Method for forming thin film photovoltaic interconnects using self-aligned process

#The present invention relates generally to photovoltaic devices, and more particularly to a system and method for making improved interconnects in thin-film photovoltaic devices.

#Thin film solar modules offer an attractive way to achieve low manufacturing cost with reasonable efficiency. These modules are made from a variety of materials, including amorphous silicon, amorphous silicon germanium, copper indium gallium selenide (CIGS), and cadmium telluride. A common feature of these solar modules is the deposition on a large area insulator such as a glass sheet.

#Another common feature of these modules is the use of scribes and interconnects to divide the large area deposited layer into a number of cells and/or sub-cells. A top view of a typical module divided in this fashion is shown in FIG. 1. As shown in FIG. 1, a module 100 is divided into a plurality of cells 102 (i.e. stripes) that are series connected (e.g. electrically connected together in a horizontal direction in this drawing) via interconnects 104. The interconnects are typically formed in the module using scribes and conductors. However, it should be noted here that the length L of such modules 100 can be 1 meter or more. Meanwhile, the width of the interconnects (corresponding to the dimension W in FIG. 2), which typically run almost the entire length L of the module, are typically around 700-1000 μm, and the width of the cells (i.e. stripes) are typically about 1 cm. As will be understood by those of skill in the art, FIG. 1 is a simplified, not-to-scale drawing of a typical module, and that the module can further include other passive and active components not shown in FIG. 1 such as electrodes, protect diodes and terminals. Moreover, the module will typically also include external contacts and/or be environmentally encapsulated.

#These and other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures, wherein:

#FIG. 1 is a top view of a conventional module of thin film photovoltaic cells separated by interconnects;

#FIGS. 2A-E show a process of forming an interconnect between thin film photovoltaic cells according to a co-pending application; and

#The following describes the reference numerals used in the drawings. This description is intended to be illustrative rather than limiting and those skilled in the art will appreciate that various substitutions and modifications can be made while remaining within the scope of the invention:

#The present invention will now be described in detail with reference to the drawings, which are provided as illustrative examples of the invention so as to enable those skilled in the art to practice the invention. Notably, the figures and examples below are not meant to limit the scope of the present invention to a single embodiment, but other embodiments are possible by way of interchange of some or all of the described or illustrated elements. Moreover, where certain elements of the present invention can be partially or fully implemented using known components, only those portions of such known components that are necessary for an understanding of the present invention will be described, and detailed descriptions of other portions of such known components will be omitted so as not to obscure the invention. In the present specification, an embodiment showing a singular component should not be considered limiting; rather, the invention is intended to encompass other embodiments including a plurality of the same component, and vice-versa, unless explicitly stated otherwise herein. Moreover, applicants do not intend for any term in the specification or claims to be ascribed an uncommon or special meaning unless explicitly set forth as such. Further, the present invention encompasses present and future known equivalents to the known components referred to herein by way of illustration.

#In general the present invention relates to methods of forming interconnects in thin-film photovoltaic devices that use processes similar to conventional IC fabrication processes. Such processes leverage certain self-alignment and scalability advantages inherent in using IC fabrication techniques.