CN109148312A - The detection method and its detection system of metal layer work function - Google Patents
The detection method and its detection system of metal layer work function Download PDFInfo
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- CN109148312A CN109148312A CN201710455900.9A CN201710455900A CN109148312A CN 109148312 A CN109148312 A CN 109148312A CN 201710455900 A CN201710455900 A CN 201710455900A CN 109148312 A CN109148312 A CN 109148312A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
- H01L22/10—Measuring as part of the manufacturing process
- H01L22/14—Measuring as part of the manufacturing process for electrical parameters, e.g. resistance, deep-levels, CV, diffusions by electrical means
Abstract
A kind of detection method and its detection system of metal layer work function, detection method include: offer substrate, the metal layer to be measured including substrate and on substrate, and substrate has substrate work function；The light source that output power is at least 100 watts is provided；Reference electrode is provided；Light source is closed, the first contact potential difference between metal layer and reference electrode to be measured is obtained；Light source is opened, layer on surface of metal to be measured is irradiated, the second contact potential difference between metal layer and reference electrode to be measured is obtained；According to the difference between the first contact potential difference and the second contact potential difference, the surface potential barrier potential difference of metal layer to be measured is obtained；According to the difference between substrate work function and surface potential barrier potential difference, the work function of metal layer to be measured is obtained.The present invention is irradiated layer on surface of metal to be measured using the light source that output power is at least 100 watts when detecting the second contact potential difference, to eliminate metal layer equipotential screen effect, and then improves the work function detection accuracy of metal layer to be measured.
Description
Technical field
The present invention relates to field of semiconductor manufacture more particularly to a kind of detection methods and its detection system of metal layer work function
System.
Background technique
Work function is an important parameter in the research such as semiconductor devices, photoelectric device and integrated circuit technology.Function
Function mainly influences the carrier injection of semiconductor devices, to influence the performance of semiconductor devices.Therefore, in semiconductors manufacture
In field, the accurate work function that detects becomes particularly important.
But the detection accuracy of prior art work function is lower.
Summary of the invention
Problems solved by the invention is to provide the detection method and its detection system of a kind of metal layer work function, improves work content
Several detection accuracy.
To solve the above problems, the present invention provides a kind of detection method of metal layer work function, comprising: provide substrate, institute
Stating substrate includes substrate and the metal layer to be measured on the substrate, and the substrate has substrate work function；Light is provided
Source, the output power of the light source are at least 100 watts；Reference electrode is provided；The light source is closed, the metal layer to be measured is obtained
The first contact potential difference between the reference electrode；The light source is opened, the layer on surface of metal to be measured is irradiated,
Obtain the second contact potential difference between the metal layer to be measured and the reference electrode；According to first contact potential difference and
Difference between second contact potential difference obtains the surface potential barrier potential difference of the metal layer to be measured；According to the substrate
Difference between work function and the surface potential barrier potential difference obtains the work function of the metal layer to be measured.
Optionally, first contact potential difference and the second contact potential difference, and institute are obtained by Kelvin probe system
Stating Kelvin probe system includes the reference electrode.
Optionally, the light source is LED light source.
Optionally, the light source is green-light source or green-light source and white light source.
Optionally, the light source be green-light source and white light source, the white light source for generation wavelength be 450nm extremely
The light of 465nm.
Optionally, in the step of substrate is provided, the substrate further include positioned at the substrate and the metal layer to be measured it
Between dielectric layer.
Optionally, the dielectric layer be gate dielectric layer, the gate dielectric layer include boundary layer and be located at the boundary layer
On high-k gate dielectric layer.
Optionally, the metal layer to be measured is work-function layer.
Optionally, the metal layer to be measured is single layer structure or laminated construction.
Optionally, the material of the metal layer to be measured be TiN, TaN, TaSiN, TiSiN, TiAl, TiAlC, TaAlN,
One or more of TiAlN, TaCN and AlN.
Correspondingly, the present invention also provides a kind of detection systems of metal layer work function, comprising: load bearing unit, for carrying
Part to be measured, the part to be measured include substrate and the metal layer to be measured on the substrate；Illumination unit, for described
Layer on surface of metal to be measured is irradiated, and the illumination unit includes light source, and the output power of the light source is at least 100 watts；Inspection
Unit, including reference electrode are surveyed, for obtaining the metal layer to be measured and the reference electricity in the state that light source is closed
The first contact potential between pole, and in the state that the light source is irradiated the layer on surface of metal to be measured, obtain
The second contact potential difference between the metal layer to be measured and the reference electrode；Computing unit, for being connect according to described first
Difference between potential difference of getting an electric shock and second contact potential difference obtains the surface potential barrier potential difference of the metal layer to be measured, and
According to the difference between the substrate work function and the surface potential barrier potential difference, the work function of the metal layer to be measured is obtained.
Optionally, the detection unit is integrated in Kelvin probe system.
Optionally, the light source is LED light source.
Optionally, the light source is green-light source or green-light source and white light source.
Optionally, the light source be green-light source and white light source, the white light source for generation wavelength be 450nm extremely
The light of 465nm.
Optionally, the part to be measured further includes the dielectric layer between the substrate and the metal layer to be measured.
Optionally, the dielectric layer be gate dielectric layer, the gate dielectric layer include boundary layer and be located at the boundary layer
On high-k gate dielectric layer.
Optionally, the metal layer to be measured is work-function layer.
Compared with prior art, technical solution of the present invention has the advantage that
In the step of obtaining the second contact potential difference between metal layer and reference electrode to be measured, extremely using output power
The layer on surface of metal to be measured is irradiated for 100 watts of light source less, the output power of the light source is larger, therefore is conducive to
Surface potential barrier is eliminated, so as to eliminate metal layer equipotential screen effect (Metal Layer Equipotential
Screening Effect), and then improve the detection accuracy of the work function of the metal layer to be measured.
In optinal plan, the metal layer to be measured is work-function layer, by accurately detecting the work function of the work-function layer,
To be conducive to effectively control and improve the electric property of semiconductor devices.
Detailed description of the invention
Fig. 1 to Fig. 3 is the corresponding structural schematic diagram of one embodiment of detection method of metal layer work function of the present invention；
Fig. 4, which is different metal layers to be measured, is greater than 100 watts and light source output power less than 100 watt two in light source output power
Work function box figure in the case of kind；
Fig. 5 is that the detection system of metal layer work function of the present invention unifies the corresponding functional block diagram of embodiment.
Specific embodiment
It can be seen from background technology that the detection accuracy of metal layer work function is lower.Now in conjunction with a kind of detection method of work function
The lower reason of analysis detection precision.
In the art of semiconductor manufacturing, to obtain metal layer to be measured usually in such a way that mos capacitance (MOSCAP) is detected
Work function.It could be obtained, MOS since mos capacitance need to be tested complete semiconductor structure (such as C-V test)
The detection of capacitor need to carry out after completing aluminum manufacturing procedure, so detection efficiency is lower, testing cost is higher.
SDI (Semiconductor Diagnose) board is introduced at present.Work function is obtained compared to by mos capacitance
Mode after metal layer to be measured is formed on the substrate, can carry out online (inline) to the metal layer to be measured by SDI board
Work function detection, therefore can simplify processing step, improve detection efficiency, reduce testing cost.
But after metal layer to be measured is formed on the substrate, since the metal layer to be measured covers entire substrate surface,
It is easy to appear metal layer equipotential screen effect (Metal Layer Equipotential Screening Effect), thus
The detection accuracy of work function is caused to decline.
In order to solve the technical problem, the present invention contacts electricity in second obtained between metal layer and reference electrode to be measured
In the step of potential difference, the layer on surface of metal to be measured is irradiated using the light source that output power is at least 100 watts, the light
The output power in source is larger, therefore is conducive to eliminate surface potential barrier, so as to eliminate metal layer equipotential screen effect, in turn
Improve the detection accuracy of the work function of the metal layer to be measured.
To make the above purposes, features and advantages of the invention more obvious and understandable, with reference to the accompanying drawing to the present invention
Specific embodiment be described in detail.
Fig. 1 to Fig. 3 is the corresponding structural schematic diagram of one embodiment of detection method of metal layer work function of the present invention.
It with reference to Fig. 1, provides substrate (not indicating), the substrate includes substrate 100 and on the substrate 100
Metal layer 110 to be measured, the substrate 100 have substrate work function.
The substrate 100 provides technique platform for the formation of semiconductor structure.
In the present embodiment, the substrate 100 is silicon substrate.In other embodiments, the material of the substrate can also be
Germanium, SiGe, silicon carbide, GaAs or gallium indium, the substrate can also be on the silicon substrates or insulator on insulator
Germanium substrate or glass substrate.The material of the substrate 100 can choose the material for being suitable for process requirements or being easily integrated.
The substrate 100 has substrate work function.In the present embodiment, the work function for defining the substrate 100 is WF (Si).
Wherein, the 100 work function WF (Si) of substrate is depending on the material of the substrate 100.
The metal layer to be measured 110 is for a part as formed semiconductor devices, to realize the semiconductor device
The normal operation of part.
In the present embodiment, the metal layer 110 to be measured is work-function layer, such as P-type workfunction layer or N-type workfunction layer.
The metal layer to be measured 110 is used to adjust the threshold voltage of semiconductor devices.
In other embodiments, the metal layer to be measured can also be the functional layer for being suitable for process requirements.
The metal layer to be measured 110 can be single layer structure or laminated construction, and the material of the metal layer 110 to be measured is
One or more of TiN, TaN, TaSiN, TiSiN, TiAl, TiAlC, TaAlN, TiAlN, TaCN and AlN.The present embodiment
In, it is illustrated so that the metal layer 110 to be measured is single layer structure as an example.
Subsequent step includes detecting to the metal layer 110 to be measured, obtains the work content of the metal layer 110 to be measured
Number.
It should be noted that the substrate further includes positioned at the substrate 100 and described to be measured in the step of providing substrate
Dielectric layer 150 between metal layer 110.
In the present embodiment, the detection method is used to detect the work function of work-function layer, therefore the dielectric layer 150 is grid
Dielectric layer, the gate dielectric layer include boundary layer (IL, Interfacial Layer) and the high k on the boundary layer
Gate dielectric layer.
The boundary layer is used to provide good interface basis to form the high-k gate dielectric layer, to improve to be formed
The quality of high-k gate dielectric layer reduces the interface state density between the high-k gate dielectric layer and the substrate 100, and avoids described
Adverse effect caused by high-k gate dielectric layer is directly contacted with the substrate 100.In the present embodiment, the material of the boundary layer is
Silica.
The material of the high-k gate dielectric layer is the gate medium material that relative dielectric constant is greater than silica relative dielectric constant
Material.In the present embodiment, the material of the high-k gate dielectric layer is HfO2.In other embodiments, the material of the high-k gate dielectric layer
Material can also be HfSiO, HfSiON, HfTaO, HfTiO, HfZrO, ZrO2Or Al2O3。
With reference to Fig. 2, light source (not indicating) is provided, the output power of the light source is at least 100 watts；Reference electrode is provided
(Reference Electrode)220。
In the present embodiment, the work function of the metal layer to be measured 110 is obtained subsequently through Kelvin probe system, it is described
Kelvin probe system includes the reference electrode 220, i.e., the described reference electrode 220 is one of the Kelvin probe system
Point.
Correspondingly, subsequently through the Kelvin probe system, using contact potential difference (Contact Potential
Difference, CPD) detection mode, obtain the work function of the metal layer 110 to be measured.
Wherein, the Kelvin probe system integration is in SDI (Semiconductor Diagnose) board.
The light source is used to eliminate the surface potential barrier of the metal layer to be measured 110, to make surface potential barrier potential difference VSBFor
Zero；Therefore by the opening and closing of the light source, the detection under illumination and no light both of which may be implemented, to obtain
The surface potential barrier potential difference V of the metal layer to be measured 110SB。
The metal layer to be measured 110 covers entire substrate 100, by increasing the output power of the light source, makes the light
The output power in source is at least 100 watts；The output power of the light source is larger, therefore using the light source to the metal to be measured
After 110 surface of layer are irradiated, the output power of the light source is enough to eliminate the surface potential barrier of the metal layer to be measured 110, from
And metal layer equipotential screen effect can be eliminated, and then the work function detection of the subsequent metal layer 110 to be measured can be improved
Precision.
In the present embodiment, the light source is LED light source.LED light source is relatively strong with light intensity, light stability is higher and responds
The advantages such as the time is short, to be conducive to improve subsequent detection efficiency and detection accuracy.
In the present embodiment, the light source is green-light source 210 and white light source 300.
Wherein, the green-light source 210 is integrated in the SDI board, and by the way that white light is added into the SDI board
The mode of light source 300, to obtain the light source being made of green-light source 210 and white light source 300.So keeping the green light
In the case where the former output power of light source 210, by way of newly-increased white light source 300, it can be obtained with higher output power
The light source of value, simple process and exploitativeness are higher.
Specifically, the light that the white light source 300 is 450nm to 465nm for generation wavelength.
In other embodiments, the light source is only the green-light source, correspondingly, adjusting the output of the green-light source
Power makes the output power of the green-light source be at least 100 watts.
In the present embodiment, the green-light source 210 and white light source 300 are integrated in the SDI board, therefore can
It opens and simultaneously closes off while realizing the green-light source 210 and white light source 300.That is, under illumination mode into
When row detection, the green-light source 210 and white light source 300 are opened simultaneously, described green when being detected under no light mode
Radiant 210 and white light source 300 simultaneously close off.
The reference electrode 220 is used to obtain the surface potential barrier potential difference V of the metal layer 110 to be measured in detectionSBWhen make
For referring to the electrode compared, the effect of the reference electrode 220 includes: to distinguish subsequently through under illumination and no light mode
Obtain the contact potential difference V between the metal layer to be measured 110 and the reference electrode 220CPD, to obtain the gold to be measured
Belong to the surface potential barrier potential difference V of layer 110SB。
Specifically, in the work function detection process of the subsequent metal layer 110 to be measured, the metal layer to be measured 110 with
The reference electrode 220 constitutes capacitance-type vibration, due to the fermi level of the metal layer 110 and the reference electrode 220 to be measured
Difference, so as to detect the contact potential difference V obtained between the metal layer 110 to be measured and the reference electrode 220CPD。
In the present embodiment, the Kelvin probe system further include: chuck 200, for carry and fix be formed with it is described
The substrate 100 of metal layer 110 to be measured, that is to say, that the chuck 200 is for carrying and fixing silicon wafer (Wafer).Wherein, institute
Chuck 200 is stated also to be integrated in the SDI board.
Same as the prior art to the specific descriptions of the SDI board and Kelvin probe system, the present embodiment is herein not
It repeats again.
It with continued reference to Fig. 2, closes the light source (not indicating), obtains the metal layer to be measured 110 and the reference electrode
The first contact potential difference V between 220CPD-Dark。
In the present embodiment, after the substrate 100 is fixed on the chuck 200, the Kelvin probe system is opened, with
Detect the first contact potential difference VCPD-Dark。
In the present embodiment, by simultaneously closing off the green-light source 210 and white light source 300, so that the Kelvin visits
Needle system is detecting the first contact potential between the metal layer to be measured 110 and the reference electrode 220 under no light mode
Poor VCPD-Dark。
Specifically, the first contact potential difference VCPD-DarkFor the metal layer 110 to be measured and the reference electrode 220
Work function φms, the metal layer 110 to be measured surface potential barrier potential difference VSBAnd the potential difference of the dielectric layer 150
VOXThe sum of；That is, VCPD-Dark=φms+VSB+VOX.Wherein, the metal layer to be measured 110 and the reference electrode 220
Work function φmsAnd the potential difference V of the dielectric layer 150OXFor fixed value.
With reference to Fig. 3, the light source (not indicating) is opened, 110 surface of metal layer to be measured is irradiated, described in acquisition
The second contact potential difference V between metal layer 110 and the reference electrode 220 to be measuredCPD-Light。
In the present embodiment, by opening simultaneously the green-light source 210 and white light source 300, to eliminate described to be measured
The surface potential barrier of metal layer 110, that is to say, that make the surface potential barrier potential difference V of the metal layer to be measured 110SBIt is zero.
Therefore, the second contact potential difference VCPD-LightFor the metal layer 110 to be measured and the reference electrode 220
Work function φmsAnd the potential difference V of the dielectric layer 150OXThe sum of；That is, VCPD-Light=φms+VOX。
It should be noted that the work function φ of the metal layer to be measured 110 and the reference electrode 220ms, Yi Jisuo
State the potential difference V of dielectric layer 150OXFor fixed value, therefore under no light mode and under illumination mode, the work function
φmsIt is identical, and the potential difference VOXIt is identical.
Wherein, the output power of the light source is at least 100 watts, and the output power of the light source is enough to eliminate described to be measured
The surface potential barrier of metal layer 110 makes the surface potential barrier potential so as to preferably eliminate metal layer equipotential screen effect
Poor VSBIt is zero, and then improves the second contact potential difference VCPD-LightData accuracy, correspondingly, subsequent institute can be improved
State the work function detection accuracy of metal layer 110 to be measured.
In the present embodiment, the second contact potential difference V is obtainedCPD-LightAfterwards, according to first contact potential difference
VCPD-DarkWith the second contact potential difference VCPD-LightBetween difference, obtain the surface potential barrier potential difference of the metal layer 110 to be measured
VSB。
Specifically, the first contact potential difference VCPD-DarkRelational expression be VCPD-Dark=φms+VSB+VOX, described second
Contact potential difference VCPD-LightRelational expression be VCPD-Light=φms+VOX, therefore, the surface potential barrier potential difference VSBRelational expression
For VSB=VCPD-Dark-VCPD-Light。
In the present embodiment, the surface potential barrier potential difference V of the metal layer 110 to be measured is obtainedSBAfterwards, according to the substrate work content
Number WF (Si) and the surface potential barrier potential difference VSBBetween difference, to obtain the work function of the metal layer to be measured 110.
Specifically, work function obtained is the equivalent work function EWF (Effective of the metal layer 110 to be measured
Work Function) that is, the relational expression of the equivalent work function EWF of the metal layer to be measured 110 is EWF=WF (Si)-
VSB。
It should be noted that being illustrated so that the metal layer 110 to be measured is single layer structure as an example in the present embodiment.When
When the metal layer to be measured 110 is laminated construction, the detection accuracy of 110 work function of metal layer to be measured is still available to be mentioned
It is high.
Reference table 1, and combine and refer to Fig. 4, table 1 shows the material and corresponding thickness of 5 kinds of metal layers to be measured, schemes
4, which show 5 kinds of metal layers to be measured, is greater than 100 watts and light source output power less than 100 watts two kinds in light source output power
In the case of work function box figure (Box-plot).
Specifically, Fig. 4 show that the light source be green-light source and the green-light source output power less than 100 watts,
And work function of the light source for green-light source and white light source and in the case of the light source output power is greater than 100 watts two kinds
Box figure.
Table 1
Specifically, reference table 1, data group A indicate that the metal layer to be measured is single layer structure, the material of the metal layer to be measured
Material is TiN, and the thickness of the metal layer to be measured is less thanData group B indicates that the metal layer to be measured is laminated construction, institute
State metal layer to be measured include the first TiN layer, the TaN layer in first TiN layer, the TiAl layer on the TaN layer,
And the second TiN layer on the TiAl layer, and the thickness of the metal layer to be measured of laminated construction is less thanNumber
Indicate that the metal layer to be measured is single layer structure according to group C, the material of the metal layer to be measured is TiAl, the metal layer to be measured
Thickness is less thanData group D indicates that the metal layer to be measured is laminated construction, the metal layer to be measured includes TiAl layers, with
And the TiN layer on the TiAl layer, and the thickness of the metal layer to be measured of laminated construction is less thanData group E table
Show that the metal layer to be measured is laminated construction, the metal layer to be measured includes the first TiN layer, in first TiN layer
TaN layers, the TiAl layer on the TaN layer, the second TiN layer on the TiAl layer, be located at second TiN layer on
Ti layer, and it is Ti layers described on be formed with Al layers, and the metal layer to be measured of laminated construction and Al layers of the overall thickness are big
In
In the present embodiment, the metal layer to be measured of data group A is P-type workfunction layer, the metal to be measured of data group B
Layer is P-type workfunction layer, and the metal layer to be measured of data group C is N-type workfunction layer, the metal layer to be measured of data group D
For N-type workfunction layer, the metal layer to be measured of data group E is P-type workfunction layer.
In conjunction with reference Fig. 4, the longitudinal axis indicates work function.Specifically, box figure A1 indicates gold to be measured corresponding to the data group A
Belong to the layer work function measured in no white light source, that is to say, that detecting the second contact potential difference VCPD-LightStep
In rapid, the green-light source only with output power less than 100 watts is irradiated the layer on surface of metal to be measured；Box figure A2 table
Show the work function that metal layer to be measured is measured using green-light source and white light source corresponding to data group A.
Similarly, box figure B1 indicates that metal layer to be measured corresponding to the data group B is measured in no white light source
Work function, box figure B2 indicates metal layer to be measured corresponding to data group B using green-light source and white light source
Measured work function；Box figure C1 indicates that metal layer 110 to be measured is in no 300 situation of white light source corresponding to the data group C
Lower measured work function, box figure C2 indicate that metal layer to be measured is using green-light source and white light source corresponding to data group C
In the case where measured work function；Box figure D1 indicates that metal layer to be measured is in no white light source feelings corresponding to the data group D
Measured work function under condition, box figure D2 indicate that metal layer 110 to be measured is using green-light source and white light corresponding to data group D
Measured work function in the case where light source；Box figure E1 indicates that metal layer to be measured is in no white light light corresponding to the data group E
Measured work function in the case of source, box figure E2 indicate metal layer to be measured corresponding to data group E using green-light source and white
Measured work function in the case where radiant.
Wherein, virtual coil 111 indicates work function corresponding to the metal layer to be measured of P-type workfunction layer type, virtual coil 112
Indicate that the metal layer to be measured of the N-type workfunction layer type work function measured in no white light source, virtual coil 113 indicate
The metal layer to be measured of N-type workfunction layer type work function measured using green-light source and white light source.
As shown in Figure 4, the detection method through the invention can be with when the light source output power of use is greater than 100 watt-hours
Improve the precision of obtained work function, the especially metal layer to be measured of N-type workfunction layer type.And it is in the metal layer to be measured
When the thickness of laminated construction or the metal layer to be measured is larger, the light source can still eliminate metal layer equipotential shielding effect
It answers, to obtain accurate work function.
With reference to Fig. 5, the detection system for showing metal layer work function of the present invention unifies the corresponding functional block diagram of embodiment.Accordingly
, the present invention also provides a kind of detection system of metal layer work function, the detection system includes:
Load bearing unit 410, for carrying part to be measured, the part to be measured includes substrate 100 (as shown in Figure 3) and is located at
Metal layer to be measured 110 (as shown in Figure 3) on the substrate 100；Illumination unit 420, for 110 table of metal layer to be measured
Face is irradiated, and the illumination unit 420 includes light source (not indicating), and the output power of the light source is at least 100 watts；Detection
Unit 430, including reference electrode 220 (as shown in Figure 3), for obtaining the gold to be measured in the state that the light source is closed
Belong to the first contact potential V between layer 110 and the reference electrode 220CPD-Dark, and in the light source to the metal to be measured
In the state that 110 surface of layer are irradiated, second obtained between the metal layer 110 to be measured and the reference electrode 220 is connect
Get an electric shock potential difference VCPD-Light；Computing unit 440, for according to the first contact potential difference VCPD-DarkWith the second contact electricity
Potential difference VCPD-LightBetween difference, obtain the surface potential barrier potential difference V of the metal layer 110 to be measuredSB, and according to the substrate
Work function and the surface potential barrier potential difference VSBBetween difference, obtain the work function of the metal layer 110 to be measured.
In the present embodiment, the substrate 100 is silicon substrate.In other embodiments, the material of the substrate can also be
Germanium, SiGe, silicon carbide, GaAs or gallium indium, the substrate can also be on the silicon substrates or insulator on insulator
Germanium substrate or glass substrate.The material of the substrate 100 can choose the material for being suitable for process requirements or being easily integrated.
The substrate 100 has substrate work function.In the present embodiment, the work function for defining the substrate 100 is WF (Si).
Wherein, the 100 work function WF (Si) of substrate is depending on the material of the substrate 100.
The metal layer to be measured 110 is for a part as semiconductor devices, to realize the semiconductor devices just
Often running.
In the present embodiment, the metal layer 110 to be measured is work-function layer, such as P-type workfunction layer or N-type workfunction layer.
The metal layer to be measured 110 is used to adjust the threshold voltage of semiconductor devices.
In other embodiments, the metal layer to be measured can also be the functional layer for being suitable for process requirements.
The metal layer to be measured 110 can be single layer structure or laminated construction, and the material of the metal layer 110 to be measured is
One or more of TiN, TaN, TaSiN, TiSiN, TiAl, TiAlC, TaAlN, TiAlN, TaCN and AlN.
It should be noted that the part to be measured further include: between the substrate 100 and the metal layer to be measured 110
Dielectric layer 150 (as shown in Figure 3).
In the present embodiment, the dielectric layer 150 be gate dielectric layer, the gate dielectric layer include boundary layer (IL,
Interfacial Layer) and high-k gate dielectric layer on the boundary layer.Specifically, the high-k gate dielectric layer
Material is HfO2, the material of the boundary layer is silica.
To the specific descriptions of the dielectric layer 150, the corresponding description in previous embodiment is please referred to, details are not described herein.
In the present embodiment, the detection system is integrated in SDI (Semiconductor Diagnose) board.
The detection system is used to detect the work function of the metal layer to be measured 110, therefore the detection unit 430 is integrated
In Kelvin probe system.By the Kelvin probe system, using contact potential difference (Contact Potential
Difference, CPD) detection mode, to obtain the work function EWF of the metal layer to be measured 110.Correspondingly, the Kai Er
Literary probe system is also integrated in the SDI board.
In the present embodiment, the load bearing unit 410 includes chuck 200, and the chuck 200 is for carrying and fixing with institute
State the substrate 100 of metal layer 110 to be measured, that is to say, that the chuck 200 is for carrying and fixing silicon wafer (Wafer).
Same as the prior art to the specific descriptions of the SDI board and Kelvin probe system, the present embodiment is herein not
It repeats again.
The illumination unit 420 includes light source, and the light source is used to eliminate the surface potential barrier of the metal layer to be measured 110,
To make surface potential barrier potential difference VSBIt is zero；Therefore it by the opening and closing of the light source, may be implemented under no light mode
First contact potential VCPD-DarkDetection and illumination mode under the second contact potential difference VCPD-LightDetection, to obtain institute
State the surface potential barrier potential difference V of metal layer 110 to be measuredSB。
The metal layer to be measured 110 covers entire substrate 100, but the output power of the light source is at least 100 watts, described
After the output power of light source is larger, therefore the use light source is irradiated 110 surface of metal layer to be measured, the light source
Output power be enough to eliminate the surface potential barrier of the metal layer to be measured 110, so as to eliminate metal layer equipotential shielding effect
It answers, and then improves the second contact potential difference VCPD-LightData accuracy, to improve the function of the metal layer to be measured 110
Function check precision.
In the present embodiment, the light source is LED light source.LED light source is relatively strong with light intensity, light stability is higher and responds
The advantages such as the time is short, to be conducive to improve subsequent detection efficiency and detection accuracy.
In the present embodiment, the light source is green-light source 210 and white light source 300.Specifically, the white light source 300
The light for being 450nm to 465nm for generation wavelength.
In other embodiments, the light source is only the green-light source, correspondingly, the output power of the green-light source
At least 100 watts.
In the present embodiment, the green-light source 210 and white light source 300 are integrated in the SDI board, therefore can
It opens and simultaneously closes off while realizing the green-light source 210 and white light source 300.That is, under illumination mode into
When row detection, the green-light source 210 and white light source 300 are opened simultaneously, described green when being detected under no light mode
Radiant 210 and white light source 300 simultaneously close off.
The reference electrode 220 is used to obtain the surface potential barrier potential difference V of the metal layer 110 to be measured in detectionSBWhen make
To obtain the metal layer to be measured and the reference electrode 220 respectively under illumination and no light mode referring to the electrode compared
Between contact potential difference VCPD, to obtain the surface potential barrier potential difference V of the metal layer to be measured 110SB。
Specifically, in the work function detection process of the metal layer 110 to be measured, the metal layer 110 to be measured with it is described
Reference electrode 220 constitutes capacitance-type vibration, since the metal layer 110 to be measured is different from the fermi level of the reference electrode 220,
So as to detect the contact potential difference V obtained between the metal layer 110 to be measured and the reference electrode 220CPD。
In the present embodiment, the detection unit 430 is used under no light mode, is examined by the Kelvin probe system
Survey the first contact potential difference V obtained between the metal layer 110 to be measured and the reference electrode 220CPD-Dark, in illumination mode
Under, second between the metal layer to be measured 110 and the reference electrode 220 is obtained by the Kelvin probe system detection
Contact potential difference VCPD-Light。
The first contact potential difference VCPD-DarkFor the work function of the metal layer 110 and the reference electrode 220 to be measured
Difference φms, the metal layer 110 to be measured surface potential barrier potential difference VSBAnd the potential difference V of the dielectric layer 150OXThe sum of；
That is, VCPD-Dark=φms+VSB+VOX.Wherein, the work function difference of the metal layer to be measured 110 and the reference electrode 220
Value φmsAnd the potential difference V of dielectric layerOXFor fixed value.
Under illumination mode, the light source can eliminate the surface potential barrier of the metal layer to be measured 110, that is to say, that make
The surface potential barrier potential difference VSBIt is zero.Therefore, the second contact potential difference VCPD-LightFor 110 He of metal layer to be measured
The work function φ of the reference electrode 220msAnd the potential difference V of the dielectric layer 150OXThe sum of；That is,
VCPD-Light=φms+VOX。
It should be noted that the work function φ of the metal layer to be measured 110 and the reference electrode 220ms, Yi Jijie
The potential difference V of matter layerOXFor fixed value, therefore under no light mode and under illumination mode, the work function φmsIt is identical,
And the potential difference VOXIt is identical.
Therefore, the computing unit 440 is used for according to the first contact potential difference VCPD-DarkWith the second contact potential difference
VCPD-LightBetween difference, obtain the surface potential barrier potential difference V of the metal layer 110 to be measuredSB, i.e. VSB=VCPD-Dark-
VCPD-Light。
The computing unit 440 is also used to according to the substrate work function WF (Si) and the surface potential barrier potential difference VSBIt
Between difference, obtain the work function of the metal layer 110 to be measured.
Wherein, work function obtained is effective work function EWF (the Effective Work of the metal layer 110 to be measured
Function), i.e. EWF=WF (Si)-VSB。
Although present disclosure is as above, present invention is not limited to this.Anyone skilled in the art are not departing from this
It in the spirit and scope of invention, can make various changes or modifications, therefore protection scope of the present invention should be with claim institute
Subject to the range of restriction.
Claims (18)
1. a kind of detection method of metal layer work function characterized by comprising
Substrate is provided, the substrate includes substrate and the metal layer to be measured on the substrate, and the substrate has substrate
Work function；
Light source is provided, the output power of the light source is at least 100 watts；
Reference electrode is provided；
The light source is closed, the first contact potential difference between the metal layer to be measured and the reference electrode is obtained；
The light source is opened, the layer on surface of metal to be measured is irradiated, obtains the metal layer to be measured and reference electricity
The second contact potential difference between pole；
According to the difference between first contact potential difference and second contact potential difference, the metal layer to be measured is obtained
Surface potential barrier potential difference；
According to the difference between the substrate work function and the surface potential barrier potential difference, the work content of the metal layer to be measured is obtained
Number.
2. the detection method of metal layer work function as described in claim 1, which is characterized in that obtained by Kelvin probe system
First contact potential difference and the second contact potential difference are obtained, and the Kelvin probe system includes the reference electrode.
3. the detection method of metal layer work function as described in claim 1, which is characterized in that the light source is LED light source.
4. the detection method of metal layer work function as described in claim 1, which is characterized in that the light source is green-light source,
Or green-light source and white light source.
5. the detection method of metal layer work function as claimed in claim 4, which is characterized in that the light source be green-light source and
White light source, the light that the white light source is 450nm to 465nm for generation wavelength.
6. the detection method of metal layer work function as described in claim 1, which is characterized in that in the step of substrate is provided, institute
Stating substrate further includes the dielectric layer between the substrate and the metal layer to be measured.
7. the detection method of metal layer work function as claimed in claim 6, which is characterized in that the dielectric layer is gate medium
Layer, the gate dielectric layer includes boundary layer and the high-k gate dielectric layer on the boundary layer.
8. the detection method of metal layer work function as described in claim 1, which is characterized in that the metal layer to be measured is work content
Several layers.
9. the detection method of metal layer work function as claimed in claim 8, which is characterized in that the metal layer to be measured is single layer
Structure or laminated construction.
10. the detection method of metal layer work function as claimed in claim 8 or 9, which is characterized in that the metal layer to be measured
Material is one or more of TiN, TaN, TaSiN, TiSiN, TiAl, TiAlC, TaAlN, TiAlN, TaCN and AlN.
11. a kind of detection system of metal layer work function characterized by comprising
Load bearing unit, for carrying part to be measured, the part to be measured includes substrate and the metal to be measured on the substrate
Layer；
Illumination unit, for being irradiated to the layer on surface of metal to be measured, the illumination unit includes light source, the light source
Output power is at least 100 watts；
Detection unit, including reference electrode, in the state that the light source is closed, obtain the metal layer to be measured with it is described
The first contact potential between reference electrode, and the state that the layer on surface of metal to be measured is irradiated in the light source
Under, obtain the second contact potential difference between the metal layer to be measured and the reference electrode；
Computing unit, for obtaining institute according to the difference between first contact potential difference and second contact potential difference
The surface potential barrier potential difference of metal layer to be measured is stated, and according to the difference between the substrate work function and the surface potential barrier potential difference
Value obtains the work function of the metal layer to be measured.
12. the detection system of metal layer work function as claimed in claim 11, which is characterized in that the detection unit is integrated in
In Kelvin probe system.
13. the detection system of metal layer work function as claimed in claim 11, which is characterized in that the light source is LED light source.
14. the detection system of metal layer work function as claimed in claim 11, which is characterized in that the light source is green light light
Source or green-light source and white light source.
15. the detection system of metal layer work function as claimed in claim 14, which is characterized in that the light source is green-light source
And white light source, the light that the white light source is 450nm to 465nm for generation wavelength.
16. the detection system of metal layer work function as claimed in claim 11, which is characterized in that the part to be measured further includes position
Dielectric layer between the substrate and the metal layer to be measured.
17. the detection system of metal layer work function as claimed in claim 16, which is characterized in that the dielectric layer is gate medium
Layer, the gate dielectric layer includes boundary layer and the high-k gate dielectric layer on the boundary layer.
18. the detection system of metal layer work function as claimed in claim 11, which is characterized in that the metal layer to be measured is function
Function layer.
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| CN111307872A (en) * | 2020-02-21 | 2020-06-19 | 长江师范学院 | Method for measuring surface work function of ferroelectric film |
| CN112078237A (en) * | 2020-08-25 | 2020-12-15 | 北京黎马敦太平洋包装有限公司 | Hot stamping system with automatic hot stamping quality detection device |
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