Ion implantation for modification of thin film coatings on glass

Abstract

The use of non-mass analyzed ion implanter is advantageous in such application as it generates ion implanting at different depth depending on the ions energy and mass. This allows for gaining advantage from lubricity offered as a result of the very light deposition on the surface, and at the same time the hardness provided by the intercalated ions implanted below it, providing benefits for cover glass, low E enhancement, and other similar materials. In further aspects, ion implantation is used to create other desirable film properties such anti-microbial and corrosion resistance.

Claims

1. A method of fabricating a low-E glass panel, comprising: providing a glass panel; depositing a low emissivity coating on the glass panel, the low emissivity coating comprising a plurality of layers with a top layer having a top surface exposed to surrounding environment; implanting a plurality of non-mass analyzed ions only into the top layer, wherein the ions are selected to comprise Zr ions; whereby a low-E glass panel is fabricated having a hemispherical emissivity (Eh) of less than 0.16 and a normal emissivity (En) of less than 0.12.

2. A method of fabricating a low-E glass panel, comprising: providing a glass panel; depositing a low emissivity coating on the glass panel, the low emissivity coating comprising a plurality of layers with a top layer having a top surface exposed to surrounding environment; implanting a plurality of non-mass analyzed Zr ions only into the top layer; whereby a low-E glass panel is fabricated having a hemispherical emissivity (Eh) of less than 0.16 and a normal emissivity (En) of less than 0.12; and, further comprises implanting Ag ions only into the top layer.

3. The method of claim 2, wherein depositing plurality of layers comprises depositing a layer of SiNx, and wherein the implanting comprises implanting ions into the SiNx layer.

4. The method of claim 3, wherein the implanting further comprises implanting aluminum ions into the SiNx layer.

5. The method of claim 3, wherein the implanting further comprises implanting zirconium ions into the SiNx layer.

6. The method of claim 2, wherein the depositing plurality of layers comprises depositing a layer of zirconia, and wherein the implanting further comprises implanting ions selected from at least one of: N, and Ar into the ZrOx layer.

7. The method of claim 6, wherein the implanting further comprises implanting silver ions into the zirconia layer.

8. The method of claim 1, further comprising depositing a lubricious layer on the top surface simultaneously with the implanting ions.

9. The method of claim 8, wherein depositing the lubricious layer is performed to a thickness of 5 angstrom or less.

10. The method of claim 8, wherein depositing the lubricious layer comprises controlling an ion source of a non-mass analyzed ion implanter to allow for simultaneous deposition of free radicals, while implanting the ions.

11. The method of claim 1, wherein depositing the low emissivity coating comprises depositing a layer of SiNx, and wherein the implanting comprises implanting ions into the SiNx layer.

12. The method of claim 1, wherein the depositing the low emissivity coating comprises depositing a layer of zirconia, and wherein the implanting comprises implanting the ions into the zirconia layer.

13. The method of claim 1, wherein the implanting comprises implanting a total implant dose in multiple stages while allowing the glass panel to cool between each stage.

14. The method of claim 1, wherein the implanting comprises implanting a total implant dose in multiple stages while operating each stage at different power level so as to improve ion implant distribution within the coating.

15. The method of claim 1, wherein the implanting comprises serially implanting the ions with different doses.

16. A method of fabricating a low-E glass panel, comprising: providing a glass panel; depositing a low emissivity coating on the glass panel, the low emissivity coating comprising a plurality of layers with a top layer having a top surface exposed to surrounding environment; implanting a plurality of non-mass analyzed ions only into the top layer, wherein the ions are selected from at least one of: Zr, N and Ar; whereby a low-E glass panel is fabricated having a hemispherical emissivity (Eh) of less than 0.16 and a normal emissivity (En) of less than 0.12; and, wherein the implanting comprises serially implanting the ions of different species.

17. The method of claim 1, further comprising annealing the glass panel after the implanting step.

18. The method of claim 1, wherein the implanting is performed to cause the ions to implant to a depth of up to 300 Angstrom.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other aspects and features of the invention would be apparent from the detailed description, which is made with reference to the following drawings. It should be mentioned that the detailed description and the drawings provide various non-limiting examples of various embodiments of the invention, which is defined by the appended claims.

(2) The accompanying drawings, which are incorporated in and constitute a part of this specification, exemplify the embodiments of the present invention and, together with the description, serve to explain and illustrate principles of the invention. The drawings are intended to illustrate major features of the exemplary embodiments in a diagrammatic manner. The drawings are not intended to depict every feature of actual embodiments nor relative dimensions of the depicted elements, and are not drawn to scale.

(3) FIGS. 1A and 1B are cross-sections showing prior art low-E coating using DLC and Zirconium dioxide (zirconia), respectively.

(4) FIG. 2 illustrates the coating enhancement by simultaneous deposition and ion implant, according to an advantageous embodiment.

(5) FIG. 3 illustrates an ion implant chamber for non-mass analyzed implanting of low-e coated glass, according to an embodiment of the invention.

(6) FIG. 4 is a plot of the ion implant profiles for various species and doses.

(7) FIG. 5 is a plot showing Taber (wear rate measurements) of glass, performed at 7.5N force with SS ball.

(8) FIG. 6 shows typical implanted atomic profile from a non-mass analyzed system.

(9) FIG. 7 is a plot of transmission performance of various glass samples.

(10) FIG. 8 illustrates an embodiment that enables serially implanting the glass with different doses and/or different species.

DETAILED DESCRIPTION

(11) According to disclosed embodiments, the properties of the low-E coating on glass panels are enhanced using ion implantation. According to specific embodiments, non-mass analyzed ion beam or non-massed ion shower is used to enhance the durability, e.g., scratch resistance, of the coating on Low E glass. According to further embodiments, non-mass analyzed ion implantation is used to create other desirable film properties such as, e.g., UV transmittance, surface lubricity, anti-microbial and corrosion resistance.

(12) According to disclosed embodiments, non-mass analyzed ions of at least one species, e.g., zirconium, aluminum, or silver, are implanted onto the top layer of the low-E coating of glass panel. Principally, introduction of at least one species into substrate creates a series of changes that are predominantly physical. For example, as shown by the embodiments disclosed herein, the implantation of Zr into the final layer of the Low e coating creates a much higher durable layer than is currently possible or cost effective with thin-film coatings alone. The implantation of aluminum into the final layer of the Low-e coating improves the environmental performance (e.g., UV reflectance) of the low-E coating. The implantation of Ag into the final layer of the Low e coating creates an anti-microbial layer.

(13) According to further embodiments, the implant system is energized such that low energy non-mass analyzed ions of at least one species are deposited on top of the coating surface, while higher energy ions are implanted below the surface—into the coating of the glass. Intercalation and deposition of ions species is achieved simultaneously by proper control of the implantation conditions adopted. In the disclosed embodiments, this capability is enabled by the use of non-mass analyzed implant system, where control of the source allows for deposition of very low energy free radical, while control of the applied voltage and implant time provides the level of intercalation desired. This allows for gaining advantages from lubricity offered as a result of the very light deposition on the surface, while at the same time obtaining the hardness provided by the intercalated implanted ions below it, thus providing benefits for cover glass, low-E enhancement and other similar materials. Furthermore, by proper management of power, voltage and process time, novel material stoichiometry can be generated, for example Si3N4 can be formed as nitrogen rich SiNx, where x>4/3, which can provide unique electrical and mechanical properties.

(14) FIG. 2 illustrates the coating enhancement by simultaneous deposition and ion implant, according to an advantageous embodiment. In FIG. 2, reference 200 indicates the molecular structure of the coating, e.g., the bonding of silicon and oxygen atoms. By adjusting the power of the implanter, free radicals 205 and low energy ions may form a deposited lubricious surface, in this example of 5 Angstrom thickness or less. Simultaneously, by proper management of the implanter voltage, ions 210 are implanted below the surface of the coating, such that the ions are intercalated within the atomic structure of the coating.

(15) FIG. 3 illustrates an ion implant chamber 300 for non-mass analyzed implanting of low-e coated glass, according to an embodiment of the invention. The chamber is evacuated by vacuum pump 310 and gas containing the species to be implanted is provided from gas source 312 into the vacuum chamber 300 at low pressure. Then an RF applicator 315, e.g., RF power source with antenna (not shown), couples RF energy into the chamber, thereby igniting and maintaining plasma 305. An extractor 320, e.g., one or more biased grids, extracts ion species 325 from the plasma 305. Depending on the voltage and power setting of the RF applicator 315, some low energy radicals may be deposited on top of the surface of the substrate 330, while higher energy ions would be implanted below the surface of the substrate 330. In this respect, substrate 330 may be placed on top of a substrate holder 335 or may simply ride on rollers or conveyor (not shown) without a substrate holder. Unlike traditional ion implanters, the implanter of FIG. 3 has no mass analyzer, such that the ions 325 are of varied energy levels within a specified energy band, set by the power and voltage setting of the RF applicator.

(16) The following are calculations for three scenarios of non-mass analyzed implantation of low-e glass. For all of the options, we first looked at viability of the range of dose and energy to achieve the enhancement effect. The summary table describes two energies and the required dose.

(17) TABLE-US-00001 Zr into Zr into Al into Al into Ag into SiNx SiNx SiNx SiNx ZrOx (125 A, (250 A, (125 A, (250 A, (600 A, 140 keV) 200 keV) 30 keV 40 keV) 65 keV) Energy keV 140 200 30 40 65 Proj Range A 125 163 127 162 210 Delta Rp A 100 131 90 115 85 % Dilution % 10% 10% 10% 10% 5% sqrt(2*pl) 2.51 Dose cm-2 2.59E+18 3.39E+18 2.33E+18 2.98E+ 8.86E+ 18 17 Atmoic cm-3 1.03E+23 1.03E+23 1.03E+23 1.03E+ 8.32E+ density 23 22 Desired A 125 250 125 250 300 Depth

(18) FIG. 4 is a plot of the ion implant profiles for the scenarios indicated in the above table. In the plot, two energies are shown for Zr and Al, and one for Ag. The dashed lines show the thickness of the layer being implanted for implantation into coatings made of SiNx and ZrOx. While the dose is almost the same for SiNx and ZrOx, the resulting implant is deeper when implanting into a coating made of ZrOx.

(19) Ion implantation generates high compressive stress that can lead to hardening of the near surface region by several orders of magnitude in young's modulus. This is achieved by introduction of material in between the substrate atoms, where space is limited and, depending on the size of introduced ions, can deform the substrate and create compressive stresses. For glass application, this can manifest itself as hardening and improved wear rate of the top surface, leaving the bulk of the glass to maintain the desired optical properties. The wear rate improvement is demonstrated by various methods through scratching, continuous rubbing of the surface with harder materials and other similar techniques. The hardness can be tested via ring or ring testing or increased force wear rate methods.

(20) For example, Taber wear testing shows that as color changes, due to the implant dose/time changes, the wear rate (Taber) changes. Using ΔE* of 1, i.e., imperceptible color change, wear rate of 100+ can be achieved, depending on the implant conditions such as energy, dose, and other conditions. In this respect, ΔE*=[ΔL*2+Δa*2+Δb*2]½, as defined by the Commission Internationale de l'Eclairage (CIE).

(21) FIG. 5 is a plot showing Taber (wear rate measurements) at 7.5N force with SS ball, wherein the y-axis is the number of cycles before a scratch is detected on the surface and the x-axis is the change in color of the glass, after implant at various doses and conditions depicted by delta b* (db*).

(22) Wear testing may be too aggressive for some Low-E glass, so a gentler testing with cheese cloth can be used. The wear after many cycles of cheese cloth rubbing can be inspected by comparing the haze (introduction of scratches) and light transmission (removal of the top layer film) before and after the cycle. Implanted samples obtained according to disclosed embodiments showed no real change after many of these cycles, as noted in the table below—showing an implanted low-E glass after 250 cycles of cheese cloth with 9 N of force over a 50 mm length. The T is a measure of transmission and H is a measure of haze. The critical parameter is the change in these two factors. A minimal change shows that implant has hardened the surface.

(23) TABLE-US-00002 CM-5 Test: Cheesecloth, 9N 50 mm, 250 strokes LE CH4-1MP 433 dc Pre Post Δ_Pre-Post T 74.9 75 −0.1 H 0.1 0.12 −0.02 T 75.7 75.7 0 H 0.09 0.09 0 T 75.8 75.7 0.1 H 0.12 0.16 −0.04 No conditioning

(24) TABLE-US-00003 Low E glass implantation-chees cloth testing 9N of Force, 50 mm strip, 250 strokes Test Measurment Pre Post Number type testing testing Differentce 1 Transmission 74.9 75.0 −0.1 2 75.7 75.7 0.0 3 75.8 75.7 0.1 1 Haze 0.10 0.12 −0.020 2 0.09 0.09 0.000 3 0.12 0.16 −0.040

(25) Finally, the ultimate test of hardness of a material is atypical rung on ring testing where the hardened glass is placed between two rings of differing diameter and pressure is applied. The point at which failure occurs is recorded. Below, ordinary glass was used and compared with implanted glass, where a gain of 10% was achieved. The sample was only implanted on one side. It is expected that if both sides were implanted performance will improve markedly.

(26) TABLE-US-00004 Sample Type GG3 IMP Max Force, N Ave 1588 1762 Max 1925 2101 Min 1244 1399

(27) According to further embodiments, ion implant is used to change the electrical properties of the coating of low-E glass. The implanted ions, depending on their polarity, can be activated, via a thermal step, to migrate to interstitial sites and contribute to the electrical property of the coating. For Low-E glass where conductive layers are applied as coating, certain implanted ions or molecules can change the electrical properties and enhance the performance of the coating.

(28) FIG. 6 shows typical implanted atomic profile from a non-mass analyzed system, in silicon, where the implanted species are very close to the surface and only affect the very near surface regions, with a sharp drop off in depth, not affecting the bulk. The sample is then annealed and the plotted profile shows the dopant have been activated, by causing them to move around and find the interstitials sites to be able to contribute to the electron cloud within the coating.

(29) Reflectance and transmission of the low-E glass and cover glass can also be modified via the implant physical process, where intercalating the right atoms in the coating or the substrate can help with obscuring certain wavelengths. For example, it could be used for UV tailoring, where transmission of certain wavelength light can be attenuated. FIG. 7 is a plot of transmission performance of various glass samples. The implanted samples (IMP_#) show drastic attenuation of the transmission starting at about 500 nm wavelength and enhancing the attenuation at wavelengths below 500 nm. Varying the implant conditions will provide the ability to tailor the cutoff frequency and the amount of attenuation.

(30) FIG. 8 illustrates an embodiment that enables serially implanting the glass with different doses and/or different species. The system has multiple chambers similar to the chamber illustrated in FIG. 3, so reference number in FIG. 8 are the same as in FIG. 3, except that they are in the 8xx series. A vacuum gate 835 is provided in the entrance to the system, between each two chambers, and at the exit from the system. This enables maintaining individual vacuum environment in each of the implant chambers 800. Each chamber 800 may have different gas injected to it from its corresponding gas supply 812. Each chamber may also operate at different voltage and/or different power level, provided by its corresponding RF power supply 815. This may be useful to provide a better than Gaussian distribution within the depth required. Of course, all of the chambers may use the same gas at the same voltage and power levels, such that the system implants the required total implant dose in multiple stages. This also will help with cooling of the glass during its transfer from one chamber to the next. Alternatively, cooling stations 840 may be provided in between implant chambers 800.

(31) Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.