Specific Process Knowledge/Thermal Process/Oxidation

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Oxidation

At Danchip we have seven furnaces for oxidation: A1, A2, A3, C1, C3, D1 and nobel. Oxidation can take place either by a dry process or a wet process. The film quality of dry oxide is better than for wet oxide with regards to density and dielectric constant. If the film quality for the wet oxide is acceptable then the thickness and the time it takes to grow the oxide often decides if a dry or wet oxidation is chosen.

  • Dry oxide is used from 5 nm - 200 nm. Can be grown in furnaces: A1, A2, A3, C1, C3.
  • Wet oxide with O2 and H2 can be grown in furnace: A1, A3.
  • Wet oxide with H2O in a bubbler can be grown in furnaces: C1, C3, D1, nobel.

The standard recipes, quality control limits and results for the Boron Drive-in and Phosphorus Drive-in furnaces can be found here:

Comparison of the six oxidation furnaces

' A1
Boron drive-in 		A3
Phosphorous drive-in 		C1
Anneal oxide 		A2
Gate oxide 		C3
Anneal bond 		D1
APOX 		Noble
General description Drive-in of boron deposited in the boron pre-dep furnace(A2) or drive-in of ion implanted boron. Can also be used for dry and wet oxidation. Drive-in of phosphorous deposited in the phosphorous pre-dep furnace(A2) or drive-in of ion implanted phosphorous. Can also be used for dry and wet oxidation. Oxidation and annealing of wafers from the B-stack and PECVD1. At the moment also used for general oxidation of 6" wafers. Oxidation of gate-oxide and other especially clean oxides. Oxidation and annealing of wafers from NIL. Oxidation of very thick oxides Oxidation and annealing for all materials.
Dry oxidation x x x x(with special permission) x . x (after request)
wet oxidation with torch (H2+O2) x x . . . . .
Wet oxidation with bubbler (water steam + O2) . . x . x x x after request
Process temperature [ oC ] 800-1150 800-1150 800-1150 800-1150 800-1150 1075 .
Cleanliness of dry oxide (rated 1-5, 1 is best) 2 2 3 1 4 . >5
Cleanliness of wet oxide (rated 1-5, 1 is best) 1 1 2 . 4 3 >5
Batch size max. 30 wafers of 4" or 2" max. 30 4" wafers or 2" wafers max. 30 wafers of 6",4" or 2" max. 30 4" wafers or 2" wafers max. 30 4" wafers or 2" wafers max. 200 4" max. 30 wafers
Which wafers are allowed to enter the furnace: A1
Boron drive-in 		A3
Phosphorous drive-in 		C1
Anneal oxide 		A2
Gate oxide 		C3
Anneal bond 		D1
APOX 		Noble
RCA clean* Si wafers with no history of Metals on x x x x (with special permission) x . x
From Predep furnace directly (e.g. incl. Predep HF*) From A1 From A4 x . x . x
Wafers directly from PECVD2 . . x . x . x
Wafers directly from NIL bonding . . . . x . x
All materials must enter the furnace . . . . . . x

*These wafers must be placed in a "transport box from RCA to furnace" using the RCA carrier when doing RCA or the pre-dep carrier after pre-dep.

A1: Boron Drive-in A2: Gate Oxide A3: Phosphorous Drive-in C1: Anneal Oxide C3: Anneal Bond D4: APOX Noble furnace
Generel description Drive-in of boron deposited in the boron pre-dep furnace(A1) or drive-in of ion implanted boron. Can also be used for dry and wet oxidation. Oxidation of gate-oxide and other especially clean oxides. Drive-in of phosphorous deposited in the phosphorous pre-dep furnace(A4) or drive-in of ion implanted phosphorous. Can also be used for dry and wet oxidation. Oxidation and annealing of 6" wafers. Oxidation of new wafer with out RCA cleaning. Annealing of wafers from the LPCVD furnaces and PECVD1. Oxidation and annealing of wafers from EVG-NIL, PECVD3 and wafers with aluminum. Oxidation of very thick oxides, thickness higher than 4 µm. Oxidation and annealing for all materials.
Oxidation method
  • Dry: 5 SLM O2
  • Wet: Torch
  • Dry: 5 SLM O2
  • Dry: 5 SLM O2
  • Wet: Torch
  • Dry: 5 SLM O2
  • Wet: Steamer
  • Dry: 5 SLM O2
  • Wet: Bobbler
  • Dry: 5 SLM O2
  • Wet: Bubbler
  • Dry: 5 SLM O2
  • Wet: Bubbler
Annealing gas
  • N2
  • Ar
  • N2
  • N2
  • N2
  • N2
  • N2
  • N2
  • Ar
Substrate and Batch size
  • 1-30 50 mm wafers
  • 1-30 100 mm wafers

Including one test wafer

  • 1-30 50 mm wafers
  • 1-30 100 mm wafers

Including one test wafer

  • 1-30 50 mm wafers
  • 1-30 100 mm wafers

Including one test wafer

  • 1-30 50 mm wafers
  • 1-30 100 mm wafers
  • 1-30 150 mm wafers

Including one test wafer

  • Small samples on carrier wafer, horizontal
  • 1-30 50 mm wafers
  • 1-30 100 mm wafers

Including one test wafer

  • 1-150 100 mm wafers
  • Small samples on carrier wafer, horizontal
  • 1-25 50 mm wafers
  • 1-25 100 mm wafers, vertical and horizontal
Allowed materials
  • All wafers have to be RCA cleaned.
  • All wafers have to be RCA cleaned.
  • All wafers have to be RCA cleaned.


Oxidation curves

Generic calculator for wet/dry oxide thickness calculation

The following links give an approximate oxide time/thickness based on a general formula.

Wet Oxidation on <100>

The curves below are based on measurements in our specific furnaces and give more accurate results.

  • Wet oxidation
  • A1 Furnace <100>-Si Wet Oxidation
    A1 Furnace <100>-Si Wet Oxidation
  • A3 Furnace <100>-Si Wet Oxidation
    A3 Furnace <100>-Si Wet Oxidation


Dry Oxidation on <100> and <111> wafer

  • Dry oxidation
  • Dry oxide on <100> wafer. The y-axis is in Å and the x-axis is in minutes.
    Dry oxide on <100> wafer. The y-axis is in Å and the x-axis is in minutes.
  • Dry oxide on <111> wafer. The y-axis is in Å and the x-axis is in minutes.
    Dry oxide on <111> wafer. The y-axis is in Å and the x-axis is in minutes.
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