SILICON MEMBER AND METHOD OF PRODUCING THE SAME

Abstract

A silicon member and a method of producing the silicon member are provided. Cracking is suppressed in the silicon member even if the silicon member is used in a condition where it is heated. The silicon member 10 includes a coating layer 11 that coats a surface of the silicon member 10, wherein the coating layer 11 is composed of a product of silicon formed by reaction of the silicon on the surface, and a thickness of the coating layer is 15 nm or more and 600 nm or less. It is preferable that the coating layer is a silicon oxide film or a silicon nitride film.

Claims

1. A silicon member that is used in a condition where the silicon member is heated, the silicon member comprising a coating layer that coats a surface of the silicon member with micro-cracks, wherein the coating layer is composed of a product of silicon formed by reaction of the silicon on the surface, and a thickness of the coating layer is 15 nm or more and 600 nm or less.

2. The silicon member according to claim 1, wherein the coating layer is a silicon oxide film.

3. The silicon member according to claim 2, wherein a thickness of the silicon oxide film is 30 nm or more and 520 nm or less.

4. The silicon member according to claim 1, wherein the coating layer is a silicon nitride film.

5. A silicon member that is used in a condition where the silicon member is heated, wherein after forming a coating layer composed of a product of silicon formed by reaction of the silicon on a surface of the silicon member, the surface is exposed by removing the coating layer.

6. The silicon member according to claim 5 wherein a coating layer composed of a product of silicon is re-formed on the exposed surface.

7. A silicon member that is used in a condition where the silicon member is heated, wherein a strained-layer on a surface layer is removed and an arithmetic average roughness Ra is 2 nm or less by polishing or etching a surface of the silicon member.

8. The silicon member according to claim 1, wherein the silicon member is made of a poly-crystalline silicon.

9. The silicon member according to claim 1, wherein the silicon member is made of a pseudo-single-crystalline silicon.

10. The silicon member according to claim 1, wherein a dimension of the silicon member is: width W is 500 mm to 1500 mm; length is 500 mm to 1500 mm; and thickness is 5 mm to 50 mm.

11-15. (canceled)

16. The silicon member according to claim 1, wherein the silicon member is a holding plate for deposition and heat treatment.

17. The silicon member according to claim 1, wherein the surface of the holding plate is free of scratches and micro-cracks.

18. The silicon member according to claim 1, wherein a maximum load in four-point bending of the holding plate is between 188 to 265 MPa.

19. The silicon member according to claim 1, wherein the silicon member is excised from a unidirectionally solidified columnar crystal ingot.

20. The silicon member according to claim 1, wherein the coating layer is a silicon nitride film having a thickness of 15 nm or more and 50 nm or less.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is a perspective view of the silicon member of the first embodiment of the present invention.

[0032] FIG. 2 is an enlarged cross-sectional view in the vicinity of the surface of the silicon member shown in FIG. 1.

[0033] FIG. 3 is an explanatory diagram of the method of producing the silicon member of the first embodiment of the present invention.

[0034] FIG. 4 is an enlarged cross-sectional view in the vicinity of the silicon member of the second embodiment of the present invention.

[0035] FIG. 5 is an explanatory diagram of the method of producing the silicon member of the third embodiment of the present invention.

[0036] FIG. 6 is an explanatory diagram of the method of producing the silicon member of the fourth embodiment of the present invention.

[0037] FIG. 7 is a schematic diagram of the columnar crystal silicon ingot manufacturing apparatus 50 used for producing the pseudo-single-crystalline silicon ingot or the poly-crystalline silicon ingot, which is the material of the silicon member of the embodiments of the present invention.

EMBODIMENTS OF THE INVENTION

[0038] The silicon member of the first embodiment of the present invention is explained in reference to FIGS. 1 to 3.

[0039] The silicon member 10 of the present embodiment is in the plate shape as shown in FIG. 1 and used as the holding plate that holds the liquid crystal panel during the heat treatment process in the liquid crystal panel production. In the present embodiment, the silicon member 10 is the large-sized plate material with the dimension: width W being 500 mm to 1500 mm; length L being 500 mm to 1500 mm; and thickness H being 5 mm to 50 mm.

[0040] As shown in FIG. 2, the coating layer composed of the product of silicon is formed on the surface of the silicon member 10. In the present embodiment, the silicon oxide film 11 is formed as the coating layer.

[0041] The thickness to of the silicon oxide film 11 (coating layer) is in the range of 15 nmt.sub.0600 nm. Preferably, it is in the range of 30 nmt.sub.0520 nm.

[0042] The silicon member 10 is produced by following the processes described below.

[0043] First, a single-crystalline silicon ingot, a pseudo-single-crystalline silicon ingot, or a poly-crystalline silicon ingot, which will be the raw material of the silicon member 10, is prepared.

[0044] The single-crystalline silicon ingot that will be the raw material of the silicon member 10 is manufactured by the Czochralski CZ method.

[0045] Also, the pseudo-single-crystalline silicon ingot and the poly-crystalline silicon ingot that will be the raw material of the silicon member 10 are manufactured by using the columnar crystal silicon ingot manufacturing apparatus 50 shown in FIG. 7.

[0046] The columnar crystal silicon ingot manufacturing apparatus 50 includes: a crucible 60 storing the silicon melt L; a chill plate 52 on which the crucible 60 is placed; an under the floor heater 53 supporting the chill plate 52 from the lower side; and the ceiling heater 54 provided above the crucible 60. Also, an insulating material 55 is provided around the crucible 60.

[0047] The chill plate 52 is in a hollowed-structure, and it is configured that Ar gas is supplied to the inside of the chill plate 52 through a supply pipe 56.

[0048] The columnar crystal silicon ingot is produced by solidifying the silicon melt upward from the bottom part of the crucible 60 by: inserting the silicon raw materials in the crucible 60 of the above-described columnar crystal silicon ingot manufacturing apparatus 50; producing the silicon melt by heating and dissolving them; and adjusting outputs of the under the floor heater 53 and the ceiling heater 54.

[0049] The pseudo-single-crystalline silicon ingot is produced by growing each of single crystals from multiple seed crystals in the crucible 60 by solidifying silicon melt upward from the bottom part of the crucible 60 by: placing the multiple seed crystals made of single-crystalline silicon plates on the bottom part of the crucible 60 of the above-described columnar crystal silicon ingot manufacturing apparatus 50; inserting the silicon raw materials in the crucible 60; producing the silicon melt by heating and dissolving them; and adjusting outputs of the under the floor heater 53 and the ceiling heater 54. The pseudo-single-crystalline silicon ingot is the silicon ingot having multiple single-crystalline parts grown from the seed crystals. Depending on the way to arrange the seed crystals, it is possible for the entire body of the silicon ingot to be almost single-crystalline.

[0050] Next, the single-crystalline silicon ingot, the pseudo-single-crystalline silicon ingot, or the poly-crystalline silicon ingot is sawed with the band saw or the wire saw to excise the plate material 16 in a predetermined size out.

[0051] Next, the surface of the excised plate material 16 is grinded and polished. Then, etching treatment is performed. In the present embodiment, the mixed solution of hydrofluoric acid and nitric acid is used as the etching liquid. Because of the treatment, the strained-layer existing in the surface layer of the plate material 16 is removed.

[0052] Then, oxidation treatment is performed on the plate material 16. The silicon oxide film 11 (coating layer) is formed by oxidizing silicon on the surface of the plate material 16 by: inserting the plate material 16 in a vacuum container; heating it to a predetermined temperature; and introducing an oxidized gas into the vacuum container. The thickness to of the silicon oxide film 11 (coating layer) can be controlled by adjusting the temperature and the flow rate of the gas during the oxidation treatment.

[0053] At this time, there are scratches and micro-cracks on the surface of the plate material 16. By oxidation treating the surface to form the silicon oxide film 11, the silicon oxide film 11 grows (penetrates) even toward the internal side of the plate material 16 as shown in FIG. 3, and the previously existing scratches and micro-cracks are eliminated. More specifically, oxygen in the silicon oxide film 11 diffuses in the solid state body, and diffuses to the part corresponding to the plate material 16 (in the downward direction in FIG. 3). When the diffused oxygen reacts with silicon of the plate material 16 existing under the diffused location, the silicon oxide film 11 grows (penetrates) toward the internal side of the plate material 16.

[0054] In the present embodiment, the t.sub.1 (penetration depth t.sub.1 into silicon), which is the thickness of the silicon oxide film 11 grown toward the internal side of the plate material 16 from the surface S of the plate material 16 before the formation of the silicon oxide film 11, with respect the entire thickness to of the silicon oxide film 11, is set to satisfy the formula, t.sub.1=0.45t.sub.0, as shown in FIG. 3.

[0055] The silicon member 10 of the present embodiment configured as described above is used as the holding plate for the liquid crystal panel and heated to the high temperature such as 600 C. to 800 C. during the heat treatment process.

[0056] According to the silicon member 10 of the present embodiment configured as described above, the scratches and micro-cracks on the surface are eliminated in the process that the silicon oxide film 11 (coating layer) is formed, since it has the silicon oxide film 11 (coating layer) formed by oxidizing silicon on the surface of the plate material 16 on its surface. Thus, cracking originated from the scratches and micro-cracks can be suppressed. Because of this, cracking due to thermal stress or the like can be suppressed even if the large-sized and plate-shaped silicon member 10, which has the dimension of: width W being 500 mm to 1500 mm; length L being 500 mm to 1500 mm; and thickness H being 5 mm to 50 mm, is used in the high-temperature condition.

[0057] Also, in the present embodiment, the thickness to of the silicon oxide film 11 (coating layer) is set to be 15 nm or more. Thus, the scratches and micro-cracks on the surface can be eliminated and occurrence of cracking can be suppressed reliably. Furthermore, the thickness to of the silicon oxide film 11 (coating layer) is set to be 600 nm or less. Thus, the lapse time for the oxidation treatment can be shortened, and the silicon member 10 can be produced efficiently.

[0058] When the thickness to of the silicon oxide film 11 (coating layer) is set to be 30 nm or more, the scratches and micro-cracks on the surface can be eliminated more sufficiently and occurrence of cracking can be suppressed reliably. Also, when the thickness to of the silicon oxide film 11 (coating layer) is set to be 520 nm or less, the lapse time for the oxidation treatment can be shortened further, and the silicon member 10 can be produced efficiently.

[0059] In addition, in the present embodiment, the t.sub.1 (penetration depth t.sub.1 into silicon), which is the thickness of the silicon oxide film 11 grown toward the internal side of the plate material 16 from the surface S of the plate material 16 before the formation of the silicon oxide film 11, with respect the entire thickness to of the silicon oxide film 11, is set to satisfy the formula, t.sub.1=0.45t.sub.0. Therefore, the scratches and micro-cracks can be eliminated reliably by forming the silicon oxide film 11 (coating layer).

[0060] Next, the silicon member 110 of the second embodiment of the present invention is explained in reference to FIG. 4.

[0061] In the second embodiment, the coating layer formed on the surface of the silicon member 110 is the silicon nitride film 111. The thickness t.sub.10 of the silicon nitride film 111 (coating layer) is set to satisfy the formula, 15 nmt.sub.1050 nm.

[0062] The silicon nitride film 111 (coating layer) is formed by performing the thermal nitridation treatment on the surface of the silicon plate material 116. The t.sub.11 (penetration depth t.sub.11 into silicon), which is the thickness of the silicon nitride film 111 grown toward the internal side of the plate material 116 from the surface S of the plate material 116 before the formation of the silicon nitride film 111, with respect the entire thickness t.sub.10 of the silicon nitride film 111, is set to satisfy the formula, t.sub.11=0.88t.sub.10, as shown in FIG. 4.

[0063] According to the silicon member 110 of the present embodiment configured as described above, the scratches and micro-cracks on the surface are eliminated in the process that the silicon nitride film 111 (coating layer) is formed, since it has the silicon nitride film 111 (coating layer) formed by nitriding silicon on the surface of the plate material 116 on its surface. Thus, cracking originated from the scratches and micro-cracks can be suppressed.

[0064] Also, in the present embodiment, the thickness t.sub.10 of the silicon nitride film 111 (coating layer) is set to be 15 nm or more. Thus, the scratches and micro-cracks on the surface can be eliminated and occurrence of cracking can be suppressed reliably. Furthermore, the thickness t.sub.10 of the silicon nitride film 111 (coating layer) is set to be 50 nm or less. Thus, the lapse time for the nitridation treatment can be shortened, and the silicon member 110 can be produced efficiently.

[0065] In addition, in the present embodiment, the t.sub.1 (penetration depth t.sub.11 into silicon), which is the thickness of the silicon nitride film 111 grown toward the internal side of the plate material 116 from the surface S of the plate material 116 before the formation of the silicon nitride film 111, with respect the entire thickness t.sub.10 of the silicon nitride film 111, is set to satisfy the formula, t.sub.11=0.88t.sub.10. Therefore, the scratches and micro-cracks can be eliminated reliably by forming the silicon nitride film 111 (coating layer).

[0066] Next, the silicon member of the third embodiment of the present invention is explained in reference to FIG. 5.

[0067] In the third embodiment, it is configured that after forming the coating layer composed of the silicon oxide film 211 on the surface of the silicon member 210, silicon is exposed by removing the silicon oxide film 211 (coating layer) as shown in FIG. 5. When the silicon oxide film is thick, it is polished while a part of the silicon oxide layer is still left, and the remaining silicon oxide film layer is removed by a buffered hydrofluoric acid solution. In the case of the silicon oxide film being thin, it is removed directly by the buffered hydrofluoric acid solution. Removal of the silicon oxide film layer by the buffered hydrofluoric acid solution can be performed by using a solution of the composition of HF:NH.sub.4F=7:1 at the room temperature.

[0068] The silicon oxide film 211 formed on the surface of the plate material 216 grows even toward the internal side of the plate material 216, and the scratches and micro-cracks previously existed on the surface of the plate material 216 are eliminated. In the present embodiment, the t.sub.21 (penetration depth t.sub.21 into silicon), which is the thickness of the silicon oxide film 211 grown toward the internal side of the plate material 216 from the surface S of the plate material 216 before the formation of the silicon oxide film 211, with respect the entire thickness t.sub.20 of the silicon oxide film 211, is set to satisfy the formula, t.sub.21=0.45t.sub.20, as shown in FIG. 5.

[0069] Then, since the silicon oxide film 211 is removed later on, the part corresponding to the thickness t.sub.21 is removed from the surface S of the original plate material 216 in the silicon member 210 of the present embodiment.

[0070] In the silicon member 210 in this configuration, the silicon oxide film 211 (coating layer) is formed by oxidizing the silicon on the surface of the plate material 216. Thus, fine scratches and micro-cracks on the surface are eliminated during the formation of the silicon oxide film 211 (coating layer). Then, since this silicon oxide film 211 (coating layer) is removed later on, the silicon member 210 free of the scratches and micro-cracks can be obtained. Furthermore, contamination of impurities, such as oxygen, nitrogen, or the like, to other members during heat treatment can be suppressed.

[0071] In addition, new silicon oxide film or silicon nitride film can be re-formed on the surface of the silicon member 210 since the other members will not be contaminated by the impurities such as oxygen, nitrogen, or the like at 300 C. to 900 C., which is a temperature range of a low heat treatment temperature. The coating layer on the surface layer prevents formation of scratches, and also eliminates micro-scratches formed after removal of the old coating layer. Thus, cracking originated from these scratches and micro-cracks can be suppressed.

[0072] Next, the silicon member of the fourth embodiment of the present invention is explained in reference to FIG. 6.

[0073] In the fourth embodiment, the surface of the plate material 316 is polished and then the etching treatment is performed as shown in FIG. 6, to remove the scratches and micro-cracks on the surface. Then, the arithmetic average roughness Ra of the surface is set to be 2 nm or less.

[0074] In the present embodiment, the part corresponding to the thickness t.sub.31 is removed from the surface S of the original plate material 316 by the polishing and the etching treatment. The thickness of t.sub.31 is set in the range to satisfy the formula, 100 nmt.sub.315000 nm.

[0075] In the silicon member 310 configured as described above, the silicon member 310 with a smaller number of scratches and micro-cracks can be obtained since the scratches and micro-cracks on the surface are removed and the arithmetic average roughness Ra of the surface is set to be 2 nm or less by: polishing the surface of the silicon member 310; and performing the etching treatment afterward. Moreover, contamination of impurities such as oxygen, nitrogen, or the like to the other members during the heat treatment can be suppressed. Also, the scratches and micro-cracks can be eliminated reliably in the present embodiment since the thickness t.sub.31 removed by the polishing and the etching treatment is set to be in the range to satisfy the formula, 100 nmt.sub.315000 nm.

[0076] The silicon members of the embodiments of the present invention are explained above. However, the scope of the present invention is not restricted by the descriptions of the embodiments and the configurations can be modified as needed.

[0077] For example, the embodiments are explained referring the silicon member in the plate shape as shown in FIG. 1. The scope of the present invention is not restricted by the description, and the silicon member can be the silicon ring material, silicon disc material, silicon plate material, or the like placed in the semiconductor manufacturing apparatus, and the silicon rectangular pillar material, silicon bar material, silicon bulk material, or the like used in the heat treatment apparatus.

EXAMPLE

[0078] Results of confirmatory experiments performed to confirm the effects of the present invention are shown.

[0079] The silicon members (silicon plate) of Examples 1-21 of the present invention and those of Comparative examples 1-2 were produced by following the procedures described below. Then, the measurement of surface roughness (arithmetic average roughness Ra) and the four-point bending test were performed on the obtained silicon members.

Examples 1-8 of the Present Invention

[0080] Plate materials, which had the dimension of 1000 mm1000 mm20 mm (widthlengththickness), were excised from the poly-crystalline silicon ingot (unidirectionally solidified columnar crystal ingot), which had the dimension of 1000 mm1000 mm300 mm (widthlengthheight), with a band saw.

[0081] Next, both sides of the plate materials were etched by the mixed solution of hydrofluoric acid and nitric acid after polishing the both sides of the plate materials with a polishing machine. Then, they were washed with pure water thoroughly.

[0082] The obtained plate materials were inserted in the oxidation furnace. The silicon oxide films shown in Table 1 were formed on the silicon plates by retaining them for the lapse time shown Table 1 at 900 C. by wet oxidation (pyrogenic oxidation).

Examples 9-10 of the Present Invention

[0083] Plate materials, which had the dimension of 1000 mm1000 mm20 mm (widthlengththickness), were excised from the pseudo-single-crystalline silicon ingot (unidirectionally solidified columnar crystal ingot using seed crystals), which had the dimension of 1000 mm1000 mm300 mm (widthlengthheight), with a band saw.

[0084] Next, both sides of the plate materials were etched by the mixed solution of hydrofluoric acid and nitric acid after polishing the both sides of the plate materials with a polishing machine. Then, they were washed with pure water thoroughly.

[0085] The obtained plate materials were inserted in the oxidation furnace. The silicon oxide films shown in Table 1 were formed on the silicon plates by retaining them for the lapse time shown Table 1 at 900 C. by wet oxidation (pyrogenic oxidation).

Example 11 of the Present Invention

[0086] A plate material, which had the dimension of 1000 mm1000 mm20 mm (thickness), was excised from the pseudo-single-crystalline silicon ingot (unidirectionally solidified columnar crystal ingot using seed crystals), which had the dimension of 1000 mm1000 mm300 mm (height), with a band saw.

[0087] Next, both sides of the plate material were etched by the mixed solution of hydrofluoric acid and nitric acid after polishing the both sides of the plate material with a polishing machine. Then, it was washed with pure water thoroughly.

[0088] The obtained plate material was inserted in the heat treatment furnace. The silicon nitride film with the thickness of 15 nm was formed on the silicon plates by retaining it for 90 minutes at 1050 C. while ammonia was flowed into the furnace.

Example 12 of the Present Invention

[0089] Using the silicon plate of the above-described Example 5 of the present invention, the silicon oxide film formed on the silicon plate was removed. Removal of the silicon oxide film was performed at the room temperature for 2 minutes using the mixed acid solution with the composition: hydrofluoric acid (48%):nitric acid (70%):pure water=3:2:6.

Example 13 of the Present Invention

[0090] Using the silicon plate of the above-described Example 5 of the present invention, the silicon oxide film formed on the silicon plate was removed. Removal of the silicon oxide film was performed at the room temperature for 1 minute 30 seconds using the mixed acid solution with the composition: hydrofluoric acid (48%):nitric acid (70%):pure water=3:2:6. Then, the remaining silicon oxide film was removed by treating it with the buffered hydrofluoric acid solution for 30 minutes at the room temperature.

Examples 14-15 of the Present Invention

[0091] Using the silicon plate of the above-described Example 9 of the present invention, the silicon oxide films formed on the silicon plates were removed. Removal of the silicon oxide films was performed at the room temperature for 1 minute 30 seconds using the mixed acid solution with the composition: hydrofluoric acid (48%):nitric acid (70%):pure water=3:2:6. Then, the remaining silicon oxide films were removed by treating it with the buffered hydrofluoric acid solution for 30 minutes at the room temperature.

Examples 16-17 of the Present Invention

[0092] The silicon plates of the above-described Example 13 of the present invention were inserted in the oxidation furnace. The silicon oxide films shown in Table 2 were formed on the silicon plates by retaining them for the lapse time shown Table 2 at 900 C. by wet oxidation (pyrogenic oxidation).

Examples 18-19 of the Present Invention

[0093] The silicon plates of the above-described Example 15 of the present invention were inserted in the oxidation furnace. The silicon oxide films shown in Table 2 were formed on the silicon plates by retaining them for the lapse time shown Table 2 at 900 C. by wet oxidation (pyrogenic oxidation).

Example 20 of the Present Invention

[0094] Using the silicon plate of the above-described Example 1 of the present invention, the silicon oxide film formed on the silicon plate was removed. Removal of the silicon oxide film was performed at the room temperature using the buffered hydrofluoric acid solution. Then, the obtained plate material was inserted in the heat treatment furnace. The silicon nitride film with the thickness of 15 nm was formed on the silicon plates by retaining it for 90 minutes at 1050 C. while ammonia was flowed into the furnace.

Example 21 of the Present Invention

[0095] Plate materials, which had the dimension of 1000 mm1000 mm20 mm (widthlengththickness), were excised from the poly-crystalline silicon ingot (unidirectionally solidified columnar crystal ingot), which had the dimension of 1000 mm1000 mm300 mm (widthlengthheight), with a band saw.

[0096] After polishing the both sides of the plate materials with a polishing machine, both sides of the plate materials were etched by the mixed acid solution with the composition: hydrofluoric acid (48%):nitric acid (70%):pure water=3:2:6. By these polishing and the etching treatment, the portion of the surface of the plate material was removed to the thickness of 5 m.

Comparative Example 1

[0097] A plate material, which had the dimension of 1000 mm1000 mm20 mm (widthlengththickness), were excised from the poly-crystalline silicon ingot (unidirectionally solidified columnar crystal ingot), which had the dimension of 1000 mm1000 mm300 mm (widthlengthheight), with a band saw. Then, the both sides of the plate material were grinded by a grinding machine.

Comparative Example 2

[0098] A plate material, which had the dimension of 1000 mm1000 mm20 mm (widthlengththickness), were excised from the poly-crystalline silicon ingot (unidirectionally solidified columnar crystal ingot), which had the dimension of 1000 mm1000 mm300 mm (widthlengthheight), with a band saw. Then, the both sides of the plate material were polished by a polishing machine.

[Thickness of the Silicon Oxide Film and the Silicon Nitride Film]

[0099] Thicknesses of the obtained silicon oxide films and the obtained silicon nitride films in Examples 1-11 and 16-20 of the present invention were measured. Also, the thickness of growth of the formed film from the surface of the plate material before the film formation toward the internal side of the plate material (penetration depth) was evaluated based on calculation. The thickness of the silicon oxide films and the silicon nitride films was measured with a spectroscopic ellipsometer. When to is defined as the total thickness of the silicon oxide film, it is understood that the silicon oxide film grew by the amount of t.sub.1=0.45t.sub.0 toward the internal side based on the density and the molecular weight of Si and SiO.sub.2. When to is defined as the total thickness of the silicon nitride film, it is understood that the silicon nitride film grew by the amount of t.sub.11=0.88t.sub.10 toward the internal side based on the density and the molecular weight of Si and Si.sub.3N.sub.4. The measurement results are shown in Tables 1 and 2.

[Surface Roughness Ra]

[0100] The surface roughnesses in Examples 1-21 of the present invention and Comparative example 2 were measured with an AFM (Atomic Force Microscope).

[0101] The surface roughness in Comparative example 1 was measured with the Dektak surface roughness meter (10 m scan).

[0102] The measurement results are shown in Tables 1 and 2.

[Four-Point Bending Test]

[0103] The four-point bending test was performed on the obtained testing materials. The four-point bending test was performed based on the JIS R1601 standard. The testing materials had the sample size of: length being 40 mm; width being 4 mm; and thickness being 3 mm. The measurement results are shown in Tables 1 and 2.

TABLE-US-00001 TABLE 1 Maximum Film load in Surface forming Film Penetration four-point roughness Measurement Crystal time thickness depth bending Ra method type hr nm nm MPa nm 4 m(sq.) Example 1 of the Columnar Oxide 0.15 30 14 195 0.3 AFM present invention crystal film Example 2 of the Columnar Oxide 0.25 45 20 200 0.3 AFM present invention crystal film Example 3 of the Columnar Oxide 0.5 80 36 207 0.5 AFM present invention crystal film Example 4 of the Columnar Oxide 1 150 68 212 0.7 AFM present invention crystal film Example 5 of the Columnar Oxide 2 250 113 220 1 AFM present invention crystal film Example 6 of the Columnar Oxide 4 420 189 239 1.2 AFM present invention crystal film Example 7 of the Columnar Oxide 6 520 234 252 1.3 AFM present invention crystal film Example 8 of the Columnar Oxide 8 600 270 248 1.5 AFM present invention crystal film Example 9 of the Pseudo-single Oxide 2 255 115 240 0.4 AFM present invention crystal film Example 10 of the Pseudo-single Oxide 6 515 232 265 0.7 AFM present invention crystal film Example 11 of the Columnar Nitride 1.5 15 13 203 0.8 AFM present invention crystal film

TABLE-US-00002 TABLE 2 Maximum Film load in Surface forming Film Penetration four-point roughness Measurement Crystal time thickness depth bending Ra method type hr nm nm MPa nm 4 m(sq.) Example 12 of the Columnar Oxide film 215 0.8 AFM present invention crystal Removed Example 13 of the Columnar Oxide film 224 0.7 AFM present invention crystal Removed Example 14 of the Pseudo-single Oxide film 215 0.5 AFM present invention crystal Removed Example 15 of the Pseudo-single Oxide film 221 0.3 AFM present invention crystal Removed Example 16 of the Columnar Oxide film 0.15 28 13 225 0.8 AFM present invention crystal Reformed Example 17 of the Columnar Oxide film 0.25 45 20 227 0.7 AFM present invention crystal Reformed Example 18 of the Pseudo-single Oxide film 0.15 30 14 244 0.5 AFM present invention crystal Reformed Example 19 of the Pseudo-single Oxide film 0.25 44 20 248 0.5 AFM present invention crystal Reform Example 20 of the Columnar Oxide film 1.5 15 13 205 0.8 AFM present invention crystal Removed Nitride film Reformed Example 21 of the Columnar Polishing + 188 0.2 AFM present invention crystal Etching Comparative Columnar Grinding 30 50 10 m scan example 1 crystal with Dektak Comparative Columnar Polishing 154 0.9 AFM example 2 crystal

[0104] In Comparative example 1, where the surface of the silicon plate was grinded, the calculated average roughness of the surface Ra was 50 m, and the maximum load in the four-point bending test was 30 MPa, which was a low value, meaning the silicon member of Comparative example 1 is prone to be cracked easily.

[0105] Also, in Comparative example 2, where the surface of the silicon plate was polished, the calculated average roughness of the surface Ra was 0.9 m, and the maximum load in the four-point bending test was 154 MPa. There was an improvement compared to Comparative example 1. However, the silicon member of Comparative example 2 was still prone to be cracked easily.

[0106] Contrary to that, in Examples 1-21 of the present invention, the maximum loads in the four-point bending test were even higher, confirming that cracking was suppressed. Particularly, in Examples 1-11 and 16-19 of the present invention, where the silicon oxide films or the silicon nitride films were formed, results in the four-point bending test were good regardless of the surface roughness. Moreover, in Examples 9-10, and 18-19 of the present invention, results in the surface roughness and the four-point bending test were good.

[0107] Based on the results explained above, it was confirmed that the silicon member, in which cracking is suppressed even if it is used in the condition where the silicon member is heated, can be provided according to Examples of the present invention.

BRIEF DESCRIPTION OF THE REFERENCE SYMBOLS

[0108] 10, 110, 210, 310: Silicon member [0109] 11: Silicon oxide film (coating layer) [0110] 111: Silicon nitride film (coating layer) [0111] 16, 116, 216, 316: Plate material