ENERGY STORAGE DEVICE WITH ENCAPSULATION ANCHORING
Approaches herein provide improved encapsulation of an energy storage device. In one approach, a thin film storage device stack is formed atop a first side of a substrate, and an encapsulant is formed over the thin film storage device stack. A recess formed in the substrate adjacent the thin film storage device stack provides an anchoring point for the encapsulant. In some approaches, the recess is provided partially through a depth of the substrate, and has a geometry to promote physical coupling between the encapsulant and the substrate.
1 . A micro energy storage device comprising:
a thin film storage device stack formed atop a first side of a substrate;
an encapsulant formed over the thin film storage device stack; and
a recess formed in the substrate adjacent the thin film storage device stack, wherein the encapsulant extends into the recess.
2 . The micro energy storage device of claim 1 , wherein the recess is an anchoring trench formed partially through a depth of the substrate.
3 . The micro energy storage device of claim 1 , further comprising a plurality of recesses formed in the substrate.
4 . The micro energy storage device of claim 3 , wherein two or more recesses of the plurality of recesses are formed on opposite sides of the thin film storage device stack.
5 . The micro energy storage device of claim 1 , wherein the recess has a lower section and an upper section, and wherein a width of the lower section is greater than a width of the upper section.
6 . The micro energy storage device of claim 5 , wherein the lower section comprises a cavity extending laterally within the substrate.
7 . The micro energy storage device of claim 1 , wherein the encapsulant comprises a plurality of encapsulation layers.
8 . The micro energy storage device of claim 7 , wherein a first layer of the plurality of encapsulation layers is formed over the thin film storage device stack and terminates along the first side of the substrate, and wherein a second layer of the plurality of encapsulation layers is formed over the first layer of the plurality of encapsulation layers and extends into the recess formed in the substrate.
9 . A micro battery, comprising:
a thin film storage device stack formed atop an upper surface of a substrate;
a thin film encapsulant formed over the substrate, the thin film encapsulant adhering to exposed surfaces of the thin film storage device stack and to the upper surface of the substrate; and
a recess formed in the substrate adjacent the thin film storage device stack, wherein the thin film encapsulant is secured within the recess.
10 . The micro battery of claim 9 , wherein the recess is an anchoring trench formed partially through a depth of the substrate.
11 . The micro battery of claim 9 , further comprising a plurality of recesses formed in the substrate.
12 . The micro battery of claim 11 , wherein two or more recesses of the plurality of recesses are formed on opposite sides of the thin film storage device stack.
13 . The micro battery of claim 9 , wherein the recess has a lower section and an upper section, a width of the lower section being greater than a width of the upper section.
14 . The micro battery of claim 13 , wherein the lower section comprises a cavity extending laterally within the substrate.
15 . The micro battery of claim 9 , wherein the thin film encapsulant comprises a plurality of encapsulation layers, wherein a first layer of the plurality of encapsulation layers is formed over the thin film storage device stack and terminates along the upper side of the substrate, and wherein a second layer of the plurality of encapsulation layers is formed over the first layer of the plurality of encapsulation layers and extends into the recess formed in the substrate.
16 . A method of forming a micro battery cell, comprising:
providing a thin film storage device stack on a first side of a substrate;
providing a recess in the substrate adjacent the thin film storage device stack; and
forming a thin film encapsulant over the thin film storage device stack, wherein the thin film encapsulant is further formed within the recess formed in the substrate.
17 . The method of claim 16 , further comprising forming a plurality of recesses in the substrate, wherein two or more recesses of the plurality of recesses are formed on opposite sides of the thin film storage device stack.
18 . The method of claim 16 , wherein the recess includes a lower section and an upper section, and wherein a width of the lower section is greater than a width of the upper section.
19 . The method of claim 16 , wherein forming the thin film encapsulant comprises:
forming a first layer over the thin film storage device stack, wherein the first layer terminates along the first side of the substrate; and
forming a second layer over the first layer, wherein the second layer extends into the recess formed in the substrate.
20 . The method of claim 16 , wherein the recess is an anchoring trench formed partially through a depth of the substrate.