Screen printing apparatus and screen printing method using same

Abstract

Provided is a screen printing apparatus comprising: a substrate; a screen mask disposed to be spaced apart from the substrate by an interval; a screen frame for fixing both sides of the screen mask; a squeegee disposed on the screen mask to apply pressure to the screen mask; and a guide member having a guide part formed on the screen mask so that the squeegee reciprocates along the guide part. The screen mask is disposed to have an inclination with respect to the substrate.

Description

Screen printing device and screen printing method using the same

[0001] The present invention relates to a screen printing device and a screen printing method using the same.

[0002] Screen printing, which is a method of printing electrode paste on a substrate using a patterned screen to print a certain pattern of electrodes on a substrate, is widely used. In a conventional screen printing method, as shown in Fig. 1, the screen is arranged parallel to the substrate with a certain gap, paste is loaded onto the screen mounted parallel to the substrate, and the electrode paste is extruded to the patterned area using a squeegee so that it is printed on the substrate.

[0003] Meanwhile, the screen is separated from the substrate by its own tension (plate separation), and the force for the separation of the substrate and the screen is proportional to the vertical force acting on the screen, i.e., Tsin θ, when the angle between the screen and the substrate at the position after the squeegee passes is θ. However, when the substrate and the screen are arranged parallel, as the squeegee moves from the beginning to the end of the printing, the angle between the screen and the substrate gradually decreases, and the force for plate separation gradually decreases, so that as the printing progresses, a delay in plate separation occurs, and there is a problem that poor print quality occurs in the latter half of the printing.

[0004] The purpose of the present invention is to improve the quality of the latter half of printing by maintaining a constant force for separating a substrate and a screen through a screen printing method including an inclined screen.

[0005] In order to achieve the above-described object, one embodiment of the present invention discloses a screen printing device including a substrate, a screen mask arranged to be spaced apart from the substrate, a screen frame for fixing both sides of the screen mask, a squeegee arranged on the screen mask to apply pressure to the screen mask, and a guide member formed on the screen mask such that the squeegee reciprocates along the guide member, wherein the screen mask is arranged to have an incline with respect to the substrate.

[0006] Another embodiment of the present invention for achieving the above-described purpose discloses a screen printing method using a screen mask and a squeegee, comprising the steps of: arranging the screen mask so as to be spaced apart from a substrate and at an angle to the substrate; loading electrode paste onto the screen mask; and extruding the electrode paste loaded onto the screen mask using the squeegee to print it on the substrate.

[0007] The screen printing method according to an embodiment of the present invention controls the angle formed between the screen and the substrate after the squeegee passes by adjusting the inclination of the screen through a spacer, thereby maintaining the force separating the substrate and the screen constant from the beginning to the end of printing, thereby improving the deterioration of printability in the latter half of printing that occurs when using a highly viscous or sticky electrode paste.

[0008] FIG. 1 is a side view schematically illustrating an example of a screen printing device according to one embodiment of the present invention.

[0009] Figures 2a and 2b are schematic drawings illustrating an example of a screen printing method using the screen printing device of Figure 1.

[0010] Figures 3a and 3b are schematic drawings illustrating an example of a conventional screen printing method.

[0011] Figure 4 is a flowchart illustrating an example of a screen printing method according to one embodiment of the present invention.

[0012] Figures 5a to 5d are photographs showing the electrode coating appearance in the early and late stages of printing.

[0013] In order to achieve the above-described object, one embodiment of the present invention discloses a screen printing device including a substrate, a screen mask arranged to be spaced apart from the substrate, a screen frame for fixing both sides of the screen mask, a squeegee arranged on the screen mask to apply pressure to the screen mask, and a guide member formed on the screen mask such that the squeegee reciprocates along the guide member, wherein the screen mask is arranged to have an incline with respect to the substrate.

[0014] A spacer may further be included between the screen frame and the guide member.

[0015] The inclination of the slope of the substrate and the screen mask may be 0.8% to 1.2%.

[0016] The gap between the screen mask and the substrate may increase from the beginning to the end of printing.

[0017] Another embodiment of the present invention for achieving the above-described purpose discloses a screen printing method using a screen mask and a squeegee, comprising the steps of: arranging the screen mask so as to be spaced apart from a substrate and at an angle to the substrate; loading electrode paste onto the screen mask; and extruding the electrode paste loaded onto the screen mask using the squeegee to print it on the substrate.

[0018] The screen mask may include a guide member formed on the screen so that the squeegee can reciprocate along the guide member.

[0019] Both sides of the above screen mask are fixed to a screen frame, and a spacer may be placed between the screen frame fixing one side of the screen mask and the guide member.

[0020] The above spacer may have a thickness of 3 mm to 5 mm.

[0021] The inclination of the slope of the substrate and the screen mask may be 0.8% to 1.2%.

[0022] The gap between the screen mask and the substrate may increase from the beginning to the end of printing.

[0023] The present invention is capable of various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention, as well as the methods for achieving them, will become clearer with reference to the embodiments described in detail below, along with the drawings. However, the present invention is not limited to the embodiments disclosed below and can be implemented in various forms.

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. When describing with reference to the drawings, identical or corresponding components are given the same drawing reference numerals, and redundant descriptions thereof will be omitted.

[0025] In the examples below, the terms first, second, etc. are not used in a limiting sense, but are used for the purpose of distinguishing one component from another.

[0026] In the examples below, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0027] In the examples below, terms such as “include” or “have” mean that a feature or component described in the specification is present, and do not preclude the possibility that one or more other features or components may be added.

[0028] For convenience of explanation, the sizes of components in the drawings may be exaggerated or reduced. For example, the sizes and thicknesses of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and thus the present invention is not necessarily limited to what is shown.

[0029] In the following examples, the x-axis, y-axis, and z-axis are not limited to three axes on an orthogonal coordinate system, and can be interpreted in a broad sense that includes them. For example, the x-axis, y-axis, and z-axis may be orthogonal to each other, but may also refer to different directions that are not orthogonal to each other.

[0030] In some embodiments, where implementations are otherwise feasible, specific process sequences may be performed in a different order than described. For example, two processes described in succession may be performed substantially simultaneously, or in a reverse order from the described order.

[0031] One embodiment of the present invention for achieving the above-described purpose relates to a screen printing device, and another embodiment of the present invention for achieving the above-described purpose relates to a screen printing method, which will be described with reference to FIGS. 1 to 5d.

[0032] FIG. 1 is a side view schematically illustrating an example of a screen printing device according to one embodiment of the present invention, and FIGS. 2a and 2b are drawings schematically illustrating an example of a screen printing method using the screen printing device of FIG. 1.

[0033] Referring to FIGS. 1 to 2B, the screen printing device includes a screen mask (100) fixed to a screen frame (101, 102), a substrate (200) spaced apart from the screen mask (100), a spacer (300) and a squeegee (400) arranged to provide an inclination (Φ) to the screen mask (100), and may include a guide member (A) formed with a guide portion so that the squeegee (400) is fixed and can reciprocate.

[0034] The screen mask (100) can be fixedly placed on the screen frame (101, 102), and since the pattern to be formed is opened, the desired pattern can be printed on the substrate (200). At this time, the electrode paste (500) can be loaded on the screen mask (100), and when the loaded electrode paste (500) is applied with pressure by moving the squeegee (400) back and forth on the screen mask (100), the desired pattern can be printed on the substrate (200) through the opening of the screen mask (100).

[0035] As an optional embodiment, the screen mask (100) may be formed by weaving wires into a mesh shape, and each wire may be fixed to a mask frame (101, 102) while maintaining a certain tension. At this time, the wire may be composed of various materials, including polyester, stainless steel, etc.

[0036] The substrate (200) may be a single-crystal or polycrystalline silicon wafer, may include p-type silicon, n-type silicon, or silicon in the form of a Pn junction, and may include any one selected from borosilicate glass, quartz glass, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polycarbonate (PC), polypropylene (PP), triacetyl cellulose (TAC), or polyether sulfone (PES), but is not limited thereto.

[0037] As an optional embodiment, the substrate (200) may be a substrate used for manufacturing a solar cell or a tandem solar cell, and a hole transport layer, a photoactive layer, an electron transport layer, etc. for manufacturing a solar cell or a tandem solar cell may be formed on one side of the substrate (200).

[0038] As an optional embodiment, the substrate (200) may be a solar wafer of 182 * 182 mm, M10 size.

[0039] The guide member (A) has a square frame shape, and guide portions may be formed on two frames that follow the printing direction of the substrate (200), so that the squeegee (400) can be coupled to the guide portion and reciprocate along the guide portion.

[0040] As an optional embodiment, the guide member (A) may include an adapter, which may serve to automatically reciprocate along the guide member after the squeegee is coupled to the guide member (A).

[0041] The spacer (300) can be placed between the guide member (A) and the screen mask (100) so that the screen mask (100) has an inclination (Φ). At this time, the spacer (300) can be placed on the first screen frame (101) that fixes one side of the screen mask (100), so that the first screen frame (101) can be positioned lower than the second screen frame (102) that fixes the other side of the screen mask (100) by the thickness of the spacer (300).

[0042] Referring to FIGS. 2a and 2b, after the squeegee (400) passes, the screen mask (100) can be separated (plate separated) from the substrate (200) by its own tension. At this time, the plate separation force can be proportional to the tension in the vertical direction, i.e., Tsinθ (0°<θ<90°).

[0043] To explain this specifically, a screen mask (100) fixed to a screen frame (101, 102) is installed on a substrate (200) at a constant interval, and a squeegee (400) can horizontally move while applying a constant pressure to the screen mask (100) and bringing the screen mask (100) into contact with the surface of the substrate (200). At this time, when the squeegee (400) applies a constant pressure to the screen mask (100), the screen mask (100) is elastically deformed and the length of the screen mask (100) increases from AB to APB, and a tension that tries to restore the length of the screen mask (100) to the original AB is applied to point P, so that plate separation of the screen mask (100) and the substrate (200) may occur. At this time, the plate separation force may be proportional to the tension in the vertical direction, that is, Tsinθ.

[0044] Figures 3a and 3b are schematic drawings illustrating an example of a conventional screen printing method.

[0045] Referring to FIGS. 3a and 3b, as the squeegee (400) moves from the beginning of printing (FIG. 3a) to the latter half of printing (FIG. 3b), the magnitude of θ decreases (θ3>θ4), so that the vertical separation force, i.e., Tsinθ4, may decrease. For this reason, in the case of an electrode paste (500) with high viscosity or stickiness, a delay in separation of the plates may occur as the printing progresses to the latter half of printing (FIG. 3b), which may result in poor print quality in the latter half.

[0046] However, the separation of the latter half of the printing may vary depending on the inherent elasticity of the screen mask (100) and the gap (d1, d2) between the screen mask (100) and the substrate (200).

[0047] Referring again to FIGS. 2a and 2b, the vertical component of the tension of the screen, which is a force involved in plate separation, and the size of the Tsinθ value can be adjusted according to the gap (d1, d2) between the screen mask (100) and the substrate (200). At this time, by giving the screen mask (100) an inclination (Φ), the gap (d2) between the screen mask (100) and the substrate (200) in the latter half of the printing (FIG. 2b) can be adjusted according to the inclination (Φ) of the screen mask (100), and as a result, the size of θ2 in the latter half of the printing (FIG. 2b) can be adjusted, so that the size of the Tsinθ value can be adjusted.

[0048] In order to adjust the inclination (Φ) of the screen mask (100), for example, the thickness of the spacer (300) placed between the guide member (A) and the screen mask (100) can be adjusted.

[0049] The spacer (300) can be placed on the first screen frame (101) that fixes one side of the screen mask (100), so that the first screen frame (101) is positioned lower by the thickness of the spacer (300) than the second screen frame (102) that fixes the other side of the screen mask (100), thereby allowing the inclination (Φ) of the screen mask (100) to be adjusted.

[0050] By adjusting the inclination (Φ) of the screen mask (100) through the spacer (300) in this way, the gap (d2) between the screen mask (100) and the substrate (200) in the latter half of printing (Fig. 2b) can be increased, and as a result, the value of θ2 in the latter half of printing (Fig. 2b) is made large, thereby increasing the value of Tsinθ2, thereby preventing the plate separation from being delayed in the latter half of printing (Fig. 2b).

[0051] Meanwhile, at this time, the gap (d1, d2) can be arranged on the first screen frame (101) where the spacer (300) fixes one side of the screen mask (100), so that the slope can increase from the beginning of printing (Fig. 2a) to the end of printing (Fig. 2b), and therefore, the gap can increase (d1 < d2) from the beginning of printing (Fig. 2a) to the end of printing (Fig. 2b).

[0052] That is, as the gap (d2) in the latter half of the print increases, the angle (θ) formed by the screen mask (100) and the substrate (200) at point P 1, The size of θ2) may increase, and accordingly, the inclination of the screen mask (100) with respect to the substrate (200) may increase. In addition, conversely, as the gap (d2) in the latter half of the printing decreases, the angle (θ) formed by the screen mask (100) and the substrate (200) at point P 1, The size of θ2) can be reduced, and accordingly, the inclination of the screen mask (100) with respect to the substrate (200) can be reduced.

[0053] The spacer (300) may have a thickness of 3 mm to 5 mm to impart an inclination (Φ) to the screen mask (100). If the thickness of the spacer (300) is less than 3 mm, the inclination (Φ) imparted to the screen mask (100) is too small, so that the increase in the θ2 value in the latter half of the printing (Fig. 2b) is minimal, which causes a problem of delayed plate separation. If the thickness of the spacer (300) exceeds 5 mm, the gap (d2) in the latter half of the printing is too large, which may cause a problem of poor contact between the screen mask (100) and the substrate (200).

[0054] Meanwhile, when the spacer (300) has a thickness of 3 mm to 5 mm, the inclination (Φ) of the screen mask (100) may be 0.8% to 1.2%.

[0055] The following describes the screen printing method.

[0056] Screen printing is a method of manufacturing a material to be coated in the form of a paste and passing the paste through a screen mask (100) having a specific pattern formed thereon to form a pattern on a substrate (200).

[0057] Figure 4 is a flowchart illustrating an example of a screen printing method according to one embodiment of the present invention.

[0058] Referring to FIG. 4, the screen mask may include a step (s100) of arranging the screen mask to be spaced apart from the substrate and at an angle to the substrate, a step (s200) of loading the electrode paste onto the screen mask, and a step (s300) of extruding the electrode paste loaded onto the screen mask using a squeegee and printing it on the substrate.

[0059] In the step (s100) of arranging the screen mask so as to be spaced apart from the substrate and have an incline with respect to the substrate, the screen mask (100) composed of a screen mesh can be fixed on the substrate to be printed so as to be spaced apart from the substrate at a certain interval and have an incline. At this time, in order to impart an incline to the screen mask (100), a spacer (300) can be placed on the first screen frame (101) that fixes one side of the screen mask (100), and the spacer (300) placed on the first screen frame (101) in this way has a thickness, and by the thickness of the spacer (300), the first screen frame (101) is positioned lower than the second screen frame (102) that fixes the other side of the screen mask (100) by the thickness of the spacer (300), whereby an incline (Φ) can be imparted to the screen mask (100).

[0060] In the step (s200) of loading the electrode paste onto the screen mask, a predetermined amount of the pre-prepared electrode paste (500) can be applied onto the screen mask (100) to correspond to the area of ​​the substrate (200).

[0061] In the step (s300) of printing on the substrate by extruding the electrode paste loaded on the screen mask using a squeegee, the electrode paste (500) is applied on the screen mask (100), and the squeegee (400) is pressed with a certain pressure so that the screen mask (100) touches the substrate, and then the squeegee (400) is moved horizontally, so that the paste penetrates into the open part of the screen mesh by the pressure of the squeegee and can be printed on the substrate (200).

[0062]

[0063] Example 1

[0064] A 450 mm screen mask and a 182 * 182 mm, M10 size substrate were used, and a 3.4 mm thick spacer was used on one side of the screen mask to give the screen mask an incline, and then it was placed so as to be spaced apart from the substrate.

[0065]

[0066] Comparative Example 1

[0067] A 450 mm screen mask and a 182 * 182 mm, M10 size substrate were used, and the screen mask and substrate were placed parallel to each other.

[0068] Distinction d1 (mm) d2 (mm) First half of printing θ (degree) Second half of printing θ (degree) Example 125.4 1.05 1.06 Comparative example 1221.05 0.39

[0069] Table 1 shows the gap (d1) and θ value in the early part of printing and the gap (d2) and θ value in the latter part of printing for Example 1 and Comparative Example 1. Referring to Table 1, when the tension of the screen is T, it can be seen that the TSinθ value in the early part of printing in Example 1 is Tsin(1.05°) and is approximately 0.87T, and the TSinθ value in the latter part of printing is Tsin(1.06°) and is approximately 0.87T. That is, it can be confirmed that the TSinθ value, which affects plate separation, is maintained constant in both the early part of printing and the latter part of printing in Example 1, and through this, it can be expected that the screen and the substrate will be separated quickly without delay in plate separation. On the other hand, in Comparative Example 1, the TSinθ value in the early part of printing is Tsin(1.05°), which is approximately 0.87T, and the TSinθ value in the latter part of printing is Tsin(0.39°), which is approximately 0.38T. When the TSinθ value in the latter part of printing is compared with the TSinθ value in the early part of printing, the TSinθ value in the latter part of printing is found to have decreased by approximately 56%. In other words, since the TSinθ value, which affects plate separation, decreases in Comparative Example 1 from the early part of printing to the latter part of printing, it can be expected that a plate separation delay phenomenon will occur.

[0070] Figures 5a to 5d are photographs showing the electrode coating appearance in the early and late stages of printing.

[0071] Referring to FIGS. 5a to 5b, FIGS. 5a and 5b are enlarged photographs of the electrode coating in the early and late printing stages of Comparative Example 1, and FIGS. 5c and 5d are enlarged photographs of the electrode coating in the early and late printing stages of Example 1.

[0072] Referring to FIGS. 5a and 5b, it can be seen that the electrode formed by the method of Comparative Example 1 has a rough and unsmooth surface. On the other hand, referring to FIGS. 5c and 5d, it can be seen that the surface of the electrode formed by the method of Example 1 is uniform and smooth.

[0073] Through this, it can be confirmed that when printing electrodes on a substrate using a screen printing method using a tilted screen mask according to an embodiment of the present invention, the printing quality of not only the latter half of printing but also the early half of printing is improved, and it can be judged that this is possible because problems such as spreading of electrode paste due to delayed plate separation are minimized due to rapid plate separation.

[0074] As a result, the screen printing method according to the embodiment of the present invention controls the angle formed between the screen and the substrate after the squeegee passes by adjusting the inclination of the screen through a spacer, thereby maintaining the force separating the substrate and the screen constant from the beginning to the end of printing, thereby preventing delay in plate separation that occurs when using a high viscosity or sticky electrode paste, thereby improving the deterioration of printability in the latter half of printing.

[0075] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0076] The scope of the present invention is indicated by the claims described below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. Substrate; A screen mask arranged at a distance from the substrate; A screen frame that fixes both sides of the above screen mask; a squeegee placed on the screen mask and applying pressure to the screen mask; and A guide member formed on the screen mask so that the squeegee reciprocates along the guide member; A screen printing device in which the above screen mask is arranged to have an incline with respect to the substrate.

2. In paragraph 1, A screen printing device further comprising a spacer disposed between the screen frame and the guide member.

3. In paragraph 1, A screen printing device, wherein the slope of the inclination between the substrate and the screen mask is 0.8% to 1.2%.

4. In paragraph 1, A screen printing device, wherein the gap between the screen mask and the substrate increases from the beginning of printing to the end of printing.

5. In a screen printing method using a screen mask and a squeegee, A step of arranging the above screen mask so as to be spaced apart from the substrate and at an angle to the substrate; A step of loading electrode paste onto the screen mask; and A screen printing method, comprising a step of printing on the substrate by extruding the electrode paste loaded on the screen mask using the squeegee.

6. In paragraph 5, A screen printing method comprising a guide member formed on the screen mask so that the squeegee reciprocates along the guide member.

7. In paragraph 6, Both sides of the above screen mask are fixed to the screen frame, A screen printing method, wherein a spacer is placed between the screen frame that fixes one side of the screen mask and the guide member.

8. In paragraph 7, The above spacer has a thickness of 3 mm to 5 mm, a screen printing method.

9. In paragraph 5, A screen printing method wherein the slope of the inclination of the substrate and the screen mask is 0.8% to 1.2%.

10. In paragraph 5, A screen printing method in which the gap between the screen mask and the substrate increases from the beginning of printing to the end of printing.

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