JP7752410B2 - Scribing method for bonded brittle substrates having terminals - Google Patents

Description

The present invention relates to a method for processing brittle substrates for displays, and more specifically to a method for scribing bonded brittle substrates having terminal portions that does not cause cutting defects in the terminal portions at the ends of the bonded brittle substrates.

Dicing and scribing are two typical methods for cutting thin, brittle substrates, including glass substrates, to the required size. Dicing involves cutting grooves into the surface of the substrate with a diamond blade, while scribing involves forming scribe lines on the surface of the substrate with a scribing wheel, causing cracks to form in the thickness direction.

Furthermore, some products that use brittle substrates also use bonded brittle substrates. For example, a liquid crystal display panel has a color filter on one substrate and a TFT on the other, with liquid crystal injected between the two substrates and bonded together.

However, as shown in Figure 1, bonded brittle substrates have a terminal portion (13a) on one side of the substrate, so if special care is not taken when cutting, the terminal portion may crack, making the bonded brittle substrate unusable.

Figure 1 is a diagram illustrating the problems with conventional scribing methods for bonded brittle substrates (10).

As shown in the figure, the bonded brittle substrate (10) has a laminated structure of a lower plate (15) and an upper plate (13). A terminal portion (13a) is located at one end of the upper plate (13). The terminal portion (13a) is suspended above the table (T) by the thickness of the lower plate (15).

To form a scribe line on the bonded brittle substrate (10) having the above structure, the scribe wheel (19) is positioned on one side of the upper part of the bonded brittle substrate (10), and the wheel is pushed downward while simultaneously moving in the direction of arrow a toward the terminal portion (13a).

However, this method poses manufacturing problems because the terminal portion (13a) may bend downwards and crack when the scribing wheel (19) moves over the terminal portion (13a), or the scribe line may not be formed properly on the terminal portion (13a).

Patent Document 1 therefore discloses a method and device for scribing bonded substrates. The disclosed scribing method uses two opposing cutter wheels to scribe a bonded substrate in the direction of the terminal area, where a portion of the edge of the first substrate has been removed and a terminal area has been formed on the edge of the second substrate, thereby creating scribe lines for dividing the substrate on the top and bottom surfaces. The method includes the steps of moving the second cutter wheel, which scribes the second substrate having the terminal area, along a running line parallel to the surface of the second substrate until it reaches the vicinity of the terminal area's end position, then running it gradually away from the surface of the terminal area from the vicinity of the terminal area's end position to the terminal area's end position, and instantly retracting it from the terminal area with zero downtime upon reaching the terminal area's end position. However, the technology disclosed in Patent Document 1 is insufficient in terms of producing a non-defective product.

Korean Patent Publication No. 10-2019-0078494

The present invention was created to solve the above problems, and aims to provide a method for scribing bonded brittle substrates with terminals that allows for accurate scribe lines to be formed and prevents cracking of the terminals by controlling the cutting depth of the scribing wheel on the substrate, adjusting the load, and controlling the running speed.

The present invention provides a method for scribing a bonded brittle substrate having a terminal portion as a means for solving the problem of achieving the above objective. The method forms a scribe line on a bonded brittle substrate having a terminal portion, and includes: a division setting step for dividing the planned travel path of a scribe wheel into a pre-cutting section, a main cutting section, and a terminal portion cutting section; a wheel positioning step for positioning the scribe wheel at the start point of travel of the pre-cutting section; a pre-cutting section line forming step for pressing the scribe wheel positioned at the start point of travel against the bonded brittle substrate and running it while accelerating to a set speed; a main cutting section line forming step for running the scribe wheel at the set speed after passing the pre-cutting section to form a scribe line in the main cutting section; a deceleration step for decelerating the travel speed of the scribe wheel after passing the main cutting section before it reaches the terminal portion, so that the control signal input per unit time is received at a shorter travel distance than before deceleration; and a terminal portion cutting section line forming step for running the scribe wheel through the terminal portion cutting section at the same travel speed decelerated in the deceleration step to form a scribe line on the terminal portion.

The terminal cutting section line forming step also includes the steps of storing the position of the scribe wheel immediately before entering the terminal section, resetting the cutting depth within the cutting section to the cutting depth at the current position, and, after resetting, changing the cutting depth to be applied in the terminal cutting section to the target position based on the current position.

In addition, the average depth of cut imparted to the scribe wheel passing through the pre-cutting section and terminal cutting section is less than or equal to the depth of cut imparted to the scribe wheel in the actual cutting section.

The wheel load with which the scribe wheel presses the bonded brittle substrate in the terminal cutting section is relatively greater than the wheel load with which the scribe wheel presses the bonded brittle substrate in the main cutting section.

The scribing method for bonded brittle substrates having terminal portions according to the present invention, performed as described above, allows for accurate formation of scribe lines by controlling the cutting depth, load adjustment, and running speed of the scribe wheel on the substrate during the scribing process. In particular, cracking of the terminal portion can be prevented by changing the cutting depth in multiple stages.

1A and 1B are diagrams for explaining problems with a conventional scribing method for bonded brittle substrates. 1 is a block diagram illustrating a scribing method according to an embodiment of the present invention. 1 is a side view of a bonded brittle substrate for explaining a division setting step in a scribing method according to an embodiment of the present invention; 1 is a graph illustrating a scribing method according to an embodiment of the present invention.

One embodiment of the present invention will now be described in more detail with reference to the accompanying drawings.

The scribing method of the present invention is designed to cut bonded brittle substrates having terminal portions more efficiently and without damaging the terminal portions. To achieve this, the planned travel path of the wheel on the bonded brittle substrate is divided into sections, and the wheel speed, load, and cutting depth within each section are controlled in a controlled manner.

The basic structure of this scribing method, which forms a scribe line on a bonded brittle substrate having a terminal portion, includes a division setting step of dividing the planned travel path of a scribe wheel into a pre-cutting section, a main cutting section, and a terminal portion cutting section; a wheel positioning step of positioning the scribe wheel at the start point of travel in the pre-cutting section; a pre-cutting section line forming step of pressing the scribe wheel positioned at the start point of travel against the bonded brittle substrate and traveling while accelerating to a set speed; a main cutting section line forming step of traveling the scribe wheel without changing its speed after passing through the pre-cutting section to form a scribe line in the main cutting section; a deceleration step of decelerating the traveling speed of the scribe wheel after passing through the main cutting section before reaching the terminal portion, so that the scribe wheel receives a control signal input per unit time at a shorter travel distance than before deceleration; and a terminal portion cutting section line forming step of traveling the scribe wheel through the terminal portion cutting section at the same traveling speed decelerated in the deceleration step to form a scribe line on the terminal portion.

Figure 2 is a block diagram showing a method for scribing a bonded brittle substrate having a terminal portion according to one embodiment of the present invention, and Figure 3 is a side view of a bonded brittle substrate to explain the partition setting step in the scribing method. Figure 4 is a graph showing the scribing method according to one embodiment of the present invention.

As shown in the figure, the scribing method for a bonded brittle substrate having a terminal portion according to this embodiment includes a section setting step (101), a wheel positioning step (103), a pre-cutting section line forming step (105), a main cutting section line forming step (107), a deceleration step (109), a terminal portion cutting section line forming step (111), and a wheel raising step (113).

The division setting step (101) is the process of dividing the planned travel path of the scribe wheel (19) into a pre-cutting section (A), a main cutting section (B), and a terminal cutting section (C).

Such section settings are made by inputting set values into a controller installed in the scribing device. That is, the operator determines the pre-cutting section (A) from one end of the bonded brittle substrate (10) to a point several millimeters away, and the actual cutting section (B) from the pre-cutting section to a specific point, and inputs the determined values. The length of each section is determined differently depending on the size, shape, material properties, etc. of the bonded brittle substrate (10).

However, it is recommended that the distance of the pre-cutting section (A) be set to 5% or less of the total travel distance (L) of the scribe wheel (19). For example, if the total travel distance is 500 mm, it should be set to 25 mm or less.

The pre-cutting section (A) is a preparation section through which the scribe wheel (19) runs before entering the actual cutting section (B).

Furthermore, the main cutting section (B) ends before the point where the terminal section (13a) begins. In other words, the boundary between the main cutting section (B) and the terminal section cutting section (C) is located in front of the upstream side of the terminal section (13a). "Upstream" refers to the direction in which the scribe wheel (19) approaches. The reason for positioning the boundary between the main cutting section (B) and the terminal section cutting section (C) in front of the upstream side of the terminal section is to allow the scribe wheel to enter the terminal section (13a) while decelerating.

Once the pre-cutting section (A), main cutting section (B), and terminal cutting section (C) have been determined through the section setting step (101), the wheel positioning step (103) follows.

The wheel positioning step (103) is a process of positioning the scribe wheel (19) at the starting point of the pre-cutting section (A). The scribe wheel (19) is installed on the head of the scribing device and is configured to move up or down.

The next step, pre-cutting section line formation step (105), is the process of starting the scribing wheel (19) to form a scribing line in the pre-cutting section (A). That is, the scribing wheel (19) is positioned at the starting point of its travel and presses against the brittle substrate (10) to accelerate its travel.

The pre-cutting section line formation step (105) includes an acceleration process (105a), a cutting depth primary adjustment process (105b), and a wheel load primary adjustment process (105c). The acceleration process (105a) is a process of increasing the moving speed of the scribe wheel (19) from 0 mm/s to the traveling speed in the actual cutting section (B). The speed of the scribe wheel (19) in the actual cutting section (B) can be, for example, 300 mm/s.

The first cutting depth adjustment process (105b) is a process for adjusting the cutting depth within the pre-cutting section (A). The cutting depth is the maximum depth to which the wheel axis of the scribing wheel (19) can be lowered. In other words, it is the maximum depth to which the wheel axis can be lowered when the surface of the bonded brittle substrate (10) is set to 0. The cutting depth varies depending on the thickness of the bonded brittle substrate (10), and can be, for example, -0.02 mm (on the graph).

The cutting depth is set by inputting the cutting depth into the control controller. For example, inputting 0.02 into the control controller sets the maximum depth the wheel shaft can descend to 0.02 mm below the surface of the bonded brittle substrate (10). If the cutting depth is set to a value greater than the thickness of the bonded brittle substrate (10), the wheel shaft will be able to penetrate the surface of the table (T) and descend to the bottom.

The input cutting depth is determined according to the condition of the bonded brittle substrate (10). For example, if the bonded brittle substrate (10) in the pre-cutting section (A) is thin or weak, the cutting depth is reduced. Conversely, if the bonded brittle substrate inside the pre-cutting section (A) is thick and firmly supported by the table, the cutting depth is set deeper (the cutting amount is increased). The deeper the cutting depth, the deeper the actual depth to which the scribing wheel (19) can descend. This cutting depth can be adjusted in multiple stages as needed.

The first wheel load adjustment process (105c) is a process of adjusting the pressure applied to the feel axis. In other words, it adjusts the force with which the scribe wheel (19) presses against the brittle substrate (10) to be bonded. Adjusting the wheel load is separate from adjusting the cutting depth. The cutting depth and wheel load are input independently through the controller. However, if the wheel load is increased too much, the depth that can be reduced with the set wheel load cannot exceed the set cutting depth.

The average depth of cut imparted by the scribe wheel as it passes through the pre-cutting section (A) and the terminal cutting section (C) described below is relatively smaller than the depth of cut in the actual cutting section (B).

The wheel load in the pre-cutting section (A) can be appropriately controlled through the first wheel load adjustment process (105c). For example, to reduce the stress applied to the bonded brittle substrate (10) at the moment cutting begins, a wheel load smaller than the wheel load planned for the main cutting section (B) can be applied, or (depending on the size and shape of the bonded brittle substrate) a wheel load relatively larger than the wheel load in the main cutting section can be applied. The greater the wheel load, the deeper the scribe line.

The main cutting section line formation step (107) is a process in which the scribe wheel (19) that has passed through the pre-cutting section (A) travels at a constant speed through the main cutting section (B). The scribe wheel (19) that has entered the main cutting section (B) passes through the main cutting section (B) without changing speed and enters the terminal cutting section (C).

The cutting depth within the actual cutting section (B) is greater than the average cutting depth within the pre-cutting section (A). The cutting depth at the boundary between the pre-cutting section (A) and the actual cutting section (B) is the same as the cutting depth within the actual cutting section (B). While the scribe wheel (19) crosses the boundary between the pre-cutting section (A) and the actual cutting section (B), the cutting depth is increased by the control of the controller.

In addition, the wheel load in the actual cutting section (B) may be smaller than the wheel load in the pre-cutting section (A) and the terminal cutting section (C). For example, if the wheel loads in the pre-cutting section (A) and the terminal cutting section (C) are 6N and 7N, respectively, the wheel load in the actual cutting section (B) may be 5N. However, the magnitude of the wheel load in each section may vary depending on the thickness of the bonded brittle substrate (10) and the length of each section.

The scribe wheel (19) passes through the main cutting section (B) while maintaining the speed, wheel load, and cutting depth described above, forming a scribe line in the main cutting section (B).

The subsequent deceleration step (109) is a process of slowing down the traveling speed of the scribe wheel after passing through the main cutting section (B) before it reaches the terminal portion. That is, the scribe wheel (19) is decelerated within the deceleration section (E). The deceleration section (E) is the section between the boundary between the main cutting section (B) and the terminal portion cutting section (C) and the point where the lower plate (15) ends. The terminal portion (13a) begins from the point where the lower plate (15) ends. The decelerated speed of the scribe wheel (19) varies depending on the condition of the bonded brittle substrate (10) and can be, for example, 8 mm/s.

The reason for slowing down the speed of the scribe wheel (19) in this way is to make the control signal input per unit time be received once per shorter travel distance than before the speed reduction.

Typically, the controller in a scribing device outputs control signals in scan units without rest. One scan is, for example, 100 ms. The controller outputs the necessary control signals within the 100 ms time, and at 100 ms time intervals. The output of such control signals is independent of the movement speed of the scribing wheel (19). The faster the movement speed of the scribing wheel (19) over a certain distance, the fewer control signals are received by the scribing wheel. Naturally, the fewer control signals are received, the lower the operating precision of the device will be.

For example, if the scribe wheel (19) travels a 100 mm path in 100 ms, the scribe wheel will receive only one control signal. (By coincidence, it is possible for the scribe wheel to receive two signals, at the 0 mm and 100 mm points, but this is out of the question.)

In comparison, if the scribe wheel (19) travels a distance of 100 mm in 10 seconds, it receives a control signal 100 times in those 10 seconds. In other words, the scribe wheel receives a control signal after moving a short distance, and then receives another control signal after moving a short distance further. Naturally, receiving control signals more frequently in this way increases operational precision.

In this embodiment, the deceleration step (109) reduces the traveling speed of the scribe wheel (19) before it enters the terminal portion (13a) to improve the control precision of the scribe wheel (19) at the terminal portion (13a). The reason for improving the control precision is to prevent cracking of the terminal portion (13a) and to achieve clear scribe lines at the terminal portion (13a).

The terminal cutting section line formation step (111) includes a secondary cutting depth adjustment step (111a) and a secondary wheel load adjustment step (111b). In some cases, the secondary wheel load adjustment step (111b) can be omitted.

The secondary cutting depth adjustment process (111a) stores the position of the scribe wheel (19) immediately before it enters the terminal portion, resets the cutting depth in the main cutting section (B) to the current position, and after resetting, changes the cutting depth to be applied in the terminal cutting section (C) to the target position based on the current position of the scribe wheel (19) (the position immediately before it enters the terminal portion).

The reason for performing the secondary cutting depth adjustment process (111a) is, of course, to adjust the depth to which the scribe wheel (19) penetrates into the brittle substrate (10) to obtain a good cutting line at the terminal portion (13a).

As mentioned above, by adjusting the cutting depth based on the current position immediately before entering the terminal cutting section (C), it is possible to avoid the effects of variations in the flatness of the table or the bonded brittle substrate (10). This is because, for example, when multiple scribing heads simultaneously form multiple parallel scribe lines, the cutting depth of the terminal portion (13a), i.e., the target position, can be adjusted for each head based on the current position of the scribe wheel.

In other words, scribing precision is consistent regardless of variations in the flatness of the bonded brittle substrate (10). In other words, if the cutting depth in the terminal cutting section (C) is set based on the surface position of the substrate in a pre-cutting section, the penetration depth of the scribe wheel of each head into the terminal section during terminal cutting may vary depending on the flatness of the substrate. However, in this embodiment, even with equipment using multiple heads, the flatness of the bonded brittle substrate (10) does not affect the cutting depth.

The secondary wheel load adjustment process (111b) is a process of increasing the wheel load. In this cutting section (B), the upper plate (13) is supported by the lower plate (15), so a clear scribe line is formed even with a relatively small wheel load. However, if the same wheel load is applied to the terminal portion (13a) floating in the air, the terminal portion (13a) may elastically deform downward, resulting in a faint scribe line or no scribe line at all.

The secondary wheel load adjustment process (111b) is performed within the range of elastic deformation of the terminal portion (13a). For example, the load, which was 5N in the main cutting section (B), can be increased to 7N within the range of elastic deformation. By increasing the wheel load in this way, a clear scribe line can be formed even on the top surface of the terminal portion (13a) that is floating in the air.

The following wheel lifting step (113) is a process of lifting the scribing wheel (19) after completing the formation of the scribe line on the terminal portion (13a). The scribing process is completed through this wheel lifting step (113).

In the explanation of this embodiment, we have used as an example a scribing method for a bonded brittle substrate (10) set on a table (T), but the scribing method of this embodiment can also be applied to a simultaneous top and bottom scribing method in which the scribe wheels are located on both the top and bottom of the substrate.

The present invention has been described in detail above through specific examples, but the present invention is not limited to these examples and can be modified in various ways by those skilled in the art within the scope of the technical concept of the present invention.

10: Bonded brittle substrate 13: Upper plate 13a: Terminal portion 15: Lower plate 19: Scribe wheel T: Table

Claims (4)

A method for forming a scribe line on a bonded brittle substrate having a terminal portion, comprising:
A section setting step of dividing the planned travel path of the scribe wheel into a pre-cutting section, a main cutting section, and a terminal cutting section;
a wheel positioning step of positioning the scribing wheel at a travel start point of the pre-cutting section;
a pre-cutting section line forming step in which a scribing wheel positioned at a travel starting point is pressed against the bonded brittle substrate and travels at a set speed; and a main cutting section line forming step in which the scribing wheel that has passed through the pre-cutting section is traveled at a set speed to form a scribe line in a main cutting section;
a deceleration step of decelerating the traveling speed of the scribe wheel after passing through the main cutting section before the scribe wheel reaches the terminal portion, so that the control signal input per unit time is received for each moving distance shorter than before the deceleration;
and a terminal portion cutting section line forming step of passing the scribing wheel through the terminal portion cutting section at the traveling speed reduced in the deceleration step to form a scribe line on the terminal portion.
A method for scribing a bonded brittle substrate having a terminal portion. The method for scribing a bonded brittle substrate having a terminal portion according to claim 1 ,
The step of forming a line for cutting the terminal portion includes:
a step of storing the position of the scribe wheel immediately before entering the terminal portion, resetting the cutting depth in the actual cutting section to the cutting depth at the current position, and changing the cutting depth to be applied in the terminal portion cutting section to a target position based on the current position after resetting;
A method for scribing a bonded brittle substrate having a terminal portion. The method for scribing a bonded brittle substrate having a terminal portion according to claim 1 ,
an average cutting depth imparted to the scribe wheel passing through the pre-cutting section and the terminal portion cutting section is equal to or less than an cutting depth imparted to the scribe wheel in the main cutting section;
A method for scribing a bonded brittle substrate having a terminal portion. The method for scribing a bonded brittle substrate having a terminal portion according to claim 1 ,
a wheel load applied by the scribing wheel to press the bonded brittle substrate in the terminal portion cutting section is relatively larger than a wheel load applied by the scribing wheel to press the bonded brittle substrate in the main cutting section;
A method for scribing a bonded brittle substrate having a terminal portion.