Alkali metal plane target material binding method and alkali metal target material assembly

Abstract

The invention belongs to the technical field of alkali metal plane target material binding, and discloses an alkali metal plane target material binding method, which comprises the following steps of: bonding a pretreated alkali metal target blank and a back plate by using a conductive adhesive, and doping a conductive medium in the conductive adhesive, the resistance between the alkali metal target material and the back plate is also reduced while good adhesion is provided; in addition, the invention further discloses a conductive adhesive, graphite is added into the conductive adhesive to replace traditional carbon black, and the conductivity of a target material interface is improved; in addition, the invention further provides a lithium target material assembly which is prepared through the conductive adhesive and alkali metal plane target material binding method.

Description

Technical Field

[0001] The invention relates to the technical field of alkali metal planar target binding, and in particular to an alkali metal planar target binding method and an alkali metal target assembly. Background Art

[0002] In recent years, with the vigorous development of electronic information and high-tech industries, the demand for new thin film materials has been increasing. The application of thin film materials has directly affected the development of information technology in my country.

[0003] Sputtering targets are raw materials for preparing thin films, and the comprehensive quality of the targets will have a significant impact on the performance of the films. In practical applications, the sputtering targets need to be combined with metal alloy backing plates to form target components for sputtering. If the bonding between the target and the backing plate is poor, the target will deform, crack, and deviate from the target during the sputtering process, which will not only affect the performance of the sputtered film, but in severe cases will also damage the sputtering machine.

[0004] Chinese patent application 201910015776.3 discloses a method for manufacturing a lithium target assembly, which comprises providing a lithium target blank having a first main surface and a first back side opposite to the first main surface; providing a back plate having a second main surface and a second back side opposite to the second main surface; plating the second main surface of the back plate with lithium to form a lithium plating layer; arranging and fitting the first main surface of the lithium target blank and the lithium plating layer on the second main surface of the back plate relative to each other to form an initial assembly; applying pressure to the initial assembly in a vacuum environment to combine the lithium target blank with the lithium plating layer, thereby completing the binding of the lithium target blank and the back plate, thereby forming a lithium target assembly.

[0005] The bonding technology used in this scheme is diffusion welding technology, which uses the lithium target and lithium plating layer to diffuse lithium atoms to form a new diffusion layer under the action of temperature and pressure to achieve welding bonding. Among the existing bonding technologies, there are few bonding technologies for lithium target materials.

[0006] The problem that this solution needs to solve is: How to propose a method for binding alkali metal planar targets that reduces costs and increases efficiency. Summary of the invention

[0007] The purpose of the present invention is to provide a method for binding an alkali metal planar target material, which improves the direct bonding force with the target material and reduces the resistance between the two through the epoxy resin and the conductive medium in the conductive glue.

[0008] To achieve the above object, the present application discloses a method for binding an alkali metal planar target, comprising the following steps:

[0009] Step 1: Drying the alkali metal plane target and the backing plate;

[0010] Step 2: Applying conductive adhesive to the alkali metal plane target material binding surface and the back plate binding surface respectively;

[0011] Step 3: placing the binding surface of the alkali metal plane target coated with conductive glue on the binding surface of the back plate coated with conductive glue, standing, extruding, and curing to complete the binding of the alkali metal plane target;

[0012] The conductive adhesive consists of 20 to 50 parts of epoxy resin, 20 to 50 parts of copper powder, 5 to 20 parts of graphite, 1 to 10 parts of silicon dioxide, 1 to 10 parts of aluminum oxide and 1 to 10 parts of calcium carbonate by weight.

[0013] Preferably, the alkali metal planar target is a lithium target.

[0014] Preferably, two parallel copper wires solidified by conductive adhesive are placed on the backplane binding surface in step 2, and the diameter of the copper wires is 0.1-0.5 mm;

[0015] Preferably, the operation of coating the conductive glue on the binding surface of the alkali metal planar target is: evenly coating the conductive glue on the binding surface of the alkali metal planar target, letting it stand, scraping the residual conductive glue on the surface with a silicone sheet, and repeating the above operation twice to complete the coating of the conductive glue.

[0016] The thickness of the conductive glue on the binding surface of the alkali metal planar target is 0.1-0.5 mm.

[0017] Preferably, the standing time in step 3 is 3 to 10 minutes.

[0018] Preferably, in step 3, the curing temperature is 60-100° C. and the curing time is 2-4 hours.

[0019] Preferably, xylene is further added to the conductive adhesive, and the xylene accounts for 25-75% of the total mass of the conductive adhesive.

[0020] Preferably, the epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and polyphenol glycidyl ether.

[0021] Preferably, the alkali metal planar target binding method needs to be performed in an environment where the water oxygen value is lower than 0.1 ppm.

[0022] In addition, an alkali metal target assembly is also disclosed. The alkali metal target assembly is obtained by binding an alkali metal planar target to a back plate using any of the above-mentioned alkali metal planar target binding methods.

[0023] The beneficial effects of the present invention are:

[0024] The present invention provides a method for binding an alkali metal flat target material, which improves the bonding force between the target material and the conductive adhesive and reduces the resistance between the two by using epoxy resin and conductive medium in the conductive adhesive, and assists in improving the conductivity of the target material interface; the binding process not only has simple equipment and preparation process, and the yield rate can reach more than 90%, but also will not cause violent chemical reactions of the alkali metal and has good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of conductivity site test, A, B, C are red pen test points, and D is black pen test point. DETAILED DESCRIPTION

[0026] In the description of the present invention, it should be noted that, if the specific conditions are not specified in the examples, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0027] Examples 1-5

[0028] A conductive adhesive, the composition of which is shown in Table 1:

[0029] Table 1

[0030]

[0031]

[0032] The epoxy resin described in Examples 1-5 is bisphenol A type epoxy resin.

[0033] The conductive adhesive is prepared by mixing copper powder, graphite, silicon dioxide, aluminum oxide and calcium carbonate according to the ratio in the above formula, adding the mixture into bisphenol A epoxy resin, putting the mixture into a mixer, and homogenizing the mixture at 12 to 30 r / min for 2 hours to obtain the conductive adhesive.

[0034] Application Example 1

[0035] Step 1: Dry the lithium target and back plate at 50°C for 2h;

[0036] Step 2: by coating the lithium target binding surface with conductive glue, letting it stand, scraping the residual conductive glue on the surface with a silicone sheet, and repeating the above operation twice, a lithium target binding surface coated with 0.3 mm conductive glue is obtained, and a conductive glue with the same height as the 0.3 mm diameter copper wire is coated on the back plate binding surface to obtain a back plate binding surface coated with conductive glue;

[0037] Step 3: Place the binding surface of the alkali metal plane target coated with conductive glue on the binding surface of the back plate coated with conductive glue, let it stand for 6 minutes, squeeze it, and cure it at 80°C for 3 hours to complete the binding of the alkali metal plane target;

[0038] The conductive adhesive is the conductive adhesive prepared in Example 1, and xylene accounts for 33% of the total mass of the conductive adhesive.

[0039] Application Example 2

[0040] Step 1: Dry the lithium target and back plate at 50°C for 2h;

[0041] Step 2: by coating the lithium target binding surface with conductive glue, letting it stand, scraping the residual conductive glue on the surface with a silicone sheet, and repeating the above operation twice, a lithium target binding surface coated with 0.1 mm conductive glue is obtained, and a conductive glue with the same height as the 0.1 mm diameter copper wire is coated on the back plate binding surface to obtain a back plate binding surface coated with conductive glue;

[0042] Step 3: Place the binding surface of the alkali metal plane target coated with conductive glue on the binding surface of the back plate coated with conductive glue, let it stand for 6 minutes, squeeze it, and cure it at 80°C for 3 hours to complete the binding of the alkali metal plane target;

[0043] The conductive adhesive is the conductive adhesive prepared in Example 1, and xylene accounts for 33% of the total mass of the conductive adhesive.

[0044] Application Example 3

[0045] Step 1: Dry the lithium target and back plate at 50°C for 2 hours and place them in an environment with a water oxygen value below 0.1ppm for later use;

[0046] Step 2: by coating the lithium target binding surface with conductive glue, letting it stand, scraping the residual conductive glue on the surface with a silicone sheet, and repeating the above operation twice, a lithium target binding surface coated with 0.5 mm conductive glue is obtained, and a conductive glue with the same height as the 0.5 mm diameter copper wire is coated on the back plate binding surface to obtain a back plate binding surface coated with conductive glue;

[0047] Step 3: Place the binding surface of the alkali metal plane target coated with conductive glue on the binding surface of the back plate coated with conductive glue, let it stand for 6 minutes, squeeze it, and cure it at 80°C for 3 hours to complete the binding of the alkali metal plane target;

[0048] The conductive adhesive is the conductive adhesive prepared in Example 1, and xylene accounts for 33% of the total mass of the conductive adhesive.

[0049] Application Example 4

[0050] It is basically the same as Application Example 1, except that the conductive adhesive is the conductive adhesive prepared in Example 2.

[0051] Application Example 5

[0052] It is basically the same as Application Example 1, except that the conductive adhesive is the conductive adhesive prepared in Example 3.

[0053] Application Example 6

[0054] The method is basically the same as Application Example 1, except that the xylene accounts for 25% of the total mass of the conductive adhesive.

[0055] Application Example 7

[0056] The method is basically the same as Application Example 1, except that the xylene accounts for 75% of the total mass of the conductive adhesive.

[0057] Application Example 8

[0058] It is basically the same as Application Example 1, except that the conductive adhesive is the conductive adhesive prepared in Comparative Example 1.

[0059] Application Example 9

[0060] It is basically the same as Application Example 1, except that the conductive adhesive is the conductive adhesive prepared in Comparative Example 2.

[0061] Application Example 10

[0062] It is basically the same as Application Example 1, except that carbon black is used instead of graphite in the conductive adhesive.

[0063] Application Example 11

[0064] It is basically the same as Application Example 1, except that the water oxygen value of the binding operating environment is 0.15 ppm.

[0065] Performance Test:

[0066] Adhesion strength: tested according to GB / T 39163-2020 target and backplane bonding strength test method;

[0067] Resistance between the target and the backing plate: After curing, the target is removed and polished with sandpaper and wiped with a dust-free cloth. After polishing and wiping, the resistance of the target is tested. Figure 1 shown.

[0068] The test results are shown in Table 2:

[0069] Table 2

[0070]

[0071]

[0072] Result analysis:

[0073] 1. It can be seen from application examples 1-3 that the copper wire fixed on the backplane binding surface is used to determine the thickness of the conductive glue between the backplane binding surface and the alkali metal plane target binding surface. Therefore, in application example 1, the thickness of the conductive glue between the backplane binding surface and the alkali metal plane target binding surface is 0.3 mm;

[0074] In Application Example 2, the thickness of the conductive adhesive between the back plate binding surface and the alkali metal plane target binding surface is 0.1 mm;

[0075] In Application Example 3, the thickness of the conductive adhesive between the back plate bonding surface and the alkali metal plane target bonding surface is 0.5 mm, and combined with the data in Table 3, it can be seen that:

[0076] Table 3

[0077] resistance Adhesion strength Application Example 1 0.10Ω 5.1MPa Application Example 2 0.09Ω 4.6MPa Application Example 3 0.20Ω 5.2MPa

[0078] It can be seen from the experimental data that when the thickness of the conductive glue is reduced from 0.3mm to 0.1mm, due to the reduction in the thickness of the conductive glue, the glue curing thickness provided is too low and the bonding ability becomes poor, resulting in a decrease in adhesion strength by 0.5MPa; as we all know, the size of the resistance is proportional to the length. When the thickness of the conductive glue increases from 0.3mm to 0.5mm, the adhesion strength it brings is not much improved, but the resistivity is increased by 0.1Ω due to the thickening of the conductive glue.

[0079] 2. It can be seen from Application Example 1 and Application Examples 4-5 that in the three application examples, the conductive adhesives used correspond to those obtained in Example 1 and Examples 2-3, respectively. After the binding is completed, the data of the obtained binding target materials are shown in Table 4:

[0080] Table 4

[0081]

[0082]

[0083] From the data, we can see that when the content of graphite and copper powder in the conductive adhesive increases, its resistivity will gradually decrease; and as the mass fraction of epoxy resin in the conductive adhesive increases, the adhesion it brings will also increase because the total thickness of the conductive adhesive remains unchanged.

[0084] 3. It can be seen from Application Examples 1 and 6-7 that in Application Example 1, xylene accounts for 33% of the total mass of the conductive adhesive;

[0085] In Application Example 6, xylene accounts for 25% of the total mass of the conductive adhesive;

[0086] In Application Example 7, xylene accounts for 75% of the total mass of the conductive adhesive. From the experimental data in Table 5, it can be seen that:

[0087] Table 5

[0088] resistance Adhesion strength Application Example 1 0.10Ω 5.1MPa Application Example 6 0.20Ω 4.5MPa Application Example 7 0.30Ω 5.2MPa

[0089] It can be seen from the experimental data that when there is too much xylene used for dilution in the conductive glue, the conductive glue is over-diluted, resulting in its effective ingredients being relatively diluted, so the resistance and adhesion strength of the target material it binds will deteriorate; and when there is too little xylene used for dilution in the conductive glue, although its adhesion strength is better, due to its poor fluidity, the graphite and copper powder cannot be spread evenly, resulting in different resistances at different locations of the target material.

[0090] 4. It can be seen from Application Example 1 and Application Examples 8-9 that, compared with Application Example 1, no graphite is added to the conductive adhesive in Application Example 8;

[0091] No copper powder was added to the conductive adhesive in Application Example 9. The experimental data are shown in Table 6:

[0092] Table 6

[0093]

[0094]

[0095] It can be seen from the experimental data that the lack of graphite or copper powder in the conductive glue will cause a significant increase in the resistance between the target material and the back plate, so graphite and copper powder components are indispensable.

[0096] Compared with Application Example 1 and Application Example 10, carbon black, which is also carbon, is used to replace graphite in the conductive glue of Application Example 10. Compared with the conductive glue without graphite added in Application Example 8, carbon black can also reduce the resistance between the target material and the backing plate, but the reduction is much smaller than that of graphite.

[0097] 5. By comparing Application Example 1 with Application Example 11, in Application Example 11, the alkali metal flat target is bound in an environment with a water oxygen value of 0.15 ppm. Because the moisture content in the environment is high, the alkali metal target will react with water to produce gas, which will cause the surface of the target to be irregular on the one hand, and will also produce gas, resulting in gaps inside the conductive adhesive, causing the resistance between the target and the backplane to increase.

[0098] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A method for binding an alkali metal planar target, characterized in that: The following steps are involved: Step 1: Drying the alkali metal plane target and the backing plate; Step 2: Applying conductive adhesive to the alkali metal plane target material binding surface and the back plate binding surface respectively; Step 3: placing the binding surface of the alkali metal plane target coated with conductive glue on the binding surface of the back plate coated with conductive glue, standing, extruding, and curing to complete the binding of the alkali metal plane target; The conductive adhesive consists of 20 to 50 parts of epoxy resin, 20 to 50 parts of copper powder, 5 to 20 parts of graphite, 1 to 10 parts of silicon dioxide, 1 to 10 parts of aluminum oxide and 1 to 10 parts of calcium carbonate by weight.

2. The alkali metal planar target binding method according to claim 1, characterized in that: The alkali metal planar target is a lithium target.

3. The alkali metal planar target binding method according to claim 1, characterized in that: Two parallel copper wires solidified by conductive adhesive are placed on the back panel binding surface in step 2, and the diameter of the copper wires is 0.1-0.5 mm.

4. The alkali metal planar target binding method according to claim 1, characterized in that: The operation of coating the conductive glue on the binding surface of the alkali metal planar target is: coating the conductive glue on the binding surface of the alkali metal planar target, letting it stand, scraping the residual conductive glue on the surface with a silicone sheet, and repeating the above operation twice to complete the coating of the conductive glue; The thickness of the conductive glue on the binding surface of the alkali metal planar target material is 0.1-0.5 mm.

5. The alkali metal planar target binding method according to claim 1, characterized in that: The standing time of step 3 is 3 to 10 minutes.

6. The alkali metal planar target binding method according to claim 1, characterized in that: In step 3, the curing temperature is 60-100° C. and the curing time is 2-4 hours.

7. The alkali metal planar target binding method according to claim 1, characterized in that: Xylene is also added into the conductive adhesive, and the xylene accounts for 25-75% of the total mass of the conductive adhesive.

8. The method for binding an alkali metal planar target according to claim 1, characterized in that: The epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and polyphenol glycidyl ether.

9. The method for binding an alkali metal planar target according to claim 1, characterized in that: The alkali metal planar target binding method needs to be performed in an environment where the water oxygen value is lower than 0.1 ppm.

10. An alkali metal target assembly, characterized in that: The alkali metal target assembly is obtained by binding an alkali metal planar target to a back plate using the alkali metal planar target binding method described in any one of claims 1 to 9.

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