JPH0726948B2 - Chromatographic column and method for producing the same - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a chromatography column, and more particularly to a chromatography column excellent for high performance liquid chromatography and a method for producing the same.

[Technical background of the invention and its problems]

High-performance liquid chromatography has attracted attention as one of the separation techniques for liquid components (reference; high-performance liquid chromatographic analysis, edited by the Japan Society for Analytical Chemistry, Kanto Chapter, 1983). This is a method in which a thin tube called a column is filled with an adsorbent, and a sample to be separated is adsorbed and separated by flowing it together with a liquid such as alcohol under high pressure.

Conventionally, a stainless tube with an inner diameter of 20 [mm] and a length of 30 [cm] has been used as a column for high-performance liquid chromatography, but due to the demands of workability and downsizing of equipment, the column can be made smaller. Is being considered. For example,
There is a method of using a fluororesin tube with an inner diameter of about 0.5 mm and a quartz glass capillary. Miniaturization has the advantages of reducing the amount of waste solvent after use of the medium liquid and enabling in-situ analysis. However, this type of method has problems such as weak mechanical strength and so protection. There was a limit to the miniaturization of the column itself due to the necessity of the body and the like.

On the other hand, as a glass chromatography column, there is one in which a spiral groove is formed on the surface of a Si substrate and a glass plate is bonded to the surface of the Si substrate with an adhesive so as to cover the groove. However, in the case of this structure, the bonding strength between the Si substrate and the glass plate is not sufficient, and it cannot be used as it is as a column for high performance liquid chromatography. That is, in the case of gas, it is sufficient if it can withstand a pressure of several [Kg / cm ² ], but in the case of liquid, it is several tens to several tens.
It is necessary to withstand a pressure of 0 [Kg / cm ² ], and a method using an adhesive cannot withstand this pressure.
In addition, since the adhesive is used, there is a risk that the liquid flowing in the groove may react with the adhesive (melting the adhesive), resulting in poor reliability.

[Object of the Invention]

The present invention has been made in consideration of the above circumstances, and its object is to be excellent for high-speed chromatography,
It is to provide a compact and highly reliable column for chromatography.

Another object of the present invention is to provide a method for producing the chromatography column having the above structure.

[Outline of Invention]

The gist of the present invention is to form a column by directly joining a first Si substrate having a groove and a second Si substrate serving as a “lid” closing the groove without using an adhesive. Especially.

In the case of liquid chromatography as described above, for example,
Since a high pressure of several hundred [Kg / cm ² ] is applied, a strong bond is required at the joint to withstand this pressure.
And, the direct bonding between Si substrates can sufficiently withstand this pressure.

Direct bonding between Si substrates may be performed as follows. For example, by mirror polishing or the like, the surface is polished to have a surface roughness of 500 [Å] or less to make the surface hydrophilic. The hydrophilic state is confirmed by the fact that when water droplets are placed on the surface, it does not repel water and spreads thinly. Examples of the hydrophilic treatment method include washing treatment or exposing to the air. Normal,
The strictly controlled Si substrate surface is water repellent, but it becomes hydrophilic by such treatment. Such hydrophilicity is
It is considered that a natural oxide film is formed. The natural oxide film can be formed by using a method such as heating in air.

A strong bond can be obtained by bringing hydrophilic Si substrates into close contact with each other in a clean atmosphere in which no foreign matter such as dust is present and heating them to 200 [° C.] or higher. This joint has high reliability without leakage even under high pressure conditions such as liquid chromatography. Of course, it goes without saying that it can also be used for gas chromatography. Since the Si substrates are adhered to each other, there is no warp or the like even after the joining, and the Si substrate has a shape in which a groove is embedded, so that the mechanical strength is sufficient.

The formation of the groove on the Si substrate may be carried out by using an ordinary etching method. By removing the resist and thoroughly washing with water,
It can be the hydrophilic surface described above. The shape of the groove is
It may have any shape as long as it is continuous, but it is preferable to form it in a spiral shape because the flow of the liquid sample is not easily obstructed. If it is desired that the inner surface of the column is covered with SiO ₂ , the grooved wafer to be bonded and the wafer as the lid are processed in advance in an oxidizing furnace or the like, and the entire surface including the inner surface of the groove is covered with SiO _{2. The two} films should be attached and then joined. Also,
By providing a diffusion resistance layer on the surface of the Si substrate on the lid side,
It is possible to have a function to keep the temperature of the column constant.

Although the bonding mechanism between Si substrates is not clear, the active silanol group (Si
It is considered that dehydration condensation by heating (-OH) produces a strong bond (so-called covalent bond).

The present invention has been made paying attention to such a point, and in a column for chromatography, a first Si substrate having a continuous groove formed on the surface and the above-mentioned groove are sealed to form a continuous hole. The second bonded directly to the first Si substrate
The Si substrate and the first or the second so as to communicate with the hole.
An introduction hole for introducing the sample to be measured into the hole provided in the Si substrate, and a discharge for discharging the sample to be measured from the hole provided in the first or second Si substrate so as to communicate with the hole. It will be done.

Further, in addition to the above configuration, a diffusion resistance layer is provided by selectively doping impurities on the surface of the second Si substrate.

The present invention also provides a method for producing a chromatography column having the above-described structure, wherein each surface of the first and second Si substrates is mirror-polished to form a continuous groove on the surface of the first Si substrate. The first or second Si substrate is provided with an introduction hole for introducing a sample to be measured into the groove and a discharge hole for discharging the sample, and then the first and second Si substrates are subjected to a predetermined treatment. To make each surface of these substrates hydrophilic, and then to adhere the surfaces of the first and second Si substrates in a clean atmosphere, and in this state, heat to 200 [° C.] or more to allow each of the substrates to work together. This is the method of joining.

Further, in addition to the above method, a diffusion resistance layer is formed by impurity doping.

〔The invention's effect〕

According to the present invention, since the direct bonding between Si substrates is extremely strong as compared with the conventional bonding method, it is possible to sufficiently withstand a high pressure of about 100 [Kg / cm]. Here, the reason for withstanding the high pressure is that the Si substrates or the wafers having the SiO ₂ coating are directly bonded. In the conventional electrostatic bonding method, the temperature could not be raised sufficiently during bonding due to the movement of Na ions, etc., and it was virtually impossible to obtain a column that could withstand a pressure of 100 [Kg / cm]. . Further, since it is not necessary to use an adhesive, there is no possibility that the adhesive reacts with the sample to be measured or a liquid such as alcohol. Therefore, it is possible to increase the speed, and it is possible to configure ultra-compact and high-speed chromatography.

Example of Invention

 Hereinafter, the details of the present invention will be described with reference to the illustrated embodiments.

1 and 2 are each for explaining the schematic structure of a liquid chromatography column according to an embodiment of the present invention. FIG. 1 is a plan view and FIG. 2 is a sectional view.
A spiral groove 11 is formed on the surface of the first Si substrate 10, and an introduction hole 12 and a discharge hole 13 for the sample to be measured which penetrate the Si substrate 10 are formed at the beginning and the end of the groove 11, respectively. Has been done. Then, the first and second Si substrates 10 and 20 are
It is directly bonded without using an adhesive.

3 (a) to 3 (h) are cross-sectional views showing the manufacturing process of the above-mentioned embodiment column.

First, the first Si substrate 1 having a diameter of 3 inches and a thickness of 450 [μm] 1
After mirror-polishing the surface of 0 to a surface roughness of 500 [Å] or less,
As shown in FIG. 3A, a SiO ₂ film 31 having a thickness of about 10000 [Å] was formed on the polished surface. Next, as shown in FIG. 3 (b), holes were formed by laser using the resist pattern 32 formed on the back surface side of the Si substrate 10 as a mark to form the introduction hole 12 and the discharge hole 13.

Next, as shown in FIG. 3C, a resist pattern 33 for forming a groove was formed on the surface side of the Si substrate 10 with the holes 12 and 13 as marks. This resist pattern 33 has a groove width of 100 [μ
m] and a pitch of 250 [μm] between grooves
The number of turns was 95. The drawing was performed using Archimedes' formula. Next, as shown in FIG. 3D, the SiO ₂ film 31 on the front surface side was etched with an etching solution of HF + NH ₄ F using the resist pattern 33 to form a SiO ₂ mask 31a. Then, as shown in FIG. 3 (e), a SiO ₂ mask 31a is formed.
Etching of Si substrate 10 (HNO ₃ + HF + CH ₃ COO
H) was performed to form spiral grooves 11. Then H
F + NH ₄ F is etched, and as shown in FIG.
The iO ₂ film 31 was removed. The first Si substrate 10 thus obtained
Was thoroughly washed with water to make it hydrophilic, and then spinner dried.

On the other hand, as shown in FIG.
After washing with water in the same manner as the Si substrate 10, the spinner was dried. Then, in a clean atmosphere of class 1000 or less,
As shown in FIG. 3 (h), the groove 11 of the first Si substrate 10 is
The first and second Si substrates 10 and 20 are brought into close contact with each other so that the Si substrate 20 is closed, and heating is performed in this state for 1150 [° C.] × 2 hours,
The respective substrates 10 and 20 were joined.

A pressure resistance test was conducted using the column thus obtained. For the test, groove width 100 [μm], depth 20 [μ
m], the introduction hole 12 and the discharge hole 13 are used to bond wafers processed to have a hole diameter of 100 μm, and after filling the column with water as a pressurized test liquid, the discharge hole 13 is closed and introduced. It was pressurized from the hole 12 with a pump. As a result, the product withstands 120 [Kg / cm ² ] sufficiently, and above this pressure, some cracks appeared on the wafer, but no peeling of the joint was observed.

Next, a column was prepared in which a SiO ₂ film was provided on the inside of the groove and on the surface of the lid before bonding by 1000 [Å] by steam oxidation, and then a wafer subjected to cleaning treatment before bonding was bonded. When this column was also measured in the same manner as above, 120 [Kg / cm ² ]
It was confirmed that it could withstand the pressure of.

From the above results, the pressure resistance is higher than the column by the conventional method, and in addition to being compact, the volume velocity can be sufficiently increased even if the total length of the column is increased, and the high-speed high theoretical plate number (10 More than double) columns have been created.

As described above, according to the present embodiment, by forming the groove in the Si substrate 10 and columnizing the groove, the column can be downsized and the mechanical strength can be improved. Moreover, the first and second Si bases 10 and 20 can be directly bonded without using an adhesive to form a strong bond. Therefore, it is extremely effective in realizing high performance liquid chromatography, and can be downsized. Further, since no adhesive is used, there is no inconvenience that the liquid flowing in the groove reacts with the adhesive,
It will be reliable.

4A to 4C are cross-sectional views showing a column manufacturing process according to another embodiment of the present invention.

This embodiment differs from the above-described embodiments in that a diffusion resistance layer is provided on the surface of the first Si substrate 10 and
Also, an insulating film is provided on the surfaces of the second bases 10 and 20.

That is, after the step shown in FIG. 3 (f), the SiO ₂ film 41 is formed on the surface of the first Si substrate 10 as shown in FIG. 4 (a), inside the groove and inside the hole by steam oxidation or the like. Was coated. On the other hand, on the surface of the second Si substrate (P-type wafer) 20, an N-type diffusion resistance layer 42 was formed by selectively doping N-type impurities as shown in FIG. 4 (b). Here, the pattern of the resistance layer 42 was one curved line capable of covering the entire surface of the substrate 20 as shown in FIG. Then, the surface of the second Si substrate 20 was also coated with the SiO ₂ film 43 by steam oxidation or the like.

Then, as shown in FIG. 4 (c), first and second Si substrates
As in the previous case, 10, 10 were brought into close contact with each other in a clean atmosphere, and heat-treated to bond the respective substrates 10, 20. After that, a part of the SiO ₂ film 43 was removed to form a contact hole for energizing the resistance layer 42. By forming a notch in a part of the first Si substrate 10, the electrode connection portion 45 of the diffusion resistance layer 42 can be exposed even after the bonding as shown in FIG.

The column thus formed is composed of the first and second Si substrates 1
The bonding strength of 0,20 is sufficiently high, and therefore the first
The same effect as that of the embodiment can be obtained. In addition, the diffusion resistance layer 42
Since it is provided, the temperature of the entire column can be made uniform without using a constant temperature bath. Therefore, there is an advantage that the system can be simplified. Further, when the electrostatic pressure bonding method is used, the heater resistance fluctuates due to the diffusion of Na ions, but this embodiment does not have such a disadvantage.

The present invention is not limited to the above-mentioned embodiments. For example, the diffusion resistance layer is not limited to a series of series heaters, but may be separately formed on the surface of the second Si substrate as shown in FIG. In this case, since the respective resistance layers can be controlled independently, it becomes possible to more effectively equalize the temperature of the column. That is, although the column is formed in a substantially point symmetry from the center of the wafer, it is necessary to suspend the column for practical use, and heat flows out from this suspension portion, and the temperature in the vicinity is lowered. For this reason, in the method of separately forming the resistance layer, it is possible to increase the heater power of the suspension portion or the like to make the entire temperature uniform.
Further, by forming the first Si substrate to have a smaller diameter than the second Si substrate, the electrode connection portion of the resistance layer can be provided on the column outer peripheral portion as shown in FIG. Further, it is not always necessary to provide a notch in the first Si substrate or to provide the first Si substrate with a diameter smaller than that of the second Si substrate for electrode connection of the resistance layer. Contact holes may be provided from the contact hole to the resistance layer.

Further, the heating temperature for joining the first and second Si substrates is not limited to 1150 [° C], but 200 [° C] or more,
It is preferably 1000 [° C.] or higher. Furthermore, the first
The surface of the second Si substrate may be polished to a surface roughness of 500 [Å] or less. Further, it is needless to say that it can be used not only for the column for liquid chromatography but also for the column for gas chromatography. In addition, various modifications can be made without departing from the scope of the present invention.

[Brief description of drawings]

FIG. 1 and FIG. 2 are respectively for explaining the schematic constitution of a liquid chromatography column according to one embodiment of the present invention. FIG. 1 is a plan view, FIG. 2 is a sectional view, and FIG. )-(H) are cross-sectional views showing the manufacturing process of the above-mentioned example column, FIGS. 4 (a)-(c) are cross-sectional views showing the manufacturing process of the chromatography column according to another embodiment, and FIG. FIG. 6 is a plan view showing a resistance layer pattern, FIG. 6 is a plan view showing an electrode connecting portion, and FIG. 7 is a plan view for explaining a modification. 10 ... First Si substrate, 11 ... Spiral groove, 12 ... Introduction hole, 13 ... Discharge hole, 20 ... Second Si substrate, 31, 41, 43 ...
… SiO ₂ film, 32, 33 …… Resist pattern, 42 …… Diffusion resistance layer, 45 …… Electrode connection part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eisaku Yonehara, 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Inside the Toshiba Research Institute Co., Ltd. No. 1 Incorporated company Toshiba Research Institute (72) Inventor Yoji Umeya 3-4 of Ikejiri, Setagaya-ku, Tokyo 302 (56) Reference US Patent 3538744 (US, A)

Claims (17)

[Claims] 1. A first Si substrate having a continuous groove formed on its surface, and a second Si substrate directly covalently bonded to the first Si substrate so as to seal the groove into a continuous hole. A Si substrate, and an introduction hole that is provided in the first or second Si substrate so as to communicate with the hole and that introduces a sample to be measured into the hole.
A chromatography column, comprising: a discharge hole which is provided in the first or second Si substrate so as to communicate with the hole and discharges the sample to be measured from the hole. 2. The chromatography column according to claim 1, wherein the groove is formed in a spiral shape. 3. The chromatography column according to claim 2, wherein the introduction hole and the discharge hole are formed at the start and end of a spiral groove. 4. The chromatography column according to claim 1, wherein the surface of the first Si substrate is covered with a SiO ₂ film. 5. A first Si substrate having a continuous groove formed on the surface thereof, and a second Si substrate directly bonded by covalent bonding to the first Si substrate so as to seal the groove into a continuous hole. A Si substrate, and an introduction hole that is provided in the first or second Si substrate so as to communicate with the hole and that introduces a sample to be measured into the hole.
A discharge hole that is provided in the first or second Si substrate so as to communicate with the hole and discharges the sample to be measured from the hole, and is formed by selectively doping impurities on the surface of the second Si substrate. And a resistance layer and an insulating film coated on the surface of the second Si substrate. 6. The chromatography column according to claim 5, wherein the groove is formed in a spiral shape. 7. The chromatography column according to claim 6, wherein the introduction hole and the discharge hole are formed at the start and end of a spiral groove. 8. The chromatography column according to claim 5, wherein the surface of the first Si substrate is covered with a SiO ₂ film. 9. The chromatography column according to claim 5, wherein the resistance layer is divided into a plurality of pieces on the surface of the second Si substrate. 10. The second Si is formed on a part of the first Si substrate.
6. The chromatography column according to claim 5, wherein a notch is provided so that a part of the surface of the substrate is exposed, and an electrode connecting portion of the resistance layer is provided in this notch. 11. The first Si substrate has a diameter smaller than that of the second Si substrate, and an electrode connection portion of the resistance layer is provided on a surface exposed portion of the second Si substrate. The chromatography column according to claim 5 or 9. 12. A step of mirror-polishing each surface of the first and second Si substrates, a step of forming continuous grooves on the surface of the first Si substrate, and the first or second Si substrate. A step of providing an inlet hole for introducing a sample to be measured into the groove and an outlet hole for discharging the sample, and then making each surface of the first and second Si substrates hydrophilic. Next, a step of closely adhering the surfaces of the first and second Si substrates in a clean atmosphere, heating in this state to 200 [° C.] or higher, and joining the respective substrates by covalent bonding And a method for producing a chromatography column. 13. The method for producing a chromatography column according to claim 12, wherein the groove is formed in a spiral shape. 14. The method for producing a chromatography column according to claim 13, wherein the introduction hole and the discharge hole are formed at the start and end of a spiral groove. 15. The method for producing a chromatography column according to claim 12, wherein the surface of the first Si substrate is covered with a SiO ₂ film. 16. The method for producing a chromatography column according to claim 12, wherein, as the step of making hydrophilic, each of the substrates is washed with water or exposed to clean air. 17. A surface roughness of 500 as the polishing step.
[A] The method for producing a chromatography column according to claim 12, wherein mirror polishing is performed below.