In the inkjet printing process for semiconductor-based high-end display panels, the ejection uniformity and volume accuracy of micro droplets directly govern pixel film formation quality, film thickness consistency and product yield, serving as core inspection indicators of the inkjet quality control system. Traditional methods such as contact measurement and high-speed camera observation suffer from low precision, potential micro-structure damage and inability to achieve accurate volume quantification. They fail to meet the stringent precision requirements for manufacturing high-end display devices including Mini-LED and OLED. Accordingly, establishing a standardized, high-precision inkjet quality control workflow has become critical for the industry to improve quality and efficiency.
Targeting the precision inspection demands of semiconductor displays, this paper presents a full-chain inkjet quality control workflow for high-end displays. Leveraging the non-contact 3D measurement technology of White Light Interferometer (WLI), it realizes high-precision quantitative measurement of micro droplet volume and complies with the refined quality control criteria for display panel inkjet processes. The complete workflow consists of five core modules: sample preprocessing, dynamic data acquisition, 3D reconstruction, data calibration and deviation analysis. Fully compliant with SOP specifications for semiconductor manufacturing, it supports routine and accurate quality control in mass production.
In the core inspection stage, the white light interferometer adopts combined algorithms of Vertical Scanning Interferometry (VSI) and Phase Shifting Interferometry (PSI), delivering nanometer-level vertical resolution and micrometer-level lateral scanning accuracy. It captures the microscopic 3D profiles of landed and spread micro droplets in a non-destructive manner, and accurately collects key parameters such as droplet height, diameter and curved surface morphology. Compared with Atomic Force Microscopy (AFM) which features low testing efficiency and Scanning Electron Microscopy (SEM) that requires a vacuum environment, the white light interferometer enables non-contact, high-speed full-area scanning. It effectively eliminates measurement errors caused by micro droplet deformation and contamination, generates fitted 3D models and automatically calculates micro droplet volume.
Furthermore, the workflow integrates a data traceability mechanism for semiconductor processes. It collects and stores micro droplet volume data in real time, and automatically calculates key quality indicators including volume deviation rate and ejection stability of single nozzles and multi-nozzle arrays. It accurately identifies process defects such as nozzle clogging, abnormal injection pressure and ink viscosity fluctuation, and provides quantitative data for parameter optimization and closed-loop process control of inkjet printing. This solution addresses the industry pain points of inaccurate micro droplet quantification and inconsistent quality control standards in high-end display inkjet manufacturing, and significantly enhances film uniformity and process stability of display panels.
Recrom — Professional Provider of Integrated Optical 3D Measurement Solutions
Large-Field 3D White Light Interferometer – Full-Range Measurement Solution (Industrial & Semiconductor Use)
Breaking the constraints of conventional measurement technologies and setting a new paradigm for precision measurement. Powered by core innovative technologies, this large-field 3D white light interferometer delivers nanoscale measurement for diverse application scenarios. It redefines the efficiency and accuracy of industrial metrology with outstanding performance, providing comprehensive technical support for the inspection of semiconductors, optical components and various precision parts, and fully complying with stringent measurement requirements across multiple industries.
Four Core Technological Innovations (Industrial Grade, Optimized for Semiconductor Applications)
I. Large Field of View & High Precision, Breaking Industry Norms
Surpassing the limitations of traditional equipment, objective lenses below 1× are applicable to diverse scenarios, enabling both large-field observation and high-precision measurement on a single device. Equipped with a newly developed lightweight 0.6× lens, it features an ultra-large single frame field of view of 14 mm. Combined with a turret design supporting four objective lenses, the unit fully satisfies the demands for large-field observation and high-precision measurement. It adapts to the inspection of various complex samples, eliminates frequent equipment switching, and greatly boosts inspection efficiency and data accuracy.
(The above shows the measured flatness of a 14 mm end face. Precise control of component flatness lays a solid foundation for subsequent measurement of semiconductor devices and precision optical components.)
(Measured data: 6 pm = 0.006 nm. It accurately characterizes surface roughness (Ra/Rz) to meet the ultra-precision measurement requirements for semiconductor chips and high-precision components.)
II. 80° Inclined Measurement, Beyond Planar Measurement Limits
Challenging the conventional view that white light interferometry is only for flat surfaces, it adopts advanced high-angle measurement technology to reliably measure steep inclined planes and conical surfaces up to 80° with excellent compatibility. A single device handles full-scenario measurement without extra dedicated instruments, further expanding its application scope. It is ideal for inspecting special-shaped components in semiconductor packaging, precision machining and other fields.
III. True-Color 3D Measurement, Delivering a Brand-new Experience
Breaking through technical bottlenecks in the industry, the system retains the capability of monochrome CMOS to analyze interference fringes and supports RGB true color imaging. It overcomes the limitation of traditional white light interferometers that only generate monochrome images.
It clearly presents sample morphology and color details, providing more comprehensive measurement information and more intuitive analysis. The resultant data features higher reference value, making the system well-suited for sophisticated scenarios such as surface defect detection of semiconductor devices.
IV. Upper and Lower Surface Parallelism Measurement for Diverse Scenarios
Adopting a proprietary optical path design, the system can measure the thickness and upper/lower surface parallelism of opaque workpieces. It meets the measurement requirements of various opaque precision parts and multi-layer semiconductor devices. This further expands application scenarios, enhances measurement versatility and reduces costs associated with purchasing multiple devices.
Friction Surface Characterization Cases (Industrial & Semiconductor Exclusive)
Comparative friction tests of different lubricantsMeasure scratch depth and wear area of friction surfaces to visually distinguish lubrication performance. It provides data support for optimizing lubrication systems of industrial equipment and maintaining transmission parts of semiconductor devices.
Friction surface measurement of curved rollersThe original friction surfaces of curved rollers cannot be quantified. After surface flattening, wear amount can be accurately measured and evaluated. This solution applies to quality inspection of mechanical transmission components and rollers for semiconductor equipment.
Friction surface characterization after laser drillingPerform texture detection on friction test surfaces post laser drilling. It accurately analyzes the influence of process parameters on surface roughness and flatness, and is applicable to semiconductor packaging, precision machining and other fields.
Roughness measurement for friction surfaces of automotive and semiconductor componentsConduct precise testing of roughness (Ra/Rz) on automotive friction parts and contact surfaces of semiconductor devices. It delivers authoritative data for component quality control and reliability verification of semiconductor products.
Recrom Optics delivers professional integrated optical 3D measurement solutions. Empowered by core technologies, we serve scenarios including precision measurement, semiconductor characterization and industrial quality inspection, helping diverse industries achieve high-quality development and product iteration and upgrading.