JP2002235045A - Method for producing composite substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a composite substrate having high uniformity of film thickness of an adhesive and improved in a degree of parallelization between two substrates in a short time when producing the composite substrate by laminating a thin-film coating material on a substrate in which various kinds of functions are imparted to the surface through the adhesive. SOLUTION: This method comprises fixing a surface plate 2 having a flat surface improved in planarity on a spinner 1 in which a rotational speed can be changed so that the flat surface becomes the upper side, adhering the thin plate (a primary substrate 3) on the surface plate 2, dripping the adhesive 4 on the primary substrate 3 and mounting a secondary substrate 5 on the adhesive 4. The drip of the adhesive 4 is carried out so that the adhesive draws at least in two linear shapes such as X shape or Y shape at the time. The adhesive is extended to the vicinity to the peripheral part of the composite substrate by rotating the spinner 1 at a low speed. The surplus adhesive is then removed from the gap between the primary and secondary substrates by rotating the spinner 1 at a high speed to generate centrifugal force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a composite substrate formed by bonding two substrates via an adhesive, and more specifically, to a method for applying an adhesive to a substrate having various functions. The present invention relates to a manufacturing method suitable for manufacturing a composite substrate by laminating a thin film covering material through the intermediary.

[0002]

2. Description of the Related Art Composite substrates in which two substrates are bonded together via an adhesive are known in various fields. For example, in the case of electronic components and optical components, thin glass or the like (first substrate) is provided on the surface of a substrate (second substrate) provided with various functions.
Bonded together as a thin film coating material. In such a component, a high flatness is required for the surface of the thin plate used for the coating as the first substrate.

As an improved method of manufacturing such a composite substrate, Japanese Patent Application Laid-Open No. 2000-160107 discloses the following method. That is, a platen having a flat surface with improved flatness is fixed on a spinner installed in a spin coating machine, and a thin first substrate such as a thin glass plate or a film is fixed thereon. Put. Next, a liquid adhesive is dropped on the surface of the first substrate, and a second substrate 5 having a thickness larger than that of the first substrate is placed on the adhesive in an uncured state. In this state, the platen is rotated at a high speed and excess adhesive is shaken off by centrifugal force.
To obtain a composite substrate laminated with the substrate with high parallelism via an adhesive. If the adhesive is thermosetting, the composite substrate is heated with a heater or warm air, and if the adhesive is ionizing radiation curable, ionizing radiation (eg, electron beam or ultraviolet). To cure the adhesive, thereby obtaining a composite substrate covered with a thin plate (first substrate) having high surface flatness.

[0004]

In the manufacturing method described above, the adhesive is dropped in a mountain-like state substantially at the center of the first substrate. When the second substrate is placed thereon, the second substrate
The substrate is inevitably in a slightly inclined posture due to the influence of the adhesive in a mountainous state. In that state,
Spinner spins at high speed (usually 1000-5000rpm)
m), the spread of the adhesive due to the centrifugal force becomes uneven, and the thickness of the adhesive on the first substrate becomes uneven (for example, a thickness unevenness of about 5 μm occurs in a plane of 150 mm square). . Since the adhesive is cured in that state, the parallelism between the first substrate and the second substrate of the manufactured composite substrate becomes insufficient, resulting in a defective product.

The present invention has been made in view of the above circumstances, and has as its object to provide a composite substrate formed by bonding two substrates via an adhesive, and more specifically, a thin film coating material. When a composite substrate is manufactured by bonding substrates having various functions to the surface through an adhesive dropped on the surface of the substrate, the parallelism between the two substrates caused by the dropped adhesive is produced. It is an object of the present invention to provide a method of manufacturing a composite substrate, which can effectively avoid shortage of components and thereby greatly reduce the probability of occurrence of defective products.

[0006]

A method for manufacturing a composite substrate according to the present invention for solving the above-mentioned problems is provided on a surface plate having a flat surface with a variable rotation speed and improved flatness. A step of bringing a first substrate into close contact, a step of dropping an adhesive on the first substrate,
Placing the second substrate on the first substrate, rotating the first and second substrates by rotating the platen, and applying extra centrifugal force between the first and second substrates by the action of centrifugal force. And a step of sequentially removing the agent. In the method of manufacturing a composite substrate, the adhesive is dropped onto the first substrate so as to form at least two or more linear bodies. This is characterized in that at least two or more radial linear bodies are formed from the substantially central position of the substrate toward the peripheral portion.

According to the manufacturing method of the present invention, the adhesive immediately after being dropped on the first substrate is preferably at least two or more linear bodies having substantially the same thickness, more preferably. Is formed as at least two or more radial linear bodies having substantially the same thickness and extending from the substantially central position of the first substrate toward the peripheral portion. When the second substrate is placed on the first substrate, the inclination of the second substrate with respect to the first substrate is smaller than that of the conventional method in which an equal amount of adhesive is dropped in a mountain shape. The degree is greatly reduced and both are kept substantially parallel. Therefore, even if the surface plate is rotated at a high speed (usually 1000 to 5000 rpm) after the second substrate is placed,
The spread of the adhesive due to centrifugal force becomes uniform,
The thickness of the adhesive on the substrate becomes uniform. as a result,
The parallelism between the first substrate and the second substrate of the composite substrate manufactured after the curing of the adhesive becomes very high, and the yield of defective products is greatly reduced.

In a preferred aspect, in the method for manufacturing a composite substrate according to the present invention, the dropped adhesive is used as a first step before the step of removing excess adhesive by rotating the platen.
And a step of extending the vicinity of the peripheral portion between the first substrate and the second substrate. According to the experiments of the present inventors, by performing such a pre-process, the film thickness of the adhesive between the first and second substrates becomes more uniform, and no air bubbles are contained. It was confirmed that the parallelism of the substrate was further increased. Then, even when the first substrate was extremely thin (about 50 μm), high flatness was ensured. The time required for the dropped adhesive to reach the vicinity of the peripheral portion between the first and second substrates is as follows:
Compared with the conventional method in which an equal amount of the adhesive is dripped in a mountain-like state substantially at the center of the first substrate, the time according to the present invention is greatly reduced, and the time required for manufacturing the composite substrate is reduced. It became possible.

In order for the dropped adhesive to spread to the vicinity of the peripheral portion between the first and second substrates, basically the second adhesive is used.
This is performed by applying the weight of the substrate to the adhesive to stretch the adhesive. Since the upper second substrate is usually thick and has a certain amount of mass, the stretching of the adhesive proceeds smoothly. Other processes can be performed simultaneously to reduce the time. As other processing, for example, a processing of heating the adhesive to reduce its viscosity or a processing of giving vibration to the adhesive may be performed, and may be performed at a speed lower than the number of rotations when removing excess adhesive by the action of centrifugal force. The spinner may be rotated at a low rotation speed (about 100 to 500 rpm). A plurality of processes may be performed simultaneously.

The composite substrate manufactured as described above is
Next, a step of curing the adhesive is performed. The optimal curing process is performed according to the type of adhesive used.However, due to the uniformity and rapidity of curing, it is not possible to use an ionizing radiation curable adhesive as the adhesive and perform the curing process by ionizing radiation irradiation. This is a particularly preferred embodiment.

The method of the present invention can be used for a method of manufacturing an arbitrary composite substrate in which two substrates are laminated with an adhesive therebetween, and the two substrates are not particularly limited.
As described above, this is a particularly effective manufacturing method when the lower first substrate is very thin and the upper second substrate is thick and large in mass. For example, the second
The method of the present invention is effective when the first substrate is a functional substrate obtained by laminating a functional material such as an optical film, and the first substrate is a thin glass covering material such as a thin glass plate or a film. Thus, a composite substrate having a high surface flatness and a high degree of parallelism between two substrates can be easily and quickly manufactured with high reproducibility.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a view for explaining the manufacturing method of the present invention in the order of steps. In this example, a spin coater provided with a spinner 1 is used as an apparatus. An application body is fixed to one end of the spinner 1 by vacuum suction.
The coating liquid is stored in another pressurized tank, and a certain amount of paint is discharged by adjusting the opening and closing time of the solenoid valve and dropped on the object to be coated. Is spread on the surface of the object to be coated. Such a spin coater is suitable for coating a relatively small plate-like body, and is often used for coating a resist in the production of electronic components and the like. In the following example, the above device is used as a device for dropping an adhesive.

First, as shown in FIG. 1A, a platen 2 is fixed on a spinner 1. Usually this kind of spinner 1
Can be rotated at an arbitrary rotational speed from a stopped state to a high-speed rotation of about 10,000 rpm by a drive device and a control mechanism (not shown). The platen 2 may be fixed by means other than vacuum suction, such as mechanically. The front surface of the platen 2, that is, the surface opposite to the surface fixed by the spinner 1, is a flat surface with improved flatness. The platen 2 is preferably made of quartz glass having a flatness of 0.5 μm or less. By increasing the planarity in this way, the surface plate 2 and the first substrate 3 (corresponding to the “first substrate” in the present invention, hereinafter referred to as the first substrate 3) come into contact with each other without any gap. The close contact between the platen 2 and the first substrate 3 is maintained without performing an operation of continuing vacuum suction.

Although the surface plate 2 and the first substrate 3 are in close contact with each other because of their high flatness, they may be pressed from above the first substrate in order to improve the adhesion. Since the surface of the surface plate 2 maintains a high degree of flatness, the first substrate 3 adhered to the surface of the surface plate 2 is not affected even if the first substrate 3 itself has a thickness unevenness or some bending. The lower surface of the first substrate 3, that is, the surface in contact with the surface plate 2 has the flatness of the surface plate 2. In this state, the liquid adhesive 4 is dropped onto the surface of the first substrate 3 so as to form at least two or more linear bodies (FIG. 1).
b) A laminate 5 a of the functional material layer 6 and the second substrate 5 is placed thereon with the functional material layer 6 facing the first substrate 3. The mode of dropping the adhesive 4 will be described later in detail.

Preferably, leave in that state for a while,
The adhesive 4 is stretched by the weight of the laminate 5a so that the adhesive 4 spreads between the first substrate 3 and the laminate 5a to the vicinity of the periphery thereof as shown in FIG. 1c. As a result, the adhesive 4 spreads between the first substrate 3 and the laminate 5a with a more uniform thickness, and the first substrate 3 and the laminate 5
a (parallel with the second substrate 5) is further ensured.
During the standing, vibration may be applied to the adhesive 4 by an appropriate vibration generating means according to the type of the adhesive as a complementary means of stretching, and the adhesive 4 may be heated to reduce its viscosity. Processing may be performed. Further, the spinner 1 is
The adhesive 4 may be rotated at a low speed of about 00 to 500 rpm, whereby the adhesive 4 is stretched between the first substrate 3 and the laminate 5a by the action of centrifugal force. A plurality of the above processes may be performed simultaneously.

As described above, at the stage where the adhesive 4 has spread to the vicinity of the periphery between the first substrate 3 and the laminate 5a (the state shown in FIG. 1C), the spinner 1 is rotated at a high speed (10 degrees).
When it is set to about 00 to 5000 rpm, the first adhesive 4
The thickness between the substrate 3 and the laminate 5a decreases uniformly, and the excess adhesive 4 protrudes from the surroundings and is shaken off by centrifugal force (FIG. 1d). At this time, the thickness of the adhesive 4 can be appropriately controlled by adjusting the viscosity of the adhesive, the number of rotations (rpm) with respect to the elapsed time, and the rotation time. Through the above steps, the first substrate 3 and the second substrate 5 (laminate 5a) are laminated with the adhesive 4.

After the high-speed rotation, if the adhesive is thermosetting, it is heated with a heater or warm air, and if the adhesive is ionizing radiation-curable, it is irradiated with ionizing radiation. The adhesive is cured (FIG. 1e). After this, the second
The composite substrate B in which the substrate 5 (laminated plate 5a) and the first substrate 3 are integrated is separated from the surface plate 2 using a separator 7 such as an air blow or a plastic spatula (FIG. 1f). Then, the peeled composite substrate 8 is placed in an oven or the like, and a heat treatment (for example, 120 ° C., 1 hour) is applied to completely cure the adhesive. Through the above steps, a composite substrate according to the present invention is produced.

Next, a mode of dropping the liquid adhesive 4 on the surface of the first substrate 3 and a dropping device used for dropping will be described. FIG. 2 shows an embodiment of the adhesive dropping device. In FIG. 2, reference numeral 10 denotes a dispenser having an adhesive discharge nozzle 11 at its tip, which serves as a flow control opening / closing valve for starting and stopping the discharge of the liquid adhesive and adjusting the discharge amount, and a flow path of the liquid adhesive. And other piping. The dispenser 10 itself is conventionally known.

The dispenser 10 is supported by a computer-controlled three-axis (XYZ) moving stage 20, and is a flat plate 3 (in a practical example, a "first substrate", Hereinafter, it is referred to as a first substrate 3)
Z axis so that it can be moved in the X-axis and Y-axis directions (horizontal direction) so that it can be moved to any position above, and the tip position of the nozzle 11 can be adjusted from the surface of the first substrate 3 to a predetermined height. It is also possible to move in the direction (vertical direction). Such a three-axis (XYZ) direction moving stage 20 is also conventionally known, and a detailed description thereof will be omitted.

Reference numeral 30 denotes a tank for storing the liquid adhesive, which is provided with a pressurizing device (not shown) therein so that the stored liquid adhesive can be sent out by the pressure in the tank. Such a liquid sending pressure tank may be a conventionally known one. The dispenser 10 and the tank 30 are connected by a liquid feed pipe 31 and the dispenser 10
A predetermined amount of adhesive is discharged from the nozzle 11 of the dispenser 10 by controlling the flow rate control on / off valve disposed in the dispenser 10.

Reference numeral 40 denotes a system controller.
As shown in FIG. 5, a control circuit 41 for controlling the three-axis direction moving stage 20 and a dispenser control circuit 42 for controlling the opening / closing timing and opening of the flow rate adjusting on / off valve of the dispenser 10 are provided. An input keyboard 43 and a display 44 are provided.

As shown in FIG. 2, at the start of the dropping operation, the first substrate 3 is set on a worktable (table). Then, the drop start position r of the adhesive on the first substrate 3
(One or more) and the drop stop position R (one or more) are input as coordinates, and then an ejection start signal is input. As a result, the dispenser 10 moves to the start position r, and after arriving, the nozzle 11 of the dispenser 10 descends to start discharging the adhesive at a predetermined height. While continuing to discharge the adhesive, the dispenser 10 moves to the stop position R.
And discharge of the adhesive is stopped there. Thereby, as shown in FIG. 4B-1, for example, the first linear body made of an adhesive passes through substantially the center of the first substrate 3 and extends from the vicinity of one side to the vicinity of the other side. L1 is formed. Next, after rotating the first substrate 3 by 90 degrees or displacing the dispenser 10 by 90 degrees, the same dropping operation is performed. Thereby, a second linear body L2 that intersects at an angle of 90 degrees at a substantially central position in the longitudinal direction of the first linear body L1 is formed.

Using the apparatus shown in FIG. 2, the drop start position r
By appropriately setting the coordinate position of the dropping stop position R, two or more linear bodies having substantially the same thickness on the first substrate 3, preferably substantially the center of the first substrate 3. The adhesive 4 can be dropped as at least two or more radial linear bodies having substantially the same thickness extending from the position toward the peripheral portion. FIG. 4C-1 shows an embodiment in which an adhesive is dropped as two radial linear bodies running on a diagonal line of the first substrate 3, and FIG. 4D-1 shows three radial bodies as a whole having a Y shape. In this embodiment, the adhesive is dropped as a linear body. Many other aspects can be taken. The dropped adhesive gradually spreads to the vicinity of the peripheral portion of the first substrate 3, for example, as B-1 → B-2 → B-3 by being left standing.

[0024]

Next, the present invention will be described by way of examples. [Example 1] A thin glass (AF) corresponding to the first substrate 3
45: manufactured by Shott Co., thermal expansion coefficient 45 × 10−7 / ° C.,
Surface plate 2 (AL glass: manufactured by Asahi Glass Co., Ltd., thermal expansion coefficient: 37 × 10 −7 / ° C., thickness: 6.3)
5 mm, 140 mm square, flatness 5 μm or less), and a flat surface plate 2 with the first substrate 3 side facing up.
Was fixed on the spinner 1. Both the surface plate 2 and the first substrate 3 were cleaned and used in a clean bench with a high degree of cleanliness in a clean room in order to prevent the entry of foreign matter and the like at the time of sticking.

Next, the adhesive 4 (Norland 65, Norland Co., viscosity: 1000 [Y]) was formed on the first substrate 3 by using a dispenser (Multipen 4980, manufactured by Eppendorf) as described above. [cps] 23 ° C) was added dropwise. After dropping, a second substrate 5 (blanks (quartz: manufactured by Asahi Glass Co., Ltd., thickness 2.3)
mm, 150 mm square, flatness 5 μm or less)). When the rotary chuck 1 is rotated at a high speed (1000 to 5000 rpm) after being left for a while in this state, the adhesive completely and uniformly spreads over the entire composite substrate. The agent shook off to the periphery without soiling the composite substrate. After the adhesive 4 was cured, the composite substrate was separated from the surface plate 2 using an air blow. The composite substrate 10 was completed through the above steps.

Example 2 FIGS. 4B-1 and 4C- 4 show the dripping of 4 g of the adhesive by the dispenser in Example 1.
1, and performed so as to have a shape shown in FIG. 4D-1. Leave it standing still and allow the adhesive to reach the active area (in this example,
The time (the time until the state shown in FIGS. 4B-3, 4C-3, and 4D-3 is substantially reached) reaching the area of 110 m square in the 150 mm square first substrate was measured. Table 1 shows the results.

[Embodiment 3] 4 g of the adhesive was dropped by the dispenser in the embodiment 1 as shown in FIGS. 4B-1 and 4C-.
1, a second substrate 5 (blanks (quartz: made by Asahi Glass Co., thickness 2.3 mm, 150 mm square, flatness 5 μm) made of Asahi Glass Co., Ltd.) having a shape shown in FIG.
m or less) and left for 4 minutes. Thereafter, the rotating chuck 1 was rotated at a high speed (1000 to 5000 rpm) to shake off excess adhesive, and then irradiated with ionizing radiation to cure the adhesive, thereby completing a composite substrate. For each, the uniformity σ of the adhesive film thickness and the average film thickness were measured. The parallelism between the two substrates was also measured. Table 1 shows the results.
Shown in

[Comparative Example 1] 4 g of the same adhesive at the center of the substrate
4A-1 was dropped in a mountain-like manner as shown in FIG. 4A-1, and thereafter, in the same manner as in Examples 2 and 3, the time required to reach the effective use area, film thickness uniformity, average film thickness, and parallelism were measured. . Table 1 shows the results.

[0029]

[Table 1] (The room temperature at the time of dropping was 22 ° C, and the dropping time was 1
Performed at 0 seconds. The film thickness is 16 within the effective area of 110 mm square.
The points (in a grid pattern) were measured. )

Table 1 shows that the conventional dropping method (FIG. 4A-1)
On the other hand, in the dropping method according to the present invention, it can be seen that the time required for the adhesive to spread is shortened, and that the thickness uniformity and the parallelism of the obtained composite substrate are both improved.

For the measurement of the parallelism, a Fizeau interferometer (Fujinon: Fuji Fix 05) was used. The parallelism is measured by placing the composite substrate on a flat white paper so that information on the reflected light from the bottom surface of the composite substrate can be obtained. The number was counted and the parallelism was calculated. As the measurement position, the number of interference fringes in eight set areas (25H × 35 W [mm]) in the effective area (110 mm square) at the center of the composite substrate was measured. Also, the interference fringe count is
The images were captured as still images in a video printer and counted. The thickness of the adhesive between the two substrates is measured by a surface analysis device (manufactured by Keyence: LT8100, two-point mode).
It measured using.

Example 4 An adhesive of 3.5 g instead of 4 g was dropped on the pattern of FIG.
When the time required to obtain the shape shown in FIG.
2 seconds. This is almost the same time as the time required in the conventional example shown in FIG. 4A-1, and when the composite substrate is manufactured by the manufacturing method of the present invention at the conventional manufacturing speed,
This shows that the required composite substrate can be manufactured with a smaller amount of adhesive. This also shows the effectiveness of the production method of the present invention.

[0033]

According to the present invention, for example, when a composite substrate is manufactured by laminating a thin film coating material via an adhesive to a substrate provided with various functions on the surface thereof, A composite substrate with high thickness uniformity and improved parallelism between two substrates can be manufactured in a shorter time.

[Brief description of the drawings]

FIG. 1 is a view for explaining a manufacturing process of a manufacturing method according to the present invention.

FIG. 2 is a diagram illustrating an embodiment of an adhesive dropping device used in the manufacturing method of the present invention.

FIG. 3 is a block diagram of a system controller of the adhesive dropping device shown in FIG. 3;

FIGS. 4A-1 to 4A-3 are views for explaining a mode of dropping an adhesive onto a first substrate and how the adhesive spreads, and FIGS. 4A-1 to 4A-3 show conventional ones; FIGS. 4B-3, FIG.
FIGS. C-1 to 4C-3 and FIGS. 4D-1 to 4D-3 show an embodiment according to the present invention.

[Explanation of symbols]

1. Spinner, 2. Platen, 3. First substrate (thin plate),
4 adhesive, 5 second substrate, 10 dispenser,
11: Nozzle, 20: 3-axis (XYZ) direction moving stage, 30: Liquid adhesive storage tank, 40: System controller, r: Adhesive drop start position, R: Adhesive drop end position

Claims (5)

[Claims] 1. A step of bringing a first substrate into close contact with a surface plate having a flat surface with a variable rotation speed and improved flatness on its surface, wherein an adhesive is dropped on the first substrate. Process,
Placing the second substrate on the first substrate from above the adhesive, rotating the first and second substrates by rotating the surface plate, and applying the first and second substrates by the action of centrifugal force. A method of manufacturing a composite substrate, comprising sequentially removing an excess adhesive from between two substrates and curing the adhesive, wherein at least two or more adhesives are dropped on the first substrate. A method for manufacturing a composite substrate, wherein the method is performed so as to obtain a linear body. 2. An adhesive is dropped onto the first substrate so as to form at least two or more radial linear bodies from a substantially central position to a peripheral portion of the first substrate. The method according to claim 1, wherein the method is performed. 3. The method according to claim 1, further comprising a step of distributing the dropped adhesive to the vicinity of the peripheral portion between the first and second substrates as a step before the step of removing excess adhesive by rotating the surface plate. 3. The method for manufacturing a composite substrate according to claim 1, wherein: 4. The method according to claim 1, wherein the adhesive is of an ionizing radiation curing type. 5. The method according to claim 1, wherein the second substrate is a functional substrate obtained by laminating a functional material such as an optical film, and the first substrate is a thin film covering material such as a thin glass plate or a film. The method for manufacturing a composite substrate according to any one of claims 1 to 4, wherein: