Thin passivation layer on 3D devices
Embodiments of the invention include a device with stacked substrates. Conducting interconnecting structures of one substrate are bonded to conducting interconnecting structures of another substrate. A passivating layer may be on the conducting interconnecting structures between the substrates and may be formed by an atomic layer deposition process or a with a Langmuir-Blodgett technique.
1. A method, comprising:
forming a first passivating layer on conductive interconnecting structures of a first substrate, using a process chosen from a group consisting of an atomic layer deposition process and a Langmuir-Blodgett technique;
forming a second passivating layer on conductive interconnecting structures of a second substrate, using a process chosen from a group consisting of an atomic layer deposition process and a Langmuir-Blodgett technique;
aligning the first substrate to the second substrate so that the conductive interconnecting structures of the first and second substrates are in physical contact but are separated by the first and second passivating layers; and
thermo compression bonding the first substrate to the second substrate, thereby causing the conductive interconnecting structures of the first and second substrates to make electrical contact through the passivating layers.
2. The method of claim 1 , wherein forming the passivating layer on conductive interconnecting structures of the first substrate comprises forming the passivation layer by an atomic layer deposition process and wherein the passivating layer is an insulating layer.
3. The method of claim 2 , wherein forming the passivating layer on conductive interconnecting structures of the second substrate comprises forming the passivation layer by Langmuir-Blodgett technique.
4. The method of claim 1 , wherein at least some of the material of the passivating layers between the conductive interconnecting structure of the first substrate and the conductive interconnecting structure of the second substrate prior to bonding remains in a bonded region between the conductive interconnecting structure of the first substrate and the conductive interconnecting structure of the second substrate after bonding.
5. The method of claim 1 , wherein the passivating layers have a thickness less than about 30 angstroms.
6. The method of claim 1 , wherein the passivating layers are formed by a Langmuir-Blodgett technique and substantially consists of a monolayer of molecules.
7. The method of claim 1 , wherein the passivating layers are formed by a Langmuir-Blodgett technique and is formed after bonding the first substrate to the second substrate.