JP2936601B2 - Screen printing method of print paste - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a screen printing method for printing a printing paste on a substrate by a screen printing machine.

(Prior Art) When a circuit pattern or the like is printed on a substrate by a screen printing machine, the mask and the substrate must be accurately matched.

FIG. 5 shows a conventional matching means.
100 is a substrate, 101A and 101B are reference points provided at corners of the substrate 100, 102 is a mask of a screen printing machine, 103 is a mask 10
2, a pattern hole opened in 2, a camera 104 that is driven by an XY table 105 and moves in the XY direction, 106 and 107 are positioning members for positioning the substrate 100 at an observation position and a printing position,
108 is a squeegee.

In this method, first, the substrate 100 is positioned by the positioning member 106, and in this state, the camera 104 is moved in the XY direction to observe the reference points 101A and 101B, thereby obtaining the XYθ of the substrate 100.
Detects the direction displacement. Next, the substrate 100 is
, And positioned by the positioning member 107 (see the broken line in the figure).
By moving the squeegee 108 in the Yθ direction to correct the positional deviation, the squeegee 108 is slid to print a circuit pattern.

(Problems to be Solved by the Invention) In the above-mentioned conventional means, the observation position of the substrate 100 is different from the print position immediately below the mask 102, and the position is detected at the observation position, and then the substrate 100 is moved to the print position. Then, printing is performed after correcting the positional deviation.
Therefore, if there is a misalignment between the positioning member 106 and the positioning member 107, even if the displacement of the substrate 100 is accurately detected as described above, and the above-described correction is performed based on this, Due to the misalignment of the positioning members 106 and 107, the substrate 100 is not correctly matched to the mask 102, and the circuit pattern is not accurately printed at a predetermined position. In addition, while printing the printing paste on the substrate through the pattern holes of the mask, the printing paste gradually adheres to the edges of the pattern holes, and as a result, the effective opening area of the pattern holes gradually decreases, resulting in poor printing.

Therefore, an object of the present invention is to provide means capable of solving the problem of the conventional means.

(Means for Solving the Problems) For this purpose, according to the present invention, a substrate set on an XY table is moved in the XY direction and positioned directly below a mask, and in this state, the substrate is passed through a window provided on the mask. A camera provided above the mask observes a reference point formed on the substrate, detects a displacement of the substrate in the XYθ direction, and then drives the XY table and the θ table to XYθ by the amount of the positional deviation in the XYθ direction.
After correcting the misalignment by moving in the direction, the printing paste is printed on the substrate through the pattern holes of the mask, and then the pattern holes are observed by a camera, and the pattern hole is determined from the complete opening area and the current opening area. This is to determine the presence or absence of a print paste adhering to the edge of the pattern hole.

(Operation) According to the above configuration, since the observing position of the displacement of the substrate and the printing position of the print pattern are the same, the displacement does not occur as in the above-described conventional means, and the print pattern is moved to a predetermined position. Can be printed accurately. In addition, the pattern hole is observed with a camera, and the presence or absence of the printing paste adhering to the edge of the pattern hole is determined from the complete opening area of the pattern hole and the current opening area.

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

FIG. 1 is a perspective view of a screen printing machine, and FIG. 2 is a front view. The printing machine includes an XY table device 1 and a screen device 3 provided above one side thereof.

The XY table device 1 includes an XY table 5,
A Y table 6, a rotary table 7, and a Z table 8 are mounted in stages. The X table 5 is mounted on an X-direction rail 11 provided on the base plate 4 via a slider 12, and reciprocates in the X direction by a motor MX and a feed screw 13.

The Y table 6 is mounted via a slider 16 on a Y-direction rail 15 provided on the X table 5, and reciprocates in the Y direction by a motor MY and a feed screw 17. The rotary table (θ table) 7 is mounted on the Y table 6 via a rotary shaft 18 at the corner so as to be horizontally rotatable.
A motor Mθ and a feed screw 19 are provided on the Y table 6. Numeral 20 is a nut screwed on the feed screw 19,
Reference numeral 21 denotes a roller which is attached to the tip of an arm 22 extending from the rotary table 7 and fits into the nut 20. Therefore, the motor Mθ is driven and the nut 20 is
, The rotary table 7 rotates horizontally about the shaft 18.

The Z table 8 is attached to an actuator MZ composed of a cylinder provided at the center of the rotary table 7. 23 is a guide rod part. Reference numeral 24 denotes a substrate positioned on the Z table 8, and reference points A1 and B1 for observing positional deviation are provided at diagonal corners thereof.

The screen device 3 includes a mask supported by the frame 32.
The mask 33 includes a squeegee 34 which is driven by a driving device (not shown) and slides on the mask 33. The mask 33 is provided with reference points A2 and B2. Reference numeral 35 denotes a pattern hole formed in the mask 33. 36 and 37 are the above substrates 24 of the mask 33
Windows provided at positions corresponding to the reference points A1 and B1,
Is a camera provided movably in the XY direction above the window 36, and is mounted on the XY table 45. This window
36 and 37 are formed by opening the mask 33 or attaching a transparent plate.

This screen printing machine has the above configuration,
Next, the operation will be described.

The XY tables 5 and 6 are driven to move the substrate 24 directly below the mask 33, and then the Z table 8 is driven to raise the substrate 24 and bring the substrate 24 close to the lower surface of the mask 33 (see the chain line in FIG. 2). reference). In this state, the camera 38,
The reference points A1 and B1 of the substrate 24 are observed by 39 (see FIG. 3), and the positional deviation of the reference points A1 and B1 from the reference points A2 and B2 in the XYθ direction is detected. The positions of the reference points A2 and B2 of the mask 33 are observed and stored in advance by the cameras 38 and 39.

Next, based on the observation results of the cameras 38 and 39, the board 24 is moved in the XYθ direction by the detected position shift in the XYθ direction, and after correcting this position shift, the squeegee 34 is slid and the circuit 24 is moved. Print the pattern. In other words, the conventional means differs in that the observation position of the substrate and the correction position of the positional deviation are different, whereas the present means realizes the observation of the positional deviation of the substrate 24 and the correction of the positional deviation in the same position, that is, the printing position. 33
Therefore, the circuit pattern can be printed accurately at a predetermined position.

By the way, while the squeegee 34 is slid and the circuit pattern is repeatedly printed, the printing paste 40 easily adheres to the edge of the pattern hole 35 (see FIG. 4A). Printing pastes are roughly classified into pastes that form circuit patterns such as conductive pastes and resistive pastes, and cream solders that are applied to the electrode portions of the circuit patterns. Since the solvent contained therein volatilizes and the viscosity tends to increase, the solvent tends to adhere considerably to the edge. When the printing paste 40 adheres to the edge of the pattern hole 35 in this manner, the shape of the circuit pattern 41 applied to the substrate 24 deteriorates (see FIG. 4B).

Therefore, the pattern holes 35 are appropriately observed by the cameras 38 and 39, and the degree of adhesion of the paste 40 is inspected. If the degree of adhesion is large, printing is interrupted, and the mask 33 is replaced or cleaned. In this case, the ratio (K = S2 / S1) between the complete opening area S1 of the pattern hole 35 and the current opening area S2 is obtained, and if this ratio becomes a predetermined value or less, the printing is automatically interrupted. At the same time, it is advisable to notify that effect by a notification means such as a buzzer or a lamp.

(Effects of the Invention) As described above, according to the present invention, since the observation of the displacement of the substrate and the correction of the displacement are performed at the same position, that is, immediately below the mask at the printing position, the mask and the substrate can be easily and accurately placed. The circuit pattern can be printed by matching. In addition, by observing the pattern hole with a camera, it is possible to accurately determine the presence or absence of the printing paste adhering to the edge of the pattern hole from the complete opening area of the pattern hole and the current opening area, and to reduce the effective opening area of the pattern hole. Printing defects can be eliminated.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a perspective view of a screen printer, FIG. 2 is a front view of the same, FIG. 3 is a plan view during observation, and FIG. FIG. 5 is a plan view of the conventional means. 5, 6 XY table 24 Board 33 Mask 36, 37 Window 38, 39 Camera A1, B1 Reference point

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41F 15/08 303 B41F 15/18-15/26 B41F 15/40-15/42 H05K 3/12 610 H05K 3/34 505

Claims (1)

(57) [Claims] 1. A substrate set on an XY table is moved in the XY direction to be positioned directly below a mask, and in this state, a camera provided above the mask is passed through a window provided on the mask. By observing the reference points formed on the substrate, the displacement of the substrate in the XYθ direction is detected,
Next, the XY table and the θ table are driven, and the substrate is moved in the XYθ direction by the amount of the positional deviation in the XYθ direction. After correcting the position deviation, the printing paste is printed on the substrate through the pattern holes of the mask. And thereafter, observing the pattern holes with a camera, and judging the presence or absence of the printing paste adhering to the edge of the pattern holes based on the complete opening area of the pattern holes and the current opening area. Printing method