Bonding process of bubble-free thinned piezoelectric single crystal

Abstract

The invention relates to a bonding process of a bubble-free thinned piezoelectric single crystal. The bonding process of the bubble-free thinned piezoelectric single crystal comprises the following steps: S1, mixing beeswax and rosin in proportion to obtain rosin wax; s2, a glass slide is placed on a high-temperature heating table, rosin wax is smeared on the glass slide, and a piezoelectric single crystal is placed in the middle of the glass slide; s3, putting the glass slide with the piezoelectric single crystal into a vacuum bag, and vacuumizing for vacuum treatment; and S4, carrying out normal-temperature pressure curing on the glass slide on which the piezoelectric single crystal is placed after the vacuum treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of piezoelectric single crystal preparation, and relates to a bonding process of a piezoelectric single crystal, and specifically to a bonding process of a bubble-free thinned piezoelectric single crystal. Background Art

[0002] Relaxor ferroelectric single crystal lead magnesium niobate titanate has the advantages of high piezoelectric constant, high electromechanical coupling coefficient, good temperature stability, etc., so it has broad application prospects in the field of piezoelectric manufacturing. At present, in the process of thinning piezoelectric single crystals, the fixation of piezoelectric single crystals is crucial. Most manufacturers use wax bonding to fix piezoelectric single crystals, and the bonding wax, bonding technology, bonding temperature, bonding humidity, and the flatness of the bonding surface will affect the quality of bonding. In the subsequent thinning process, severe cases will cause the crystal to break. Therefore, how to improve the bonding quality of piezoelectric single crystals is particularly important.

[0003] At present, the commonly used method of bonding piezoelectric single crystals is to bond the piezoelectric single crystal to a glass slide or a glass plate. First, the glass slide is heated by a heating method, and then beeswax is placed to dissolve. The piezoelectric single crystal is placed in the middle of the beeswax, removed and pressed to complete the bonding of the piezoelectric single crystal. However, due to factors such as insufficient machining accuracy of the piezoelectric single crystal surface, uneven application of beeswax, and insufficient pressing force, this method of directly bonding the piezoelectric single crystal to the glass slide is prone to produce pores at the bonding point. Due to the presence of pores, the piezoelectric single crystal will produce certain protrusions, and in the subsequent thinning process, it is easy to produce problems such as uneven thickness, crystal falling and crystal fragmentation. These problems greatly affect the quality of the prepared device. Summary of the invention

[0004] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a bonding process for a piezoelectric single crystal, wherein the surface of the glass slide and the crystal are first wiped clean with alcohol, and then vacuum hot pressing is used to fix the single crystal and the glass slide well together. The reduction of pores on the bonding surface reduces the occurrence of various problems in the subsequent thinning process, thereby improving the accuracy of the piezoelectric single crystal.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a bubble-free thinned piezoelectric single crystal bonding process, comprising the following steps: S1: mixing beeswax and rosin in proportion to obtain rosin wax; S2: Place a glass slide on a high-temperature heating table, apply rosin wax on the glass slide, and place the piezoelectric single crystal in the middle of the glass slide; S3: placing the glass slide with the piezoelectric single crystal in a vacuum bag and evacuating the bag for vacuum treatment; S4: The vacuum-treated glass slide with the piezoelectric single crystal is subjected to pressure curing at room temperature.

[0006] Preferably, in step S1, the mass ratio of beeswax to rosin is 5:1 to 7:1.

[0007] Preferably, in step S1, the preparation method of rosin wax comprises: firstly preparing beeswax and rosin according to a mass ratio, heating and mixing under stirring conditions, and then continuously stirring and placing in a water bath and heating to 120-135° C. to obtain a uniformly mixed rosin wax; wherein, during the heating and mixing process, the stirring time is 10-20 min.

[0008] Preferably, in step S2, the temperature of the high temperature heating stage is 120-150°C.

[0009] Preferably, in step S2, the piezoelectric single crystal is at least one of PMN-PT and PIN-PMN-PT; and the thickness of the piezoelectric single crystal is 0.3-2 mm.

[0010] Preferably, in step S2, the area of ​​the glass slide coated with rosin wax is larger than the area of ​​the piezoelectric single crystal; The thickness of the rosin wax applied on the slide is 0.02 to 0.05 mm.

[0011] Preferably, in step S3, the vacuum bag is placed on a heating table for vacuum treatment; the vacuum degree of the vacuum treatment is 80-90 kPa.

[0012] Preferably, in step S4, the pressure of the normal temperature pressure curing is the pressure of a 5kg iron block or the force of a human palm pressing downward; and the time of the normal temperature pressure curing is 5 to 10 minutes.

[0013] Preferably, the bonding process further comprises: after pressure curing at room temperature, scraping off the solidified rosin wax around the piezoelectric single crystal with a scraper, and then wiping the surface and surroundings of the piezoelectric single crystal with alcohol to prevent residual rosin wax from contaminating the grinding disc.

[0014] Beneficial effects: (1) The present invention uses rosin wax uniformly mixed with beeswax and rosin as an adhesive, and utilizes the high adhesiveness of rosin to effectively improve the firmness of the bonding process and significantly reduce the risk of crystal shedding; (2) Different from the traditional bonding method, the present invention utilizes the vacuum hot pressing method in the whole process, which can effectively avoid the problems such as the generation of pores on the bonding surface causing crystal shedding and cracking, and can significantly improve the yield of the piezoelectric single crystal bonding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the overall assembly structure of the piezoelectric single crystal bonding process in Example 1; Figure 2A partial schematic diagram of a piezoelectric single crystal for implementing the piezoelectric single crystal bonding process in Example 1; 1- glass slide, 2- glue layer, 3- piezoelectric single crystal, 4- vacuum bag, 5- pressing block, 6- heating table, 7- vacuum sealing machine, 8- stage; Figure 3 The flatness comparison diagram is a diagram of a piezoelectric single crystal obtained by the bonding process of the present invention and a piezoelectric single crystal obtained by a traditional bonding method, respectively measured by an electronic outer diameter screw micrometer. DETAILED DESCRIPTION

[0016] To further explain the content, features and practical effects of the present invention, the present invention is described in detail below in conjunction with the embodiments. It should be pointed out that the modification method of the design of the present invention is not limited to these specific implementation methods. Without departing from the spirit and connotation of the design of the present invention, the equivalent replacement and modification made by those skilled in the art on the basis of reading the content of the present invention are also within the scope of the present invention.

[0017] The present invention provides a bonding process for a piezoelectric single crystal, the principle of which is that rosin wax softens or melts when heated, and can better contact the surface of the single crystal. The glass slide with the piezoelectric crystal bonded thereto is heated to inhibit the solidification of the rosin wax, and at the same time, a vacuum treatment is performed on it, and the pressure during the vacuum treatment is used to squeeze out the tiny pores between the piezoelectric single crystal and the glass slide, so as to improve the firmness and flatness of the bonding. When the rosin wax is cooled, the rosin wax will re-solidify to form a close contact with the surface of the single crystal, forming a firm connection.

[0018] The following is an exemplary description of the bonding process of the bubble-free thinned piezoelectric single crystal provided by the present invention.

[0019] First, wipe the surface of the glass slide and the piezoelectric crystal clean with alcohol.

[0020] Preparation of rosin wax. Prepare beeswax and rosin according to the mass ratio, then heat and mix the beeswax and rosin, stir with a glass rod for 10 to 20 minutes (e.g., 15 minutes), and finally place in a water bath and heat to 120 to 135°C. It should be noted that stirring should be continued during the process of placing in the water bath to obtain a uniformly mixed rosin wax.

[0021] In an optional embodiment, the mass ratio of beeswax to rosin is 5:1 to 7:1 (for example, 6:1). If the mass ratio of beeswax to rosin is too high, it will be difficult to remove the bonded sample, and if it is too low, the bonded sample will not be firmly bonded.

[0022] The glass slide is placed on a high-temperature heating table, and then rosin wax is evenly applied on the glass slide, and the piezoelectric single crystal is placed in the middle of the glass slide, wherein the area of ​​the glass slide where the rosin wax is applied is larger than the area of ​​the piezoelectric single crystal.

[0023] In an optional embodiment, the temperature of the high temperature heating stage is 120-150°C.

[0024] In an optional embodiment, the piezoelectric single crystal is at least one of PMN-PT and PIN-PMN-PT; the thickness of the piezoelectric single crystal is 0.3 to 2 mm.

[0025] In an optional embodiment, the thickness of the rosin wax applied on the glass slide is 0.02-0.05 mm.

[0026] Remove the glass slide with the piezoelectric single crystal and immediately put it into a vacuum bag, then place the vacuum bag on a heating table to prevent the wax from solidifying, and put the open end of the vacuum bag into a vacuum sealer for vacuuming. The vacuum sealer includes: a cover, a body, a 5mm double heating wire, high-quality air-sealing cotton, a display panel, and a support platform.

[0027] In an optional embodiment, the vacuum degree of the vacuum treatment is 80-90 kPa (such as 85 kPa).

[0028] The vacuum bag after vacuum treatment is removed from the heating table, and the bonded piezoelectric single crystal is pressure-cured at room temperature.

[0029] In an optional embodiment, the pressure of the normal temperature pressure curing is the pressure of a 5kg iron block or the force of a human palm pressing downward; and the time of the normal temperature pressure curing is 5 to 10 minutes.

[0030] After curing is completed, use a scraper to scrape off the solidified rosin wax around the piezoelectric single crystal, and then use alcohol to wipe the surface and surrounding areas of the piezoelectric single crystal to prevent residual rosin wax from contaminating the grinding disc.

[0031] The following further examples are given to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention belong to the scope of protection of the present invention. The specific process parameters and the like in the following examples are also only examples within a suitable range, that is, those skilled in the art can make a selection within a suitable range through the description herein, and are not limited to the specific values ​​​​exemplified below.

[0032] Example 1

[0033] This embodiment 1 provides a bonding process for lead magnesium niobate-lead titanate (PMN-PT) piezoelectric single crystal (the overall assembly structure diagram of the piezoelectric single crystal bonding process is shown in FIG. Figure 1 As shown), comprising the following steps: (1) beeswax and rosin are prepared in a mass ratio of 6:1, heated and mixed at 135° C., stirred with a glass rod for 15 min, and then placed in a water bath and heated to 135° C., and stirred continuously during the placing process to obtain a uniformly mixed rosin wax; (2) Place the glass slide on a high-temperature heating table at 150° C. and evenly apply rosin wax to cover the entire glass slide; (3) Take a lead magnesium niobate-lead titanate (PMN-PT) piezoelectric single crystal with a thickness of 1 mm and an area smaller than the glass slide and place it in the middle of the glass slide; (4) Remove the glass slide with the lead magnesium niobate-lead titanate (PMN-PT) piezoelectric single crystal and immediately put it into a vacuum bag. Then put one end of the vacuum bag into a vacuum sealer and perform vacuum treatment under the condition of a vacuum degree of 85 kPa. During the vacuuming process, the vacuum bag needs to be placed on a heating table to prevent the adhesive wax from solidifying, and a 5 kg weight is used to press the piezoelectric single crystal to prevent the piezoelectric single crystal from moving out of the middle of the glass slide during the vacuuming process. (5) Take out the vacuum bag after vacuum treatment, press the piezoelectric single crystal with a 5 kg weight, and perform room temperature curing for 10 minutes; (6) Use a scraper to scrape off the solidified rosin wax around the piezoelectric single crystal, and then use alcohol to wipe the surface and surroundings of the piezoelectric single crystal to prevent the residual rosin wax from contaminating the grinding disc (the partial schematic diagram of the obtained piezoelectric single crystal is shown in Figure 2 shown).

[0034] The thickness of the piezoelectric single crystal obtained by the bonding process of the present invention and the piezoelectric single crystal obtained by the conventional bonding method at the four corners and the middle of the piezoelectric single crystal was measured by an electronic outer diameter screw micrometer. Figure 3 The test results are shown in Table 1.

[0035] Table 1:

[0036] The thickness of the piezoelectric single crystal obtained by the bonding method of the present invention is measured by an electronic outer diameter screw micrometer to be 0.75 mm. Figure 3 As shown in Table 1, the samples bonded by the bonding method of the present invention have higher flatness and are closer to the size of the samples, that is, the thickness of the rosin wax is smaller. However, the samples bonded by the traditional method have poor flatness and a greater thickness of the rosin wax, resulting in inconsistent crystal sizes during thinning.

Claims

1. A bubble-free thinned piezoelectric single crystal bonding process, characterized in that: The following steps are involved: S1: mixing beeswax and rosin in proportion to obtain rosin wax; S2: Place a glass slide on a high-temperature heating table, apply rosin wax on the glass slide, and place the piezoelectric single crystal in the middle of the glass slide; S3: placing the glass slide with the piezoelectric single crystal in a vacuum bag and evacuating the bag for vacuum treatment; S4: The vacuum-treated glass slide with the piezoelectric single crystal is subjected to pressure curing at room temperature.

2. The bonding process according to claim 1, characterized in that: In step S1, the mass ratio of beeswax to rosin is 5:1 to 7:

1.

3. The bonding process according to claim 1 or 2, characterized in that: The preparation method of the rosin wax comprises: firstly preparing beeswax and rosin according to a mass ratio, heating and mixing under stirring conditions, and then continuously stirring and placing in a water bath and heating to 120-135° C. to obtain a uniformly mixed rosin wax; wherein, during the heating and mixing process, the stirring time is 10-20 minutes.

4. The bonding process according to any one of claims 1 to 3, characterized in that: In step S2, the temperature of the high temperature heating stage is 120-150°C.

5. The bonding process according to any one of claims 1 to 4, characterized in that: In step S2, the piezoelectric single crystal is at least one of PMN-PT and PIN-PMN-PT; the thickness of the piezoelectric single crystal is 0.3-2 mm.

6. The bonding process according to any one of claims 1 to 5, characterized in that: In step S2, the area of ​​the glass slide coated with rosin wax is larger than the area of ​​the piezoelectric single crystal; The thickness of the rosin wax applied on the slide is 0.02 to 0.05 mm.

7. The bonding process according to claim 6, characterized in that: In step S3, the vacuum bag is placed on a heating table for vacuum treatment; the vacuum degree of the vacuum treatment is 80-90 kPa.

8. The bonding process according to claim 6 or 7, characterized in that: In step S4, the pressure of the normal temperature pressure curing is the pressure of a 5kg iron block or the force of a human palm pressing downward; and the time of the normal temperature pressure curing is 5 to 10 minutes.

9. The bonding process according to any one of claims 6 to 8, characterized in that: The bonding process also includes: after pressure curing at room temperature, scraping off the solidified rosin wax around the piezoelectric single crystal with a scraper, and then wiping the surface and surroundings of the piezoelectric single crystal with alcohol to prevent residual rosin wax from contaminating the grinding disc.

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