SCREEN MASK

What is screen mask?

Screen mask is the original plate used in the screen printing process, which is essential in the production of electronics products. In combination of frame, screen mesh and high quality in-house developed emulsion, we can provide a variety of screen masks to satisfy customer requirements.

Products of screen mask

Lineup

FOR FINE PATTERN PRINTING

Combines high resolution emulsion and high precision mesh such as ST640, ST500, etc. Handles line width to the 15µm level. (Less than 10µm is now under development)*(1)

• [Main applications: ]Printing of touch panel wiring, inductors, solar cell finger electrodes, high frequency parts, etc.
• [Recommended mesh:*(2)]
  • 30μm⇒ST640･ST500
  • 50μm⇒ST500
  • 70μm⇒ST400

*(1)The smallest possible line varies, depending on mesh, emulsion thickness and image area, etc. Please contact us for details.
*(2)Varies depending on emulsion thickness, paste, etc.

FOR HIGH PRECISION POSITIONING

TOPRO provides high tension screen mesh combined with various processing options, for excellent initial dimensions precision, and durable specifications.

• [Main applications: ]Thin layer printing in condensers, etc
• [Recommended mesh:]ST640CAL, ST500CAL, etc

*Achievable precision varies depending on substrates, options and the plate used.

FOR THIN FILM PRINTING

Excellent surface smoothness, and prevents printing deterioration at low thickness of emulsion.
Handles down to 0µm emulsion thickness.*

*Handles wire diameters under 25µm. Please contact us about 25µm or higher wire diameters.

Enables printing with reduced thickness of mesh and emulsion, thinner printing and reduced saddle phenomena.

• [Main applications: ]Thin layer printing for electrodes in condensers, etc
• [Recommended mesh: ]ST640CAL, ST500CAL, etc

Comparison of printing

FOR THICK FILM PRINTING

Achieves high quality printing at stable tension and film thickness

• [Main applications: ]Printing for sealing resins, adhesives, etc
• [Recommended mesh:]Low mesh such as ST70, ST100, etc.

FOR LARGE PRINTING

High precision plates are available for bulk patterning in large area of pattern printing. Solid plates can achieve uniform coating for solid printing.
In combination with the options processing to achieve higher accuracy and additional functions.

• [Main applications:]For large display lines using EL seal printing, EL drying agents, etc.
• [Recommended mesh:]Wide mesh such as ST325, ST400, etc.
• Please contact us for the supported sizes.

METALLIC SCREEN MASK (NE Mask, MS Mask)

NE Mask is called a Metal Screen Mask that Nickel foil is substituted for emulsion on screen mask.

NE Mask (Screen Mesh + Nickel foil)

Mesh: ST500-18-26 / Thickness: 15μm

Initial stage precision

Pitch width: 32.5mm, 25marks in total.
Total pitch width: 130mm/one side Error range in all 25 marks at initial stage precision is within ±5μm.
(Using Mesh: NSX430-13CAL)

*The precision can be changed by strength and /or tension of mesh.

Precision after printing –NE Mask can keep its initial stage precision after repeated printing

Pitch precision of NE Mask hardly changes after 10,000 shots for printing.

• *Printing conditions

• attack pressure of squeegee: 0.4MPa
• Clearance: 1.0mm
• squeegee speed: 150mm/sec

Specifications

• Frame size: MAX 800mm×800mm
• Metal size: MAX 450mm×450mm
• Metal thickness: 5μm~50μm
• Screen Mesh thickness: Basically, applicable to almost all types of meshes.
• Pasted plating thickness: R2
  *For some particular law meshes like 200mesh or less – pasted plating thickness is R5 or above.
• Precision (varies according to pattern)
  • Precision of thickness: ±3μm against total thickness (theoretical value)
    *Except 200mesh or less of law meshes and 30㎛ or above of metal thickness.
  • Precision of opening: ±3μm (condition = opening dimension is 300μm or less)
  • Precision of position: ±0.0010% against L (length) Note: 100mm or less of L is ±10μm

Please contact us about any other specifications.

MS Mask (Micro Sieve + Nickel foils)

MS Mask can freely design number of threads per inch , diameter of a thread and thickness of screen unlike Non Emulsion masks that consists of meshes on the market. It is possible that Ultra-thin printing and hyperfine line printing would be provided by Micro sieve. That cannot be made by Screen mask. Also, MS Mask solves a pitch width problem that is happened to Screen Mask.

*For any other specifications , please contact us.

Mesh standard for MS mask

Mesh count (Line/Inch)	Mesh pitch (μm)	Sheet size (Max) (mm)	Effective area *Note1 (mm)	Opening size Min~Max (μm)	Opening ratio Min~Max (%)	Remarks
1000L	25.4	350×350	within Φ250mm	5~13	3.9~26.2	*Note2
876L	29.0	350×350	within Φ250mm	5~14	3.0~23.3	*Note2
750L	33.9	350×350	within Φ250mm	5~20	2.2~34.8
640L	39.7	350×350	within Φ250mm	7~23	3.1~33.6
500L	50.8	350×350	within Φ250mm	10~35	3.9~47.5
400L	63.5	350×350	within Φ250mm	15~47	5.6~54.8
325L	78.2	350×350	within Φ250mm	20~62	6.5~62.9	*Note2

• *Note1: Available area – in case of the specification based on opening width precision is within ± 1μ.
• *Note2: Under development.(Please contact us for more details.)
• *Opening width can be adjusted according to your request. (Adjustable range of opening width is approximately from 1 to 5 μm.）

Initial stage precision

Pitch width: 37.5mm , 16 marks in total.

Total pitch width: 150mm /one side Error Range in all 16 marks at initial stage precision is within ±5μm.
(Using Mesh: MS750-14)

*The Precision can be changed by strength and/or tension of mesh.

The Precision after printing- MS Mask can keep its initial stage precision after repeated printing

Pitch precision of MS Mask hardly changes after 10,000 shots for printing.

• *Printing conditions

• attack pressure of squeegee: 0.4MPa
• clearance: 1.0mm
• squeegee speed: 150mm/sec

MESH LINEUP

Stailless-steel screen

• Plain weave meshes made of reliable stainless-steel wire with excellent printability.
• Available in various types from 70-mesh screens for thick film printing up to calendered 730-mesh screens for fine pitch patterns.
• Adjustment of discharge by calendering process.

Polyester mesh screen

• Cost-effective screen with a higher modulus of elasticity.
• Widely preferred screen for a wide range of applications such as PCB, FPC and membrane sheets.

Plated screen

• Metal coating fixes the mesh structure and keeps the elongation of a screen to a minimum, improving significantly the image size accuracy.
• Ideal for applications in which ultimate image accuracy is of prime importance.
• More detailed adjustment of discharge by controlling plating thickness.

High-tension stailless-steel screen

• The wire material used for high-tension stainless-steel screens has a tensile strength three times greater than conventional stainless-steel wire, showing no more than one-eighth of the usual elongation. ※Refer to graph SX230, SX300 as below.
• Such properties of the wire material allow ultra-thin wires to be used, thus realizing meshes with a high open area percentage – ideal for fine-pitch pattern printing.
• Even high-viscosity paste can be printed easily with low pressure, giving outstanding image accuracy in pattern printing.
• Twill can also be ordered.

Others

• Tungsten mesh
• V screen
• Metal mesh

EMULSIONS LINEUP

Radar chart comparing characteristics of main emulsions

Emulsion name	Radar chart	Characteristics
NOA		Standard emulsion of TOPRO. Our emulsions offer excellent stencil resolution, abrasion resistance and solvent resistance. High solvent resistance that resistance to polar solvent like N-methyl-2-pyrrolidinone.
ARK		Soften NOA emulsion. Minimized cracking such as at the corners of alumina boards.
NCS		For MLCC printing. Excellent stencil resolution, and it suppresses the blurring of MLCC paste. Excellent abrasion resistance with its softness.
TAX-G		For MLCC printing. In combination with the BK processing (fluorine coat processing) to suppress blurring.
NEX-S		For solar cell printing. Good passing property of the paste due to its fine stencil constituent particles with weak releasability.
PAL		For LTCC printing. High resolution screen printing can be obtained because it prevents the leakage of paste at the backside of the stencil with its softness.

*Further special emulsions are also available for individual applications. Please enquire.

Options

Combination meshing

• In this construction, a steel wire mesh is suspended on a supporting polyester mesh. Thus the advantages of both elastic polyester mesh and stable steel wire mesh are combined.
• High tension level.

Backings for supporting mesh

• The stability of supporting mesh is reinforced by backing materials, which improves the reliability of combination-meshed screens.
• It contributes to dimensional stability.

Corner R

• It reduces the damage during printing.
  * Patent No. 3462125

Polygon combination

• Combination of pentagon or more (Unusual-shaped combination)
  * Patent No. 3492651 (Taiwan, China, South Korea patented)

BK Mask

• Fluorine application on the emulsion surface to have hydro and oil repellency.

Flattening

• This process aims to make the emulsion surface flat and smooth, preventing the emulsion from forming bumps on the knuckles of the mesh. (The effect is especially prominent in thin coatings.)

FRAME

Screen frames play a vital role in screen printing.
As the dimensional accuracy and the correct screen tensioning are essential for the quality of high-precision screen printing, it is important to select the right frames for the accuracy and strength of the construction.

*Cast Aluminum frames ~ 800

Recommended frame

TOPRO general-purpose frame size	Frame types･Size （H×W×t）
	cast	B material	C material	SPC4
	–	20×30×1.5	30×40×2.0	30×40×3.0
320×320	○	○
380×380	○	○
450×450	○		○
550×550	○		○	○
550×650	○		○	○
650×750	○		○	○
750×750	○			○
950×950				○
1000～
TOPRO general-purpose frame size	Frame types･Size （H×W×t）
	Ｉ material	SPCK	SPHK	SPK
	30×50×2.74	32×42×5.0（4.0）	30×60×4.0（3.0）	40×80×3.0
320×320
380×380
450×450
550×550		○
550×650		○
650×750	○	○
750×750	○	○	○
950×950	○	○	○	○
1000～	○	○	○	○

Frame strength

Deflection(mm): manufacturers’ catalog value (Short side / Long side)

Frame size	Frame types･Size
	cast	B material	C material	SPC4
320×320	0.095	0.070	–	–
450×450	0.086	0.275	0.080	0.058
550×550	–	0.613	0.179	0.129
550×650	0.008/0.251	0.094/1.810	0.027/0.527	0.020/0.381
650×750	0.031/0.363	0.360/3.086	0.105/0.898	0.076/0.650
736×736	–	–	0.572	0.414
800×800	0.343	–	0.799	0.578
950×950	–	–	1.589	1.149
Frame size	Frame types･Size
	I material	SPCK	SPHK	SPK
320×320	–	–	–	–
450×450	–	0.031	–	–
550×550	–	0.070	–	–
550×650	–	0.011/0.207	–	–
650×750	–	0.041/0.353	–	–
736×736	0.235	0.225	0.104	–
800×800	0.328	0.314	0.145	–
950×950	0.653	0.625	0.288	※□1500：0.070