Low stress films for advanced semiconductor applications
Films that can be useful in large area gap fill applications, such as in the formation of advanced 3D NAND devices, involve processing a semiconductor substrate by depositing on a patterned semiconductor substrate a doped silicon oxide film, the film having a thickness of at least 5 μm, and annealing the doped silicon oxide film to a temperature above the film glass transition temperature. In some embodiments, reflow of the film may occur. The composition and processing conditions of the doped silicon oxide film may be tailored so that the film exhibits substantially zero as-deposited stress, substantially zero stress shift post-anneal, and substantially zero shrinkage post-anneal.
1. A method of processing a semiconductor substrate, the method comprising:
providing a patterned semiconductor substrate;
depositing on the patterned semiconductor substrate a doped silicon oxide film, wherein the doped silicon oxide film has a thickness of at least 5 μm; and
annealing the doped silicon oxide film to a temperature above the film glass transition temperature,
wherein the doped silicon oxide film is deposited by a chemical vapor deposition (CVD) process using precursors for silicon oxide and a dopant selected from the group consisting of B, P, and Ge, and
wherein each of the precursors for the dopant is selected from the group consisting of triethylborate (TEB), triethylphosphate (TEPO), and an organogermanium compound.
2. The method of claim 1 , wherein the silicon oxide precursor is tetraethyl orthosilicate (TEOS).
3. The method of claim 1 , wherein the CVD is a plasma enhanced CVD (PECVD) process.
4. The method of claim 1 , further comprising depositing an undoped silicon oxide capping layer on the doped silicon oxide film.
5. The method of claim 1 , wherein the doped silicon oxide film has a dopant concentration in the range of up to about 10 wt % of the film; or 0.5 to 10%; or 2-5%; or 2.5-3.5%.
6. The method of claim 5 , wherein the doped silicon oxide film has a dopant concentration in the range of about 0 to 10 wt % of the film B, 0 to 10% P, 0 to 10% Ge.
7. The method of claim 1 , wherein the patterned semiconductor substrate is a 3D NAND structure having alternating oxide and nitride or polysilicon layers in a staircase pattern, and the doped silicon oxide film is deposited over the staircase pattern.
8. The method of claim 1 , wherein the doped silicon oxide film has a thickness of at least 10 μm.
9. The method of claim 1 , wherein the doped silicon oxide film is deposited at a thickness up to 20 μm by a single-pass deposition.
10. The method of claim 1 , wherein the doped silicon oxide film is deposited at a rate of at least 1 μm per minute.
11. The method of claim 1 , wherein the annealing of the doped silicon oxide film causes reflow of the film to occur.
12. A semiconductor device, comprising:
a 3D NAND structure having alternating oxide and nitride or polysilicon layers in a staircase pattern; and
a doped silicon oxide film disposed and annealed on the staircase pattern, wherein the doped silicon oxide film has a thickness of at least 5 μm,
wherein the doped silicon oxide film is deposited by a chemical vapor deposition (CVD) process using precursors for silicon oxide and a dopant selected from the group consisting of B, P, and Ge,
wherein each of the precursors for the dopant is selected from the group consisting of triethylborate (TEB), triethylphosphate (TEPO), and an organogermanium compound, and
wherein the doped silicon oxide film disposed and annealed on the staircase pattern exhibits substantially zero as-deposited stress, substantially zero stress shift post-anneal, and substantially zero shrinkage post-anneal.
13. The semiconductor device of claim 12 , wherein the doped silicon oxide film has a dopant concentration in the range of up to about 10 wt % of the film; or 0.5 to 10%; or 2-5%; or 2.5-3.5%.
14. The semiconductor device of claim 13 , wherein the doped silicon oxide film has a dopant concentration in the range of about 0 to 10 wt % of the film B, 0 to 10% P, 0 to 10% Ge.
15. The semiconductor device of claim 12 , wherein the doped silicon oxide film has a thickness of at least 10 μm.
16. An apparatus for processing substrates, the apparatus comprising:
a process chamber having a chuck;
a gas source connected with the process chambers and associated flow-control hardware;
substrate handling hardware; and
a controller having a processor and a memory, wherein:
the processor and the memory are communicatively connected with one another,
the processor is at least operatively connected with the flow-control and substrate handling hardware, and
the memory stores computer-executable instructions for controlling the processor to at least control the flow-control hardware and substrate handling hardware by:
providing a patterned semiconductor substrate;
depositing on a patterned semiconductor substrate disposed in the chamber a doped silicon oxide film having a thickness of at least 5 μm; and
annealing the doped silicon oxide film to a temperature above the film glass transition temperature,
wherein the doped silicon oxide film is deposited by a chemical vapor deposition (CVD) process using precursors for silicon oxide and a dopant selected from the group consisting of B, P, and Ge, and
wherein each of the precursors for the dopant is selected from the group consisting of triethylborate (TEB), triethylphosphate (TEPO), and an organogermanium compound.
17. The apparatus of claim 16 , wherein the annealing of the doped silicon oxide film causes reflow of the film to occur.