Etch rate enhancement at low temperatures

Abstract

A method etching a glass material comprises providing an etchant comprising 10-30% HF, 5-15% HNO.sub.3,and at least 10% H.sub.3PO.sub.4 by volume constituted such that the ratio HF:HNO.sub.3 by volume is in the range of 1.7:1 to 2.3:1, providing a glass material to be etched, and contacting the glass material with the etchant. The etchant desirably has no other acid components. The method may be performed with the etchant temperature within the range of 20-30° C. The glass material may be an aluminosilicate glass. Ultrasound energy may be applied to the etchant, to the glass material, or both.

Claims

1. A method of etching a glass material comprising: providing an etchant comprising 19-21% HF, 9.5-10.5% HNO.sub.3, and at least 40% H.sub.3PO.sub.4 by volume, where HF corresponds to 49% HF, HNO.sub.3 corresponds to 63% HNO.sub.3 and H.sub.3PO.sub.4 corresponds to 85% H.sub.3PO.sub.4; providing a glass material to be etched; and contacting the glass material with the etchant.

2. The method according to claim 1, further comprising the step of controlling the temperature of the etchant to a temperature within the range of 20-30° C.

3. The method according to claim 1, wherein the step of providing a glass material to be etched comprises providing an aluminosilicate glass material to be etched.

4. The method according to claim 1 wherein the step of providing an etchant comprises providing an etchant containing only three acid components: HF, HNO.sub.3, and H.sub.3PO.sub.4.

5. The method according to claim 1 wherein the step of providing an etchant comprises providing an etchant containing only water and three acid components: HF, HNO.sub.3, and H.sub.3PO.sub.4.

6. The method according to claim 1, further comprising the step of controlling the temperature of the etchant to a temperature within the range of 22-28° C.

7. The method according, to claim 1, further comprising the step of applying ultrasound to the etchant.

8. The method according to claim 1, further comprising the step of applying ultrasound to the glass material to be etched.

Description

DETAILED DESCRIPTION

(1) For the purposes of describing and defining the present disclosure it is noted that the term “about” is utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The term “about” is also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

(2) According to one embodiment of the present disclosure, a method is provided of etching a glass material, the method comprising providing an etchant comprising 10-30% HF, 5-15% HNO.sub.3, and at least 10% H.sub.3PO.sub.4 by volume. The etchant is also constituted such that the ratio HF:HNO.sub.3 by volume is in the range of 1.7:1 to 2.3:1. The method further includes providing a glass material to be etched and contacting the glass material with the etchant.

(3) As one alternative or addition to the method, the temperature of the etchant to a temperature within the range of 20-30° C., or to within the range of 22-28° C.

(4) As another alternative or addition, the step of providing a glass material to be etched may comprise providing an aluminosilicate glass material to be etched, and may comprise providing an Eagle XG® glass material to be etched.

(5) As yet other alternatives, the step of providing an etchant may include providing an etchant wherein the ratio HF:HNO.sub.3 by volume is in the range of 1.8:1 to 2.2:1, or 1.9:1 to 2.1:1, or even 1.95:1 to 2.05:1.

(6) As still other alternatives, the step of providing an etchant may include providing an etchant comprising at least 20% H.sub.3PO.sub.4, or even at least 40% H.sub.3PO.sub.4.

(7) As yet more alternatives, the step of providing an etchant comprises providing an etchant may include providing an etchant comprising 15-25% HF and 7.5-12.5% HNO.sub.3, or even 19-21% HF and 9.5-10.5% HNO.sub.3.

(8) As yet another aspect of the method, the step of providing an etchant may further include providing an etchant having no additional acid constituents other than HF, HNO.sub.3, and H.sub.3PO.sub.4. As a related alternative aspect, water may be the only additional constituent other than HF, HNO.sub.3, and H.sub.3PO.sub.4.

(9) As another alternative addition to any of the various embodiments, ultrasound energy may be applied to the etchant or to the glass material or both.

EXAMPLES

Comparative Example 1

HF+HNO3 Solution with No H3PO4 and No Ultrasound at 25° C.

(10) One thousand (1000 ml) of solution which contained 20% by volume of HF and 10% by volume of HNO.sub.3 was prepared in a 2000 ml beaker by first filling it with 700 ml of Deionized water (DIW). About 100 ml of 63% stock HNO.sub.3 solution was added to the DIW followed by the addition of about 200 ml of a 49% HF stock solution. The final solution was allowed to stand in a water bath till it cooled down and the temperature was about 25±2° C. The solution concentration so prepared was 5.75M HF and 1.54 M HNO.sub.3. Two 50 mm×50 mm Eagle XG® coupons were obtained and their thickness was measured. The coupons were etched at the same time in the solution for about 5 minutes with ultrasonic agitation. The etched samples were rinsed thoroughly in DIW, dried and their thickness was measured again. The etch rate was 4.5 μm per minute, determined by taking the ratio of amount of material removed to the residence time in the etch solution.

Comparative Example 2

HF+HNO3 Solution with No H3PO4 with Ultrasound at 25° C.

(11) One thousand (1000 ml) of solution which contained 20% by volume of HF and 10% by volume of HNO.sub.3 was prepared in a 2000 ml beaker by first filling it with 700 ml of Deionized water (DIW). About 100 ml of 63% stock HNO.sub.3 solution was added to the DIW followed by the addition of about 200 ml of a 49% HF stock solution. The final solution was allowed to stand in a water bath till it cooled down and the temperature was about 25±2° C. The solution concentration so prepared was 5.75M HF and 1.54M HNO.sub.3.

(12) Two 50 mm×50 mm Eagle XG® glass coupons were obtained and their thickness was measured. The coupons were etched at the same time in the solution for about 5 minutes this time using ultrasonic agitation at 40 kHz. The etched samples were rinsed thoroughly in DIW, dried and their thickness was measured again. The etch rate was 5.7 μm per minute, determined by taking the ratio of amount of material removed to the residence time in the etch solution.

Comparative Example 3

HF+HNO3 Solution with No H3PO4 with Ultrasound at 40° C.

(13) One thousand (1000 ml) of solution which contained 20% by volume of HF and 10% by volume of HNO.sub.3 was prepared in a 2000 ml beaker by first filling it with 700 ml of Deionized water (DIW). About 100 ml of 63% stock HNO.sub.3 solution was added to the DIW followed by the addition of about 200 ml of a 49% HF stock solution. The final solution was allowed to stand in a heated water bath till the etch solution temperature was stable at 40±2° C. The solution concentration so prepared was 5.75 M HF and 1.54 M HNO.sub.3.

(14) Two 50 mm×50 mm Eagle XG® glass coupons were obtained and their thickness was measured. The coupons were etched at the same time in the solution while keeping the temperature stable at about 40C for about 5 minutes, with ultrasonic agitation at 40 kHz. The etched samples were rinsed thoroughly in DIW, dried and their thickness was measured again. The etch rate was 8.1 μm per minute, determined by taking the ratio of amount of material removed to the residence time in the etch solution.

Disclosed Example 1

HF+HNO3 Solution with 20% H3PO4 and No Ultrasound at 25° C.

(15) One thousand (1000 ml) of solution which contained 20% by volume of HF and 10% by volume of HNO.sub.3 was prepared in a 2000 ml beaker by first filling it with 500 ml of Deionized water (DIW). About 100 ml of 63% stock HNO.sub.3 solution was added to the DIW followed addition of 200 ml of 85% stock H.sub.3PO.sub.4 solution. Finally 200 ml of 49% stock HF solution was added to obtain a final mixture consisting of 20%:10%:20% of HF:HNO.sub.3:H.sub.3PO.sub.4 by volume. The final solution was allowed to stand in a water bath till it cooled down and the temperature was about 25±2° C. The solution concentration so prepared was 5.75M HF and 1.54M HNO.sub.3 and 2.92M H.sub.3PO.sub.4.

(16) Two 50 mm×50 mm Eagle XG® glass coupons were obtained and their thickness was measured. The coupons were etched at the same time in the solution for about 5 minutes without using ultrasonic agitation. The etched samples were rinsed thoroughly in DIW, dried and their thickness was measured again. The etch rate was 6.7 μm per minute, determined by taking the ratio of amount of material removed to the residence time in the etch solution.

Disclosed Example 2

HF+HNO3 Solution with 40% H3PO4 and No Ultrasound at 40° C.

(17) One thousand (1000 ml) of solution which contained 20% by volume of HF and 10% by volume of HNO.sub.3 was prepared in a 2000 ml beaker by first filling it with 300 ml of Deionized water (DIW). About 100 ml of 63% stock HNO.sub.3 solution was added to the DIW followed addition of 400 ml of 85% stock H.sub.3PO.sub.4 solution. Finally 200 ml of 49% stock HF solution was added to obtain a final mixture consisting of 20%:10%:40% of HF:HNO.sub.3:H.sub.3PO.sub.4 by volume. The final solution was allowed to stand in a water bath till it cooled down and the temperature was about 25±2° C. The solution concentration so prepared was 5.75M HF and 1.54M HNO.sub.3 and 5.85M H.sub.3PO.sub.4.

(18) Two 50 mm×50 mm Eagle XG® glass coupons were obtained and their thickness was measured. The coupons were etched at the same time in the solution for about 5 minutes without using ultrasonic agitation. The etched samples were rinsed thoroughly in DIW, dried and their thickness was measured again. The etch rate was 8.1 μm per minute, determined by taking the ratio of amount of material removed to the residence time in the etch solution.

(19) It is noted that one or more of the following claims utilize the term “wherein” as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”

(20) It should be understood that any two quantitative values assigned to a property may constitute a range of that property, and all combinations of ranges formed from all stated quantitative values of a given property are contemplated herein.

(21) Having described the subject matter of the present disclosure in detail and by reference to specific embodiments thereof, it is noted that the various details disclosed herein should not be taken to imply that these details relate to elements that are essential components of the various embodiments described herein, even in cases where a particular element is illustrated in each of embodiments that accompany the present description. Rather, the claims appended hereto should be taken as the sole representation of the breadth of the present disclosure and the corresponding scope of the various embodiments described herein. Further, it will be apparent that modifications and variations are possible without departing from the scope of the appended claims.