JP2009066762A - Screen printing method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screen printing method capable of sufficiently restraining vibration of a screen immediately after being pulled off a substrate. <P>SOLUTION: In a process for pulling the printed circuit board 1 off a metal screen 5, the leading end of each plate-like spring 6 presses or comes into contact with the lower side of the metal screen 5 while returning upwards during at least the beginning of the process. This restrains an amount of downward elastic deformation of the metal screen 5 and also restrains resilience accumulated in the metal screen 5. In addition, even if the metal screen 5 starts to vibrate as a result of releasing the metal screen 5 from the resilience all at once, the vibration of the metal screen is absorbed and relaxed by each plate-like spring 6. This prevents the metal screen 5 from coming into contact with a pattern of soldering paste 8 on the surface of the printed circuit board 1 and prevents damage to the pattern of the soldering paste 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a screen printing method and apparatus for applying a paste to a substrate surface via a screen.

  In this type of printing method, for example, as shown in FIG. 7A, a substrate 101 such as a printed circuit board is set on a printing table 102, and a metal screen 103 having a plurality of pattern openings is provided on a screen support table 104. The substrate 101 and the metal screen 103 are supported in parallel with each other, and as shown in FIG. 7B, the printing table 102 and the screen support table 104 are brought close to each other, and the substrate 101 and the metal screen 103 are overlaid. 7C, a paste 106 such as a solder paste or an adhesive is filled in each pattern opening of the metal screen 103 by the squeegee 105, and at the same time, a pattern of the paste 106 is applied to the surface of the substrate 101, and subsequently As shown in FIG. 7D, the printing plate 102 and the screen support table 104 are separated from each other, and the substrate 101 is separated. At this time, the paste filled in each pattern opening of the metal screen 103 is transferred to the surface of the substrate 101, and a pattern of the paste 106 is formed on the surface of the substrate 101 as shown in FIG. Yes.

  Usually, the printing stand is placed below the screen support, the printing stand is raised, the substrate and the metal screen are overlapped, the printing stand is lowered, and the substrate is often pulled away from the screen. You may raise and lower.

  The board is called a printed circuit board, a printed wiring board, or the like, and there are various materials. The solder paste is a cream made by kneading solder alloy powder and viscous flux.

  By the way, when the substrate is pulled away from the screen, the paste filled in the opening of the screen is punched against the viscous force. At this time, the paste pattern stretches with its edge pulled toward the opening of the screen, its center pulled toward the substrate, and its center recessed. Along with this, the edge of the opening of the screen is also pulled toward the substrate side, the screen is elastically deformed, and the restoring force of the screen is accumulated. Then, when the edge of the paste pattern is cut off from the opening of the screen, the restoring force of the screen is released at once, the screen is elastically deformed in the direction away from the substrate, and then the screen approaches the substrate by the reaction. Then, the screen is elastically deformed alternately in these two directions, that is, the screen vibrates, that is, the screen continues to vibrate until the previously restored restoring force disappears.

  In particular, immediately after the edge of the paste pattern is cut off from the opening of the screen, the amplitude of the screen is large, which may cause the screen to contact the paste pattern on the substrate surface and damage the paste pattern. .

  In recent years, electronic components have become lighter, thinner, smaller, and narrower in pitch with higher functionality and smaller size, reducing the amount of solder required for soldering and making metal screens thinner. Tend to be. For this reason, the screen is easily deformed, and as described above, the screen is likely to vibrate immediately after being peeled off from the substrate, and the paste pattern on the substrate surface is frequently damaged due to the screen contact. Yes.

  For this reason, in the patent document 1, after the printing with the squeegee is completed, the substrate and the screen are kept overlapped, only the substrate is moved to the screen side, the substrate is pressed against the screen, and the screen is elastically deformed in a substantially bow shape. The paste filled in the opening of the screen is punched out.

In Patent Document 2, two guide members are brought into contact with both edges of the screen to suppress fine movement and vibration of the screen.
Japanese Patent Laid-Open No. 11-214836 JP 2003-260782 A

  However, in Patent Document 1, when the screen is elastically deformed into a substantially bow shape, the paste filled in the opening of the screen is die-cut, but the number of pattern openings formed in the screen, Depending on the position and size, the screen may not be elastically deformed in a substantially arcuate shape or may not be partially deformed, and thus the paste is not necessarily punched out reliably. For this reason, when the screen is separated from the substrate, the screen may vibrate immediately after being peeled off from the substrate as described above, and the screen comes into contact with the paste pattern on the substrate surface.

  Further, in Patent Document 2, since only two guide members are brought into contact with both edges of the screen, the vibration of the screen immediately after being peeled off from the substrate as described above can be sufficiently suppressed. The contact of the screen with the paste pattern on the substrate surface could not be reliably prevented.

  Therefore, the present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a screen printing method and apparatus capable of sufficiently suppressing the vibration of the screen immediately after being peeled off from the substrate. And

  In order to solve the above-described problems, the screen printing method of the present invention includes a stacking step in which the substrate and the screen are overlapped with each other, a coating step in which a paste is applied to the substrate surface through the screen, and a pulling out step in which the screen is separated from the substrate In the superimposing step, the elastic member is brought into pressure contact with the screen surface, and the elastic member is brought into contact with the screen surface by restoring the shape of the elastic member even at least in the initial stage of the separating step.

  For example, the substrate is a printed circuit board on which electronic components are mounted, and the paste is a solder paste mixed with solder alloy powder and flux.

  Next, in the screen printing apparatus of the present invention, the substrate and the screen are overlapped with each other while supporting the substrate and the screen, the support means for separating the screen from the substrate, and the substrate and the screen are overlapped with each other by the support means. Paste application means for applying the paste to the substrate surface through the screen in a combined state, and an elastic member pressed against the screen surface when the substrate and the screen are overlapped with each other by the support means The elastic member is in contact with the surface of the screen by restoring the shape of the elastic member at least at the initial stage of the step of separating the screen from the substrate by the support means.

  For example, the elastic member is a plate spring provided in the support means, and when the substrate and the screen are overlapped with each other by the support means, the plate spring is pressed against the screen surface and elastically deformed. The plate spring comes into contact with the surface of the screen by restoring the shape of the plate spring at least at the initial stage of the step of separating the screen from the substrate by the support means.

  The plate springs may be provided at a plurality of locations on the screen surface. In this case, the direction of at least one of the plate springs is preferably different from the other directions.

  Further, the elastic member has a contact member provided in the support means and a spring for biasing the contact member, and when the substrate and the screen are overlapped with each other by the support means, The contact member is pressed against the surface of the screen against the elastic force of the spring, the spring is elastically deformed, and at least the initial stage of the step of separating the screen from the substrate by the support means, the contact member is recovered by restoring the shape of the spring. Contacts the screen surface.

  The contact member and the spring may be provided at a plurality of locations on the screen surface. In this case, it is preferable that at least one of the contact members has a different contact height with respect to the screen surface.

  The support means supports a plurality of substrates and one screen, while the substrates and the screen are overlapped with each other, or the screen is separated from each substrate. The paste may be applied to the surface of each substrate through the screen in a state where the screen and the screen are overlapped with each other.

  According to the printing method of the present invention having such a configuration, the substrate and the screen are overlapped with each other in the overlapping step, the paste is applied to the substrate surface through the screen in the applying step, and the screen is separated from the substrate in the separating step. Yes. In the overlapping step, the elastic member is brought into pressure contact with the screen surface, and the elastic member is brought into contact with the screen surface by restoring the shape of the elastic member even at least in the initial stage of the separating step.

  Here, in the initial stage of the separation process, the screen is not cut off from the paste, and the screen is pulled toward the substrate, and the screen is elastically deformed. However, since the elastic member is in contact with the screen surface by restoring the shape of the elastic member, the amount of elastic deformation of the screen is suppressed. When the screen is separated from the paste, the restoring force of the screen is released at once, and the screen vibrates. At this time, the vibration of the screen is absorbed and relaxed by the elastic member, and the vibration amplitude of the screen is immediately attenuated. For this reason, the screen does not contact the paste pattern on the substrate surface, and the paste pattern on the substrate surface is not damaged.

  Similarly, in the printing apparatus of the present invention, when the substrate and the screen are overlapped with each other, the elastic member is pressed against the surface of the screen and is separated from the substrate at least in the initial stage by restoring the shape of the elastic member. Since the elastic member comes into contact with the screen surface, the amount of elastic deformation of the screen is suppressed, and the vibration of the screen is suppressed. For this reason, the screen does not contact the paste pattern on the substrate surface, and the paste pattern on the substrate surface is not damaged. As a result, it is possible to achieve higher efficiency of the printing operation of the paste by the screen, improvement of printing accuracy or quality, higher density of printing, etc. without particularly increasing the cost.

  The effect of suppressing the elastic deformation amount and vibration of the screen due to the contact of the elastic member can be obtained regardless of the material and thickness of the screen, and reliably prevent the screen from contacting the paste pattern on the substrate surface. Can do.

  As the substrate, various materials can be applied. In addition to the solder paste, an adhesive, a resist, or the like can be applied as the paste.

  For example, a plate spring can be applied as the elastic member. The shape and position of the plate spring is set appropriately, and when the substrate and the screen are overlapped with each other, the plate spring is pressed against the screen surface and elastically deformed, and the screen is separated from the substrate. At least initially, the plate spring is brought into contact with the screen surface by restoring the shape of the plate spring.

  If a plurality of plate springs are provided, the vibration of the screen can be more effectively suppressed. Further, even if the direction of at least one plate spring is set to be different from the other direction, the vibration of the screen can be more effectively suppressed.

  In addition, a combination of an abutting member that abuts on the screen and a spring that biases the abutting member can be applied as the elastic member. When the contact member comes into pressure contact with the screen surface, the spring is elastically deformed, and at least in the initial stage of the process of separating the screen from the substrate, the contact member is brought into contact with the screen surface by restoring the shape of the spring.

  Also in this case, if a plurality of sets of contact members and springs are provided, the vibration of the screen can be more effectively suppressed. Moreover, even if it sets so that the contact height with respect to the screen surface may differ from others about at least 1 contact member, the vibration of a screen can be suppressed more effectively.

  The method and apparatus of the present invention can also be applied to a case where a plurality of substrates are arranged and paste is printed on each substrate using a single screen.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1A is a cross-sectional view schematically showing a first embodiment of the screen printing apparatus of the present invention. In the apparatus of the present embodiment, the printed circuit board 1 is bonded and fixed onto the transport pallet 2 via a double-sided Kapton tape (not shown), and the transport pallet 2 is carried into the apparatus and set on the printing stand 3. . The screen support 4 is arranged above the printing table 3, supports the metal screen 5 by the screen support 4, and arranges the printed circuit board 1 and the metal screen 5 to face each other in parallel. Then, the printed circuit board 1 and the metal screen 5 are aligned. The printing table 3 is driven up and down, and the screen support table 4 is fixed.

  A plurality of plate springs 6 protrude from the transport pallet 2. As shown in FIG. 2, each plate spring 6 is formed by making U-shaped cuts at a plurality of locations on the conveyance pallet 2 made of a metal plate, and bending these cut portions into a U-shape. It arrange | positions so that the printed circuit board 1 on the conveyance pallet 2 may be enclosed. Each plate spring 6 has elasticity, and a bent portion 6 a of these plate springs 6 protrudes upward from the printed circuit board 1.

  After the transport pallet 2 is set on the printing stand 3 in this way, the printed circuit board 1 and the metal screen 5 on the transport pallet 2 are arranged opposite to each other in parallel, and the printed circuit board 1 and the metal screen 5 are aligned. As shown in FIG. 1B, the printing stand 3 is raised, and the printed circuit board 1 and the metal screen 5 on the transport pallet 2 are overlapped and brought into close contact with each other. At this time, the plate springs 6 of the transport pallet 2 are pressed against the lower surface of the metal screen 5 and elastically deformed downward.

  The close contact state between the printed circuit board 1 and the metal screen 5 is referred to as on-contact. Normally, due to the close contact, the pressure of the squeegee is reduced when the paste is filled with the squeegee thereafter. In addition, the press stroke of the squeegee can be reduced to reduce printing misalignment due to screen tension deviation, and high-precision printing is possible.

  Next, as shown in FIG. 1C, the squeegee unit 7 is reciprocated above the metal screen 5, and the squeegee 7 a of the squeegee unit 7 is slid on the upper surface of the metal screen 5. It extends and fills each pattern opening 5a of the metal screen 5. At the same time, the pattern of the solder paste 8 is applied to the surface of the printed circuit board 1.

  The solder paste 8 has a good thixotropy, for example, an alloy powder having a component ratio such as Sn63 / Pb37, Sn96.5 / Ag3.0 / Cu0.5, and a high-viscosity flux based on a resin or the like. It is desirable that the product conforms to JIS standard Z 3284. In addition, the alloy powder particles are not indefinite, but are spherical and have a particle size of 5-15 μm, 10-25 μm, etc. Is suitable.

  Next, as shown in FIG. 1D, the printing stand 3 is lowered, and the printed circuit board 1 on the transport pallet 2 is pulled away from the metal screen 5. At this time, since the solder paste 8 filled in the pattern opening 5a of the metal screen 5 is punched against the viscous force, the edge of the pattern of the solder paste 8 is the pattern opening 5a of the metal screen 5. The center is pulled to the printed circuit board 1 side, and the center is extended in a recessed state. Along with this, the edge of the opening 5a of the metal screen 5 is also pulled toward the printed circuit board 1, and the metal screen 5 is elastically deformed downward, and the restoring force of the metal screen 5 is accumulated.

  However, although the plate springs 6 of the transport pallet 2 are in the middle of separating from the metal screen 5, the bent portions 6a of the plate springs 6 return upward and press the lower surface of the metal screen 5 due to their shape restoration. continuing. For this reason, the downward elastic deformation amount of the metal screen 5 is suppressed, and the restoring force accumulated in the metal screen 5 is also suppressed.

  Furthermore, when the edge of the pattern of the solder paste 8 is cut off from the opening 5a of the metal screen 5, the restoring force of the metal screen 5 is released at once, and the metal screen 5 vibrates. Absorption is alleviated by each plate spring 6, and the vibration amplitude of the metal screen 5 is immediately attenuated.

  Thus, in the step of separating the printed circuit board 1 from the metal screen 5, at least at the initial stage, the bent portion 6 a of each plate spring 6 presses or contacts the lower surface of the metal screen 5 while returning upward. The amount of elastic deformation in the downward direction is suppressed, the restoring force accumulated in the metal screen 5 is also suppressed, and even if the restoring force of the metal screen 5 is released at a stretch and the metal screen 5 starts to vibrate, the vibration of the metal screen 5 does not vibrate. Absorption is alleviated by each plate spring 6. For this reason, the metal screen 5 does not come into contact with the pattern of the solder paste 8 on the surface of the printed circuit board 1, and the pattern of the solder paste 8 is not damaged.

  In order to press or contact the lower surface of the metal screen 5 while the bent portion 6a of each plate spring 6 returns upward at least at the initial stage of the step of pulling the printed circuit board 1 away from the metal screen 5, It is necessary to set the protruding height of the bent portion 6a of the plate spring 6 appropriately. The thickness of the solder paste 8 on the surface of the printed circuit board 1 is substantially the same as the thickness of the metal screen 5, and the distance of the printed circuit board 1 from the metal screen 5 is two to five times the thickness of the solder paste 8. Until the bent portion 6a of each plate spring 6 presses or contacts the lower surface of the metal screen 5, the vibration of the metal screen 5 can be sufficiently suppressed. It is considered that the printed circuit board 1 is easily pulled away from the metal screen 5 by being pushed back. For example, if the thickness of the metal screen 5 is 0.1 mm, the protruding height of the bent portion 6a of each plate spring 6 from the surface of the printed circuit board 1 is 0.2 mm to 0.5 mm. If the thickness is 0.3 mm, the total height of each plate spring 6 is set to 0.5 mm to 0.7 mm.

  When the printing stand 3 is lowered and the printed circuit board 1 on the transport pallet 2 is completely separated from the metal screen 5, the plate springs 6 of the transport pallet 2 are also completely separated from the metal screen 5, as shown in FIG. As shown in (e), the solder paste 8 filled in each pattern opening 5a of the metal screen 5 is transferred to the surface of the printed circuit board 1, and a pattern of the solder paste 8 is formed on the surface of the printed circuit board 1.

  Further, when the printing stand 3 is lowered, the transport pallet 2 becomes free, and the transport pallet 2 can be transported to the next process.

  Note that each plate spring 6 as shown in FIG. 3 may be used in place of each plate spring 6 of the transport pallet 2 as shown in FIG. Each of the plate springs 6 in FIG. 3 has both a right-facing direction and a left-facing direction, so that even if the vibration direction of the metal screen 5 changes, each plate spring 6 and the metal screen 5 is ensured, and the vibration of the metal screen 5 can be reliably suppressed.

  Further, as shown in FIGS. 4A and 4B, the heights of the plate springs 6 may be uneven. Thereby, the period when the bending part 6a of each plate-like spring 6 presses or contacts the lower surface of the metal screen 5 becomes longer, and the vibration of the metal screen 5 can be reliably suppressed. Furthermore, the metal screen 5 is reliably pushed back by the plate springs 6, so that the printed circuit board 1 can be easily separated from the metal screen 5.

  In addition, as shown in FIG. 5, a plurality of printed circuit boards 1 may be bonded onto one transport pallet 2, and solder paste 8 may be simultaneously printed on each printed circuit board 1 by a single metal screen 5. In this case, each plate spring 6 is provided around each printed circuit board 1.

  Further, the plate springs 6 shown in FIGS. 3 and 4 may be mixed, or the plate spring 6 shown in FIG. 3 or 4 may be provided on the transport pallet 2 shown in FIG.

  FIG. 6A is a sectional view schematically showing a second embodiment of the screen printing apparatus of the present invention. 6 (a) to 6 (e), the same reference numerals are given to the portions that perform the same operations as those in FIGS. 1 (a) to 1 (e).

  In the apparatus of the present embodiment, a transport pallet 2A and a printing stand 3A are used instead of the transport pallet 2 and the printing stand 3 in the apparatus of FIG. The transport pallet 2A is provided with a plurality of U-shaped support pieces 21 on the lower surface thereof, and supports the respective contact bar bodies 22 by the U-shaped support pieces 21. The spring 23 is biased upward.

  Each abutting bar body 22 has a stopper 22a at substantially the center thereof, and the upper end of each abutting bar body 22 protrudes upward through each hole of the transport pallet 2A, and the lower end of each abutting bar body 22 is Each U-shaped support piece 21 protrudes downward through a hole at the bottom. Each spring 23 is disposed between the stopper 22a of each contact bar body 22 and the bottom of each U-shaped support piece 21 to urge each contact bar body 22 upward.

  The printing table 3A has a plurality of recesses 31 on the surface thereof, and when the conveyance pallet 2A is set on the printing table 3A, each U-shaped support piece 21 of the conveyance pallet 2A is attached to the printing table 3A. Each recess 31 is allowed to descend and each contact rod 22 is allowed to descend.

  Next, the printing procedure of the solder paste 8 by the apparatus of this embodiment will be briefly described. In addition, each contact rod body 22 and each spring 23 of 2 A of conveyance pallets have the same effect as each plate-shaped spring 6 of Fig.1 (a). Also in the apparatus of this embodiment, the solder paste 8 is printed on the printed circuit board 1 in the same procedure as in the apparatus of FIG.

  First, as shown in FIG. 6A, the transport pallet 2A is set on the printing stand 3A, the printed circuit board 1 and the metal screen 5 on the transport pallet 2A are arranged in parallel and opposed to each other, and the printed circuit board 1 and the metal screen are arranged. After the alignment of 5, the printing stand 3 </ b> A is raised as shown in FIG. 6B, and the printed circuit board 1 and the metal screen 5 on the transport pallet 2 </ b> A are overlapped and adhered to each other. At this time, the upper ends of the contact bars 6 of the transport pallet 2A are in pressure contact with the lower surface of the metal screen 5, and the contact bars 6 are lowered against the elastic force of the springs 23. Each of the springs 23 is pressed by the 6 stoppers 22a and shortened.

  As shown in FIG. 6C, the squeegee unit 7 is reciprocated above the metal screen 5, and the solder paste 8 is extended by the squeegee 7 a to fill each pattern opening 5 a of the metal screen 5. At the same time, the pattern of the solder paste 8 is applied to the surface of the printed circuit board 1.

  As shown in FIG. 6D, the printing stand 3 </ b> A is lowered and the printed circuit board 1 on the transport pallet 2 </ b> A is pulled away from the metal screen 5. At this time, the edge of the pattern of the solder paste 8 is pulled toward the pattern opening 5a side of the metal screen 5, the center thereof is pulled toward the printed circuit board 1, and the center extends. Along with this, the edge of the opening 5a of the metal screen 5 is also pulled toward the printed circuit board 1, and the metal screen 5 is elastically deformed downward, and the restoring force of the metal screen 5 is accumulated.

  Each contact bar 22 of the transport pallet 2 </ b> A is in the middle of being separated from the metal screen 5, but the upper end of each contact bar 22 returns upward due to the shape restoration of each spring 23 and presses the lower surface of the metal screen 5. to continue. For this reason, the downward elastic deformation amount of the metal screen 5 is suppressed, and the restoring force accumulated in the metal screen 5 is also suppressed.

  Further, when the edge of the pattern of the solder paste 8 is cut off from the opening 5a of the metal screen 5, the restoring force of the metal screen 5 is released at once, and the metal screen 5 vibrates. Absorption is alleviated by the springs 23 through the contact rods 22, and the vibration amplitude of the metal screen 5 is immediately attenuated.

  In this way, each contact bar 22 is biased upward by each spring 23, and the upper end of each contact bar 22 presses or contacts the lower surface of the metal screen 5, so that the metal screen 5 is elastically deformed downward. Even if the amount is suppressed, the restoring force accumulated in the metal screen 5 is also suppressed, and the restoring force of the metal screen 5 is released at once, and the metal screen 5 starts to vibrate, the vibration of the metal screen 5 is not affected by each contact rod. 22 is absorbed and relaxed by each spring 23.

  When the printing stand 3A is lowered and the printed circuit board 1 on the transport pallet 2A is completely separated from the metal screen 5, each contact bar 22 of the transport pallet 2A is also completely separated from the metal screen 5, as shown in FIG. 6 (e), the solder paste 8 filled in each pattern opening 5a of the metal screen 5 is transferred to the surface of the printed circuit board 1, and a pattern of the solder paste 8 is formed on the surface of the printed circuit board 1. .

  Further, when the printing stand 3A is lowered, the transport pallet 2A becomes free, and the transport pallet 2A can be transported to the next process.

  Note that the height of the contact bar 22 may be changed. For example, the contact rod body 22 is a screw rod, the contact rod body 22 is screwed into the center of the stopper 22a, and the height of the contact rod body 22 is changed according to the screwing amount of the contact rod body 22. If the height of each contact bar 22 is set appropriately, the contact height of the upper end of each contact bar 22 with respect to the metal screen 5 is made uneven, and the upper end of each contact bar 22 is placed on the metal screen 5. The period during which the lower surface is pressed or contacted can be lengthened, and the vibration of the metal screen 5 can be reliably suppressed. Further, the metal screen 5 is surely pushed back by the tip of each contact rod body 22, and the printed circuit board 1 can be easily separated from the metal screen 5. Moreover, you may change suitably the position, number, etc. of the contact | abutting rod body 22. FIG.

  Further, instead of the combination of the plate spring and the contact rod body and the spring, an elastic member having another shape, material, structure, etc. may be applied.

(A) is schematic sectional drawing of 1st Embodiment of the screen printing apparatus of this invention, Comprising: It is a figure which shows the process of arrange | positioning a printed circuit board and a metal screen, (b) is a printed circuit board and a metal. It is a figure which shows the process which overlap | superposed the screen, (c) is a figure which shows the process of apply | coating solder paste to a printed circuit board via a metal screen, (d) is the process of pulling a metal screen away from a printed circuit board. (E) is a figure which shows the state after separating the metal screen from the printed circuit board. It is a perspective view which shows the conveyance pallet in the apparatus of Fig.1 (a). It is a perspective view which shows the modification of the conveyance pallet in the apparatus of Fig.1 (a). It is a perspective view which shows the other modification of the conveyance pallet in the apparatus of Fig.1 (a). It is a perspective view which shows another modification of the conveyance pallet in the apparatus of Fig.1 (a). (A) is schematic sectional drawing of 2nd Embodiment of the screen printing apparatus of this invention, Comprising: It is a figure which shows the process of arrange | positioning a printed circuit board and a metal screen, (b) is a printed circuit board and a metal. It is a figure which shows the process which overlap | superposed the screen, (c) is a figure which shows the process of apply | coating solder paste to a printed circuit board via a metal screen, (d) is the process of pulling a metal screen away from a printed circuit board. (E) is a figure which shows the state after separating the metal screen from the printed circuit board. (A) is schematic sectional drawing of the conventional printing apparatus, Comprising: It is a figure which shows the process which has arrange | positioned a board | substrate and a metal screen, (b) is a figure which shows the process which piled up the board | substrate and the metal screen. (C) is a figure which shows the process of apply | coating a paste to a board | substrate via a metal screen, (d) is a figure which shows the process of pulling a metal screen away from a board | substrate, (e) is a figure which pulls a metal screen away from a board | substrate. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printed circuit board 2, 2A Conveying pallet 3, 3A Printing stand 4 Screen support stand 5 Metal screen 6 Plate-like spring 7 Squeegee unit 8 Solder paste 21 U-shaped support piece 22 Contact rod 23 Spring

Claims (11)

An overlapping process of overlapping the substrate and the screen with each other;
An application step of applying the paste to the substrate surface via a screen;
A separation step of separating the screen from the substrate,
A screen printing method, wherein the elastic member is brought into pressure contact with the screen surface in the overlapping step, and the elastic member is brought into contact with the screen surface by restoring the shape of the elastic member at least at the initial stage of the separating step. The board is a printed circuit board on which electronic components are mounted,
The screen printing method according to claim 1, wherein the paste is a solder paste mixed with a solder alloy powder and a flux. A supporting means for supporting the substrate and the screen while superimposing the substrate and the screen on each other or separating the screen from the substrate;
Paste applying means for applying the paste to the surface of the substrate through the screen in a state where the substrate and the screen are overlapped with each other by the supporting means;
An elastic member pressed against the screen surface when the substrate and the screen are overlapped with each other by the support means;
The screen printing apparatus according to claim 1, wherein the elastic member is in contact with the surface of the screen by restoring the shape of the elastic member at least at an initial stage of the step of separating the screen from the substrate by the supporting means. The elastic member is a plate-like spring provided in the support means;
When the substrate and the screen are overlapped with each other by the support means, the plate spring is pressed against the screen surface and elastically deformed,
4. The screen printing apparatus according to claim 3, wherein the plate spring comes into contact with the surface of the screen by restoring the shape of the plate spring at least at an initial stage of the step of separating the screen from the substrate by the support means.   The screen printing apparatus according to claim 4, wherein the plate springs are respectively provided at a plurality of locations on the screen surface.   The screen printing apparatus according to claim 5, wherein an orientation of at least one of the plate springs is different from other orientations. The elastic member has a contact member provided on the support means and a spring for biasing the contact member,
When the substrate and the screen are overlapped with each other by the support means, the contact member is pressed against the screen surface against the elastic force of the spring, and the spring is elastically deformed,
4. The screen printing apparatus according to claim 3, wherein the contact member contacts the surface of the screen by restoring the shape of the spring at least at an initial stage of the step of separating the screen from the substrate by the support means.   The screen printing apparatus according to claim 7, wherein the contact member and the spring are provided at a plurality of locations on the screen surface.   The screen printing apparatus according to claim 8, wherein at least one of the contact members has a different contact height with respect to the screen surface. The support means supports a plurality of substrates and one screen, and superimposes the substrates and the screens on each other, or separates the screens from the substrates.
4. The screen printing apparatus according to claim 3, wherein the paste applying unit applies the paste to the surface of each substrate through the screen in a state where the substrate and the screen are overlapped with each other by the support unit. . The board is a printed circuit board on which electronic components are mounted,
The screen printing apparatus according to claim 3, wherein the paste is a solder paste in which a solder alloy powder and a flux are mixed.

Images