JP3329295B2 - Impurity concentration measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impurity concentration measuring method applied to secondary ion mass spectrometry and the like, and more particularly, to an impurity concentration measuring method capable of performing highly accurate measurement from the back side of a sample.

[0002]

2. Description of the Related Art Recently, with the miniaturization of semiconductor devices,
It has become important to accurately evaluate the concentration distribution in the depth direction of impurities existing in an extremely shallow region of the surface, and secondary ion mass spectrometry (Secondary Ion Mass Spect
The analysis in the depth direction of impurities in a semiconductor sample by rometry (SIMS) has been widely used.

[0003] However, SIMS uses accelerated ions (primary ions) such as oxygen, cesium, gallium, and argon.
Is applied to the sample surface and mass spectrometry is performed on ions (secondary ions) emitted from the sample surface by the sputtering phenomenon. Therefore, when the acceleration energy of the primary ions is high, atoms in the sample are originally The effect of being pushed deeper than the existing position (knock-on effect) may increase. In this case, particularly when measuring impurities in a shallow region from the surface, the accuracy of the profile obtained by the measurement in the depth direction is significantly reduced.

Accordingly, NS Smith (NSSS)
"Secondary Ion Mass Spectrometry SIMSX"
spectometry SIMSX) pp. 363-366 ", a method has been adopted in which the measurement is performed with an extremely low accelerating voltage of primary ions.

However, even if the acceleration voltage is lowered, a film such as a polysilicon film formed on a substrate and having a large unevenness on a surface, such as a material film or a metal film, which is not uniformly sputtered by SIMS is formed. When present, the resolution in the depth direction of the impurity profile obtained by SIMS is significantly reduced due to the presence of irregularities in the shape of the surface of the analysis region.

Therefore, in a method of examining the concentration distribution of elements in a depth direction of a thin film formed on a substrate, an intermediate layer inactive with respect to an etchant for removing the substrate is provided between the substrate and the thin film. Yoshida et al. Discloses a method of preparing a sample for analysis by using the above-mentioned etchant to remove only the substrate and then measuring from the back side by SIMS (JP-A-6-194285).

When analyzing a specific region of the sample from the back surface, a hole having the same depth is formed around the analysis region from the front surface side, and the sample is polished from the back surface side, so that the hole is formed from the back surface side. A method of performing a back surface analysis of a specific area by exposing the exposed area is disclosed (Japanese Patent No. 2624211).

[0008]

However, a bonded SOI (Silicon On Insulator) substrate or SIMO
If the substrate is an Si substrate such as an X (Separation by Implanted Oxygen) substrate having an oxide film inside, hydrazine or a mixed solution of hydrofluoric acid, nitric acid and acetic acid is active on Si and on SiO ₂ And inert,
By removing the iO ₂ layer with a hydrofluoric acid solution, the impurities in the Si substrate can be evaluated from the back side of the substrate by SIMS as in the method disclosed in JP-A-6-194285. This method has a problem that it is impossible to perform analysis by SIMS from the back side by using this method for a Si substrate which is widely used for a semiconductor device and has no oxide film inside.

Further, in the method described in Japanese Patent No. 2624211, since the substance existing in the hole opened by the surface processing is an adhesive, the polishing sample actually polished from the back side is used. The polishing rate difference between the (silicon substrate) and the adhesive is small, it is difficult to control the polishing thickness with high accuracy, and it is difficult to obtain a highly accurate profile.

The present invention has been made in view of such a problem, and measures the impurity concentration distribution with high accuracy even on a substrate having no layer inactive to an etchant such as a buried oxide film. It is an object of the present invention to provide a method for measuring impurity concentration which can be performed.

[0011]

SUMMARY OF THE INVENTION An impurity concentration measuring method according to the present invention comprises the steps of forming one or more holes having a uniform depth on the surface of a sample for secondary ion mass spectrometry ; a step of polishing rate the dosage forms therewith than slow membrane the pores formed on the side surface of the sample, a step of bonding a holding substrate with an adhesive prior to the Kimaku, said sample said predetermined before the back side of the hole using the abrasive
Kimaku is characterized by having a, a step of polishing to expose.

In the present invention, the surface to the depth of the sample to form a homogeneous one or more holes, the polishing rate by a predetermined abrasive said hole a more Slow film that of the sample is formed is formed on the surface side, since polishing is performed from the back side using a predetermined abrasive, it is possible to stop the polishing when the front Kimaku is exposed on the back side. Therefore, the polishing thickness can be controlled with high precision, and the obtained impurity concentration distribution also has high precision.

In the present invention, the step of forming the hole may be a step of forming the hole using a focused ion beam device, a secondary ion mass spectrometer, or an ion milling device.

The step of forming the hole includes the step of forming a photoresist having an opening in a predetermined region on the surface of the sample, and the step of dry etching or wet etching the surface of the sample using the photoresist as a mask. a step of, may have.

Furthermore, before Kimaku a silicon oxide film, it may be made of one kind of film selected from the group consisting of diamond-like carbon film and a silicon nitride film. In addition,
The diamond-like carbon film refers to a carbon film having a crystal structure close to a diamond structure.

[0016] Furthermore, the step of forming the pre Kimaku may be by chemical vapor deposition or sputtering.

Further, the step of forming the pre Kimaku may be a step of forming a pre Kimaku below a temperature profile of the measured impurities in the sample begins to change.

Further, the adhesive may be insoluble in the predetermined abrasive.

[0019] Furthermore, polishing the sample, the sample until the exposed front Kimaku using a slurry containing at least one powder selected from the group consisting of diamond powder and alumina powder Polishing step;
Polishing the sample until Kimaku <br/> is exposed using at least one solution selected from the group consisting of piperazine solution and colloidal silica solution may have.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for measuring an impurity concentration according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a view showing a sample to be measured in a first embodiment of the present invention, where (a) is a schematic plan view,
(B) is a sectional view taken along line AA of (a).

In the sample in which the impurity (boron ion) concentration is measured according to the first embodiment, the thickness is about 7 mm.
A gate oxide film 4 having a thickness of 5 nm and a polysilicon layer 3 having a thickness of 20 nm are formed in this order on a 00 μm silicon substrate 1. Further, oxide films 5 and 6 are formed on the side surfaces of the gate oxide film 4 and the polysilicon layer 3, respectively.
The polysilicon layer 3 has an acceleration voltage of 10 keV,
Boron is ion-implanted under the condition of a dose amount of 5 × 10 ¹⁵ cm ⁻² and heat treatment is performed. In this way, a square device region 2 having a side length of about 500 μm in plan view is formed on the silicon substrate 1.

In the first embodiment, the gate insulating film 4
In order to investigate the concentration distribution of boron in the silicon substrate 1 directly below in the depth direction, first, a drilling hole deeper than the measurement depth is formed by drilling the periphery of the device region 2 for the above-described sample. . 2A and 2B are diagrams illustrating a drill hole formed in a sample, where FIG. 2A is a schematic plan view, and FIG. 2B is a cross-sectional view taken along line BB of FIG. In this step,
Specifically, by excavating the peripheral regions 7 to 10 which are partitioned outside the four sides of the device region 2 and have a long side length of 500 μm and a short side length of 20 μm using a focused ion beam apparatus. Drilling holes 7a to 10 each having a depth of 1 μm
a is formed.

FIGS. 3A to 3C are sectional views showing the impurity concentration measuring method according to the first embodiment of the present invention in the order of steps. After forming the drilled holes 7a to 10a as shown in FIGS. 2 (a) and 2 (b), as shown in FIG. A 0.5 μm silicon oxide film 11 is formed. At this film forming temperature, the boron concentration profile in the sample does not change.

Next, as shown in FIG. 3B, an epoxy-based adhesive 12 is applied to the entire front surface side, and a holding substrate 13 is bonded.

After that, the back surface of the silicon substrate 1 has a grain size of 9
Polishing is performed using a slurry containing diamond powder of μm until the thickness of the silicon substrate 1 is about 20 μm. Further, the back surface of the silicon substrate 1 is polished using an aqueous solution containing piperazine (piperazine polishing liquid). Since the silicon oxide film is hardly polished with the piperazine polishing liquid, the polishing is reliably stopped when the silicon oxide film 11 is exposed, as shown in FIG.

FIG. 4 is a schematic diagram showing the back surface of a sample after polishing with a piperazine polishing liquid. After polishing with the piperazine polishing liquid until the silicon oxide film 11 is exposed,
As shown in FIG. 4, since the presence of the silicon oxide film 11 embedded in the peripheral regions 7 to 10 around the device region 2 is also confirmed from the back side of the silicon substrate 1, these peripheral regions 7 to 10 The length of one side surrounded by is 30
By performing SIMS measurement on a square region of about 0 μm, highly accurate impurity concentration measurement can be obtained.

Actually, according to the first embodiment, the sample having the device region formed by the same process
The result of the MS measurement and the SIM
The result was compared with the result of the S measurement. Specifically, the acceleration voltage is 2 k in a SIMS device equipped with a quadrupole mass detector.
Irradiation is performed while scanning the back or front surface of the sample with an O ₂ ⁺ primary ion beam focused under the conditions of eV and a primary ion current amount of 50 nA, and the length of one side is 10 μm at the center of the irradiation region.
¹¹ B ⁺ secondary ions in a square area of the sample were detected. The result is shown in FIG. FIG. 5 shows the depth from the interface on the horizontal axis,
FIG. 5 is a graph showing a boron concentration profile in a sample with the ion concentration of ¹¹ B ⁺ taken on the vertical axis. In FIG. 5, a solid line indicates a measurement result according to the first embodiment, and a broken line indicates a measurement result according to a conventional measurement method.

As shown in FIG. 5, in the boron concentration profile obtained by the first embodiment of the present invention, since the measurement is performed from the back side, the unevenness formed on the surface of the polysilicon layer 3 is obtained. And the ion concentration of boron at the gate oxide film / silicon substrate interface was not more than the detection limit concentration (3 × 10 ¹⁵ cm ⁻³ ). That is, the boron implanted in the polysilicon layer 3 does not diffuse into the silicon substrate 1 through the gate oxide film 4.

On the other hand, in the boron concentration profile measured from the surface side by the conventional method, the resolution in the depth direction is reduced due to the influence of the unevenness formed on the surface of the polysilicon layer 3. At a depth of 50 nm from the interface of, a boron that should not exist was detected at about 1 × 10 ¹⁸ cm ⁻³ .

In the first embodiment, the excavation hole 7
Although the focused ion beam is used to form the holes a to 10a, the borehole may be formed using a secondary ion mass spectrometer or an ion milling device.

Next, a second embodiment of the present invention will be described. 6A and 6B are views showing a sample to be measured in the second embodiment of the present invention, wherein FIG. 6A is a schematic plan view, and FIG. 6B is a cross-sectional view taken along line CC of FIG.

According to the second embodiment, impurities (phosphorus ions)
In the sample whose concentration is to be measured, the thickness is about 700
The length of one side is 5 in plan view on the silicon substrate 101 of μm.
A tungsten silicide film 102 having a square shape of 00 μm and a thickness of 100 nm is formed by a sputtering method. In addition, the tungsten silicide film 102 includes
Under the conditions of an acceleration voltage of 10 keV and a dose of 5 × 10 ¹⁵ cm ⁻² , phosphorus is ion-implanted, and an activation heat treatment of phosphorus using an electric furnace is performed.

In the second embodiment, in order to investigate the concentration distribution in the depth direction of phosphorus in the silicon substrate 101 immediately below the tungsten silicide film 102, first, the tungsten silicide film 102 By drilling the periphery, a drill hole deeper than the measurement depth is formed. FIGS. 7A and 7B are diagrams showing a drill hole formed in a sample, where FIG. 7A is a schematic plan view, and FIG. 7B is a cross-sectional view taken along line DD of FIG. In this step, specifically, a photoresist having an opening in the peripheral region 103 defined around the tungsten silicide film 102 is applied to the entire surface and exposed. Thereafter, the sample is heated to about 100 ° C. in an electric furnace to bake the photoresist, and a peripheral region 103 is formed using a mixed solution of hydrofluoric acid, glacial acetic acid, and nitric acid.
By etching the silicon substrate 101 in the above, a drilled hole 103a having a depth of 1 μm is formed. Then, the photoresist is removed using an organic solvent.

FIGS. 8A to 8C are sectional views showing a method of measuring the impurity concentration according to the second embodiment of the present invention in the order of steps. As shown in FIG. 7A and FIG.
8A, a film thickness of about 0.5 is formed on the entire surface side by a CVD method at a growth temperature of 450 ° C., as shown in FIG.
A μm-like diamond-like carbon film 104 is formed. At this growth temperature, the phosphorus concentration profile in the sample does not change.

Next, as shown in FIG. 8B, a holding substrate 106 made of a silicon single crystal substrate is bonded to the entire front side using an epoxy adhesive 105.

Thereafter, the back surface of the silicon substrate 101 is polished using a slurry containing diamond powder having a particle size of 9 μm until the thickness of the silicon substrate 101 becomes about 20 μm. Further, the back surface of the silicon substrate 101 is polished using a slurry containing diamond powder having a particle diameter of 1 μm until the thickness thereof becomes about 5 μm. Furthermore, the back surface of the silicon substrate 101 is polished using a colloidal silica solution. Since the diamond-like carbon film is hardly polished with respect to the colloidal silica solution, the polishing is reliably stopped when the diamond-like carbon film 104 is exposed, as shown in FIG.

FIG. 9 is a schematic view showing a sample surface after polishing with a colloidal silica solution. After polishing with the colloidal silica solution until the diamond-like carbon film 104 is exposed, as shown in FIG. 9, the presence of the diamond-like carbon film 104 embedded in the peripheral region 103 also from the back surface side of the silicon substrate 101. It is confirmed. Therefore, after washing and drying, the surrounding area 10
By performing SIMS measurement on a square region having a side length of about 200 μm surrounded by 3, a highly accurate impurity concentration can be obtained.

Actually, the results of the SIMS measurement performed on the sample having the tungsten silicide film formed by the same process according to the second embodiment and the results obtained by performing the SIMS measurement from the front side as in the related art are shown. Compared. Specifically, the acceleration voltage is 14.5 keV and the primary ion current is 10 n in a SIMS apparatus equipped with a double focusing mass spectrometer.
The conditions cesium primary ion beam A is irradiated to the rear surface or the surface of the sample, the diameter at the center portion of the irradiated region ³¹ P of 60μm area ^- was detected secondary ions. At this time, the concentration profile of phosphorus in the above-described region in the depth direction was obtained by increasing the mass resolution and separating and detecting ³⁰ SiH ^−, whose mass was almost equal to P ⁻ . The result is shown in FIG. FIG. 10 is a graph showing a phosphorus concentration profile in a sample, where the horizontal axis represents the depth from the surface of the tungsten silicide film and the vertical axis represents the ion concentration of ³¹ P ⁻ . FIG.
At 0, the solid line indicates the measurement result according to the second embodiment,
The broken line shows the measurement result by the conventional measurement method.

As shown in FIG. 10, in the phosphorus concentration profile obtained according to the second embodiment of the present invention, since the measurement is performed from the back side, the unevenness formed on the surface of the tungsten silicide film 102 Unaffected, at a depth of about 0.3 μm from the surface of the tungsten silicide film 102, the phosphorus ion concentration in the silicon substrate reached the detection limit concentration (about 1 × 10 ¹⁶ cm ⁻³ ).

On the other hand, in the phosphorus concentration profile in the depth direction measured from the surface side of the tungsten silicide film by the conventional method, the resolution in the depth direction is significantly lowered due to the influence of the unevenness formed on the surface of the tungsten silicide film 102. Therefore, at a depth of 0.5 μm from the surface (the surface of the tungsten silicon film), 1 × 10 ¹⁸ cm ⁻³ or more of phosphorus that should not exist was detected.

Next, a third embodiment of the present invention will be described. 11A and 11B are diagrams showing a material to be measured in a third embodiment of the present invention, wherein FIG. 11A is a schematic plan view, and FIG. 11B is a cross-sectional view taken along line EE of FIG.

The sample whose impurity (tantalum) concentration is measured according to the third embodiment has a thickness of about 700 μm.
m on a silicon substrate 201 having a side length of 30 in plan view.
A tantalum pentoxide (Ta ₂ O ₅ ) film 202 having a square shape of 0 μm and a thickness of 10 nm is formed. The tantalum pentoxide film 202 is subjected to a heat treatment using an electric furnace.

In the third embodiment, in order to investigate the concentration distribution in the depth direction of tantalum in the silicon substrate 201 immediately below the tantalum pentoxide film 202, first, a tantalum pentoxide film was formed on the above-described sample. By drilling around 202, a drill hole deeper than the measured depth is formed. FIG.
3A and 3B are diagrams illustrating a drill hole formed in a sample, where FIG. 3A is a schematic plan view, and FIG. 3B is a cross-sectional view taken along line FF of FIG. In this step, specifically, a 3 mm-thick photoresist having an opening in the peripheral region 203 partitioned around the tantalum pentoxide film 202 is applied to the entire surface and exposed. After that, the sample is heated to about 100 ° C. in an electric furnace, the photoresist is baked, and the silicon substrate 201 is dry-etched to form a drilled hole 203 a having a depth of 1 μm. Then, the photoresist is removed using an organic solvent.

FIGS. 13A to 13C are cross-sectional views showing a method of measuring an impurity concentration according to the third embodiment of the present invention in the order of steps. As shown in FIGS. 12 (a) and 12 (b),
After the formation of 03a, as shown in FIG. 13A, a silicon nitride film 204 having a thickness of about 0.1 μm is formed on the entire front surface side by a plasma CVD method at a growth temperature of 300 ° C. At this growth temperature, the tantalum concentration profile in the sample does not change.

Next, as shown in FIG. 13B, a holding substrate 206 made of a silicon single crystal substrate is bonded to the entire front surface using an epoxy adhesive 205.

Thereafter, the back surface of the silicon substrate 201 is polished using a slurry containing diamond powder having a particle size of 9 μm until the thickness of the silicon substrate 201 becomes about 20 μm. Further, the back surface of the silicon substrate 201 is polished using a slurry containing diamond powder having a particle diameter of 1 μm until the thickness thereof becomes about 5 μm. Further, the back surface of the silicon substrate 201 is polished using a colloidal silica solution. Since the silicon nitride film is hardly polished against the colloidal silica solution, the polishing is reliably stopped when the silicon nitride film 204 is exposed, as shown in FIG.

FIG. 14 is a schematic diagram showing a sample surface after polishing with a colloidal silica solution. After the silicon nitride film 204 is polished with the colloidal silica solution until the silicon nitride film 204 is exposed, as shown in FIG. 14, the presence of the silicon nitride film 204 embedded in the peripheral region 203 is also confirmed from the back surface side of the silicon substrate. . Therefore, after washing and drying, the length of one side surrounded by the peripheral region 203 is 200 mm.
By performing SIMS measurement on a square region of about μm, a highly accurate impurity concentration can be obtained.

In order to check the flatness of the polished surface of the sample after polishing using the colloidal silica solution, a region corresponding to the analysis region on the back side of the silicon substrate 201 using a surface roughness meter, ie, tantalum pentoxide Roughness measurement was performed in a region matching the region where the film 202 was formed. As a result, the flatness along the line GG in FIG. 14 was 10 nm or less within 50 μm from the center point. Also,
The flatness along the line HH in FIG. 14 was 10 nm or less within 65 μm from the center point.

When the dry etching time of the silicon substrate 201 is doubled, the depth of the drill hole 203a is 2
The polishing of the silicon substrate 201 with the colloidal silica solution was reliably stopped when the thickness became about 2 μm, but the flatness at this time was as follows. The flatness along the line GG in FIG. 14 is 10 nm or less within 80 μm from the center point, and the flatness along the line HH is 1 nm within 100 μm from the center point.
It was 0 nm or less.

When the dry etching time of the silicon substrate 201 is reduced by half, the excavation hole 203a
Of the silicon substrate 201 with a colloidal silica solution has a thickness of 0.5 μm.
The stoppage was surely stopped when it reached about m, but the flatness at this time was as follows. The flatness along the line GG in FIG. 14 was 10 nm or less within 30 μm from the center point, and the flatness along the HH line was 10 nm or less within 45 μm from the center point. .

Actually, SIMS measurement was performed on samples having the same tantalum pentoxide film according to the third embodiment in which various dry etching times were applied, and SIMS measurement was performed from the surface side as in the conventional case. Was compared with the results. Specifically, similarly to the second embodiment, the acceleration voltage is 5 ke in the SIMS apparatus equipped with the double focusing mass spectrometer.
V, a primary oxygen ion beam was applied to the back or front surface of the sample under the conditions of a primary ion current of 10 nA, and tantalum secondary ions having a diameter of 8 μm were detected at the center of the irradiated area. The result is shown in FIG. FIG. 15 is a graph showing the tantalum concentration profile in the sample with the abscissa plotting the depth from the interface and the ordinate plotting the tantalum ion concentration. In FIG. 15, the solid line shows the measurement result when the depth of the borehole was set to 1 μm in the third embodiment, and the dotted line shows the measurement result when the depth of the borehole was set to 0.5 μm.
The dashed line indicates the measurement result when the depth of the excavation hole is 2 μm, and the broken line indicates the measurement result by the conventional measurement method.

As shown in FIG. 15, in the tantalum concentration profile of each sample obtained according to the third embodiment of the present invention, since the measurement is performed from the back side, the influence of the irregularities on the surface of the tantalum pentoxide film. In each of the samples, the ion concentration of tantalum in the silicon substrate reached the detection limit concentration (about 1 × 10 ¹⁶ cm ⁻³ ) at a depth of less than 0.2 μm from the surface of the tantalum pentoxide film. Was.

On the other hand, the depth of the borehole is reduced to 1 by the conventional method.
In the tantalum concentration profile in the depth direction measured from the surface side of the tungsten silicide film with μm, irregularities were formed on the surface of the tantalum pentoxide film. Was done. For this reason, the resolution in the depth direction was remarkably reduced, and 1 × 10 ¹⁸ cm ⁻³ or more of tantalum, which should not exist originally, was detected at a depth of 0.5 μm from the tantalum pentoxide film / silicon substrate interface.

[0054]

As described in detail above, according to the present invention,
Polishing can be stopped when the film formed in the hole is exposed on the back surface side. For this reason, the polishing thickness can be controlled with high precision, so that a highly accurate impurity concentration distribution can be obtained even for a substrate having no layer inactive against an etchant such as a buried oxide film.

[Brief description of the drawings]

FIG. 1 is a view showing a sample to be measured in a first embodiment of the present invention, wherein (a) is a schematic plan view, and (b) is (a).
FIG. 3 is a sectional view taken along line AA of FIG.

FIG. 2 is a view showing a drill hole formed in a sample,
(A) is a schematic plan view, and (b) is a cross-sectional view taken along line BB of (a).

FIGS. 3A to 3C are cross-sectional views illustrating a method of measuring an impurity concentration according to the first embodiment of the present invention in the order of steps.

FIG. 4 is a schematic diagram showing a back surface of a sample after polishing with a piperazine polishing liquid.

FIG. 5 is a graph showing a profile of boron concentration in a sample.

FIGS. 6A and 6B are views showing a sample to be measured in a second embodiment of the present invention, wherein FIG. 6A is a schematic plan view, and FIG.
It is sectional drawing by CC line of FIG.

FIG. 7 is a diagram showing a borehole formed in a sample,
(A) is a schematic plan view, and (b) is a cross-sectional view taken along line DD of (a).

FIGS. 8A to 8C are cross-sectional views illustrating a method of measuring an impurity concentration according to a second embodiment of the present invention in the order of steps.

FIG. 9 is a schematic diagram showing a sample surface after polishing with a colloidal silica solution.

FIG. 10 is a graph showing a phosphorus concentration profile in a sample.

11A and 11B are diagrams showing a material to be measured in a third embodiment of the present invention, wherein FIG. 11A is a schematic plan view, and FIG. 11B is a cross-sectional view taken along line EE of FIG.

FIG. 12 is a diagram showing a borehole formed in a sample,
(A) is a schematic plan view, and (b) is a cross-sectional view taken along line FF of (a).

FIGS. 13A to 13C are cross-sectional views illustrating a method of measuring an impurity concentration according to a third embodiment of the present invention in the order of steps.

FIG. 14 is a schematic diagram showing a sample surface after polishing with a colloidal silica solution.

FIG. 15 is a graph showing a tantalum concentration profile in a sample.

[Explanation of symbols]

1, 101, 201; silicon substrate 2: device region 3: polysilicon layer 4, 5, 6, 11; oxide film 7, 8, 9, 10, 103, 203; peripheral region 7a, 8a, 9a, 10a, 103a Drilling holes 12, 105, 205; Adhesives 13, 106, 206; Holding substrate 102; Tungsten silicide film 104; Diamond-like carbon film 202; Tantalum pentoxide film 204; Silicon nitride film

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/66 G01N 1/28 G01N 1/32 G01N 23/225

Claims (12)

(57) [Claims] A step of 1. A surface to a depth of the sample for secondary ion mass spectrometry to form a uniform one or more holes, a slow yet film than that of polishing rate The sample by predetermined polishing agent forming on the surface of the hole is formed side, before the step of bonding the holding substrate by the adhesive on Kimaku, from the back side of the sample using a predetermined abrasive in said bore impurity concentration measuring method characterized by having a step of polishing until <br/> before Kimaku is exposed. 2. The method according to claim 1, wherein the step of forming the hole is a step of forming the hole using a focused ion beam device. 3. The method according to claim 1, wherein the step of forming the hole is a step of forming the hole using a secondary ion mass spectrometer. 4. The method according to claim 1, wherein the step of forming the hole is a step of forming the hole using an ion milling device. Wherein the step of forming the hole includes the steps of forming a photoresist having an opening in a predetermined region on the surface of the sample, a step of dry-etching the surface of the sample as a mask the photoresist the impurity concentration measurement method according to claim 1, characterized in that it comprises a. 6. A process of forming the hole includes the steps of forming a photoresist having an opening in a predetermined region on the surface of the sample, a step of wet-etching the surface of the sample as a mask the photoresist the impurity concentration measurement method according to claim 1, characterized in that it comprises a. 7. Before Kimaku a silicon oxide film, any one of claims 1 to 6, characterized in that a kind of film selected from the group consisting of diamond-like carbon film and a silicon nitride film The method for measuring the impurity concentration described in 1. Forming a 8. Before Kimaku, the impurity concentration measuring method according to any one of claims 1 to 7, characterized in that by a chemical vapor deposition method. 9. A process for forming a pre Kimaku is claims 1 to 7, characterized in that by a sputtering method
The method for measuring an impurity concentration according to any one of the above items. 10. A process for forming a pre Kimaku are of claims 1 to 9, wherein the profile of the measured impurities in said sample is a step of forming a pre Kimaku below temperature starts changing The method for measuring an impurity concentration according to claim 1. 11. The method according to claim 1, wherein the adhesive is insoluble in the predetermined abrasive.
The method for measuring an impurity concentration according to the paragraph. 12. A process for polishing the sample, prior to using a slurry containing at least one powder selected from the group consisting of diamond powder and alumina powder Stories
Polishing the sample until the film is exposed, polishing the sample until Kimaku is exposed using at least one solution selected from the group consisting of piperazine solution and colloidal silica solution the impurity concentration measurement method according to any one of claims 1 to 11, characterized in that it has a.