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 Noble. 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, however the oxidation rate is slow for dry oxide. 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 oxidation is used from 5 nm - 200 nm and can be grown in the furnaces: A1, A2, A3, C1, C3.
  • Wet oxidation is used up to 4 µm and can be grown in the furnaces: A1, A3, Noble.
  • Very thick oxide >4 µm can be grown in D1, it is still a wet oxidation.

The standard recipes, quality control limits and results for the Boron Drive-in + Predep furnace (A1) and the Phosphorus Drive-in furnace (A3) can be found here:

Comparison of the seven oxidation furnaces

Boron Drive-in + Pre-dep (A1)

Gate Oxide (A2)

Phosphorous Drive-in (A3)

Anneal Oxide (C1)

Anneal Bond (C3)

APOX (D1)

Noble furnace

Generel description Drive-in of boron deposited in the same furnace or drive-in of ion implanted boron. Can also be used for dry and wet oxidation. Oxidation of gate-oxide and other very 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 of 4" and 6" wafers. Oxidation of new wafers without RCA cleaning. Oxidation of wafers from the LPCVD furnaces and PECVD2. Oxidation of wafers from EVG-NIL, PECVD3 and wafers with aluminum. Oxidation of very thick oxides, thickness higher than 4 µm. Oxidation of almost all materials on silicon wafers.
Oxidation method
  • Dry: O2
  • Wet: Torch
  • Dry: O2
  • Dry: O2
  • Wet: Torch
  • Dry: O2
  • Wet: Steamer
  • Dry: O2
  • Wet: Bubbler
  • Dry: O2
  • Wet: Bubbler
  • Dry: O2
  • Wet: Bubbler
Annealing gas
  • N2
  • Ar
  • N2
  • N2
  • N2
  • N2
  • Ar
  • N2
  • N2
  • Ar
Process temperature
  • 900 oC - 1150 oC
  • 900 oC - 1150 oC
  • 900 oC - 1150 oC
  • 900 oC - 1100 oC
  • 900 oC - 1150 oC
  • 550 oC for aluminium
  • 1075 oC
  • 20 oC - 1000 oC
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

  • Small samples on a carrier wafer, horizontal
  • 1-30 50 mm wafers
  • 1-30 100 mm wafers
  • 1-30 150 mm wafers

Including one test wafer

  • Small samples on a 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, except for boron pre-doped wafers from the same furnace.

All wafers have to be RCA cleaned.

All wafers have to be RCA cleaned, except for phosphorous pre-doped wafers from furnace A4.

All processed wafers have to be RCA cleaned, except for wafers from LPCVD furnaces and PECVD2.

All wafers have to be RCA cleaned, except for wafers from EVG-NIL, PECVD3 and wafers with aluminum.

Only new wafers

Almost all materials, permission is needed


Oxidation curves

Color chart for oxide/nitride thickness

Generic calculator for wet/dry oxide thickness calculation

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

Deal-Grove parameters

By Kasper Reck-Nielsen February 2015

The following table contains linear and parabolic parameters for use in the Deal-Grove model for thermal oxidation. The parameters are obtained a least squares fit to data available in the furnace logbooks. Information on wafer orientation and doping concentration, which is not available in the logbooks, has not been included in calculating the parameters.

Anneal Oxide Anneal Bond Boron Drive-in Gate Oxide Phosphor Drive-in
Recipe B [µm2/h] B/A [µm/h] RMSE [nm] B [µm2/h] B/A [µm/h] RMSE [nm] B [µm2/h] B/A [µm/h] RMSE [nm] B [µm2/h] B/A [µm/h] RMSE [nm] B [µm2/h] B/A [µm/h] RMSE [nm]
DRY900 0.000408 0.107 Too little data 0.0660 0.272 31 0.000390 0.154 Too little data 0.0028 0.079 4 (limited data) 0.0507 0.884 Too little data
DRY1000 - - - - - - 0.465 0.838 20 - - - 0.641 1.45 41
DRY1050 0.0111 0.526 27 - - - 0.0129 0.330 8 0.022 0.505 3 (limited data) 0.0134 0.362 6
DRY1100 0.020 0.930 10 - - - 0.0212 0.736 23 - - - 0.0313 0.553 14
WET950 - - - - - 0.0716 1.25 12 - - - 0.110 1.17 11
WET1000 0.192 1.54 44 - - 0.192 1.80 29 - - - 0.195 2.49 22
WET1050 0.487 0.965 29 0.477 0.899 Too little data 0.455 1.33 16 - - - 0.448 1.73 12
WET1100 0.580 1.43 8 - - - 0.519 1.186 3 - - - 0.403 9.05 7

Wet Oxidation on <100>

The curves below are based on measurements in our specific furnaces and give more accurate results. We will still recommend to make minimum one test run if the thickness is very important.

  • 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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