Specific Process Knowledge/Thermal Process/A1 Bor Drive-in furnace: Difference between revisions

Latest revision as of 13:40, 31 January 2023

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Boron Drive-in and Pre-dep furnace (A1)

The Boron Drive-in and Pre-dep furnace (A1) is a Tempress horizontal furnace for thermal oxidation of silicon wafers. Also boron pre-deposition/doping is done in this furnace. Furthermore, the furnace is used for boron drive-in after the pre-deposition or after boron ion implantation.

The furnace is mostly used for wet and dry thermal oxidation of silicon wafers. The oxidation recipes are named e.g. "WET1000" and "DRY1000", where "WET" or "DRY" indicates whether it is a wet or dry oxidation process, and the number indicates the oxidation temperature.

The purpose of the boron doping is to make conductive structures, etch stop layers etc. For pre-deposition of silicon wafers, boron-nitride source wafers are used as doping source. There are only a few source wafers available, i.e. it is not possible to dope an entire batch of 30 wafers, but both sides of the source wafers are available for doping. It is necessary to activate the source wafers before use by heating them for 1 hour at the temperature needed during the pre-deposition (but never at a temperatures lower than 1050 C). During the pre-deposition a boron phase layer is created on the silicon wafers. This layer can be removed in BHF, if argon is used instead of nitrogen for the pre-deposition (at temperatures higher then 1050 C), otherwise the wafers have to be oxidized before the BHF etch. When the boron phase layer has been removed, the wafers can go directly into the furnace again for a drive-in process with or without an oxide growth.

The Boron Drive-in and Pre-dep furnace is the top furnace tube in the furnace A-stack positioned in cleanroom B-1. The furnaces in the A-stack are the cleanest of all furnaces in the cleanroom. Please be aware of that all wafers have to be RCA cleaned before they enter the furnace, and please check the cross contamination information in LabManager, before you use the furnace. Before boron pre-deposition, also the source wafers and a dedicated carbide boat have to be RCA cleaned.

The user manual, quality control instruction and results, technical information and contact information can be found in LabManager:

Boron Drive-in and Pre-dep furnace (A1)

Process knowledge

Oxidation: look at the Oxidation page
Boron drive-in: look at the Dope with Boron page
Boron doping: look at the Dope with Boron page.

Quality Control - Parameters and Limits

Quality control (QC) for the processes "Wet1050" and "Dry1050"

QC Recipe:	WET1050	DRY1050
H₂ flow	3 slm	0 slm
O₂ flow	2 slm	5 slm
Temperature	1050 ^oC	1050 ^oC
Oxidation time	30 min	100 min

QC limits	Thickness	Non-uniformity (both over a single wafer and over the boat)
DRY1050	107.3 nm - 113.3 nm	3.2 %
WET1050	298.2 nm - 305.5 nm	3.7 %

Numbers from March 2020

Overview of the performance of the Boron Drive-in and Pre-dep furnace and some process related parameters

Purpose	Thermal oxidation of Si wafers Boron pre-deposition/doping of Si wafers Oxidation of boron phase layers Driving-in pre-deposited or ion-implanted boron	Thermal oxidation: Dry oxidation using O₂ Wet oxidation using H₂O vapour Boron pre-deposition/doping: Boron-nitride wafers are used as doping source. This is a solid doping source containing B₂O₃ Driving-in pre-deposited or ion-implanted boron Dry or wet oxidation recipes are normally used for this purpose
Performance	Film thickness	Dry oxide: ~ 0 nm - 300 nm (it takes too long to grow a thicker oxide) Wet oxide: ~ 0 nm - 3 µm (23 hours wet oxidation at 1100 ^oC for Si[100] wafers)
Process parameter range	Process Temperature	800-1150 ^oC
	Process pressure	1 atm (no vacuum)
	Gasses on the system	N₂ O₂ H₂ (in a torch, H₂ and O₂ burns into H₂O vapour for wet oxidation)
Substrates	Batch size	1-30 100 mm wafers (or 50 mm wafers) per run
Substrates	Substrate materials allowed	Silicon wafers (RCA cleaned) Boron-nitride source wafers for boron pre-deposition/doping

@@ Line 1: / Line 1: @@
 '''Feedback to this page''': '''[mailto:thinfilm@danchip.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.danchip.dtu.dk/index.php/http://labadviser.danchip.dtu.dk/index.php/Specific_Process_Knowledge/Thermal_Process/A1_Bor_Drive-in_furnace click here]'''
+''This page is written by DTU Nanolab  internal''
 [[Category: Equipment |Thermal A1]]
@@ Line 7: / Line 9: @@
-==Boron Drive-in + Pre-dep furnace (A1)==
+==Boron Drive-in and Pre-dep furnace (A1)==
-[[Image:A1.JPG|thumb|300x300px|Boron Drive-in + Pre-dep furnace (A1). Positioned in cleanroom B-1]]
+[[Image:A1.JPG|thumb|400x400px|Boron Drive-in and Pre-dep furnace (A1). Positioned in cleanroom B-1/ Photo: DTU Nanolab internal]]
-The Boron Drive-in + Pre-dep furnace (A1) is a Tempress horizontal furnace for oxidation of silicon wafers, annealing of the grown oxide, drive-in of boron after a pre-deposition and oxidation of the boron phase layer. Boron pre-deposition takes place in the same furnace. The Boron Drive-in furnace can also be used to drive-in p-doped wafers which has been ion implanted.
+The Boron Drive-in and Pre-dep furnace (A1) is a Tempress horizontal furnace for thermal oxidation of silicon wafers. Also boron pre-deposition/doping is done in this furnace. Furthermore, the furnace is used for boron drive-in after the pre-deposition or after boron ion implantation.
+The furnace is mostly used for wet and dry thermal oxidation of silicon wafers. The oxidation recipes are named e.g. "WET1000" and "DRY1000", where "WET" or "DRY" indicates whether it is a wet or dry oxidation process, and the number indicates the oxidation temperature.
+The purpose of the boron doping is to make conductive structures, etch stop layers etc. For pre-deposition of silicon wafers, boron-nitride source wafers are used as doping source. There are only a few source wafers available, i.e. it is not possible to dope an entire batch of 30 wafers, but both sides of the source wafers are available for doping. It is necessary to activate the source wafers before use by heating them for 1 hour at the temperature needed during the pre-deposition (but never at a temperatures lower than 1050 C). During the pre-deposition a boron phase layer is created on the silicon wafers. This layer can be removed in BHF, if argon is used instead of nitrogen for the pre-deposition (at temperatures higher then 1050 C), otherwise the wafers have to be oxidized before the BHF etch. When the boron phase layer has been removed, the wafers can go directly into the furnace again for a drive-in process with or without an oxide growth.
+The Boron Drive-in and Pre-dep furnace is the top furnace tube in the furnace A-stack positioned in cleanroom B-1. The furnaces in the A-stack are the cleanest of all furnaces in the cleanroom. Please be aware of that all wafers have to be RCA cleaned before they enter the furnace, and please check the cross contamination information in LabManager, before you use the furnace. Before boron pre-deposition, also the source wafers and a dedicated carbide boat have to be RCA cleaned.
-For the pre-deposition process boron source wafers are used as the doping source to dope Si wafers with boron to make conductive structures, etch stop layers etc. There are only a few source wafers, i.e. it is not possible to make an entire batch of 30 wafers, but both sides of the doping source wafers are available for pre-deposition. It is necessary to activate the source wafers before use by heating them for 1 hour at the temperature needed during the pre-deposition (but not lover than 1050 degrees Celsius). During the pre-deposition a boron phase layer is created on the device wafers. This layer can be removed in HF if the wafers are oxidised in the furnace after the pre-deposition.
-The Boron Drive-in + Pre-dep furnace is the top furnace tube in the A-stack positioned in cleanroom B-1. The furnaces in the A-stack are the cleanest of all furnaces in the cleanroom. Please be aware of that all wafers have to be RCA cleaned before they enter the furnace, and check the cross contamination information in LabManager before you use the furnace.
 '''The user manual, quality control instruction and results, technical information and contact information can be found in LabManager:'''
-'''[http://www.labmanager.danchip.dtu.dk/function.php?module=Machine&view=view&mach=47 Boron Drive-in + Pre-dep furnace (A1)]'''
+'''[http://www.labmanager.danchip.dtu.dk/function.php?module=Machine&view=view&mach=47 Boron Drive-in and Pre-dep furnace (A1)]'''
 ==Process knowledge==
+*Oxidation: look at the [[Specific Process Knowledge/Thermal Process/Oxidation|Oxidation]] page
 *Boron drive-in: look at the [[Specific Process Knowledge/Thermal Process/Dope with Boron|Dope with Boron]] page
-*Oxidation: look at the [[Specific Process Knowledge/Thermal Process/Oxidation|Oxidation]] page
-*Annealing: look at the [[Specific Process Knowledge/Thermal Process/Annealing|Annealing]] page
 *Boron doping: look at the [[Specific Process Knowledge/Thermal Process/Dope with Boron|'''Dope with Boron''']] page.
 <br clear="all" />
@@ Line 40: / Line 44: @@
 ! QC Recipe:
-! Wet1050
+! WET1050
-! Dry1050
+! DRY1050
 |-
 | H<sub>2</sub> flow
@@ Line 52: / Line 56: @@
 |-
 |Temperature
-|1050 C
+|1050 <sup>o</sup>C
-|1050 C
+|1050 <sup>o</sup>C
 |-
 |Oxidation time
@@ Line 68: / Line 72: @@
 and over the boat)
 |-
-!Dry1050
+!DRY1050
-|108-114 nm
+|107.3 nm - 113.3 nm
-|3 %
+|3.2 %
 |-
-!Wet1050
+!WET1050
-|286-302 nm
+|298.2 nm - 305.5 nm
-|5 %
+|3.7 %
 |-
 |}
 |-
 |}
+Numbers from March 2020
 |}
-==Overview of the performance of the Boron Drive-in + Pre-dep furnace and some process related parameters==
+==Overview of the performance of the Boron Drive-in and Pre-dep furnace and some process related parameters==
 {| border="2" cellspacing="0" cellpadding="2"
@@ Line 87: / Line 93: @@
 !style="background:silver; color:black;" align="center"|Purpose
 |style="background:LightGrey; color:black"|
-*Drive-in of boron
+*Thermal oxidation of Si wafers
-*Oxidation of silicon
+*Boron pre-deposition/doping of Si wafers
 *Oxidation of boron phase layers
-*Annealing of the oxide
+*Driving-in pre-deposited or ion-implanted boron
-*Boron pre-depostion using source wafer
+|style="background:WhiteSmoke; color:black"|
-|style="background:WhiteSmoke; color:black"|Oxidation:
+Thermal oxidation:
-*Dry
+*Dry oxidation using O<sub>2</sub>
-*Wet: with torch (H<sub>2</sub>+O<sub>2</sub>)
+*Wet oxidation using H<sub>2</sub>O vapour
-*dope with Boron source wafer
+Boron pre-deposition/doping:
+*Boron-nitride wafers are used as doping source. This is a solid doping source containing B<sub>2</sub>O<sub>3</sub>
+Driving-in pre-deposited or ion-implanted boron
+*Dry or wet oxidation recipes are normally used for this purpose
 |-
 !style="background:silver; color:black" align="center"|Performance
 |style="background:LightGrey; color:black"|Film thickness||style="background:WhiteSmoke; color:black"|
-*Dry oxide: 50 Å  to ~2000 Å (it takes too long to grow a thicker oxide)
+*Dry oxide: ~ 0 nm - 300 nm (it takes too long to grow a thicker oxide)
-*Wet oxide: 50 Å to ~3 µm (it takes too long to grow a thicker oxide)
+*Wet oxide: ~ 0 nm - 3 µm (23 hours wet oxidation at 1100 <sup>o</sup>C for Si[100] wafers)
 |-
 !style="background:silver; color:black" align="center" valign="center" rowspan="3"|Process parameter range
@@ Line 109: / Line 118: @@
 |style="background:LightGrey; color:black"|Process pressure
 |style="background:WhiteSmoke; color:black"|
-*1 atm
+*1 atm (no vacuum)
 |-
 |style="background:LightGrey; color:black"|Gasses on the system
 |style="background:WhiteSmoke; color:black"|
+*N<sub>2</sub>
-*O<sub>2</sub>, N<sub>2</sub> and H<sub>2</sub>
+*O<sub>2</sub>
+*H<sub>2</sub> (in a torch, H<sub>2</sub> and O<sub>2</sub> burns into H<sub>2</sub>O vapour for wet oxidation)
 |-
 !style="background:silver; color:black" align="center" valign="center" rowspan="2"|Substrates
@@ Line 124: / Line 134: @@
 |style="background:WhiteSmoke; color:black"|
 *Silicon wafers (RCA cleaned)
+*Boron-nitride source wafers for boron pre-deposition/doping
 |-
 |}