Compliant micro device transfer head with integrated electrode leads
A compliant micro device transfer head and head array are disclosed. In an embodiment a micro device transfer head includes a spring arm having integrated electrode leads that is deflectable into a space between a base substrate and the spring arm.
1. A method, comprising:
forming a dielectric layer over a substrate;
forming a first electrode layer over the dielectric layer;
forming a template on the first electrode layer, wherein the template has a mesa structure;
forming a second electrode layer over the template;
patterning the second electrode layer and first electrode layer to form a bottom electrode and a top electrode; and
removing a portion of the dielectric layer from underneath the bottom electrode to form a spring arm coupled to the substrate by a spring anchor, the spring arm including:
the mesa structure, wherein the mesa structure is suspended over the substrate;
the top electrode extending laterally from the spring anchor and over the mesa structure; and
the bottom electrode extending laterally from the spring anchor underneath the mesa structure and wrapping around and over the mesa structure, wherein the top electrode and the bottom electrode are electrically isolated from each other.
2. The method of claim 1 , wherein patterning the second electrode layer and first electrode layer includes:
forming a first negative pattern on the substrate defining a first portion of a bottom electrode;
sputtering the first electrode layer over the substrate and the first negative pattern; and
removing the first negative pattern along with portions of the first electrode layer formed on the first negative pattern.
3. The method of claim 1 , wherein patterning the second electrode layer and first electrode layer includes:
forming a second negative pattern on the template, wherein the second negative pattern defines the top electrode and a second portion of the bottom electrode;
forming the second electrode layer over the template and the second negative pattern; and
removing the second negative pattern along with portions of the second electrode layer formed over the second negative pattern.
4. The method of claim 1 , wherein patterning the second electrode layer and first electrode layer includes:
forming a pattern to define a first portion of the bottom electrode in the first electrode layer; and
patterning to remove exposed portions of the first electrode layer to form the first portion of the bottom electrode.
5. The method of claim 1 , wherein patterning the second electrode layer and first electrode layer includes:
forming a pattern to define the top electrode and a second portion of the bottom electrode in the second electrode layer; and
patterning to remove exposed portions of the second electrode layer to form the second portion of the bottom electrode.
6. The method of claim 1 , wherein removing a portion of the dielectric layer from underneath the bottom electrode comprises laterally etching a portion of the dielectric layer underneath the bottom electrode.
7. The method of claim 1 , wherein the template is formed from an insulating material.
8. The method of claim 1 , wherein the template is formed from photoresist.
9. The method of claim 1 , further comprising removing the template.
10. The method of claim 1 , further comprising forming a second dielectric layer covering the top electrode and the bottom electrode over the mesa structure.