Opening process standard of Stencil

Opening process standard of Solder Paste Stencil

1. IC Category (W represents Width, L represents Length)

(1) PITCH = 0.8 - 1.27 mm: The width is generally set between 45% and 60% of the PITCH, with the specific value depending on the pad size on the circuit layer. For smaller pads on the circuit layer, choose a smaller width, and for larger pads, choose a larger width.

(2) PITCH = 0.635 - 0.65 mm: W = 0.3 - 0.33 mm, L = 1 mm, with rounded corners on both ends.

(3) PITCH = 0.5 mm: W = 0.24 mm, L: If less than 1.5 mm, extend outward by 0.1 mm, with rounded corners on both ends.

(4) PITCH = 0.4 mm: W = 0.19 mm, L: Extend outward by 0.1 mm, with rounded corners on both ends.

(5) PITCH = 0.35 mm: W = 0.17 mm, L: Extend outward by 0.1 mm, with rounded corners on both ends.

(6) PITCH = 0.3 mm: W = 0.16 mm, L: Extend outward by 0.1 mm, with rounded corners on both ends (if the length is <0.8 mm, extend the length outward by 0.15 mm).

For the above (0.65 - 1.27), if L < 1 mm, the length needs to be extended outward by 0.1 mm.

2. BGA Category

PITCH = 0.4 mm, open 0.23 mm square with rounded corners

PITCH = 0.45 mm, open 0.26 mm

PITCH = 0.5 mm, open 0.3 mm

PITCH = 0.65 mm, open 0.35 mm

PITCH = 0.8 mm, open 0.45 mm

PITCH = 1.0 mm, open 0.55 mm

PITCH = 1.27 mm, open 0.65 mm

Important Notes:

For 0.4 PITCH, open a 0.23 mm square with rounded corners.

3.  Resistor and capacitor pads

For resistor and capacitor pads which are 0805 and larger ones, anti-solder bead treatment will be applied as below.  What's solder bead? https://jlcpcb.com/help/article/Solder-beading-Treatment

Opening process standard of Red Glue Stencil

(1) 0402 Components: Width opening 0.26 mm, length extended by 0.15 mm.

0603 Components: Width opening 0.28 mm, length extended by 0.20 mm.

0805 Components: Width opening 0.32 mm, length extended by 0.20 mm.

1206 Components: Width opening 0.5-0.6 mm (or 30%-35% of the pad spacing).

For components above 1206: Width opening 35%, length extended by 0.2 mm.

When the gap between 0603 components is greater than 0.75 mm, width opening 0.32 mm.

When the gap between 0805 components is greater than 0.95 mm, width opening 0.35 mm.

For diodes: Width according to 35%-40% of the inner distance, length extended by 0.25 mm.

For components other than diodes, if it's difficult to determine the type, open about 30% of the inner distance. If the inner distance is too small, adjust according to the situation.

(2) SOT23

L1 = 110% L

W2 = W/2 (centered opening)

W1 = 0.3~0.5 mm

(3) SOT89

W=0.4mm

L1=L

(4)SOT233 & SOT252

W1 = 30% W

If 0.5 ≤ W1 ≤ 2.5 mm (open near the larger pad)

W2 = W/3

L1 = 110% L

If W ≥ 3.5 mm, a bridge is required, with a bridge width of 0.3 mm

2. Resistor and Capacitor Arrays L

D = 45% W

W1 = 1/2 W

L1 = L

When D > 3 mm, set D = 3 mm. The number of middle circular points depends on the size of the IC, with a minimum of 2 and a maximum of 5.

When the opening width is less than 0.35 mm, please make it a 0.35 mm rectangle.

3. IC, QFP

D = 45% W

W1 = 1/2 W

L1 = L

When D > 3 mm, set D = 3 mm. The number of middle circular points depends on the size of the IC, with a minimum of 2 and a maximum of 5.

D = 1.3-3.5 mm (specifically depending on the size of the QFP; if it is too small, the middle opening can be omitted)

Circular hole position: The outer edge of the circular hole should be aligned with the outermost end of the QFP's pins.

The above can be opened as a square hole according to 35-40% of the inner distance. If the width is greater than 1.5 mm, please open it as a circular hole according to the above requirements.