ION IMPLANTATION PROCESS AND ION IMPLANTED GLASS SUBSTRATES

Abstract

The invention concerns a process for increasing the scratch resistance of a glass substrate by implantation of simple charge and multicharge ions, comprising maintaining the temperature of the area of the glass substrate being treated at a temperature that is less than or equal to the glass transition temperature of the glass substrate, selecting the ions to be implanted among the ions of Ar, He, and N, setting the acceleration voltage for the extraction of the ions at a value comprised between 5 kV and 200 kV and setting the ion dosage at a value comprised between 10.sup.14 ions/cm.sup.2 and 2.5×10.sup.17 ions/cm.sup.2.The invention further concerns glass substrates comprising an area treated by implantation of simple charge and multicharge ions according to this process and their use for reducing the probability of scratching on the glass substrate upon mechanical contact.

Claims

1. A process for increasing the scratch resistance of a glass substrate, the process comprising: maintaining the temperature of the area of the glass substrate being treated at a temperature that is less than or equal to the glass transition temperature of the glass substrate, setting the acceleration voltage for the extraction of nitrogen simple charge or multicharge ions at a value comprised between 25 kV and 60 kV, setting an ion dosage at a value comprised between 10.sup.14 ions/cm.sup.2 and 10.sup.17 ions/cm.sup.2, and implanting, within the glass, the nitrogen simple charge and multicharge ions.

2. A process according to claim 1, wherein the acceleration voltage is set at a value comprised between 25 kV and 35 kV.

3. A process according to claim 2, wherein the ion dosage is set at a value comprised between 5.0×10.sup.14 ions/cm.sup.2 and 10.sup.17 ions/cm.sup.2.

4. A process according to claim 1, wherein the glass substrate is selected among soda-lime glass and aluminosilicate glass.

5. A glass substrate comprising an area treated by implantation of simple charge and multicharge ions according to claim 1.

6-11. (canceled)

12. Glass, obtained by a process according to claim 1.

13. Glass according to claim 12, wherein the glass substrate is in the form of an architectural glazing, an automotive glazing, furniture, a white good, a shower partition, a screen, a display, a structural glazing, a barcode scanner, and a watch.

14. Glass according to claim 12, wherein an ion concentration of nitrogen within the glass, Δ/D, is from 4.5 μm.sup.−1 to lower than 21.3 μm.sup.−1.

15. Glass according to claim 12, wherein an ion concentration of nitrogen within the glass, Δ/D, is from 4.5 μm.sup.−1 to lower than 16.5 μm.sup.−1.

16. Glass according to claim 12, wherein an ion concentration of nitrogen within the glass, Δ/D, is from 4.5 μm.sup.−1 to 7.7 μm.sup.−1.

17. Glass according to claim 12, wherein an ion concentration of nitrogen within the glass, Δ/D, is from 5 μm.sup.−1 to 6 μm.sup.−1.

18. A process according to claim 2, wherein the ion dosage is set at a value comprised between 2.5×10.sup.14 ions/cm.sup.2 and 10.sup.17 ions/cm.sup.2.

19. A process according to claim 2, wherein the ion dosage is set at a value comprised between 2.5×10.sup.15 ions/cm.sup.2 and 5×10.sup.16 ions/cm.sup.2.

Description

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

[0045] The ion implantation examples were prepared according to the various parameters detailed in the tables below using an RCE ion source for generating a beam of single charge and multicharge ions.

[0046] All samples had a size of 10×10 cm.sup.2 and a thickness of 4 mm and were treated on the entire surface by displacing the glass substrate through the ion beam at a speed of 80 mm/s.

[0047] The temperature of the area of the glass substrate being treated was kept at a temperature less than or equal to the glass transition temperature of the glass substrate.

[0048] For all examples the implantation was performed in a vacuum chamber at a pressure of 10.sup.−5 mbar.

[0049] Scratch resistance of the glass substrates was determined by a progressive load scratch test. This test corresponds to a load ramp applied during a defined displacement of the sample beneath it. Here measurements were performed with a microscratch tester “MicroCombi tester” from CSM Instruments. The scratch test consists in moving a diamond stylus that is placed on the substrate surface along a specified line under a linearly increasing normal force and with a constant speed. For glass samples of soda-lime type the scratches were made with a Rockwell diamond indenter with a tip radius of 200 μm (200 μm tip) as well as with a Rockwell diamond indenter with a tip radius of 100 μm (100 μm tip). For glass samples of aluminosilicate type the scratches were made with a Rockwell diamond indenter with a tip radius of 100 μm (100 μm tip).

[0050] The stylus was moved along a straight line of 1.5 cm in length. The speed was kept constant at 5 mm/min. The normal force (load) applied on the stylus was increased from 0.03 N at the start of the scratch to 30 N at the end of the scratch. During the scratch, the penetration depth, the acoustic emission and the tangential force are recorded and the aspect of the scratch is observed as a function of the penetration depth.

[0051] The load applied on the stylus when the first cracks appear at the glass surface is the critical load with 100 μm tip or the critical load with 200 μm tip depending on the radius of the Rockwell diamond indenter used. The scratch test performed with the 100 μm tip is more severe than the scratch test performed with the 200 μm tip. The scratch resistance with a certain tip of a sample is proportional to the critical load obtained with this tip is the scratch test.

[0052] For each sample the average of at least three measurements is determined. The higher the scratch resistance the higher the load at which the first cracks appear. The appearance of cracks along the scratch make the scratch more easily detectable by the naked eye. On identical samples cracks will appear with a smaller load on the 100 μm tip and with a larger load on the 200 μm tip.

[0053] On the equipment used for the present experiments the maximum possible load was limited to 30 N.

[0054] On some samples with a very high scratch resistance no cracks appear even when the maximum load is applied to the stylus having a 200 μm tip.

[0055] In the implantation zone of a glass substrate, the depth distribution profile of nitrogen in the glass was determined by secondary ion mass spectroscopy (SIMS). The SIMS depth distribution profiles were carried out on a Cameca imsf-4 instrument. The sputter erosion conditions are: primary beam 5.5 KeV Cs+, current density 0.16 mA/cm.sup.2; sputtered area 125×125 μm.sup.2. The analyzed area has a diameter of 60 μm. MCs+ ions are detected, where M stands for the element to be detected. The detection intensity signal I(M) for each element M versus the sputtering time is recorded at predetermined time intervals, leading to an intensity profile for this element versus a time scale. The depth scale is obtained by measuring the total depth of the crater obtained after the sputter erosion using a step profiler after the SIMS measurement. The time scale is converted into a depth scale assuming a constant sputtering rate.

[0056] For each sample (treated and non-treated as reference) the integral of the depth distribution (μm) of the intensity I(CsM) of the MCs.sup.+ ions, normalized with respect to isotope ratio and Cs-intensity is calculated. In this case M stands for the elements N and Si. A semi-quantification of the Nitrogen quantities implanted is obtained by calculating the difference Δ between the values of I(CsN)/I(CsSi) integrated over the implantation depth of the treated glasses and the value of I(CsN)/I(CsSi) of the untreated reference glass. The implantation depth D of a treated sample is the depth at which the value for I(CsN)/I(CsSi) drops to the level of I(CsN)/I(CsSi) of the untreated reference glass.

[0057] For the purpose of the present invention the intensity ratio I(CsN)/I(CsSi) is calculated from the intensity signal I(CsN) of NCs+ for nitrogen and from the intensity signal I(CsSi) of SiCs+ for silicon, where the nitrogen isotope detected is .sup.14N and the silicon isotope detected is .sup.28Si.

[0058] A semi-quantification of the N ion concentration in the implantation zone is obtained by calculating the ratio Δ/D.

[0059] No suitable method for determining the distribution profile of implanted Ar or He in glass could be found.

[0060] Table 4 shows the reference example R1 which is untreated soda-lime glass and soda-lime glass substrates treated with an argon ion beam. Untreated soda-lime glass has a critical load with 200 μm tip of 12.5 N.

[0061] Examples 1 to 3 show that with increasing Ion dosage of implanted single charge and multicharge argon ions the critical load is increased. Therefore the scratch resistance of soda-lime glass increases with the implantation of argon ions.

TABLE-US-00005 TABLE 4 Critical Ion load with Implanted acceleration Ion Dosage 200 μm example Glass type ion voltage (kV) (ions/cm.sup.2) tip (N) R1 Soda-lime — — — 12.5 1 Soda-lime Argon 35 7.5 × 10.sup.16 19.0 2 Soda-lime Argon 35 10.sup.17 16.4 3 Soda-lime Argon 35 2.5 × 10.sup.17 19.2

[0062] Table 5 shows soda-lime glass substrates treated with a helium ion beam.

[0063] Examples 4 and 5 show that with an ion dosage between 10.sup.15 and 10.sup.16 ions/cm.sup.2 the critical load with 200 μm tip is higher than for untreated soda-lime glass.

[0064] Counterexample C1 shows that for an ion dosage of 10.sup.17 ions/cm.sup.2 the critical load with 200 μm tip is lower than for untreated soda-lime glass. Therefore the scratch resistance of soda-lime glass is increased with the implantation of helium up to an ion dosage of 10.sup.16 ions/cm.sup.2 at least. At higher dosages of 10.sup.17 ions/cm.sup.2 the amount of implanted helium ions is too large and the scratch resistance decreases.

TABLE-US-00006 TABLE 5 Critical Ion load with Glass Implanted acceleration Ion Dosage 200 μm example type ion voltage (kV) (ions/cm.sup.2) tip (N) 4 Soda-lime Helium 35 10.sup.15 17.5 5 Soda-lime Helium 35 5 × 10.sup.16 14.3 C1 Soda-lime Helium 35 10.sup.17 5.1

[0065] Table 6 shows soda-lime glass substrates treated with a nitrogen ion beam.

[0066] As can be seen when comparing the samples treated with N to those treated with Ar or He, much higher scratch resistance is obtained, often reaching the maximum load available on the microscratch tester with the 200 μm tip.

[0067] Examples 7 to 9 show that with an ion dosage between 10.sup.15 and 10.sup.17 ions/cm.sup.2 at an ion acceleration voltage of 20 kV, the critical load with 200 μm tip is higher than for untreated soda-lime glass.

[0068] Examples 10 to 12 show that with an ion dosage between 5×10.sup.15 and 10.sup.16 ions/cm.sup.2 at an ion acceleration voltage of 35 kV, the critical load with 200 μm tip is higher than for untreated soda-lime glass.

[0069] Counterexample C2 shows that for an ion dosage of 5×10.sup.17 ions/cm.sup.2 at an ion acceleration voltage of 35 kV the critical load with 200 μm tip is lower than for untreated soda-lime glass. Therefore the scratch resistance of soda-lime glass is increased with the implantation of nitrogen up to an ion dosage of 10.sup.17 ions/cm.sup.2. At higher dosages of 5×10.sup.17 ions/cm.sup.2 or more the amount of implanted nitrogen ions is too large and the scratch resistance decreases.

TABLE-US-00007 TABLE 6 Critical Ion Ion load with Implanted acceleration Dosage 200 μm example Glass type ion voltage (kV) (ions/cm.sup.2) tip (N) 7 Soda-Lime Nitrogen 20 10.sup.15 ≧30 8 Soda-Lime Nitrogen 20 10.sup.16 ≧30 9 Soda-Lime Nitrogen 20 10.sup.17 16.5 10 Soda-Lime Nitrogen 35 5 × 10.sup.15 ≧30 11 Soda-Lime Nitrogen 35 10.sup.16 ≧30 12 Soda-Lime Nitrogen 35 10.sup.16 25.8 C2 Soda-Lime Nitrogen 35 5 × 10.sup.17 8.6

[0070] Table 7 shows the scratch resistance of additional samples of soda-lime glass that were implanted with nitrogen in comparison with an untreated soda-lime glass sample (R1). In these examples and counterexamples the scratch resistance was determined using a 100 μm tip. For each group of samples implanted using an ion acceleration voltage of 15 kV (examples 13 to 16) or 25 kV (examples 17 to 20) respectively, the critical load and therefore the scratch resistance increases when the dose is increased from 5.0×10.sup.14 ions/cm.sup.2 to 7.5×10.sup.16 ions/cm.sup.2. For the group of samples implanted using an ion acceleration voltage of 35 kV the critical load increases when the ion dosage is increased from 5.0×10.sup.14 ions/cm.sup.2 to 7.5×10.sup.15 ions/cm.sup.2 (examples 21 to 23) and slightly decreases again at a dosage of 5.0×10.sup.16 ions/cm.sup.2 (example 24). At ion dosages above 10.sup.17 ions/cm.sup.2 (examples C3, C4 , C5, C6, C7) the critical load and therefore the scratch resistance decreases significantly. In these samples the critical load even drops below the critical load obtained on the untreated soda-lime glass sample R1. It can also be seen from the table below that for the same dosage, the critical load is higher when the ion acceleration voltage is higher.

TABLE-US-00008 Critical Ion load with Implanted acceleration Ion Dosage 100 μm example Glass type ion voltage (kV) (ions/cm.sup.2) tip (N) R1 Soda-Lime — — 6.3 13 Soda-Lime Nitrogen 15 5.0 × 10.sup.14 7.1 14 Soda-Lime Nitrogen 15 2.5 × 10.sup.15 7.3 15 Soda-Lime Nitrogen 15 7.5 × 10.sup.15 7.6 16 Soda-Lime Nitrogen 15 5.0 × 10.sup.16 7.6 17 Soda-Lime Nitrogen 25 5.0 × 10.sup.14 7.3 18 Soda-Lime Nitrogen 25 2.5 × 10.sup.15 7.4 19 Soda-Lime Nitrogen 25 7.5 × 10.sup.15 7.5 20 Soda-Lime Nitrogen 25 5.0 × 10.sup.16 7.7 21 Soda-Lime Nitrogen 35 5.0 × 10.sup.14 7.5 22 Soda-Lime Nitrogen 35 2.5 × 10.sup.15 8.0 23 Soda-Lime Nitrogen 35 7.5 × 10.sup.15 8.1 24 Soda-Lime Nitrogen 35 5.0 × 10.sup.16 8.0 C3 Soda-Lime Nitrogen 15 7.5 × 10.sup.17 4.6 C4 Soda-Lime Nitrogen 25 2.5 × 10.sup.17 4.0 C5 Soda-Lime Nitrogen 25 7.5 × 10.sup.17 4.4 C6 Soda-Lime Nitrogen 35 2.5 × 10.sup.17 5.0 C7 Soda-Lime Nitrogen 35 7.5 × 10.sup.17 3.6

[0071] As can be seen in the tables 6 and 7, nitrogen implanted soda-lime glass samples at ion dosages comprised between 5.0×10.sup.14 ions/cm.sup.2 and 10.sup.17 ions/cm.sup.2 show increased scratch resistance compared to untreated soda-lime glass.

[0072] At ion dosages comprised between 2.5×10.sup.15 ions/cm.sup.2 and 10.sup.17 ions/cm.sup.2 scratch resistance is particularly high, At ion dosages comprised between 2.5×10.sup.15 ions/cm.sup.2 and 5.0×10.sup.16 ions/cm.sup.2 the best scratch resistance results were obtained.

[0073] An increase of scratch resistance was observed on these examples at ion acceleration voltages comprised between 15 kV and 35 kV, but ion acceleration voltage may be increased up to 60 kV. The increase of scratch resistance was higher at ion acceleration voltages comprised between 25 kV and 35 kV than at an ion acceleration voltage of 15 kV. The scratch resistance increase was highest at ion acceleration voltages of 35 kV in these examples.

[0074] Table 8 shows the reference example R2 which is untreated aluminosilicate glass and an aluminosilicate glass substrate treated with a nitrogen ion beam.

[0075] This untreated aluminosilicate glass sample R2 has a critical load with 100 μm tip of 5.0 N.

[0076] Example 25 shows that the implantation with a dosage of 10.sup.16 ions/cm.sup.2 at an acceleration voltage of 35 kV of single charge and multicharge nitrogen ions the critical load is increased. Therefore the scratch resistance of aluminosilicate glass increases with the implantation of nitrogen ions. Thus the implantation of N according to the present invention can also be applied to Aluminosilicate type glass substrates.

TABLE-US-00009 TABLE 8 Critical Ion load with Implanted acceleration Ion Dosage 100 μm example Glass type ion voltage (kV) (ions/cm.sup.2) tip (N) 25 Aluminosilicate Nitrogen 35 10.sup.16 9.2 R2 Aluminosilicate — — — 5.0

[0077] Table 9 shows how the amount and depth of implanted nitrogen is related to the critical load with 200 μm tip. It was surprisingly found that there is a relation between the scratch resistance as determined by the critical load on one side and the amount and depth distribution of nitrogen implanted (determined by the ratio Δ/D) on the other side.

[0078] For high Δ/D values the amount of nitrogen becomes so high or its distribution depth becomes so low that scratch resistance is lower than the maximum (see example 9).

[0079] For too high Δ/D values the amount of nitrogen is too high or its distribution depth is too low for obtaining sufficient scratch resistance (see example C2).

[0080] In a preferred range of Δ/D values of at least 4.5 μm.sup.−1 and lower than 21.3 μm.sup.−1 the scratch resistance of the glass substrate is increased. In a more preferred range of Δ/D values of at least 4.5 μm.sup.−1 and lower than 15.4 μm.sup.−1 the scratch resistance of the glass substrate is increased further.

TABLE-US-00010 TABLE 9 Nitrogen N ion Critical load quantities concentration with 200 μm Implantation implanted Δ/D example tip (N) depth D (μm) Δ (μm.sup.−1) 7 ≧30 0.15 0.67 4.5 8 ≧30 0.35 2.10 6.0 9 16.5 0.35 5.40 15.4 10 ≧30 0.40 2.00 5.0 11 ≧30 0.35 2.71 7.7 12 25.8 0.35 2.91 8.3 C2 8.6 0.55 12.0 21.3