WO2006054406A1

WO2006054406A1 - Electrostatic chuck for vacuum bonding system

Info

Publication number: WO2006054406A1
Application number: PCT/JP2005/018678
Authority: WO
Inventors: Yoshikazu Ohtani; Takeshi Shima
Original assignee: Shin-Etsu Engineering Co., Ltd.; Tomoegawa Paper Co., Ltd.
Priority date: 2004-10-29
Filing date: 2005-10-11
Publication date: 2006-05-26
Also published as: TW200631120A; JP2008027927A

Abstract

Disclosed is an electrostatic chuck (A) for suction-holding a glass substrate (B) wherein the thickness (T) of a dielectric layer (1b) is set at 50-200 μm, the width (L) of electrodes (1a) is set at 0.5-1.5 mm, and the interval (S) between the electrodes (1a) is set at 0.5-1.5 mm.

Description

Specification

Electrostatic chuck for vacuum bonding equipment

Technical field

[0001] In the present invention, glass substrates such as CF glass and TFT glass are adsorbed and held in a vacuum during the manufacturing process of flat panel displays such as liquid crystal displays (LCDs) and plasma displays (PDPs). The present invention relates to an electrostatic chuck for a vacuum bonding apparatus used for bonding.

More specifically, the present invention relates to an electrostatic chuck for a vacuum bonding apparatus that includes two or more electrodes and a dielectric layer that covers the electrode, and holds the dielectric layer in vacuum in contact with a glass substrate by suction. Background art

Conventionally, in this type of electrostatic chuck for a vacuum bonding apparatus, as a means for holding and transporting a liquid crystal glass substrate, Cu is vacuum-deposited on the entire surface of a glass substrate by about 0.3 m, By photoetching, pattern width of the width dimension (line width) of the two-pole comb-shaped electrodes is 80 m, and the interval between the comb-shaped electrodes (pitch) is 200 μm, and then the acid is deposited by aerosol deposition method. The dielectric layer (dielectric layer) of aluminum is deposited to 10 m, or the thickness of the dielectric layer of aluminum oxide, silicon oxide, polyimide, etc. is reduced by CVD, so that it is higher at a lower voltage. The ability to generate an attractive force or the thickness of a dielectric layer such as acid-aluminum or silicon-oxide silicon by the ion plating method has been reduced, enabling higher adsorptive power to be generated at a lower voltage. There is something (eg See Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-273194 (Page 2-3, Figure 1-Figure 2)

Disclosure of the invention

Problems to be solved by the invention

[0004] However, such a conventional electrostatic chuck for a vacuum bonding apparatus can obtain a high electrostatic adsorption force because the dielectric layer is thin (10 m), but its physical strength is extremely low. When the surface of the dielectric layer is brought into contact with the glass substrate and held by adsorption, if foreign matter enters between the two by adhering to the surface of the glass substrate, the static electricity generated around the foreign material is generated. As a result, the surface of the thin dielectric layer is absorbed by the adsorption force. In addition to scratching the surface, there was a problem that the electrostatic adsorption function part was easily damaged by damaging the electrode.

If a pair of upper and lower glass substrates are attracted and held with such a conventional electrostatic chuck and pressed close together in a vacuum, the electrode will be exposed due to scratches caused by foreign objects, and if the electrode is energized in this state, There was also a problem that plasma discharge was caused at a certain timing in a vacuum, and damage to the glass substrate led to a decrease in electrostatic adsorption power.

Further, in the conventional electrostatic chuck for vacuum bonding apparatus, the comb electrode has a narrow width dimension (

80 m), electric field concentration occurs, causing breakdown and increased possibility of breakage, and the distance between the electrodes is narrow (200 m), resulting in high electrostatic attraction force. Therefore, there is a problem that the yield is high and the reliability is inferior because the dielectric breakdown is high.

[0005] Of the present invention, the invention described in claim 1 is intended to achieve stable adsorption holding while preventing damage to the electrostatic adsorption function part due to the penetration of foreign matter.

The inventions described in claims 2 and 3 are intended to achieve stable adsorption and retention while preventing accidents such as dielectric breakdown and disconnection.

Means for solving the problem

In order to achieve the above-mentioned object, the invention according to claim 1 of the present invention is characterized in that the thickness dimension of the dielectric layer is 50 to 200 μm.

The invention described in claim 2 is characterized in that the electrode has a two-pole comb-like structure, and the width dimension of the comb-teeth electrode is 0.5 to 1.5 mm.

The invention described in claim 3 is characterized in that the electrode has a two-pole comb-teeth structure, and the interval between the comb-teeth electrodes is set to 0.5 to 1.5 mm.

Here, the above-described electrostatic chuck for a vacuum bonding apparatus is provided on both or only one of the opposing surfaces of a pair of upper and lower holding plates, and holds and opposes the glass substrates so that the two glass substrates are vacuumed. An electrostatic chuck used in a vacuum laminating device that presses close together.

The invention's effect

[0007] Among the present inventions, the invention according to claim 1 is characterized in that the smaller the thickness dimension of the dielectric layer, the electrostatic adsorption Although the force increases, the physical strength becomes extremely weak at less than 50 m, and the electrode is exposed due to the penetration of foreign matter between the glass substrate and may cause plasma discharge at a certain timing in the vacuum. On the other hand, if the thickness is greater than 200 m, the electrostatic adsorption force decreases, so even if an adsorption force exceeding the weight of the glass substrate is obtained, the airflow generated around it and the glass substrate The thickness of the dielectric layer is set to 50 to 200 μm because there is a risk of falling due to variations in adsorption force.

Therefore, it is possible to achieve stable adsorption holding while preventing damage to the electrostatic adsorption function part due to the stagnation of foreign matter.

As a result, because the dielectric layer is too thin, the electrostatic adsorption function part is likely to be damaged due to the penetration of foreign matters.Damage to the glass substrate due to plasma discharge can prevent the decrease in electrostatic adsorption force compared to the conventional one. Durability is improved and it can be used for a long period of time, improving reliability.

[0008] In the invention of claim 2, if the width dimension of the comb-shaped electrode is narrower than 0.5 mm, electric field concentration occurs, and there is a high possibility of dielectric breakdown or disconnection. If the width is larger than mm, the total amount of the bipolar electric field that becomes the root of the attractive force will decrease, and the electrostatic attractive force will decrease and may fall. Therefore, the width of the comb-shaped electrode was set to 0.5 to 1.5 mm. .

Therefore, stable adsorption retention can be achieved while preventing accidents such as dielectric breakdown and disconnection.

As a result, the width of the comb-shaped electrode is too narrow, and electric field concentration occurs, resulting in the possibility of dielectric breakdown or wire breakage. The yield and reliability can be improved compared to conventional ones.

[0009] In the invention of claim 3, when the distance between the comb-shaped electrodes is narrower than 0.5 mm, a large adsorption force can be obtained, but the voltage difference between adjacent ones is large, and therefore dielectric breakdown or disconnection may occur. On the contrary, if the distance is less than 1.5 mm, the electrostatic attractive force decreases and there is a risk of dropping, so the interval between the comb-shaped electrodes was set to 0.5 to 1.5 mm.

As a result, the gap between the comb-shaped electrodes is too narrow, resulting in electric field concentration and dielectric breakdown. Yield and reliability can be improved compared to conventional products that have a high possibility of occurrence of breakage or disconnection.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In this embodiment, as shown in FIGS. 1 (a) and 1 (b), an electrostatic chuck A force electrode 1 for a vacuum bonding apparatus according to the present invention has an electrostatic adsorption function unit 1 in which a dielectric layer lb is laminated on the surface of a la. This shows a case of a plate-like laminated structure comprising a base material layer 2 provided on the back surface side of the electrode la and a pedestal member 3 bonded to the back surface of the base material layer 2.

[0011] The electrode la has a two-pole comb-teeth structure, and the width dimension L of the comb-teeth electrode la and the interval S between the comb-teeth electrodes la are set within a predetermined range (experimental force described later). By setting the distance within the range of 0.5 to 1.5 mm, it is preferable to prevent accidents such as dielectric breakdown and disconnection and achieve good adsorption and holding of the glass substrate (insulating substrate) B at the same time.

[0012] On the back surface side of the electrode la, a base material layer 2 is provided so as to cover the electrode la with an adhesive layer 2a such as an adhesive material or an adhesive in between. For example, the surface of the base member 3 formed in a plate shape with a hard insulating material such as engineering plastic or ceramics or a metal such as aluminum is attached with an adhesive layer 4 such as an adhesive or adhesive sandwiched between them. It is done.

[0013] The dielectric layer lb and the base material layer 2 will be described later by using a cushioning organic material such as polyimide, polyetheretherketone (PEEK), polyethylene naphthalate (PEN) or the like as the main constituent material. In the pressing process of the vacuum bonding apparatus, for example, damage to the glass substrate B such as TFT glass or CF glass is reduced as much as possible, and at least the thickness dimension T of the dielectric layer lb is determined within a predetermined range (about approximately) By setting the distance within the range of 50 to 200 μm, it is preferable to simultaneously prevent damage to the electrostatic chucking function part 1 due to foreign material penetration and to hold the glass substrate B well.

[0014] The electrostatic chuck A is a holding plate C, D which is a force such as a surface plate arranged opposite to the vertical direction in a vacuum bonding apparatus for manufacturing a liquid crystal display or a plasma display, for example. It is incorporated by attaching to almost the entire surface or part of only one or both of the opposite surfaces of the electrostatic chuck A, and the electrostatic chuck A is made of, for example, TFT glass or CF glass. The glass substrate B is sucked and held so as to face each other, and the two substrates B and B are adjusted and moved relative to each other in the XY 0 direction, and then they are brought into close contact with each other in a vacuum.

In the case of the illustrated example, each electrostatic chuck A as shown in FIGS. 1 (a) and 1 (b) is formed in a rectangle smaller than the size of the glass substrate B, and is formed on the opposing surfaces of the upper and lower holding plates C and D. For both, a plurality of electrostatic chucks A are arranged in parallel with each other close to each other, and each surface is arranged in a plane so that pressure unevenness does not occur. Divide and hold the entire surface of a large glass substrate B, B over 1000mm in size!

Further, an example of the mounting structure of each electrostatic chuck A, upper and lower holding plates C and D will be described. On the back surface of each electrostatic chuck A, an input terminal (not shown) communicating with the electrode la is provided. ) Is exposed, and on the opposite surface side of the upper and lower holding plates C and D, there is an output terminal (not shown) on the device side that leads to the high voltage power supply and the input terminal of each electrostatic chuck A By placing each electrostatic chuck A detachably on the opposing surface side of the upper and lower holding plates C, D with, for example, bolts and screws, the input terminals and the output terminals are in contact with each other. Apply a high voltage to the electrode la of each electrostatic chuck A!

[0017] The operation of the above-described vacuum bonding apparatus will be described in detail with reference to the illustrated example. The upper and lower static plates disposed on the opposing surfaces of the upper and lower holding plates C and D in the atmosphere as indicated by the solid line in FIG. The two glass substrates B and B are attracted and held on the electric chucks A and A, respectively, and the closed space E that can be opened and closed vertically is moved between the upper and lower substrates B and B by the close movement of the upper and lower holding plates C and D. After the inside of this closed space E reaches a predetermined degree of vacuum, the upper and lower holding plates C and D and the electrostatic chucks A and A are relatively adjusted and moved in the ΘΘ direction. The upper and lower substrates B and B are aligned with each other.

[0018] After that, as shown by the two-dot chain line, the upper and lower holding plates C and D are brought closer to each other or the upper substrate B is forcibly separated from the upper electrostatic chuck A and the annular adhesive on the lower substrate B ( (Seal material) By momentarily pressing on F, the liquid crystal is sealed and overlapped between the two, and then the atmosphere in the closed space E is returned to atmospheric pressure, so that the inside and outside of both substrates B and B The bonding process is completed by pressurizing between the substrates B and B to a predetermined gap by the generated pressure difference.

[0019] Next, in order to obtain favorable adsorption conditions by the electrostatic chuck A, the thickness of the dielectric layer lb An electrostatic chuck with a dimension T of 40 to 210 / zm, an electrostatic chuck with a width L of the comb-shaped electrode la and an interval S between the comb-shaped electrodes la of 0.4 to 1.6 mm are prepared for the liquid crystal substrate. Tables 1 to 3 below show the results of adsorption experiments on CF glass with color filters, TFT glass with TFT elements, and basic glass used for testing.

[0020] [Table 1]

* Silent adsorption force (mN) at CF glass, applied voltage (5kV)

[0021] [Table 2]

* Electrostatic adsorption force (mN) at TFT glass, applied voltage (5kV)

[0022] [Table 3] * Silent adsorption force (mN) at bare glass, applied voltage (5kV)

[0023] In this adsorption experiment, test glasses of the same size (diameter 200 mm) were made from the CF glass, TFT glass, and raw glass, and these test glasses were brought into contact with the respective electrostatic chucks and pulled up under the same conditions. The electrostatic attraction force was measured sequentially.

Force measured when applying 3kV voltage, 5kV voltage, and 7kV voltage applied to comb electrode la as the above measurement conditions. Therefore, only the measurement data with an applied voltage of 5 kV is shown here.

[0024] Table 1 shows the electrostatic adsorption force (unit: mN) when the test glass having CF glass force is pulled up by each electrostatic chuck.

Table 2 shows the electrostatic attraction force (unit: mN) when the test glass with TFT glass force is pulled up by each electrostatic chuck.

Table 3 shows the electrostatic adsorption force (unit: mN) when the test glass, which has a glass strength, is pulled up by each electrostatic chuck.

[0025] As a result, regarding the thickness dimension T of the dielectric layer lb, the electrostatic attraction force increases as the thickness decreases, but the physical strength of the dielectric layer lb becomes extremely weak when it is a very thin film of less than 50 m. It was solved by the experiment.

That is, when the dielectric layer lb becomes a very thin film having a thickness of less than 50 m, when the surface of the dielectric layer lb is brought into contact with the glass substrate B to be adsorbed and held, even if a minute foreign matter is present between the two, If it enters the surface, for example, by adhering to the surface, the electrostatic adsorption force generated around this foreign material squeezes into the dielectric layer lb, and the surface of the thin dielectric layer lb is damaged. If the electrode la is exposed and the electrode la is energized in this exposed state, it may cause a plasma discharge at a certain timing in the vacuum. For this reason, electrostatic chuck A cannot be used in a pressure region where discharge is easily caused by a Noschen curve.

[0027] On the contrary, the thickness dimension T of the dielectric layer lb T force ¾00 m thicker, the strength increases. The electrostatic adsorption force decreases, so the adsorption force more than the weight of the glass substrate B. Even if is obtained, the closed space E force may drop due to variations in airflow and suction force during evacuation. For this reason, the thickness T of the dielectric layer lb is suitably about 50 to 200 / ζ πι.

[0028] Furthermore, with regard to the width dimension L of the comb-shaped electrode la, an adsorption force greater than the weight of the glass substrate B can be obtained in the range of 0.5 to 1.5 mm, but when it becomes narrower than 0.5 mm, electric field concentration occurs. There is a high possibility of dielectric breakdown and disconnection.

[0029] On the contrary, the width of the comb-shaped electrode la is larger than 1.5 mm, and the total amount of the two-pole electric field that is the source of the attractive force decreases, so that the electrostatic attractive force decreases and the glass substrate B Even if an adsorption force greater than its own weight is obtained, there is a risk of falling due to the air current generated around it when vacuuming or variations in the adsorption force to the glass substrate B.

[0030] As for the spacing S between the comb-shaped electrodes la, an adsorption force equal to or greater than the self-weight of the glass substrate B is obtained in the range of 0.5 to 1.5 mm. If it is narrower than 0.5mm, the voltage difference between adjacent ones is large because of the bipolar type, so there is a high possibility of dielectric breakdown or disconnection.

[0031] On the other hand, when the distance S between the comb-shaped electrodes la is more than 1.5 mm, the electrostatic attractive force is reduced, and even if an attractive force that is greater than the weight of the glass substrate B is obtained, it is generated around it. There is a risk of falling due to the air current during the vacuum bow I or the fluctuation of the adsorption power to the glass substrate B.

[0032] For this reason, the width dimension L of the comb-shaped electrode la and the interval S between the comb-shaped electrodes la are appropriately about 0.5 to 1.5 mm, which is equivalent to the electrode pattern formation process. is there.

[0033] As long as the force is within the above-mentioned predetermined range, even glass glass used as a glass substrate B, which is often used for liquid crystal substrates, such as CF glass or TFT glass, is almost equivalent. Can be adsorbed with adsorption power

This is the reaction of the functional surface of the glass substrate B, that is, the surface that is in suction contact with the electrostatic chuck A. This means that a strong electrolysis force S is not applied to the opposite side, and there is little influence on the glass functional surface. Even in production using an actual vacuum bonding device, device failure due to this defect does not occur.

[0034] It should be noted that in the previous embodiment, the force shown in the case where the electrostatic chuck A for the vacuum bonding apparatus is a bipolar electrostatic chuck having the two-pole comb-teeth electrode la is limited to this. Alternatively, the electrode la may be other than the comb-tooth type or two or more electrodes.

Furthermore, although the base layer 2 and the pedestal member 3 are sequentially bonded to the back side of the electrostatic adsorption function unit 1 composed of the electrode la and the dielectric layer lb, the plate-like laminated structure is not limited, If at least the electrostatic attraction function unit 1 exists, other structures such as integration of the base member 3 and the holding plates C and D of the vacuum bonding apparatus may be used.

In the illustrated example, a plurality of electrostatic chucks A are arranged in parallel on the opposing surfaces of the upper and lower holding plates C and D, but are not limited to this. One electrostatic chuck A may be disposed over substantially the entire facing surface.

Furthermore, the method of applying a high voltage to the electrode la of the electrostatic chuck A is not limited to the above-described method, and other energization methods may be used.

Brief Description of Drawings

[0036] [Fig. 1] (a) is a longitudinal sectional view of an electrostatic chuck for a vacuum bonding apparatus showing an embodiment of the present invention, and (b) is a cross-sectional plan view showing an enlarged main part. It is.

Explanation of symbols

[0037] A electrostatic chuck B glass substrate

C, D Retaining plate E Closed space

F Ring adhesive L Electrode width dimension

S Spacing between electrodes T Dielectric layer thickness

1 Electrostatic adsorption function part la electrode (comb-shaped electrode)

lb Dielectric layer 2 Base material layer

2a Adhesive layer 3 Base

4 Adhesive layer

Claims

The scope of the claims

[1] Vacuum bonding with two or more electrodes (la) and a dielectric layer (lb) covering them, and holding the dielectric layer (lb) in contact with the glass substrate (B) in vacuum In the electrostatic chuck for equipment,

An electrostatic chuck for a vacuum bonding apparatus, wherein a thickness dimension (T) of the dielectric layer (lb) is 50 to 200 m.

[2] Vacuum bonding that includes two or more electrodes (la) and a dielectric layer (lb) covering them, and holds the dielectric layer (lb) in contact with the glass substrate (B) in vacuum. In the electrostatic chuck for equipment,

The electrode (la) has a two-pole comb-teeth structure, and the width dimension (L) of the comb-teeth electrode (la) is set to 0.5 to 1.5 mm. Electric chuck.

[3] Vacuum bonding with two or more electrodes (la) and a dielectric layer (lb) covering them, and holding the dielectric layer (lb) in contact with the glass substrate (B) in vacuum In the electrostatic chuck for equipment,

The electrostatic chuck for a vacuum bonding apparatus, wherein the electrode (la) has a two-pole comb-teeth structure, and the interval (S) between the comb-teeth electrodes (la) is 0.5 to 1.5 mm. .