JP3093747B2 - Abnormal film formation prevention mask - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormal film formation preventing mask, and more particularly to an abnormal film formation preventing mask for preventing an abnormal electric discharge between a mask and a glass substrate.

[0002]

2. Description of the Related Art A conventional example of an abnormal film formation preventing mask will be described below.

First, as a first conventional example, Japanese Patent Application Laid-Open No. 7-3
As shown in FIG. 1 of the publication, the DC magnetron sputtering method and apparatus disclosed in Japanese Patent Publication No. 10181 can eliminate the fluctuation of the plasma density by setting the mask to a floating potential and produce a uniform film on a large-area glass substrate. Is to make it possible. Further, as another embodiment of this publication, a voltmeter is connected to a mask to detect whether a large amount of a conductive film has adhered and has come into electrical contact with the ground electrode or the wall surface of a sputtering chamber. Are also described.

Next, as a second conventional example, Japanese Patent Laid-Open No. 7-2
In the method for forming a conductive film described in Japanese Patent No. 68603, when a conductive film is formed by masking sputtering on a glass substrate having a conductive film formed on the surface, the surface of the mask plate is covered with an insulator. By doing so, abnormal discharge between the mask plate and the glass substrate is not generated.

Next, a third conventional example is disclosed in
The method disclosed in Japanese Patent No. 12962 is a method of insulating a substrate holder and a mask from a ground potential so that an abnormal discharge between the mask and the glass substrate is not generated even when discharging with a large power.

Next, as a fourth conventional example, Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. 91237 describes a method in which an insulating film is formed on a mask and formed by vapor deposition, sputtering, or the like.

Next, as a fifth conventional example, Japanese Patent Laid-Open Publication No.
The method described in Japanese Patent No. 264174 discloses a method in which a DC voltage is applied to a substrate while applying a bias voltage to improve the step coverage of a thin film formed on the substrate or to form a film while removing contaminants having weak bonding by sputtering. In the bias sputtering method, the bias voltage applied to the substrate is grounded at a periodic level in order to prevent abnormal discharge caused by charging of the film on the glass substrate when the film on the substrate is an insulator. This is a method of forming a film by returning to a voltage.

Next, as a sixth conventional example, Japanese Patent Laid-Open No.
Japanese Patent No. 41686 describes a bias sputtering method in which a bias voltage is applied to a substrate to perform sputtering in the same manner as in the fifth conventional example.

[0009]

However, the above-mentioned prior art has the following problems.

First, in the first conventional example, the floating potential of the mask and the floating potential of the glass substrate are not always the same. This is because the region where the glass substrate exists in the plasma and the region where the mask exists in the plasma are different depending on the electric capacity of the mask, the size of the mask, and sputtering conditions. Due to this potential difference, abnormal discharge occurs between the glass substrate and the mask. further,
When the glass substrate comes into contact with the mask, electrical contact occurs there. When the contact is local, a large current flows locally, and abnormal film formation occurs on the glass substrate. The contact between the glass substrate and the mask is due to internal stress of a thin film formed on the glass substrate or warpage due to heating of the glass substrate. As a means for avoiding this, a sufficient gap (distance) between the mask and the glass substrate may be ensured, and the third embodiment of the gazette also states that it can be installed farther than the substrate. However, if a sufficient gap is provided between the glass substrate and the mask, the sputtered particles accumulate on almost the entire surface of the glass substrate and even on the end surface of the glass substrate. For this reason, it is difficult to limit a predetermined film formation region using a mask. Furthermore, when processing the glass substrate formed up to the end surface with the next process equipment such as a cleaning device, the thin film formed by sputtering from the glass substrate end surface is used because the alignment mechanism of the glass substrate comes into contact with the glass substrate end surface. There is a possibility of peeling. The peeled thin film remains as dust in the cleaning device or reattaches as dust on the substrate, which causes a problem of causing a transistor defect.

In the method of forming a conductive film according to the second conventional example, sputtered particles are deposited on a mask plate whose entire surface is covered with an insulator, and a conductive film is formed on the mask surface. You. This conductive film is charged by the plasma, and has a floating potential because it is insulated from the mask plate by an insulating coating. As described above, the glass substrate also has a floating potential. The floating potential of the conductive film on this mask plate,
The floating potential of the glass substrate is not the same as in the first conventional example. Therefore, abnormal discharge occurs between the conductive film on the mask plate and the glass substrate.

Further, in the second conventional example, there is another problem as follows. That is, since the conductive film is deposited on the insulating film of the mask plate, peeling of the film from the mask plate is likely to occur depending on the type of the conductive material, and the interval of the periodic maintenance is short. The peeled film is taken in as dust during sputtering, and deteriorates the quality of the thin film. The surface treatment that is usually performed to prevent film peeling and lengthen the regular maintenance interval is a thermal spray treatment of Al or Cu or a blast treatment, which means that an insulating film cannot be formed.

Further, in the third conventional example, since the vacuum vessel connected to the ground functions as an anode, the mask and the substrate holder can be set at a floating potential. However, in the case of a configuration in which the mask functions as an anode, Difficult to apply. The reason is that if there is no anode, the substrate holder and the mask that are insulated from the ground potential are charged by the flowing electrons, and the amount of charge is determined by the electric capacity of the member itself. This is because the mask does not accept the inflow of the electrons having the electric capacity or more, and eventually, the electrons are surplus in the plasma and the discharge is stopped.

Further, in the fourth conventional example, as in the second conventional example, there is a problem that an abnormal discharge occurs between the conductive film on the mask plate and the glass substrate.

Further, the method of the fifth conventional example is applicable only when there is no mask or the like for limiting a film formation region between a substrate and a target. If a mask is provided and the mask is at ground potential, a potential difference occurs between the substrate and the mask whether the potential of the substrate is at a bias voltage or at a ground potential. Even when the mask has a floating potential, the electric capacity of the mask,
Alternatively, the floating potential of the mask does not match the potential of the substrate because the region where the substrate exists in the plasma and the region where the mask exists in the plasma differ depending on the size of the mask and the conditions of sputtering. Since the mask is arranged near the substrate in order to limit the film formation region, abnormal discharge occurs due to a potential difference between the substrate and the mask. As described above, there is a problem that the method cannot be applied when a mask for limiting a film formation region is used.

Further, the sixth conventional example, like the fifth conventional example, has a problem that it cannot be applied to the case where a mask for limiting a film formation region is arranged between a substrate and a target to form a film. is there. The reason for this is that, similarly to the fifth conventional example, even when a mask is arranged and film formation is performed, an abnormal discharge occurs because a potential difference occurs between the substrate and the mask.

Accordingly, an object of the present invention is to provide an abnormal film formation preventing mask capable of preventing an abnormal electric discharge occurring between a mask plate and a glass electrode in order to solve the above problem.

[0018]

In order to achieve the above object, an abnormal film formation preventing mask according to the present invention comprises a semiconductor, an LCD and the like.
(Liquid Crystal Display), PDP (Plasma Display Panel) An abnormal film formation prevention mask that prevents abnormalities when a conductive film is formed on a glass substrate by a sputtering device used in the manufacturing process . A first mask arranged to face a target serving as a base material, for limiting a film formation region to a predetermined region, and a first mask arranged near the glass substrate using the first mask as an earth electrode. A second mask, and applying a bias voltage to the second mask while controlling the bias so that the second mask and the glass substrate have the same potential, thereby preventing abnormal discharge occurring between the second mask and the glass substrate. It is characterized by having done.

Preferably, the second mask is fixed to the first mask via an insulator.

Further, the target is a negative electrode of a DC power source,
Preferably, the first mask is connected to ground.

Preferably, a dedicated bias power supply is connected to the second mask.

Furthermore, the second mask and the glass substrate
It is preferable that the glass substrate is disposed with a gap of 1 mm or less so that a thin film is not formed on the end face of the glass substrate.

Further, it is preferable that there is no gap between the second mask and the glass substrate.

Further, a region on the glass substrate where a film is to be formed and a second
And an oscilloscope for measuring a floating potential of the glass substrate and the second mask to set a bias voltage.

Applying the present invention described above, for example, L
In a CD manufacturing process, a sputtering apparatus is used for forming a thin film such as a conductive film or an insulating film on a glass substrate. In particular, in the case of the TFT method, the conductive film functions as a liquid crystal driving electrode or a gate and drain wiring of a transistor formed for each pixel formed on a glass substrate. The thin film formed by sputtering is formed over almost the entire area of the glass substrate. If the thin film has minute defects or the like, defects such as disconnection or short circuit of the gate wiring and the drain wiring are generated as LCD panels. The fine defects in this thin film are caused by abnormal discharge generated during sputtering,
It is caused by dust and the like inside the vacuum chamber taken into the thin film. When a larger LCD panel is to be manufactured in a glass substrate having a limited size, the pixels of the LCD panel are configured up to the size of the glass substrate. At this time, the conductive film formed by sputtering is required to be a thin film having no abnormal film formation up to the limit of the size of the glass substrate, and a non-film formation region of several mm around the substrate is required. this is,
For the following reasons: When a film is formed by sputtering, sputtered particles are deposited not only on the surface of the glass substrate but also on the end surface of the glass substrate. When the glass substrate formed up to the end face is processed in the next step such as a cleaning apparatus, an impact is applied to the end face of the glass substrate by an alignment mechanism of the glass substrate, and a thin film may be peeled off from the end face of the glass substrate. The peeled thin film remains as dust in the cleaning device or re-adheres as dust on the glass substrate, thereby causing transistor defects. The present invention is applied to the case where a thin film having no abnormal film formation trace is almost formed by sputtering as described above.

[0026]

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

An embodiment of the abnormal film formation preventing mask of the present invention will be described in detail with reference to FIGS. FIG.
FIG. 2 is a schematic view showing an entire configuration of an embodiment of an abnormal film formation preventing mask of the present invention, FIG. 2 is a perspective view showing a detailed configuration of the embodiment of the present invention, and FIG. FIG.

As shown in FIG. 1, the components of the mask for preventing abnormal film formation of the present invention include a target 2 serving as a base material of a thin film on the surface of a glass substrate in a vacuum chamber 1 and a cooling mechanism for fixing the target 2. A target back plate 3, a mask A (first mask) 4 located opposite to the target 2 and serving as an anode, and a mask B (second mask) fixed to the mask A 4 via an insulator 10 There are five. Glass substrate 6
Is placed on a substrate holder 7 made of an insulating material. The target 2 and the mask A4 are arranged so as to face each other,
As shown in FIG. 2, the negative electrode of the DC power supply 8 is connected to the target 2, and the mask A4 is connected to the ground. Ar gas can be introduced into the vacuum chamber 1, and 10 ^-1 Pa
When a voltage is applied to the target 2 from the DC power supply 8 in a pressure range of the order, a sputtering phenomenon occurs using the mask A4 as an anode. The mask B4 is attached to the mask A4 via the insulator 10. The mask B5 is provided with an opening for restricting a predetermined film formation region, and the glass substrate 6 is arranged so as to face the target 2 with the mask B5 interposed therebetween. By exposing the surface, a conductive film is formed on the glass substrate 6 in a form in which the film formation region is limited. At this time, the glass substrate 6 and the mask B5 are arranged with a gap of 1 mm or less so that a thin film is not formed on the end surface of the glass substrate 6. As shown in FIGS. 2 and 3, a dedicated bias power supply 9 is connected to the mask B5. The bias power supply 9 can control an arbitrary voltage on a time axis. The voltage can be applied only to the mask B5 by being fixed to the mask A4 via. During sputtering, an arbitrary voltage controlled on the time axis is applied to the mask B5 from the bias power supply 9 so that the floating potential of the glass substrate 6, which is an insulator, and the potential of the mask B5 are set to the same potential. In addition, film deposition due to sputtering occurs on the mask A4, and as the film deposition accumulates, the film on the mask peels off. This film peeling exists as dust in the vacuum chamber 1, and if it is taken in as a foreign substance in the thin film on the glass substrate 6, it causes a transistor defect. To prevent this, the surface of the mask is subjected to thermal spraying treatment of Al, Cu or the like or blasting treatment according to the type of the conductive film, thereby realizing a longer regular maintenance interval.

[0029]

Next, an embodiment of the present invention will be described in detail with reference to FIGS. In this example, the glass substrate 6 is transferred to the vacuum chamber 1 described in the configuration of the above-described embodiment by a vacuum robot or the like. The transported glass substrate 6 is placed on the substrate holder 7 and the mask B5 and 1 m
m. This vacuum tank 1
Is supplied with Ar gas and maintained at a pressure of the order of 10 ^-1 Pa. When a high voltage is applied to the target 2 from the DC power supply 8 in this pressure state, plasma is generated using the target 2 as a cathode and the mask A4 as an anode, and target particles are sputtered from the target 2. The sputtered particles adhere to the surface of the glass substrate 6 at the opening of the mask A4 or B5. The region of the particles adhering on the glass substrate 6 in this manner is only the portion of the opening of the mask B5 that wraps around from the gap of 1 mm or less between the glass substrate 6 and the mask B5. 6 can be limited. During this sputtering, the bias power supply 9 connected to the mask B5 applies an arbitrary voltage to the mask B5 along a time axis according to preset conditions.

FIG. 4 is a schematic diagram showing conditions for setting a bias power supply in the embodiment of the present invention. The conditions for setting the bias power supply 9 in FIG. 3 are as follows: the oscilloscope 11 is connected to the region on the glass substrate 6 where the film is to be formed and the mask B5, and the film is formed under the necessary sputtering conditions in this state. The potential of the glass substrate 6 and the potential of the mask B5 during the sputtering are measured. Since the glass substrate 6 is an insulator and the mask B5 is connected to the mask A4 via the insulator 10, the oscilloscope measures these two floating potentials. Since these two floating potentials vary depending on the sputtering conditions (pressure, voltage applied to the target 2, etc.) or the size of the mask B5 (region existing in the plasma), they cannot be expressed as fixed values. The potential can be known by forming a film with the above-described configuration. According to our known data, an example in which the potential of the mask B5 during film formation is 4 to 12 V and 50
And an example of 63V. The known potential of the glass substrate 6 during film formation is set as a condition of the bias power supply 9 in accordance with a change in the time axis. When sputtering is performed in the configuration of the embodiment with the condition of the bias power supply 9 set, the floating potential on the glass substrate 6 and the potential of the mask B5 can be made the same. Here, the potential between the glass substrate 6 and the mask B5 will be described in detail below.

In general, since the glass substrate 6 is an insulator, it becomes a floating potential and is charged by plasma. The mask A4 connected to the ground has the ground potential even in the plasma, but the mask B5 fixed to the mask A4 via the insulating material has the floating potential similarly to the glass substrate 6. However, the potential of the region where the glass substrate 6 exists in the plasma and the region where the mask B5 exists in the plasma differ depending on the potential of the mask B5 and the conditions of the sputtering. Therefore, the floating potentials of the glass substrate 6 and the mask B5 are not always the same, and a potential difference occurs. As long as this potential difference exists, abnormal discharge occurs between the glass substrate 6 and the mask B5.

However, in the present invention, the potential of the glass substrate 6 and the potential of the mask B5 are made equal by the voltage applied from the bias power supply 9 connected to the mask B5. in this way,
By applying the same voltage as the floating potential of the glass substrate from the bias power supply connected to the mask B to the mask B near the glass substrate, abnormal discharge occurring between the glass substrate during film formation and the mask B can be prevented. That is, the mask B
And the glass substrate have the same potential, it is possible to prevent abnormal discharge occurring between the mask B and the glass substrate.

In general, the thin film on the glass substrate 6 generates a compressive stress and a tensile stress depending on the type of the thin film or the sputtering conditions. This stress causes the glass substrate 6 to warp, so that a gap of 1 mm or less between the glass substrate 6 and the mask B5 cannot be maintained. The mask B5 is made of metal and has been subjected to a surface treatment such as thermal spraying or blasting to prevent the film from peeling off, so that the glass substrate 6 and the mask B5 come into local contact. At this time, if there is a potential difference between the glass substrate 6 and the mask B5, a current flows through a contact portion between the glass substrate 6 and the mask B5. Since the current path is local, a large current is generated and an abnormal film formation mark is generated on the thin film. .

However, in the present invention, since the potential of the glass substrate 6 and the potential of the mask B5 are set to the same potential, no current flows even if they are locally contacted. Accordingly, the potential of the mask B5 and the potential of the glass substrate 6 are set to the same potential, so that the glass substrate 6 warps due to internal stress generated by a thin film formed on the glass substrate 6, and the glass substrate 6 and the mask B5 are locally localized. Even when contact is made, current does not flow at the contact portion, and it is possible to prevent an abnormal film formation mark of the thin film caused when the current flows.

Next, another embodiment of the present invention will be described.

In the above-described embodiment, the size of the mask B5 is not specified, but the size is not particularly limited. In particular, regarding the condition of the bias power supply, the DC power supply 8
Can be used as control information of the condition of the bias power supply 9 using the information on the change of the discharge voltage obtained from the above.

In order to improve the accuracy of the area of the thin film formed on the glass substrate 6, the gap between the glass substrate 6 and the mask B5 can be made zero.

[0038]

As described above, according to the present invention, by applying the same voltage as the floating potential of the glass substrate from the bias power supply connected to the mask B to the mask B near the glass substrate, Abnormal discharge generated between the substrate and the mask B can be prevented. That is, since the potential of the mask B and the potential of the glass substrate are set to the same potential, the mask B
This has the effect that abnormal discharge occurring between the glass substrate and the glass substrate can be prevented.

Further, since the potential of the mask B and the potential of the glass substrate are set to the same potential, the glass substrate warps due to internal stress generated by a thin film formed on the glass substrate, and the glass substrate and the mask B come into local contact. However, there is an effect that the current does not flow at the contact portion, and an abnormal film formation mark of the thin film generated when the current flows can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a perspective view showing a detailed configuration of the embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a configuration of an embodiment of the present invention.

FIG. 4 is a schematic diagram showing a method for determining a condition for setting a bias power supply.

[Explanation of symbols]

 Reference Signs List 1 vacuum tank 2 target 3 target back plate 4 mask A (first mask) 5 mask B (second mask) 6 glass substrate 7 substrate holder 8 DC power supply 9 bias power supply 10 insulating material 11 oscilloscope

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 H01L 21/285 G02F 1/1343

Claims (7)

(57) [Claims] 1. Semiconductor, LCD (Liquid Crystal Display), P
Used in DP (Plasma Display Panel) manufacturing process
An abnormal film formation preventing mask for preventing an abnormality when a conductive film is formed on a glass substrate by a sputtering apparatus to be formed, wherein the mask is disposed so as to face a target serving as a base material of a thin film on the surface of the glass substrate, and A first mask for limiting an area to a predetermined area; and a second mask using the first mask as a ground electrode and disposed near the glass substrate. Wherein the second mask and the glass substrate are made to have the same potential by applying a bias voltage while controlling the bias voltage, thereby preventing abnormal discharge occurring between the second mask and the glass substrate. Film formation prevention mask. 2. The abnormal film formation preventing mask according to claim 1, wherein said second mask is fixed to said first mask via an insulator. 3. The method according to claim 1, wherein the target is connected to a negative electrode of a DC power supply, and the first mask is connected to ground.
The abnormal film formation preventing mask according to claim 1. 4. The abnormal film formation preventing mask according to claim 1, wherein a dedicated bias power supply is connected to said second mask. 5. The method according to claim 1, wherein the second mask and the glass substrate are
It is arranged with a gap of 1 mm or less, characterized in that a thin film is not formed on the end face of the glass substrate,
The abnormal film formation preventing mask according to claim 1. 6. The second mask and the glass substrate,
The abnormal film formation preventing mask according to any one of claims 1 to 4, wherein the mask does not have a gap. 7. An oscilloscope connected to an area on the glass substrate on which a film is to be formed and the second mask, and for measuring a floating potential of the glass substrate and the second mask to set the bias voltage. The abnormal film formation preventing mask according to any one of claims 1 to 6, further comprising: