阅读说明：本技术 一种石英晶体谐振器的加工方法及装置 (Processing method and device of quartz crystal resonator ) 是由 李磊 刘涛 张明烨 王玥 冷兴龙 张凌云 李楠 赵丽莉 何萌 夏洋 于 2020-03-26 设计创作，主要内容包括：本公开提供了一种石英晶体谐振器的加工方法,包括：S1,在石英晶片的第一表面和第二表面依次沉积多层金属并在最外侧表面涂覆光刻胶,其中,第一表面和第二表面为石英晶片上相对的两表面；S2,对步骤S1得到的第一表面和第二表面进行光刻,以形成第一表面电极和第二表面电极的光刻胶图形；S3,刻蚀第一表面和第二表面的金属层,生成第一表面电极和第二表面电极；S4,激光切割步骤S3得到的结构,以得到至少一个初级石英晶体谐振器；S5,蒸镀初级石英晶体谐振器的其他两表面,以生成石英晶体谐振器的侧壁电极。解决了湿法刻蚀加工石英晶片所带来的横向刻蚀、侧壁垂直度及粗糙度较差等问题,提高了加工精度、降低了加工成本。(The present disclosure provides a method for processing a quartz crystal resonator, including: s1, sequentially depositing a plurality of layers of metal on a first surface and a second surface of the quartz wafer and coating photoresist on the outermost surface, wherein the first surface and the second surface are two opposite surfaces on the quartz wafer; s2, photoetching is carried out on the first surface and the second surface obtained in the step S1 to form photoresist patterns of the first surface electrode and the second surface electrode; s3, etching the metal layers on the first surface and the second surface to generate a first surface electrode and a second surface electrode; s4, laser cutting the structure obtained in the step S3 to obtain at least one primary quartz crystal resonator; and S5, evaporating the other two surfaces of the primary quartz crystal resonator to generate the side wall electrodes of the quartz crystal resonator. The problems of poor transverse etching, poor side wall verticality and roughness and the like caused by wet etching processing of the quartz wafer are solved, the processing precision is improved, and the processing cost is reduced.)

1. A method for processing a quartz crystal resonator comprises the following steps:

s1, sequentially depositing a plurality of layers of metal on a first surface and a second surface of a quartz wafer and coating photoresist on the outermost surface, wherein the first surface and the second surface are two opposite surfaces on the quartz wafer;

s2, photoetching is carried out on the first surface and the second surface obtained in the step S1 to form photoresist patterns of the first surface electrode and the second surface electrode;

s3, etching the metal layers on the first surface and the second surface to generate a first surface electrode and a second surface electrode;

s4, laser cutting the structure obtained in the step S3 to obtain at least one primary quartz crystal resonator;

and S5, evaporating the other two surfaces of the primary quartz crystal resonator to generate the side wall electrodes of the quartz crystal resonator.

2. The processing method according to claim 1, wherein the plurality of metal layers in step S1 are Cr and Au metal layers in sequence.

3. The method according to claim 1, wherein the thickness of the Cr metal layer is 20 to 30nm, and the thickness of the Au metal layer is 150 to 200 nm.

4. The processing method according to claim 3, wherein in the step S3, the metal layers of the first surface and the second surface are wet-etched.

5. The process of claim 4, wherein the solution for etching the Cr metal layer is a mixed solution of ammonium ceric nitrate and acetic acid, and the solution for etching the Au metal layer is a mixed solution of iodine and potassium iodide.

6. The machining method of claim 1, the laser cutting including at least one of laser stealth cutting or laser surface ablation cutting.

7. The process of claim 1, wherein electron beam evaporation is used to evaporate the other two surfaces of the primary quartz crystal resonator to form sidewall electrodes of the quartz crystal resonator.

8. The process of claim 1, further comprising masking the non-evaporation-required surface with a hard mask before step S5.

9. The process of claim 1 or 8, wherein the primary quartz crystal resonator is evaporated by tilting the primary quartz crystal resonator by 45 °.

10. A quartz crystal resonator processing apparatus, comprising:

the deposition unit is used for sequentially depositing a plurality of layers of metal on a first surface and a second surface of a quartz wafer and coating photoresist on the outermost surface, wherein the first surface and the second surface are two opposite surfaces on the quartz wafer;

the photoetching unit is used for photoetching the first surface and the second surface of the deposition unit to form photoresist patterns of the first surface electrode and the second surface electrode;

the etching unit is used for etching the metal layers on the first surface and the second surface to generate a first surface electrode and a second surface electrode;

the cutting unit is used for cutting the structure obtained by the etching unit by adopting laser so as to obtain at least one primary quartz crystal resonator;

and the evaporation unit is used for evaporating the other two surfaces of the primary quartz crystal resonator so as to generate the side wall electrode of the quartz crystal resonator.

Technical Field

The disclosure relates to the field of quartz crystal resonator processing, in particular to a quartz crystal resonator processing method and a quartz crystal resonator processing device.

Background

The quartz resonator is a device which is made by using the resonance phenomenon of the wafer caused by the piezoelectric effect when the frequency of the electric signal is equal to the natural frequency of the quartz wafer. Is a key element of crystal oscillators, narrow-band filters and the like. There are various kinds of quartz resonators, such as a tuning fork type quartz resonator, a single arm type quartz resonator, a quartz expansion resonator (LER), an inertial resonator, and the like. Quartz resonator structures are typically fabricated using processes such as photolithography, wet etching, thin film deposition, and the like, which are based on microelectronic processes. The common process comprises the steps of firstly patterning a quartz wafer by photoetching and wet etching processes, and then forming front and back electrodes of the quartz resonator by coating a film through shielding of a hard mask or forming the front and back electrodes by photoetching-etching after coating the film. Another common process is to perform photolithography processing of front and back electrodes before patterning the quartz wafer by wet etching, and then etch the metal after patterning the quartz wafer to form the front and back electrodes.

Disclosure of Invention

Technical problem to be solved

In the conventional process, the following technical problems often occur:

although the process of forming the front and back electrodes of the quartz resonator by coating through the shielding of the hard mask is simple, the alignment precision of the front and back electrodes and the quartz wafer is low, the front and back electrodes and the quartz wafer are difficult to control within 1 micron, and the dislocation problem is easy to occur.

Although the alignment precision is improved by the method for forming the front and back electrodes of the quartz resonator by the photoetching-etching method after film coating, the patterned quartz wafer is difficult to uniformly coat and easy to crack due to the fact that photoresist is difficult to uniformly coat, the precision of the front and back electrode patterns is greatly reduced, and the photoetching and etching difficulty is remarkably improved.

According to the method for photoetching the front and back electrodes before patterning the quartz wafer by wet etching, the photoresist needs to be specially treated, and the photoresist is difficult to completely resist the corrosion of chemical solution after the special treatment, so that the problems of falling, bubble generation and the like are solved.

The specially processed photoresist also has problems of deformation and the like, which can cause deviation of the etched electrode pattern. Subsequent stripping also creates great difficulty due to the special handling of the photoresist. In addition, the metal layers on the front side and the back side are used as surface electrodes of the quartz resonator and are also used as masks for wet etching of the quartz wafer, so that certain requirements are imposed on the thickness of the quartz resonator.

When the wet etching method is adopted for patterning the quartz wafer, the quartz crystal material is anisotropic, and after etching to a certain degree, the etching rate is slowed down due to the change of the crystal orientation, so that the verticality of the etched side wall is poor. Lengthening the etching time can improve the verticality of the side wall, but at the same time, the width of the lateral etching is increased, and the dimensional accuracy is influenced.

In addition, the wet etching of the quartz crystal is long, and multiple experiments are needed to find reasonable process parameters and improve the quality of the side wall, so that the cost is increased and the period is prolonged. The solution used in wet etching is also highly dangerous, and the environment can be polluted by improper treatment of the used waste liquid.

(II) technical scheme

The present disclosure provides a method for processing a quartz crystal resonator, including: s1, sequentially depositing a plurality of layers of metal on a first surface and a second surface of the quartz wafer and coating photoresist on the outermost surface, wherein the first surface and the second surface are two opposite surfaces on the quartz wafer; s2, photoetching is carried out on the first surface and the second surface obtained in the step S1 to form photoresist patterns of the first surface electrode and the second surface electrode; s3, etching the metal layers on the first surface and the second surface to generate a first surface electrode and a second surface electrode; s4, laser cutting the structure obtained in the step S3 to obtain at least one primary quartz crystal resonator; and S5, evaporating the other two surfaces of the primary quartz crystal resonator to generate the side wall electrodes of the quartz crystal resonator.

Optionally, in step S1, the multiple metal layers are Cr and Au metal layers in sequence.

Optionally, the thickness of the Cr metal layer is 20-30 nm, and the thickness of the Au metal layer is 150-200 nm.

Optionally, in step S3, the metal layers on the first surface and the second surface are wet-etched.

Optionally, the solution for etching the Cr metal layer is a mixed solution of ammonium ceric nitrate and acetic acid, and the solution for etching the Au metal layer is a mixed solution of iodine and potassium iodide.

Optionally, the laser cutting includes at least one of laser stealth cutting or laser surface ablation cutting.

Optionally, electron beams are used to evaporate the other two surfaces of the primary quartz crystal resonator to produce the sidewall electrodes of the quartz crystal resonator.

Optionally, step S5 is preceded by masking the surface that does not need to be evaporated with a hard mask.

Optionally, the primary quartz crystal resonator is evaporated in such a way that it is tilted by 45 °.

The present disclosure also provides a processing apparatus for a quartz crystal resonator, comprising: the deposition unit is used for sequentially depositing a plurality of layers of metal on a first surface and a second surface of the quartz wafer and coating photoresist on the outermost surface, wherein the first surface and the second surface are two opposite surfaces on the quartz wafer; the photoetching unit is used for photoetching the first surface and the second surface of the deposition unit to form photoresist patterns of the first surface electrode and the second surface electrode; the etching unit is used for etching the metal layers on the first surface and the second surface to generate a first surface electrode and a second surface electrode; the cutting unit is used for cutting the structure obtained by the etching unit by adopting laser so as to obtain at least one primary quartz crystal resonator; and the evaporation unit is used for evaporating the other two surfaces of the primary quartz crystal resonator so as to generate the side wall electrode of the quartz crystal resonator.

(III) advantageous effects

The invention realizes the imaging of the quartz wafer through laser processing, solves the problems of transverse etching, poor side wall verticality and roughness and the like caused by wet etching processing of the quartz wafer, and improves the side wall quality, the graphic precision of the front and back electrodes and the alignment precision. In addition, compared with a method for realizing wafer patterning by wet etching, the method has the advantages of shorter processing time, lower risk, less environmental pollution and reduced process risk.

The quartz wafer is not required to be processed by a wet etching method, so that the influence of a corrosive solution and a photoresist after special treatment is avoided when the photoetching-etching method is adopted to form the tuning fork whole-back side electrode, and the processing precision of the front and back side electrode patterns is improved. Meanwhile, the dislocation problem caused by adopting a hard mask to shield the evaporation front and back electrodes is avoided, the high-precision processing of complex electrode patterns is realized, and the complexity of the process is reduced.

Drawings

FIG. 1 is a diagram schematically illustrating steps in a method of fabricating a quartz crystal resonator in an embodiment of the disclosure;

FIG. 2A schematically illustrates a block diagram of a quartz wafer in an embodiment of the disclosure;

FIG. 2B is a schematic diagram illustrating the structure of a quartz wafer after multiple metal layers and photoresists are deposited in the embodiment of the disclosure;

FIG. 2C schematically illustrates a structure of lithographically formed first surface and second surface electrode photoresist patterns in an embodiment of the present disclosure;

FIG. 2D schematically illustrates a structure after wet etching the metal layer of FIG. 2C in an embodiment of the disclosure;

FIG. 2E schematically illustrates the structure of FIG. 2D after the photoresist is removed in an embodiment of the disclosure;

FIG. 2F schematically illustrates a primary quartz crystal resonator structure resulting from laser cutting the structure of FIG. 2E in an embodiment of the disclosure;

fig. 2G schematically shows a structural schematic diagram of a quartz crystal resonator in an embodiment of the disclosure.

Detailed Description

The invention provides a processing method of a quartz crystal resonator, as shown in figure 1, comprising the following steps: s1, sequentially depositing a plurality of layers of metal on a first surface and a second surface of the quartz wafer and coating photoresist on the outermost surface, wherein the first surface and the second surface are two opposite surfaces on the quartz wafer; s2, photoetching is carried out on the first surface and the second surface obtained in the step S1 to form photoresist patterns of the first surface electrode and the second surface electrode; s3, etching the metal layers on the first surface and the second surface to generate a first surface electrode and a second surface electrode; s4, laser cutting the structure obtained in the step S3 to obtain at least one primary quartz crystal resonator; and S5, evaporating the other two surfaces of the primary quartz crystal resonator to generate the side wall electrodes of the quartz crystal resonator.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.

And S1, sequentially depositing multiple layers of metal on the first surface and the second surface of the quartz wafer, and coating photoresist on the outermost surface, wherein the first surface and the second surface are two opposite surfaces on the quartz wafer.

The quartz wafer shown in fig. 2A is cleaned. As shown in fig. 2B, a plurality of layers of metal are sequentially deposited on the first surface and the second surface of the quartz wafer, where the first surface may be an upper surface in the direction shown in fig. 2B, and the second surface may be a lower surface in the direction shown in fig. 2B.

The sequentially deposited metals may be Cr and Au for subsequent formation of the first and second surface electrodes. The thickness of the Cr metal layer is preferably 20-30 nm, and the thickness of the Au metal layer is preferably 150-200 nm.

And uniformly coating a layer of photoresist on the surface of the outermost metal layer.

And S2, photoetching is carried out on the first surface and the second surface obtained in the step S1 to form photoresist patterns of the first surface electrode and the second surface electrode.

Exposing and developing the first surface obtained in step S1, and overlaying and developing the second surface obtained in step S1, followed by post-baking to form a photoresist pattern of the first surface electrode and the second surface electrode, as shown in fig. 2C.

And S3, etching the metal layers on the first surface and the second surface to generate a first surface electrode and a second surface electrode.

Wet etching of the metal layers of the first and second surfaces may be used, as shown in fig. 2D. The solution for etching the Cr metal layer can be a mixed solution of ammonium ceric nitrate and acetic acid, and the solution for etching the Au metal layer can be a mixed solution of iodine and potassium iodide. The photoresist is removed to obtain a first surface electrode and a second surface electrode, as shown in fig. 2E.

S4, laser cutting the structure obtained in the step S3 to obtain at least one primary quartz crystal resonator.

Before cutting, the laser beam needs to be aligned with the corresponding patterned position of the quartz wafer, and then the patterning of the quartz wafer is realized through laser cutting, as shown in fig. 2F, the laser cutting at least includes one of laser invisible cutting or laser surface ablation cutting.

And S5, evaporating the other two surfaces of the primary quartz crystal resonator to generate the side wall electrodes of the quartz crystal resonator.

Electron beam evaporation may be used to deposit the other two surfaces of the primary quartz crystal resonator to create the sidewall electrodes of the quartz crystal resonator, as shown in fig. 2G.

And (3) adopting a hard mask to shield the surface which does not need to be subjected to evaporation, and fixing the hard mask and the primary quartz crystal resonator on an evaporation source in an inclined manner at an angle of 45 degrees for evaporation to form a side wall electrode at one side of the quartz tuning fork. And then rotating the primary quartz crystal resonator by 90 degrees, and forming the side wall electrode on the other side by evaporation. The size of the hard mask needs to be reasonably designed according to the size of the side wall electrode, the inclination angle and the thickness of the hard mask, and the size precision is improved. The evaporation mode adopts electron beam evaporation.

The invention provides a micro-mechanical quartz crystal resonator structure processing method based on laser patterning, which solves a series of problems caused by realizing quartz wafer patterning through wet etching, simplifies the preparation process flow and realizes high-precision quartz resonator structure processing.

Another aspect of the present disclosure provides a quartz crystal resonator processing apparatus, including:

and the deposition unit is used for sequentially depositing a plurality of layers of metal on the first surface and the second surface of the quartz wafer and coating photoresist on the outermost surface, wherein the first surface and the second surface are two opposite surfaces on the quartz wafer.

And the photoetching unit is used for photoetching the first surface and the second surface of the deposition unit to form photoresist patterns of the first surface electrode and the second surface electrode.

And the etching unit is used for etching the metal layers on the first surface and the second surface to generate a first surface electrode and a second surface electrode.

And the cutting unit is used for cutting the structure obtained by the etching unit by adopting laser so as to obtain at least one primary quartz crystal resonator.

And the evaporation unit is used for evaporating the other two surfaces of the primary quartz crystal resonator so as to generate the side wall electrode of the quartz crystal resonator.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.