From Millimeter to Micrometer: The Precision Road of Glass Thinning Technology

Today, when smart phones are becoming thinner and thinner, folding screens are maturing, and on-board displays are becoming more and more important, the thickness of a piece of glass is no longer just a physical dimension, but a key parameter to measure whether electronic products can take the lead in the competition. Glass thinning The value of technology lies in the space competition.

The glass thinning technology is a precision process system born to meet the space and weight requirements of modern electronic equipment. Its technical essence is not simply grinding and polishing, but through physical or chemical means to achieve accurate and controllable removal of glass substrates on the premise of maintaining the structural integrity and surface quality of materials.

Chemical thinning is one of the core technology paths, which is mainly achieved through the unique chemical reaction between hydrofluoric acid (HF) and silica in glass. The reaction process is highly sensitive to concentration, temperature and type of additives. The precise formula design and process control ensure the accuracy and stability of the final thickness. For example, the etching uniformity can be optimized by properly adjusting the proportion of ammonium bifluoride buffer; A small amount of sulfuric acid is added to help reduce haze – each minor adjustment is to control the material “removal” process within the ideal range.

To achieve thinner or higher specifications Glass processing Demand, physical and chemical composite process has become an inevitable choice. After chemical etching breaks through the initial thickness limit, coupled with physical mechanical precision polishing (such as chemical mechanical flattening technology), it can further reduce the thickness and achieve the perfect repair of surface roughness at the nanometer level. In the ion exchange strengthening link, the exchange parameters need to be recalculated closely in combination with the thickness of the thinned glass to ensure that the depth of the stress layer adapts to the new structural proportion and reconstructs its ability to resist damage in the thin glass.

The value of this precision technology is deepening in many fields:

• ​ Mobile electronic equipment: The display glass thickness of mainstream flagship smart phones has moved from 0.7 mm to 0.5 mm or less. The 0.4 mm OLED ultra-thin cover glass has gradually become a high-end standard configuration. Every 0.1 mm reduction will bring huge release of internal space value.
• ​ New display applications: The core process of ultra thin flexible glass (UTG) that the inner screen of the folding screen mobile phone relies on is thinned to 30-70 μ m in depth and matched with ion exchange strengthening to form “armor”; In the high-resolution micro display screen for VR/MR devices, the thinning of the backplane glass has a direct effect on reducing the overall thickness of the optical module and optimizing the field of view angle.
• ​ Advanced semiconductor packaging: In wafer level optical elements (WLO) and wafer level packaging (WLP), temporary plate glass thinning is indispensable to ensure the reliability of thin chip processing.

The value of glass thinning process goes far beyond the reduction of physical thickness:

• ​ Breakthrough design ceiling: It enables engineers to explore more complex structural forms, such as multi curvature body glass panels or multi angle intelligent terminal devices.
• ​ Improve structural responsiveness: The inertia of the thinned glass structure is reduced, and it is more sensitive to touch, vibration feedback and other actions, which further improves the user experience.
• ​ Optimize optical performance: The application of curved cover glass can greatly reduce the possibility of optical distortion, enhance the light transmission effect, and make the display image more transparent.

The glass thinning process is also imperfect. The thinner shape will inevitably put forward more stringent requirements on the original quality of materials, and any minor defects will be easier to reveal after thinning. The waste liquid treatment generated in the chemical treatment process also challenges the environmental protection technology.

Every breakthrough in glass thinness comes from the combined efforts of materials, equipment technology and engineering science. Behind this seemingly ordinary glass is the precise wisdom of human beings to expand boundaries in the limited physical world – to carve the future in a millionth of an inch and reshape the possibility in a precise place.