the field of automotive displays:
1． Reliability issues in high temperature and high humidity environments
The ambient temperature inside a car varies greatly (-40°C~85°C), and solder joints are prone to cracks due to mismatch in the coefficient of thermal expansion (CTE) .
2． Challenges of miniaturization and high-density welding
With the application of Mini LED and Micro LED technologies, the pad size has been reduced to below 50μm, which puts higher requirements on the printing accuracy and welding process of solder paste.
3． Soldering Problems of Flexible Substrates
Flexible OLEDs and foldable displays require low-temperature soldering, but the mechanical strength of low-temperature solder paste is low, and new packaging technologies (such as laser welding and conductive adhesives) need to be combined to improve reliability.
4． Supply chain and cost pressures
The rising prices of precious metals such as silver (Ag) and indium (In) have driven the industry to look for alternative materials (such as copper sintering technology).
Packaging Material Solutions from Shenzhen Earlysun Technology Co. Ltd
Based on the above-mentioned demands, domestic packaging material companies represented by Chenri Technology have seized the opportunity, made active arrangements, and invested heavily in R&D resources. Relying on years of mass production experience, they have entered multiple key directions such as packaging structure, materials, and processes, and launched a variety of high-reliability packaging solders including solid crystal solder paste, packaging glue, Mini solder paste, Mini backlight lens glue/packaging glue, Mini display epoxy glue and other products.
Earlysun Mini solder pastes products
EM-6001 is a solid crystal solder paste developed by the company for Mini LED printing process technology. It is formulated with high-purity lead-free Sn96.5Ag3Cu0. alloy (No. 6 powder) solder powder and ROL0-level carrier. It has good printability and demoulding properties under fine pitch pad size, and has very little residue after reflow soldering, is non-corrosive, and has full and bright solder joints without collapse and welding bridge short circuit, meeting the electrical parameter requirements of high precision and high reliability.
Product Features:
◆ The particle size of tin powder is concentrated in 5-15μm, which can effectively control the precision of solder paste on a single substrate pad during flip chip and can meet the die bonding of small-sized chips such as 3*6mil and 4*7mil.
◆ Excellent anti-oxidation formula design ensures that the solder paste will not oxidize during 12 hours of printing. It is recommended to add and collect the mixture every 6 hours during printing.
◆ Good printability and demoulding properties. When printing on the steel screen, the amount of tin applied is uniform, without tailing, wire drawing, solder joint adhesion, etc., and the consistency is good.
◆ After reflow soldering, the solder joints are full and bright, the void rate is very small, there are no small tin beads, the chip will not tilt or shift, and the mounting effect is good.
Development prospects and trends
1． Exploration of new solder technology
Copper sintering technology: replaces high-cost silver materials and improves high-temperature reliability.
2． Intelligent welding process
AI+SPI (Solder Paste Inspection): Combined with machine learning to optimize solder paste printing quality.
Laser-assisted welding: improving the packaging accuracy of flexible displays.
3． Green Trend
Halogen-free solder paste: reduces environmental pollution.
Recyclable solder: driving sustainable development.
4． Industry Collaborative Innovation
Activities such as the "2025 International Smart Cockpit and In-Vehicle Display Technology Exchange Summit" will promote cooperation between vehicle manufacturers, TIER1, and material suppliers, and accelerate the implementation of new technologies.
The rapid development of in-vehicle display technology has brought huge opportunities to the packaging solder industry but also put forward higher technical requirements. In the future, with the breakthrough of new solders, intelligent processes and green materials, in-vehicle display packaging solders will develop in the direction of high reliability, miniaturization and environmental protection, providing key support for the upgrade of smart cockpits.
