Display Electrode Structure With Inorganic Depression for Fewer Masks

The patent combines multiple mask patterns into a single mask design. The mask includes a first pattern for the first metal layer and a second pattern for the inorganic layer, allowing both layers to be formed simultaneously in one photolithography step. This merging of multiple patterning operations into a single operation reduces process complexity while maintaining the precision needed for high-resolution display manufacturing.

The single mask serves multiple functions by defining patterns for both the first metal layer and the inorganic layer. The mask design includes openings that simultaneously define the source/drain electrode regions and the inorganic layer regions, making it a multi-functional patterning tool that replaces what would traditionally require separate masks for each layer.

The patent resolves the precision concern by adding a vertical dimension to the patterning process. After forming the first metal layer and inorganic layer using the single mask, a third metal layer is formed that bridges between them. This vertical stacking approach allows the single mask to define critical horizontal patterns while subsequent layers are formed to connect and integrate the structures, maintaining precision without requiring multiple masks.

The mask is designed with preliminary considerations for subsequent processing steps. The openings in the mask are strategically positioned and sized to account for later etching, deposition, and planarization steps. This preliminary design ensures that even though only one mask is used, the final pattern precision meets high-resolution display requirements by anticipating and compensating for subsequent process variations.

The patent incorporates a depression portion in the inorganic layer as a protective feature formed during the simplified single-mask process. This depression creates a physical cushion or buffer zone that prevents direct contact between the first metal layer and potential contaminants or stress points. By building this protective feature into the structure during the simplified manufacturing process, reliability is enhanced without adding process complexity.

The inorganic layer is selectively formed with different properties in different regions. The depression portion creates a local variation in the inorganic layer structure, providing enhanced protection or stress relief at specific locations where the first metal layer is present. This local quality enhancement maintains overall reliability while keeping the manufacturing process simple and unified.