Metal-Assisted Chemical Etching for Solar Cell Texturing

A method for precise and environmentally friendly etching of copper seed layers in solar cells. The process involves a degumming treatment followed by controlled reverse electrolysis, where the battery sheets undergo a chemical treatment to remove the seed layer, followed by a controlled electrolysis process to remove the seed layer while preserving the underlying copper layer. This method eliminates the need for chemical etching solutions and their disposal, while maintaining the structural integrity of the seed layer.

Source

A porous monolithic AgAu catalyst layer for uniform wet etching of silicon substrates during chemical mechanical planarization (CMP) processes. The catalyst layer comprises an Au layer with a porous structure that is selectively deposited on silicon substrates during wet etching. The porous structure of the AgAu layer is created through controlled galvanic replacement of the reduced porous Ag layer, which prevents Ag particles from moving randomly during etching. The layer's porous structure enables uniform wet etching while maintaining chemical stability, enabling the production of high-quality transparent silicon substrates for solar cells.

Source

Method to reduce residual metal on solar cells after processing steps like etching and plating. The method involves specific conditions for tin plating, heat treatment, and photoresist removal to prevent residual metal left behind. This includes increasing tin plating current density, heat treating the tin layer, washing with higher flow rate, and using lower temperature alkaline solutions. By optimizing these steps, it allows complete removal of the metal layers and prevents residue from forming.

Source

A method for creating a photovoltaic wafer surface with a controlled porosity layer that significantly reduces light reflection. The method involves applying a solution of a linear or branched-chain alcohol with 10 carbon atoms or less to the wafer surface, followed by treatment with metal ion-containing hydrofluoric acid. The alcohol treatment creates a uniform, controlled porosity structure on the wafer surface, while the hydrofluoric acid treatment selectively removes metal ions to create micropores. The resulting wafer surface exhibits significantly reduced light reflection compared to standard silicon surfaces, achieving an optimized photovoltaic performance.

Source

A method for texturing silicon wafers using room-temperature copper-assisted etching that enables high-efficiency solar cells. The method employs copper nanoparticles to create pyramid-like structures on the silicon surface during etching, where the copper nanoparticles nucleate and grow in response to the etching environment. This spontaneous growth process enables the formation of pyramid structures with controlled dimensions and orientations, significantly reducing surface reflectance compared to traditional etching methods. The method achieves an average reflectance of less than 11% across the solar spectrum, enabling efficient solar cell performance.

Source

A method for preparing metal electrodes in heterojunction solar cells that eliminates the need for mask exposure, development, and activation steps. The method involves pre-soaking the TCO layer with a body film that maintains the activation solution's stability during the subsequent electroplating process. This pre-soaking step prevents unwanted solution evaporation and maintains the activation solution's solubility, enabling rapid and efficient electrode preparation. The method achieves high-quality electrodes with reduced processing steps and costs compared to traditional methods.

Source

A selective etching solution for back-contact heterojunction solar cells that enables precise removal of P-type conductive layers without compromising the underlying insulating film. The solution combines a strong oxidizing agent with a buffer system to selectively etch the P-type layers at normal temperatures, while maintaining selectivity through the use of a buffer component. This approach eliminates the need for high-temperature alkali solutions and strong oxidizing agents, which are commonly used for conventional P-type etching. The solution is compatible with silicon-based materials and can be used in both laser and conventional etching methods.

Source

Etching method for TOPCon solar cells that reduces cost, chemical consumption, and over-etching risk compared to conventional methods. The method involves sequential acid and alkali etching steps to remove layers from the TOPCon cell. First, an acid etch removes the PSG layer on the front side. Then, an alkali etch removes the exposed polysilicon. Finally, an acid etch removes the BSG on the front side and the remaining PSG on the back side. This step-by-step approach avoids using nitric acid and sodium hydroxide together, which can lead to over-etching and waste.

Source

A novel etchant composition for metal film deposition that enables precise control of etch rate, low etch loss, and optimal taper profile during metal film etching. The composition combines a glycolic acid-azole-phenylurea system with specific additives to achieve these characteristics. The composition enables stable and controlled etching conditions, particularly beneficial in high-throughput applications where multiple substrates need to be processed simultaneously.

Source

A solar cell manufacturing process and structure that eliminates adhesion issues associated with traditional copper plating methods. The process employs an electroplating seed formed from an aluminum layer that directly connects to the solar cell's diffusion region. A nickel layer is deposited on the aluminum seed, forming a nickel-aluminum stack. Copper is then electroplated in a methanesulfonic acid-based plating bath, eliminating the need for traditional sulfuric acid-based baths and significantly reducing the manufacturing complexity and cost of solar cell fabrication.

Source

A metal film etchant composition and method for etching metal films with improved etching characteristics, particularly in processes requiring precise control over etch rate and profile. The etchant composition employs a novel combination of surfactants and additives that enable controlled etching behavior while maintaining low etch loss and appropriate taper profiles. This composition enables precise control over etch rate and profile, making it suitable for applications requiring high precision etching of metal films.

Source

Metal film etchant composition and etching method for semiconductor and liquid crystal display devices that achieve precise control over etch rate and loss while maintaining optimal etching conditions. The etchant composition comprises organic acid (imidodiaceitc acid) and azole compound (aminotetraazole), which enable precise etch rate control through the modulation of etching conditions. The composition also ensures minimal etch loss by maintaining appropriate etching conditions during the etching process. The composition's unique composition enables optimal etching characteristics, including controlled etch rate and loss, and maintains proper etching conditions during the etching process.

Source

A process for recycling silicon solar cells through selective removal of metallic contacts. The process involves selective etching of the metallic contacts, specifically the emitter contacts, while preserving the aluminum contacts on the back of the solar cell. This selective etching enables the removal of the metallic contacts without damaging the underlying silicon substrate, while maintaining the structural integrity of the solar cell.

Source

Etching method and application of silicon nitride in crystalline silicon solar cells, particularly for achieving low-temperature sintering and lead-free metallization. The method involves using tellurium glass as the front electrode in crystalline silicon solar cells, where tellurium glass forms a stable silver-silicon contact through oxidation. The tellurium glass powder is melted during the sintering process, forming a stable glass-oxide interface that enables the formation of a high-quality silver-silicon contact. This approach enables the use of tellurium glass in crystalline silicon solar cells, particularly for low-temperature sintering and lead-free metallization, while maintaining high efficiency and performance.

Source

Silver etchant composition for etching silver thin films in flat panel displays, enabling precise patterning and control of side etching profiles. The composition combines nitric acid, alkylsulfonic acids, and other organic acids to achieve superior etching properties without phosphoric acid. This composition enables selective etching of silver films while minimizing side etching and re-adsorption, allowing for precise control of etch profiles and maintaining etching performance even in multiple treatment cycles.

Source

Solar cell unit with enhanced power generation efficiency through controlled patterning of metal and insulating layers. The solar cell comprises a semiconductor substrate with a metal layer, an insulating layer, and a second semiconductor layer. A resist layer containing resin and inorganic particles is applied to the metal layer and insulating layer, with the resist layer forming conical-shaped openings that penetrate these layers. The resist layer's conical shape is optimized to ensure precise patterning while maintaining structural integrity. This controlled patterning enables precise control over the metal and insulating layer interfaces, resulting in improved electrical isolation and reduced defects in the solar cell.

Source

A metal ion-assisted non-nitric acid polishing method for high-efficiency solar cells. The method improves the reflective surface of PERC solar cells by enhancing the uniformity of the back passivation coating. The polishing process involves cleaning the polished silicon wafer, followed by a metal ion-assisted etching step that selectively removes defects and impurities while maintaining the metal ion concentration. This approach enables improved reflectivity and stability compared to conventional acid-based polishing methods, while minimizing the environmental impact of acid waste disposal.

Source

A method for forming high-performance metal contacts in solar cells through controlled deposition and patterning of metal layers. The process involves selectively depositing metal onto the solar cell substrate using a controlled flow of molten metal, followed by precise patterning and patterning of the deposited metal to create interdigitated contact patterns. The deposited metal layer is then cooled and solidified to form a continuous metal contact interface between the metal and substrate. The patterning step enables the creation of back contacts in solar cells with integrated contacts, while maintaining substrate integrity.

Source

A method for producing high-efficiency photovoltaic solar cells with improved electrical contact quality. The method involves creating a metal foil on the rear side of the solar cell precursor, which is then mechanically bonded to the solar cell structure. This metal foil contact enables precise and efficient electrical connections between the solar cell's base and emitter regions, while minimizing the formation of spiking and other defects that can compromise solar cell performance. The metal foil is electrically connected to the solar cell structure through a conductive adhesive. This approach provides a cost-effective solution for achieving high-efficiency solar cells while maintaining superior electrical contact quality compared to conventional screen-printing methods.

Source

A method for improving adhesion between a transparent electrode and a metal in solar cells, specifically targeting high contact resistance in transparent electrodes. The method employs a copper (Cu) electrode with a lower contact resistance compared to silver (Ag) while maintaining comparable electrical conductivity. The Cu electrode is deposited using a PVD process, enabling high contact resistance between the transparent electrode and metal contacts. This approach enables the creation of solar cells with improved adhesion and contact resistance between transparent electrodes and metal contacts, particularly in applications where high contact resistance is critical.

Source