Methods of forming semiconductor devices and structures with improved planarization, uniformity
Semiconductor devices and structures, such as phase change memory devices, include peripheral conductive pads coupled to peripheral conductive contacts in a peripheral region. An array region may include memory cells coupled to conductive lines. Methods of forming such semiconductor devices and structures include removing memory cell material from a peripheral region and, thereafter, selectively removing portions of the memory cell material from the array region to define individual memory cells in the array region. Additional methods include planarizing the structure using peripheral conductive pads and/or spacer material over the peripheral conductive pads as a planarization stop material. Yet further methods include partially defining memory cells in the array region, thereafter forming peripheral conductive contacts, and thereafter fully defining the memory cells.
1. A method of forming a semiconductor device, comprising:
forming a memory cell material in a peripheral region and in an array region of a semiconductor device structure;
removing the memory cell material from the peripheral region; and
after removing the memory cell material from the peripheral region:
selectively removing portions of the memory cell material from the array region to define individual memory cells in the array region;
forming a dielectric filler material in the peripheral region; and
planarizing the dielectric filler material in the peripheral region.
2. The method of claim 1 , wherein forming a memory cell material comprises forming a phase change memory cell material.
3. The method of claim 1 , further comprising:
forming contact holes in the peripheral region through the dielectric filler material; and
filling the contact holes with a conductive material to form peripheral conductive contacts.
4. The method of claim 3 , further comprising forming conductive pads over and coupled to the peripheral conductive contacts, the conductive pads each having a relatively larger upper surface area than an upper surface area of a peripheral conductive contact coupled thereto.
5. The method of claim 1 , wherein selectively removing portions of the memory cell material from the array region to define individual memory cells comprises:
forming first array trenches extending in a first direction; and
forming second array trenches extending in a second direction orthogonal to the first direction.
6. The method of claim 5 , further comprising forming peripheral contacts in the peripheral region after forming the first array trenches and prior to forming the second array trenches.
7. A method of forming a semiconductor device structure, comprising:
forming a conductive pad material coupled to peripheral conductive contacts in a peripheral region of a semiconductor device structure and coupled to a memory cell material in an array region of the semiconductor device structure;
selectively removing portions of the conductive pad material to define conductive pads in the peripheral region and to define conductive lines in the array region;
forming a spacer material over the conductive pads and the conductive lines; and
planarizing the semiconductor device structure using at least one of the conductive pad material and conductive lines, and the spacer material as a planarization stop material.
8. The method of claim 7 , wherein forming a conductive pad material coupled to a memory cell material comprises coupling the conductive pad material to the memory cell material through at least one of a cell contact material and a cell adhesion material.
9. The method of claim 7 , further comprising forming a filler material over the spacer material, wherein planarizing the semiconductor device structure comprises removing portions of the filler material over the conductive pads and conductive lines.
10. The method of claim 7 , wherein selectively removing portions of the conductive pad material comprises forming trenches, further comprising filling the trenches with at least one of the spacer material and a filler material.
11. The method of claim 10 , wherein filling the trenches with at least one of the spacer material and a filler material comprises filling the trenches with at least one of a nitride spacer material and an oxide filler material.
12. The method of claim 7 , further comprising forming first array trenches extending through and separating portions of the memory cell material in a first direction prior to forming the conductive pad material.
13. The method of claim 12 , further comprising forming second array trenches extending through and separating portions of the memory cell material in a second direction after forming the conductive pad material.
14. The method of claim 7 , further comprising forming upper conductive contacts respectively coupled to the conductive pads and to the conductive lines.
15. A method of forming a phase change memory device, comprising:
forming a phase change memory cell material in an array region;
forming first array trenches extending in a first direction through the phase change memory cell material to partially define phase change memory cells in the array region;
after forming the first array trenches, forming peripheral conductive contacts coupled to respective portions of a peripheral transistor; and
after forming the peripheral conductive contacts, forming second array trenches extending in a second direction different from the first direction through the phase change memory cell material to fully define the phase change memory cells in the array region.
16. The method of claim 15 , further comprising performing a chemical-mechanical planarization (CMP) operation over the fully defined phase change memory cells.
17. The method of claim 16 , further comprising forming conductive pads coupled to the peripheral conductive contacts and forming conductive lines coupled to the phase change memory cells, wherein performing a CMP operation over the fully defined phase change memory cells comprises using at least one of the conductive pads and the conductive lines as a CMP stop.
18. The method of claim 15 , further comprising electrically isolating adjacent phase change memory cells from each other with at least one of a nitride material and an oxide material disposed within the first array trenches and the second array trenches.
19. A method of forming a semiconductor device, comprising:
forming a memory cell material in a peripheral region and in an array region of a semiconductor device structure;
removing the memory cell material from the peripheral region; and
after removing the memory cell material from the peripheral region, selectively removing portions of the memory cell material from the array region to define individual memory cells in the array region, wherein selectively removing portions of the memory cell material from the array region to define individual memory cells comprises:
forming first array trenches extending in a first direction; and
forming second array trenches extending in a second direction orthogonal to the first direction.
20. The method of claim 19 , further comprising forming peripheral contacts in the peripheral region after forming the first array trenches and prior to forming the second array trenches.