JP2011020905A - Method for manufacturing bonded member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a bonded member mainly composed of silica which gives a bonded member tightly joined and excellent in thermal impact resistance by using hydrophilization step in bonding the member mainly composed of silica without leaving unwanted substances such as an adhesive liquid around the bonded part, and causing a rough joined surface. <P>SOLUTION: The method for manufacturing a bonded member involves a hydrophilization step to hydrophilize the bonding surfaces by immersing them in 2% ammonium fluoride solution, a tacking step to immerse the bonding surfaces in an adhesive liquid and subjecting them to tacking involving hydrogen bonding without exposing them to the atmosphere after the hydrophilization, and a permanent bonding step to take the tacked bonded member out of the adhesive liquid, and condensation-dehydrate it by heating in the atmosphere for permanent bonding. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a joined member obtained by joining members made of a plurality of glasses or the like.

In recent years, microchips having fine channels have been actively used for the purpose of antibody analysis and minimization of chemical reaction fields. These microchips and the like are manufactured by forming grooves serving as fine flow paths in a glass substrate and bonding the glass substrates together.
Further, in various types of optical elements, vacuum parts, and the like, it is generally performed by bonding different kinds of glass members.

As a conventional method for joining glass members, a fusion method (for example, see Patent Document 1) in which a glass substrate is heated to an annealing point or more, a method using hydrofluoric acid, a method using an alkaline solution (for example, a patent) Document 2), a method using an organic adhesive (for example, see Patent Document 3), and the like are known.
Further, it is disclosed that a solution of alkoxysilane or the like is used for manufacturing a microchemical chip.

Japanese Patent No. 4000076 Japanese Patent No. 3266041 Japanese Patent Laid-Open No. 2005-22935 JP 2005-139016 A

  However, bonding of glass members by the thermal fusion method requires heating the glass member to a glass annealing point or higher, and the glass member surface is distorted due to the effect of the coefficient of thermal expansion, etc., affecting the optical properties of the glass. The problem of exerting a problem is a problem.

  In addition, when the glass member is a multicomponent glass, the method of using hydrofluoric acid as a bonding agent is based on the difference in reactivity of hydrofluoric acid with respect to the glass component. Cloudy) is likely to occur.

  Even when an alkaline solution is used as the bonding liquid, unevenness and haze are likely to occur on the bonding surface due to the difference in reactivity of the alkaline solution to the glass component in the multicomponent glass. Further, haze may occur on the joint surface or whitening may occur due to the solution remaining in the joint portion. In particular, glass members such as electronic parts, optical parts, and analytical instruments are easily affected by residual alkali metals (for example, potassium and sodium) in terms of product performance. Is not preferred.

In addition, the method of applying and bonding an organic adhesive such as silicone resin on the bonding surface is difficult to prevent the adhesive from entering the microchannel of the microchip, and the microchannel is blocked. It is difficult to secure.
Furthermore, in the case of electronic parts, optical parts, analytical instruments, etc., these glass members are prone to peeling and deterioration at the joints under conditions such as laser and high temperature, and gas due to the adhesive is generated. It will adversely affect the equipment that uses the.

  In view of the above technical problem, the present inventors have applied a hydrophilic treatment to a member whose main component is silica whose surface has been mirror-polished (for example, flatness of several nm to several tens of nm). In connection with the method of bonding members such as glass, a bonding method using an effective hydrophilization method was found.

  That is, according to the present invention, in the joining of members mainly composed of silica, high adhesion can be achieved by applying a hydrophilic treatment without leaving an unnecessary substance such as a joining solution or roughening the joining surface in the joining portion. It aims at providing the method of manufacturing the joining member joined in the joining state which has the property and was excellent also in the thermal shock resistance.

In the method for manufacturing a joining member according to the present invention, the joining surfaces are mirror-polished, and the joining surfaces are made by using two members of ammonium fluoride as a hydrophilization treatment liquid. It is characterized by being subjected to a hydrophilic treatment and bonding.
By performing hydrophilic treatment using the above solution and adsorbing a large number of hydroxyl groups on the bonding surface, a bonding member having excellent adhesion can be obtained.

  In the said manufacturing method, after the said hydrophilic treatment, it is preferable to join using the solution containing a hydroxyl group as a joining liquid.

Moreover, the manufacturing method of the bonding member according to the present invention includes a step of immersing the bonding surface in a 2% ammonium fluoride solution, hydrophilizing treatment, and after hydrophilization treatment, immersing the bonding surface in the bonding liquid, In addition, the step of temporary bonding involving hydrogen bonding without the bonding part being exposed to the atmosphere, and the temporarily bonded bonding member is taken out from the bonding liquid, and condensed and dehydrated by pressurizing and heating in the atmosphere, and the main bonding. It is preferable to provide the process to do.
By passing through the said process, the joining member joined by uniform and high adhesiveness in the whole joining surface can be obtained.

  The said manufacturing method can be applied suitably, when the joint surface of the said member is a glass material which has a silica as a main component.

According to the present invention, when a member mainly composed of silica is bonded, it is possible to simply bond without joining unnecessary substances such as a bonding liquid in the bonded portion.
Moreover, the joining member obtained by this invention joined with uniform and high adhesive force, and has the joining state excellent also in the thermal shock resistance.
Therefore, the production method according to the present invention can be suitably applied to the production of a microchip having a fine channel, various optical elements, and the like.

Hereinafter, the present invention will be described in more detail.
In the method for producing a joining member according to the present invention, the joining of members mainly composed of silica whose surface is mirror-polished is used using a 2% ammonium fluoride solution as a hydrophilic treatment liquid, preferably having a hydroxyl group. Join using the solution as the joining solution.
In the joining of members such as glass and the like whose main component is silica, if a 2% ammonium fluoride solution as described above is used as a hydrophilic treatment solution, hydroxyl groups are chemically adsorbed on the joining surface of the member. Next, when bonding is performed using a bonding liquid containing a hydroxyl group, hydrogen bonding occurs between the bonding surface surface layers. Thereafter, a dehydration-condensation reaction is performed by pressurization and heat treatment to form a strong chemical bond, thereby obtaining a bonded state with high adhesion.

  Examples of the structure of the bonding surface mainly composed of silica of the members to be bonded include a glass structure or ceramics. In the present invention, a glass material whose main component of the bonding surface is silica, for example, soda lime silica glass, aluminosilicate glass, alkali-free glass, quartz glass and the like can be mentioned. The main component of the bonding surface may be silica, and the main component of the portion other than the bonding surface of the member may not be silica. A thin film such as a sputtered film mainly composed of silica may be used.

In the bonding according to the present invention, the members are bonded to each other through a hydrophilic treatment process for the bonding surface, a dipping / temporary bonding process in a bonding agent solution, and a main bonding process under pressure and heating.
The hydrophilization treatment is a very important pretreatment for uniformly bonding the entire bonding surface, and is performed by immersing the bonding surface in a 2% ammonium fluoride solution, but usually damages the member. Or under the condition that the joint surface of the member is not roughened.
However, in the case of a member having a crystal structure in the member, since the influence of the covalent bond between silicon (Si) and oxygen (O) is large, it is considered that the hydroxyl group is hardly adsorbed on the surface of the bonding surface. The effect of the hydrophilic treatment process cannot be expected. However, for crystallized glass, adsorption of hydroxyl groups can be expected by soft etching the surface layer of the joint surface and breaking the partial crystal structure of the surface layer.
In addition, it is preferable to clean in advance before the hydrophilic treatment. The cleaning is effective for both dry and wet processes.

By performing the hydrophilic treatment as described above, atoms and molecules on the bonding surface are activated, and hydroxyl groups are chemically adsorbed on the surface layer of the bonding surface. In particular, when the hydrophilic treatment is performed with a 2% ammonium fluoride solution, the hydrophilicity is increased as compared with the conventional hydrophilic treatment with an alkaline solution. It is considered that this is because, when treated with an ammonium fluoride solution, several atomic layers of the bonding surface are etched to activate the bonding surface.
Further, if the etching by the hydrophilization treatment with the 2% ammonium fluoride solution is a mirror-polished surface, the entire surface is uniformly etched. By bonding the bonding surfaces together, a bonding force due to hydrogen bonding occurs. In this bonding, it is important how much hydroxyl groups are adsorbed on the bonding surface. Therefore, it is possible to join with pure water alone after the hydrophilic treatment.

In the bonding of glass members or the like, the bonding liquid is preferably a solution that sufficiently contains hydroxyl groups. For example, an alkaline solution, a silane compound, etc. are mentioned.
In addition, when using a silane compound for bonding agent solution, it is important that it fully hydrolyzes. Examples of the silane compound include chlorosilane, silane coupling agent, silazane, and alkoxysilane. In addition, when the silane compound is not sufficiently hydrolyzed, not only the possibility of poor bonding is increased, but also there may be insufficient adhesion after bonding or peeling due to thermal shock.

  In the state where the bonding surface of the member that has been subjected to a sufficient hydrophilization treatment is immersed in the bonding liquid, pressure is applied in the bonding liquid as it is and temporary bonding is performed. By the temporary bonding step, it is possible to prevent impurities such as air from adhering to the bonding surface.

The temporary bonded product is taken out from the bonding liquid, set in a press machine, and finally bonded by a predetermined pressure, heating, and time. At this stage, the bonding liquid at the bonding interface between the members is dried, and it is presumed that the members are bonded with high adhesion by changing from hydrogen bonds to strong chemical bonds by dehydration and condensation.
Further, in the He leak test in the order of 1 × 10 ⁻¹⁰ Pa · m ³ / sec at the joint portion between the quartz glasses, no leaking portion has been confirmed, and a uniform joining member having no joint failure. Can be manufactured.

  As for the thickness of the bonding layer between the members, it is necessary to bring the members close to such an extent that an intermolecular force is sufficiently generated. Therefore, flatness of the bonding surface and uniform pressure are important. In order to perform it more strictly, it is preferable to specifically perform polishing of the joint surface, measurement of flatness, precision decompression, etc., and use a heating press system or the like.

  In the main joining, it is preferable that the member heating temperature is in the range of about 65 to 140 ° C. and the pressurizing is about 1 MPa from the viewpoint of obtaining a good joined state. If the heating temperature or pressure at the time of joining is too high, the surface of the member will be uneven or crushed due to the influence of the expansion coefficient or the like, which is not preferable.

  According to the method for producing a joining member according to the present invention as described above, in the case of a glass member, the joining surface does not cause a decrease in light transmittance due to the joining agent, and is excellent while maintaining high permeability. A member joined with high adhesion strength can be obtained.

The present invention can also be applied to bonding of different types of silica-based glasses such as quartz glass, borosilicate glass, soda glass, and silica-based kovar glass.
For example, in a metal Kovar-quartz glass bonding member used in vacuum parts or the like, an adhesive cannot be used from the viewpoint of hermeticity and the like. A plurality of glass layers having different expansion coefficients were bonded by thermal fusion with 5 to 7 layers in such a state that the thermal expansion coefficients are gradually inclined. Even in such a case, according to the present invention, since the glass layer thermally fused to the metal Kovar and the quartz glass can be joined without relying on the thermal fusion, the manufacturing process can be simplified. Can do.

Also, in optical components, different types of lenses (glass) may be bonded and used. In the case of a member having a different thermal expansion coefficient, it cannot be thermally fused. Although it has been used, the use of UV adhesive is not preferred because it impairs the transparency in the ultraviolet region.
On the other hand, according to the present invention, even in a detector cell, a reflective film, an optical measuring device, various optical elements, etc., it has an advantage that it can be joined without impairing the original optical characteristics of the member. .

EXAMPLES Hereinafter, although this invention is further demonstrated to a specific example based on an Example, this invention is not restrict | limited by the following Example.
(Preparation of bonding solution)
The following a) to e) bonding solutions were prepared.
a) Silane compound (1% solution of alkoxysilane)
Tetraethoxysilane 1% was diluted with water, ethanol 1% was added and stirred.
b) Potassium hydroxide 10% solution Potassium hydroxide was diluted 10% with water.
c) Pure water Ion exchange water is used as a bonding solution.

(Hydrophilic treatment)
Two mirror-polished disc-shaped glasses having a diameter of 30 mm and a thickness of 1 mm were immersed in H ₂ SO ₄ —H ₂ O ₂ (3: 1) for 30 minutes, and then immersed in a 2% ammonium fluoride solution at 30 ° C. Hydrophilic treatment was performed by dipping for 10 minutes.
(Joining)
Two disk-shaped glasses subjected to the hydrophilization treatment were temporarily bonded by being immersed in each of the above bonding solutions for 15 minutes, and then taken out from the solution.
The temporarily bonded glass was subjected to pressurization and heat treatment at 1 MPa and 120 ° C. for 3 hours to perform main bonding.

  Various joining evaluation was performed about the glass joined using each said bonding agent. In the observation of the bonding surface of the glass, in the case of alkali bonding, the glass may turn white due to the remaining solution on the bonding surface. No change was observed in the optical characteristics of the joined members.

The other evaluation results are shown in Table 1.
In Table 1, the evaluation of the bonding state was determined by visual inspection for the presence or absence of bonding failure. (Double-circle): There was no joining defect, (circle): The edge part unattached part was assumed.
About the thermal shock, it determined by the presence or absence of peeling of a junction part when it heated up from -20 degreeC to 100 degreeC. A: No peeling, B: Almost no peeling, B: Possibility of peeling.
Regarding the evaluation of the bonding strength (tensile strength), ◎: 0.5 N / mm ² or more and Δ: less than 0.5 N / mm ² .

  From the above evaluation results, for the bonding using the bonding liquid of the silane compound, a uniform and good bonding state is obtained without observing the bonding portion residual foreign matter, and further, the thermal shock resistance and bonding strength of the bonding portion are improved. Was also found to be in an excellent bonded state. Moreover, the bonding liquid of a silane compound functions sufficiently as a bonding liquid from the viewpoint of bonding conditions, thermal shock resistance, and the like. However, since the silane compound has poor hydrolyzability, it requires a long time stirring, which is not preferable from the viewpoint of work efficiency.

Next, an example in which a member obtained by depositing a sputtered SiO ₂ film on glass and glass is joined will be described. In this bonding, bonding was performed using the alkoxysilane 1% solution described in the bonding liquid a).
A member obtained by depositing a SiO ₂ sputtered film on a glass plate having a diameter of 30 mm and a thickness of 1 mm and a glass member not deposited with a sputtered film are represented by H ₂ SO ₄ —H ₂ O ₂ (3: 1). For 15 minutes for cleaning.
(Hydrophilic treatment)
The following hydrophilization treatments 1) and 2) were performed.
1) The cleaned member was immersed in a 10% potassium hydroxide 10% solution at 65 ° C. for 15 minutes.
2) The cleaned member was immersed in a 2% ammonium fluoride solution at 30 ° C. for 10 minutes, then cleaned with pure water, and immersed in a 10% potassium hydroxide solution for 15 minutes.
(Joining)
Each member subjected to the hydrophilization treatment is immersed in a tetraethoxysilane 1% solution for 15 minutes, and temporarily joined so as to join the sputtered film and the non-sputtered surface in the joining solution. I took it out.
The temporary bonding was performed under the pressure and heating conditions of 1 Mpa, 120 ° C., and 3 hours.

Bonding evaluation was performed on the above bonded glass.
In the observation of the bonding surface of the glass, when the hydrophilization treatment of 1) was performed, interference fringes were confirmed on the bonding surface, resulting in bonding failure. Interference fringes that were poorly bonded were not confirmed on the bonding surface of the bonding member subjected to the hydrophilic treatment of 2).

In addition to the evaluation test, a thermal shock test of the joining member was performed. The condition of the test was determined based on the presence or absence of peeling of the joint when the temperature was rapidly raised from 0 ° C. to 100 ° C. and then cooled again to 0 ° C.
It was peeled off in the case of the joint subjected to the hydrophilization treatment of 1), but the joining member in the case of 2) was not peeled off. It can be seen that the strength is high.

  Also from the results of the above test, it is considered preferable to use a 2% ammonium fluoride solution in the hydrophilization treatment step.

Claims (4)

  Joining members whose surfaces are mirror-polished and whose main component is silica using a 2% ammonium fluoride solution as a hydrophilic treatment liquid, and applying the hydrophilic treatment to the joint surfaces. A manufacturing method of a joining member.   The method for manufacturing a joining member according to claim 1, wherein after the hydrophilization treatment, joining is performed using a solution containing a hydroxyl group as a joining solution.   A step of immersing the bonding surface in a 2% ammonium fluoride solution to make a hydrophilic treatment, and a hydrophilization treatment, immersing the bonding surface in the bonding solution, and hydrogen bonding without the bonding portion being exposed to the atmosphere. A step of temporarily joining, and a step of taking out the temporarily joined joint member from the joining liquid, pressurizing and heating in the atmosphere, condensing and dehydrating, and performing a final joining. A method for producing a joining member according to 1 or 2.   The method for manufacturing a joining member according to any one of claims 1 to 3, wherein the joining surface of the member is a glass material mainly composed of silica.