Method for etching deep groove based on borosilicate glass wafer

Abstract

The invention belongs to the technical field of borosilicate glass deep grooves, and particularly relates to a method for etching a deep groove based on a borosilicate glass wafer. The method comprises the following steps: S1, evaporating a layer of titanium metal film on a non-etching surface of a transparent substrate; s2, sputtering a layer of 0.6-1 [mu] m metal mask on the etching surface of the transparent substrate; s3, a patterned mask is formed through photoetching and etching, and the photoresist is reserved; and S4, forming a deep groove through mask and etching, and removing the titanium metal film and the metal mask. According to the method, the borosilicate glass wafer can be identified by traditional chip manufacturing equipment, and deep groove process etching can be carried out on the borosilicate glass wafer.

Description

Technical Field

[0001] This invention belongs to the field of deep trench technology of borosilicate glass, and particularly relates to a method for etching deep trenches based on borosilicate glass wafers. Background Technology

[0002] Borosilicate glass with deep groove structures is widely used in microscopes, imaging, sensors, semiconductors, and MEMS. This perfect and reliable glass product can be combined to offer a wide range of thicknesses, excellent light transmittance, and high chemical resistance.

[0003] Traditional chip manufacturing equipment is based on opaque silicon substrates, allowing the equipment to easily identify notches in the silicon substrate for processing. However, because borosilicate glass substrates are transparent, traditional equipment cannot identify these notches, thus preventing processing. Therefore, borosilicate glass is currently unsuitable for wafer fabrication. Furthermore, to ensure etching depth, if chromium metal is used as a mask, a certain thickness of chromium metal needs to be sputtered. If the sputtering thickness is too thick, the substrate warpage is significant, preventing the lithography machine from adsorbing the chromium and thus hindering processing. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this invention provides a method for etching deep trenches based on borosilicate glass wafers. This invention ensures that conventional chip manufacturing equipment can recognize borosilicate glass wafers, and that vacuum adsorption by lithography machines is not a problem.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for etching deep trenches based on borosilicate glass wafers includes the following steps:

[0007] S1. Evaporate a titanium metal film on the non-etched surface of a transparent substrate;

[0008] S2. Sputter a 0.6-1µm metal mask onto the etching surface of the transparent substrate, ensuring that the metal mask has a certain thickness and uniformity so that the etching morphology meets the requirements.

[0009] S3. Use photolithography and etching to form a patterned mask and retain the photoresist. Retain a certain thickness of photoresist, thereby reducing the thickness of the chromium metal film, reducing the warpage of the substrate wafer, ensuring that the vacuum adsorption of the photolithography machine is not a problem, and normal processes can be carried out.

[0010] S4. Deep trenches are formed by masking and etching, and the titanium metal film and metal mask are removed.

[0011] Preferably, the thickness of the titanium metal film is 0.05 to 0.2 μm.

[0012] Preferably, the metal mask is a chromium metal film.

[0013] Preferably, the transparent substrate is borosilicate glass.

[0014] Preferably, the thickness of the photoresist is 3–6 μm.

[0015] Preferably, in step S3, the etching method is dry etching or wet etching.

[0016] Preferably, the etching selectivity ratio of photoresist to transparent substrate is 1:1.

[0017] Preferably, the etching rate ratio of the metal mask to the transparent substrate is 1:15. A larger etching rate ratio can ensure the etching depth and allow the metal mask to function well as a barrier layer.

[0018] Preferably, in step S4, the etching rate is 1µm / min and the etching time is 10 minutes.

[0019] Preferably, in step S4, the removal time for the titanium metal film is 2 minutes to avoid the removal solution corroding the borosilicate glass; the removal time for the metal mask is 10-15 seconds to avoid the removal solvent corroding the borosilicate glass. Neither removal time should be too long to ensure the borosilicate glass is not damaged.

[0020] The advantages of this invention are:

[0021] (1) In this invention, titanium metal is evaporated on the back side of the substrate, which can effectively ensure that the substrate is identified. At the same time, chromium metal is sputtered on the front side of the substrate, which can serve as a good barrier layer. The use of photolithography and etching to form a patterned mask and retaining a certain thickness of photoresist can reduce the thickness of the chromium metal film, thereby reducing the warpage of the substrate wafer, ensuring that the photolithography machine can vacuum-adsorb the wafer for normal processing, and ensuring the etching effect. Furthermore, when removing chromium, the front structure of the substrate is not damaged.

[0022] (2) The present invention uses sputtered chromium metal as a mask to ensure the morphology of the deep grooves etched in borosilicate glass, which can be applied to microscopes, imaging, sensors, etc.; using chromium metal as a mask can ensure the etching depth and angle, and etch out the required morphology; the chromium metal film and borosilicate glass have a large etching rate difference, which further ensures the etching depth. Attached Figure Description

[0023] Figure 1 This is a front view of the borosilicate glass of the present invention.

[0024] Figure 2 This is a cross-sectional view of the borosilicate glass before etching, as per the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] A method for etching deep trenches based on borosilicate glass wafers includes the following steps:

[0027] S1. A titanium metal film of a certain thickness is evaporated on the back side of a transparent substrate;

[0028] S2. Sputter a chromium metal film of a certain thickness on the front side of a transparent substrate;

[0029] S3. Use photolithography and etching to form a patterned mask while retaining the photoresist;

[0030] S4. A deep trench of borosilicate glass is formed by photoresist, masking and etching, and the titanium on the back side and the chromium on the front side are removed.

[0031] Example 1

[0032] like Figure 1-2 As shown, a method for etching deep trenches based on borosilicate glass wafers includes the following steps:

[0033] S1. Evaporate 0.1µm of metallic titanium on the back side of borosilicate glass. Since the titanium evaporation equipment does not need to identify the notch of the wafer (borosilicate glass) to perform the process, the evaporation of metallic titanium can be achieved.

[0034] S2. Sputter 0.8µm of metallic chromium on the front side of the borosilicate glass. Since the sputtering machine needs to identify the notch of the wafer before it can perform the process, and step S1 has evaporated the entire surface of titanium on the back side of the borosilicate glass, ensuring that it is opaque, the sputtering of metallic chromium can be achieved.

[0035] S3. A patterned mask is formed using photolithography and etching, while retaining a 4µm thick photoresist. The etching selectivity ratio of photoresist to borosilicate glass is 1:1; the etching rate ratio of metallic chromium to the transparent substrate is 1:15.

[0036] S4. A deep trench in borosilicate glass is formed by masking and etching at a rate of 1µm / min for 10 minutes. The titanium metal film and the metal mask are removed at a time of 2 minutes and 12 seconds, respectively.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for etching deep trenches based on borosilicate glass wafers, characterized in that, Includes the following steps: S1. Evaporate a titanium metal film on the non-etched surface of a transparent substrate; S2. Sputter a 0.6-1µm metal mask onto the etched surface of the transparent substrate; S3. Use photolithography and etching to form a patterned mask while retaining the photoresist; S4. Deep trenches are formed by masking and etching, and the titanium metal film and metal mask are removed.

2. The method for etching deep trenches based on borosilicate glass wafers according to claim 1, characterized in that: The thickness of the titanium metal film is 0.05 to 0.2 μm.

3. The method for etching deep trenches based on borosilicate glass wafers according to claim 1, characterized in that: The metal mask is a chromium metal film.

4. The method for etching deep trenches based on borosilicate glass wafers according to claim 1, characterized in that: The transparent substrate is borosilicate glass.

5. The method for etching deep trenches based on borosilicate glass wafers according to claim 1, characterized in that: The thickness of the photoresist is 3–6 μm.

6. The method for etching deep trenches based on borosilicate glass wafers according to claim 1, characterized in that: In step S3, the etching method is either dry etching or wet etching.

7. A method for etching deep trenches based on a borosilicate glass wafer according to claim 1 or 4, characterized in that: The etching selectivity ratio of the photoresist to the transparent substrate is 1:

1.

8. A method for etching deep trenches based on a borosilicate glass wafer according to claim 1, 3, or 4, characterized in that: The etching rate ratio of the metal mask to the transparent substrate is 1:

15.

9. The method for etching deep trenches based on borosilicate glass wafers according to claim 1, characterized in that: In step S4, the etching rate is 1µm / min and the etching time is 10 minutes.

10. The method for etching deep trenches based on borosilicate glass wafers according to claim 1, characterized in that: In step S4, the removal time for the titanium metal film is 2 minutes; the removal time for the metal mask is 10 to 15 seconds.

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