SRP原理及应用
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பைடு நூலகம்
SRP sample preparation
Measure – NanoSRP window :
Analysis process of SRP and report understanding
Analysis process :
¾ 1, original SRP curve：
Rtotal = 2 Rc + 2 Rsp +R si Rc : contact resistance of probe (ignore when contact is ohmic) Rsp : spreading resistance Rsi : resistance of si-body
Comparison of junction profiling methods
Why need calibration curve?
¾ In fact measurement , the value of spreading resistance is related with many factors :
R=f(ρ, probe state, material, conductivity type, surface finish, age of surface, RB, etc)
Length and profile depth determine bevel angle selection; Width dimension determine probe spacing; ¾Metal and Nitride removal
Probe contact :
¾ Accurate spreading resistance measurements require highly repeatable small, flat, circular metal semiconductor contacts
Raw– 原始扩展电阻测量值曲线 Rm—对个别因样品制备原因造成的异常点经过修正后的扩展电阻值曲线
Why here is definited
as a junction?
¾ 2, analysis tools
P/N (or N/P)
N－/N＋ (or P－/P)
Reason 1：take N/P for example Space charge area－depletion layer
Characteristic:
¾ Electrical active dopant profile ¾ Good spatial resolution
In theory ,ΔZ=Δ(X-Step)×Sinα ¾ Excellent dynamic range
1012cm-3 to 1021 cm-3 ¾ Profiling through multiple junctions ¾ Accuracy can be within ±10% when operation is
IMP +Poly oxidation
• Abnormal process : LPPOLY + Poly oxidation+ poly IMP +Poly oxidation
• no effect on junction depth ;
the surface concentration is
decrease
z SIMS (Second Ion Mass Spectrum） :
Basic fundamental: Getting doping profile using
impurity atoms amount changing with time Characteristic:
¾ High sensitivity and high spatial resolution
Ion implant and furnace qualification
• G0215
• B1 Furnace • Center of furnace
Process test & abnormity simulation
normal
abnormal
• Normal process: LPPOLY +poly
¾ The control of the micro-contact on a spreading resistance probe tip cannot achieved by optical inspection
¾ Contact radius value influence
Bevel angle measurement : BAM
back
SRP application :
Ion implant and furnace qualification Process test & abnormity simulation Epi reactor qualifications New Process Develop Abnormal Process Analysis
donor concentration（electrons）。
Rho—Resistivity（calibration curve） CD— Carrier Density
n = 1/qμρ
¾ Additional Sample Information from SRP
•SSM software automatically calculates and reports sheet resistance for every junctionisolated layer
¾ Full report:
SRP full report
Measurement accuracy assurance and improvement
Good sample surface :
¾Flat with a sharp bevel edge ¾Damage must be shallow or not ¾Suitable for high precision angle measurement ¾The same as the calibration sample surfaces ¾Measuring in a patterned region:
N
P
N/P junction
N
XN
XP
P
Space charge area
High resistance in space charge area because of lack of carrier
N- N+ N-/N+
N-
N+
Reason2 ：Definition of junction depth ： Xj: the junction depth is where the acceptor concentration (holes) equal to
• Chemical Stain • MOS C-V • SIMS • SRP
z Chemical Stain : Xj=L*SiNα
Characteristic:
¾ Repeatability is not good ¾ Accuracy is not ideal ¾ Apply to deeper junction (> 0.5um ) ¾ Junction depth not dopant profile
Epi reactor qualifications
• P- EPI p on p+ sub • Measure transition width
•n-doped EPI on Sb buried layer
Abnormal
• Bipolar, <111>
• Normal layers : NN+P • Abnormally : NPN+P • Autodoping during EPI
¾ Apply to shallow layer ¾ Total dopant profiles in silicon ¾ Narrow dynamic range on a given
profile (4 orders of magnitude)
z SRP (Spread Resistance Profiling ):
• Deep N well on P-Substrate • DN Junction Depth : 6.3um • P well Juntion in DN: 2.1um
Abnormal Process Analysis (一）
Good Failure
• NPC610 P-well Rs abnormal
SRP Fundamental and Application
FALAB HONGHY 2007.10.18
Content
SRP fundamental Comparison of junction profiling methods SRP sample preparation and measurement Analysis process of SRP and report understanding Measurement accuracy assurance and improvement SRP application Information needed when requested to do SRP
z MOS C-V :
High frequency with pulse C-V measurement Characteristic:
¾ Electrical active dopant profile ¾ The conductive type of layers must be same ¾ Narrow dynamic range on a given profile ¾ Apply to implant dose low than 1012cm2
∫ RS
=
⎡xj ⎢ ⎢⎣ 0
dx
⎤ −1 ⎥
ρ ( x ) ⎥⎦
•SSM software automatically calculates and reports dose for every layer
x2
Q = ∫ n(x)dx x1
Report form :
¾ One-page report :
SRP fundamental :
probe
. ................ .
Rsp Rsi
97-7rgm201
Definition : The “spreading resistance” of a probe is the resistance encountered by the current flowing through the body of the semiconductor at the probe-surface interface .
¾ The BAM system uses a vertically mounted laser depth sensor to
determine the vertical position of the probe arm. ¾ Applicable for bevel angles ranging from 17´to 5°44´.
BAM Sensor
Beveled Surface Original surface
Sample
Probe Arm
Calibration curve : Rm
校准标样 （包含8N-type&8P-type ; 电阻率范围从0.001-300 ohm.cm )
校准曲线（2.5um step)
Rho
New Process Develop
• APD DMOS
• Guard ring : B+(B/50Kev/3E13)+ R0918 Drive in • Substrate : N-Epi + N- Si • P-well : 1.41um Epi : 8.18um
• 0.5um EEPROM
பைடு நூலகம்
SRP sample preparation
Measure – NanoSRP window :
Analysis process of SRP and report understanding
Analysis process :
¾ 1, original SRP curve：
Rtotal = 2 Rc + 2 Rsp +R si Rc : contact resistance of probe (ignore when contact is ohmic) Rsp : spreading resistance Rsi : resistance of si-body
Comparison of junction profiling methods
Why need calibration curve?
¾ In fact measurement , the value of spreading resistance is related with many factors :
R=f(ρ, probe state, material, conductivity type, surface finish, age of surface, RB, etc)
Length and profile depth determine bevel angle selection; Width dimension determine probe spacing; ¾Metal and Nitride removal
Probe contact :
¾ Accurate spreading resistance measurements require highly repeatable small, flat, circular metal semiconductor contacts
Raw– 原始扩展电阻测量值曲线 Rm—对个别因样品制备原因造成的异常点经过修正后的扩展电阻值曲线
Why here is definited
as a junction?
¾ 2, analysis tools
P/N (or N/P)
N－/N＋ (or P－/P)
Reason 1：take N/P for example Space charge area－depletion layer
Characteristic:
¾ Electrical active dopant profile ¾ Good spatial resolution
In theory ,ΔZ=Δ(X-Step)×Sinα ¾ Excellent dynamic range
1012cm-3 to 1021 cm-3 ¾ Profiling through multiple junctions ¾ Accuracy can be within ±10% when operation is
IMP +Poly oxidation
• Abnormal process : LPPOLY + Poly oxidation+ poly IMP +Poly oxidation
• no effect on junction depth ;
the surface concentration is
decrease
z SIMS (Second Ion Mass Spectrum） :
Basic fundamental: Getting doping profile using
impurity atoms amount changing with time Characteristic:
¾ High sensitivity and high spatial resolution
Ion implant and furnace qualification
• G0215
• B1 Furnace • Center of furnace
Process test & abnormity simulation
normal
abnormal
• Normal process: LPPOLY +poly
¾ The control of the micro-contact on a spreading resistance probe tip cannot achieved by optical inspection
¾ Contact radius value influence
Bevel angle measurement : BAM
back
SRP application :
Ion implant and furnace qualification Process test & abnormity simulation Epi reactor qualifications New Process Develop Abnormal Process Analysis
donor concentration（electrons）。
Rho—Resistivity（calibration curve） CD— Carrier Density
n = 1/qμρ
¾ Additional Sample Information from SRP
•SSM software automatically calculates and reports sheet resistance for every junctionisolated layer
¾ Full report:
SRP full report
Measurement accuracy assurance and improvement
Good sample surface :
¾Flat with a sharp bevel edge ¾Damage must be shallow or not ¾Suitable for high precision angle measurement ¾The same as the calibration sample surfaces ¾Measuring in a patterned region:
N
P
N/P junction
N
XN
XP
P
Space charge area
High resistance in space charge area because of lack of carrier
N- N+ N-/N+
N-
N+
Reason2 ：Definition of junction depth ： Xj: the junction depth is where the acceptor concentration (holes) equal to
• Chemical Stain • MOS C-V • SIMS • SRP
z Chemical Stain : Xj=L*SiNα
Characteristic:
¾ Repeatability is not good ¾ Accuracy is not ideal ¾ Apply to deeper junction (> 0.5um ) ¾ Junction depth not dopant profile
Epi reactor qualifications
• P- EPI p on p+ sub • Measure transition width
•n-doped EPI on Sb buried layer
Abnormal
• Bipolar, <111>
• Normal layers : NN+P • Abnormally : NPN+P • Autodoping during EPI
¾ Apply to shallow layer ¾ Total dopant profiles in silicon ¾ Narrow dynamic range on a given
profile (4 orders of magnitude)
z SRP (Spread Resistance Profiling ):
• Deep N well on P-Substrate • DN Junction Depth : 6.3um • P well Juntion in DN: 2.1um
Abnormal Process Analysis (一）
Good Failure
• NPC610 P-well Rs abnormal
SRP Fundamental and Application
FALAB HONGHY 2007.10.18
Content
SRP fundamental Comparison of junction profiling methods SRP sample preparation and measurement Analysis process of SRP and report understanding Measurement accuracy assurance and improvement SRP application Information needed when requested to do SRP
z MOS C-V :
High frequency with pulse C-V measurement Characteristic:
¾ Electrical active dopant profile ¾ The conductive type of layers must be same ¾ Narrow dynamic range on a given profile ¾ Apply to implant dose low than 1012cm2
∫ RS
=
⎡xj ⎢ ⎢⎣ 0
dx
⎤ −1 ⎥
ρ ( x ) ⎥⎦
•SSM software automatically calculates and reports dose for every layer
x2
Q = ∫ n(x)dx x1
Report form :
¾ One-page report :
SRP fundamental :
probe
. ................ .
Rsp Rsi
97-7rgm201
Definition : The “spreading resistance” of a probe is the resistance encountered by the current flowing through the body of the semiconductor at the probe-surface interface .
¾ The BAM system uses a vertically mounted laser depth sensor to
determine the vertical position of the probe arm. ¾ Applicable for bevel angles ranging from 17´to 5°44´.
BAM Sensor
Beveled Surface Original surface
Sample
Probe Arm
Calibration curve : Rm
校准标样 （包含8N-type&8P-type ; 电阻率范围从0.001-300 ohm.cm )
校准曲线（2.5um step)
Rho
New Process Develop
• APD DMOS
• Guard ring : B+(B/50Kev/3E13)+ R0918 Drive in • Substrate : N-Epi + N- Si • P-well : 1.41um Epi : 8.18um
• 0.5um EEPROM