Thin film structures and devices with integrated light and heat blocking layers for laser patterning

Patent metadata

Field	Value
Publication number	US-9240508-B2
Application number	US-201514673151-A
Country	US
Kind code	B2
Filing date	Mar 30, 2015
Priority date	Aug 8, 2011
Publication date	Jan 19, 2016
Grant date	Jan 19, 2016

Abstract

Selective removal of specified layers of thin film structures and devices, such as solar cells, electrochromics, and thin film batteries, by laser direct patterning is achieved by including heat and light blocking layers in the device/structure stack immediately adjacent to the specified layers which are to be removed by laser ablation. The light blocking layer is a layer of metal that absorbs or reflects a portion of the laser energy penetrating through the dielectric/semiconductor layers and the heat blocking layer is a conductive layer with thermal diffusivity low enough to reduce heat flow into underlying metal layer(s), such that the temperature of the underlying metal layer(s) does not reach the melting temperature, T m , or in some embodiments does not reach (T m )/3, of the underlying metal layer(s) during laser direct patterning.

First claim

What is claimed is:

1. A thin film device, compatible with laser direct patterning by a laser beam for selective removal of dielectric and/or semiconductor layers, comprising:
a substrate;
a first device layer covering said substrate;
a first heat blocking layer covering said first device layer,
a first light blocking layer covering said first heat blocking layer; and
a second device layer covering said first light blocking layer;
wherein said first light blocking layer is a layer of metal characterized by the property of absorbing or reflecting a portion of the laser energy reaching said first light blocking layer and said first heat blocking layer is a conductive layer with thermal diffusivity, D, low enough to reduce heat flow through said first heat blocking layer during laser direct patterning such that the temperature of an adjacent device layer exceeds the melting temperature, T m , of said adjacent device layer.

2. The device of claim 1 , wherein said adjacent device layer is said second device layer and wherein said first light blocking layer is a layer of metal characterized by the property of absorbing or reflecting a portion of the laser energy penetrating through said second device layer towards said first device layer and said first heat blocking layer is a conductive layer with thermal diffusivity, D, low enough to reduce heat flow into said first device layer from said second device layer during laser direct patterning such that the temperature of said first device layer does not reach the melting temperature, T m ′, of said first device layer.

3. The device of claim 1 , wherein said adjacent device layer is said first device layer and wherein said first light blocking layer is a layer of metal characterized by the property of absorbing or reflecting a portion of the laser energy penetrating through said first device layer towards said second device layer and said first heat blocking layer is a conductive layer with thermal diffusivity, D, low enough to reduce heat flow into said second device layer from said first device layer during laser direct patterning such that the temperature of said first device layer exceeds the melting temperature, T m ′, of said first device layer.

4. The device of claim 1 , wherein said first heat blocking layer is a conductive layer with thermal diffusivity low enough to reduce heat flow into said first device layer from said second device layer during laser direct patterning such that the temperature of said first device layer does not reach (T m )/3 of said first device layer.

5. The device of claim 1 , wherein the thickness of said first heat blocking layer is greater than the thermal diffusion length, √(Dτ), wherein τ is the laser pulse duration.

6. The device of claim 1 , wherein said first light blocking layer and said first heat blocking layer are the same layer.

7. The device of claim 1 , further comprising:
a second heat blocking layer within said second device layer and a second light blocking layer covering said second heat blocking layer;
wherein said second device layer comprises a first portion of said second device layer covered by said second heat blocking layer and a second portion of said second device layer covering said second light blocking layer, and wherein said second light blocking layer is a layer of metal characterized by the property of absorbing or reflecting a portion of the laser energy penetrating through said second portion of said second device layer towards said first portion of said second device layer and said second heat blocking layer is a conductive layer with thermal diffusivity, D, low enough to reduce heat flow into said first portion of said second device layer from said second portion of said second device layer during laser direct patterning such that the temperature of said first portion of said second device layer does not reach the melting temperature, T m ″, of said first portion of said second device layer.

8. The device of claim 7 , wherein said thin film device is a thin film battery, said first device layer is a current collector layer and said first portion of said second device layer is a stack comprising an anode current collector, an anode, an electrolyte and a cathode, and said second portion of said second device layer is a protective coating.

9. The device of claim 1 , wherein said thin film device is a thin film battery.

10. The device of claim 9 , wherein said first device layer is a current collector layer and said second device layer is a stack comprising an anode current collector, an anode, an electrolyte and a cathode.

11. The device of claim 9 , wherein said first light blocking layer is a layer of gold metal, said layer of gold metal being less than 10 nanometers thick.

12. The device of claim 9 , wherein said first heat blocking layer is a layer of indium tin oxide.

13. The device of claim 12 , wherein said layer of indium tin oxide is greater than 100 nanometers thick and wherein said laser beam is generated by a nanosecond pulse width laser.

14. The device of claim 1 , wherein said substrate is a glass substrate.

15. The device of claim 1 , wherein said laser beam is generated by a visible light laser.

16. The device of claim 6 , wherein said first light blocking layer is a 10 nm layer of titanium and said laser beam is generated by a picosecond laser.

17. The device of claim 1 , wherein the thermal diffusivity of said heat blocking layer is less than 0.1 cm 2 /s.

18. The device of claim 1 , wherein said substrate is a glass substrate and said laser beam is generated by an ultraviolet-visible laser.

19. The device of claim 1 , wherein said substrate is a silicon substrate and said laser beam is generated by an infrared laser.

20. The device of claim 6 , wherein the heat and light blocking layer is a layer of thermoelectric material.

Assignees

• Applied Materials Inc

Inventors

• Song Daoying
• Jiang Chong
• Kwak Byung-Sung Leo
• Gordon Ii Joseph G

Classifications

• H10F19/33

  Patterning processes to connect the photovoltaic cells, e.g. laser cutting of conductive or active layers · CPC title

• H10F77/707

  of the substrates or of layers on substrates, e.g. textured ITO layer on a glass substrate · CPC title

• H10F71/00 Primary

  Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00) · CPC title

• H10F71/137 Primary

  Batch treatment of the devices · CPC title

• H10F77/60

  Arrangements for cooling, heating, ventilating or compensating for temperature fluctuations · CPC title