JP6438797B2 - Printing apparatus and printing method - Google Patents

Description

  The present invention relates to a printing apparatus and a printing method that perform resin sealing of electronic components and resin filling of a circuit board by stencil printing.

  Stencil printing using an insulating resin paste or a conductive paste as a printing material is performed in order to encapsulate a resin paste of an electronic component on a circuit board or to fill a hole in the circuit board with a conductive paste or the like. Stencil printing is to push the printing material into the holes of the stencil by moving the squeegee on the stencil after supplying the printing material onto the stencil, but when using a resin with high viscosity as the printing material, etc. It may be difficult to fill the hole with resin with a single operation of the squeegee. For this reason, in the stencil printing apparatus used for resin sealing or resin filling, a plurality of squeegee operations are desirable, and many squeegees are configured to perform alternate operations using the forward squeegee and the backward squeegee.

  Moreover, in resin sealing of electronic components and resin filling into a circuit board, it is not preferable that voids exist in the sealing resin and the filling resin from the viewpoint of the reliability of the electronic device. Therefore, the spread of vacuum printing apparatuses that perform stencil printing in a vacuum atmosphere is also progressing. In particular, by using a vacuum differential pressure filling method that lowers the degree of vacuum (closer to atmospheric pressure) between multiple stencil printings in a vacuum atmosphere, the resin sealing with less voids and excellent surface flatness and Resin filling is possible (Patent Document 1).

Japanese Patent Application Laid-Open No. 11-40590

  An example of a vacuum printing apparatus having an outward squeegee and a return squeegee is shown in FIG. Stencil printing using the vacuum printing apparatus 200 of FIG. 8 is performed as shown in FIGS. That is, after the printing material P is supplied onto the stencil 6 by the printing material supply means 3 (FIG. 9A), the forward squeegee 204 is caused to travel along the squeegee traveling shaft 9 (FIG. 9B to FIG. 9). 9 (d)) After performing the forward printing, the backward squeegee 205 is caused to travel along the traveling axis 9 in the opposite direction to the outward squeegee 204 (FIGS. 10 (e) to 10 (g)). The printing material P is applied to a portion corresponding to the hole portion of the stencil 6 of the substrate W. Note that when the forward pass printing is performed, the return squeegee 205 has a height that does not contact the printing material P on the stencil plate 6, and when performing the backward pass printing, the forward pass squeegee 204 does not contact the printing material P on the stencil plate 6. Thus, only the forward squeegee 204 functions in the forward printing, and only the backward squeegee 205 functions in the backward printing.

  By the way, although the state which looked at the outward printing shown in FIG. 9 from the top is shown in FIG. 11, by performing outward printing with respect to the state (FIG. 11 (a)) with which the printing material P was supplied on the stencil 6, FIG. (FIG. 11 (b) to FIG. 11 (d)), it can be seen that the printing material P spreads outward from both ends of the outward squeegee 204 and remains. When the return squeegee 205 has the same shape as the outward squeegee 204, the printing material P that spreads outside the squeegee width on the outward path cannot be used or collected. Further, the printing material P that was within the width of the return pass squeegee 205 at the start of the return pass printing may spread outward from both ends of the return pass squeegee 205 at the return pass printing step. In this way, the printing material P that has once spread outward from both ends of the squeegee can only be collected after the vacuum chamber is opened to the atmosphere, and the operating rate as a printing device for the labor required for collection can be increased. It was a factor to decrease.

  On the other hand, when the printing material P spreading outward from both ends of the squeegee P is not collected in order not to reduce the operation rate, the printing material P spreading outward from both ends of the squeegee is wasted, increasing the amount of waste and the cost. Up was a problem.

  The present invention has been made in view of the above problems, and a printing apparatus capable of effectively using the supplied printing material without reducing the operating rate when performing stencil printing in a vacuum, and A printing method is provided.

In order to solve the above problems, the invention described in claim 1
A printing apparatus for printing a printing material on a printing material using a stencil, a printing material supply means for supplying the printing material on the stencil, a forward squeegee for forward printing, and a movement for performing backward printing A space area including a return squeegee having a width perpendicular to the direction larger than that of the outward squeegee and an area in which the outward squeegee and the return squeegee move are blocked from outside air, and the space area is evacuated. And a vacuum chamber.

Invention of Claim 2 is a printing apparatus of Claim 1, Comprising:
Both ends of the return pass squeegee have a shape that is bent in the direction of travel during return pass printing.

Invention of Claim 3 is a printing apparatus of Claim 2, Comprising:
Both ends of the forward path squeegee have a shape that is bent toward the traveling direction during forward path printing.

Invention of Claim 4 is a printing apparatus in any one of Claims 1-3, Comprising:
The printing material supply means supplies an amount of the printing material corresponding to a plurality of printed materials at a time.

The invention described in claim 5
A printing method for printing a printing material on a substrate using a stencil under a vacuum atmosphere,
A step of supplying resin onto the stencil, a step of performing forward pass printing using an outward squeegee, and a step of performing return pass printing using a return squeegee having a width that is perpendicular to the moving direction than the forward squeegee. Consists of.

Invention of Claim 6 is the printing method of Claim 5, Comprising:
Both ends of the return pass squeegee have a shape that is bent in the direction of travel during return pass printing.

Invention of Claim 7 is the printing method of Claim 6, Comprising:
Both ends of the forward path squeegee have a shape that is bent toward the traveling direction during forward path printing.

Invention of Claim 8 is the printing method in any one of Claim 5-7, Comprising:
In the step of supplying the resin onto the stencil, an amount of the printing material corresponding to a plurality of printing materials is supplied at a time.

  According to the present invention, when performing stencil printing in a vacuum, the printing material that spreads outside the squeegee and becomes uncollectable can be reduced, and the supplied printing material can be used effectively.

1 is a diagram illustrating an apparatus configuration of a printing apparatus according to an embodiment of the present invention. It is the figure which looked at the inside of the vacuum chamber of the printing apparatus which concerns on embodiment of this invention from the top. (A) It is a figure which shows the state on the stencil before the printing material supply in the printing apparatus of embodiment of this invention. (B) The figure which shows the state on the stencil to which the printing material was supplied on the stencil in the printing apparatus. FIG. 6C is a diagram illustrating a state on the stencil when the forward squeegee moves to the place of the printing material in the printing apparatus. (D) It is a figure which shows the state on a stencil when forward printing starts with the printing apparatus of embodiment of this invention. (E) It is a figure which shows the state on a stencil in the middle of forward printing in the printing apparatus (f) FIG. 4 is a diagram showing a state on the stencil when the forward printing is finished in the printing apparatus. (G) It is a figure which shows the state on a stencil when return path printing is started with the printing apparatus of embodiment of this invention. (H) It is a figure which shows the state on the stencil in the middle of return pass printing in the printing apparatus, (i) It is a figure which shows the state on a stencil when return pass printing is complete | finished by the same printing apparatus. (A) It is a figure which shows the state on a stencil when return pass printing is started with the printing apparatus using the conventional squeegee only for forward pass printing in the embodiment of the present invention. It is a figure which shows the state on a stencil. (C) It is a figure which shows the state on a stencil when return pass printing is complete | finished with the printing apparatus. It is a figure which shows the structure provided with the front chamber in the printing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the printing apparatus which has an outward squeegee and a return squeegee and performs stencil printing in a vacuum. (A) It is a figure which shows the state in which the printing material was supplied on the stencil by the printing apparatus which performs stencil printing with the outward squeegee and the backward squeegee. (B) The outward squeegee moves to the place of the printing material in the same printing apparatus. FIG. 6 is a diagram illustrating a state in which forward printing is started. FIG. 6C is a diagram illustrating a state in the middle of forward printing in the printing apparatus. FIG. 8D is a diagram illustrating a state in which the forward printing is completed in the printing apparatus. (E) It is a figure which shows the state in which return pass printing is started with the printing apparatus which performs stencil printing with a forward pass squeegee and a return pass squeegee. (F) It is a figure which shows the state in the middle of return pass printing with the same printing apparatus. FIG. 6 is a diagram illustrating a state in which return printing has been completed in the printing apparatus. (A) It is a figure which shows the state on the stencil to which the printing material was supplied with the printing apparatus which performs stencil printing with the outward squeegee and the return squeegee. (B) The outward squeegee moves to the place of the printing material with the same printing apparatus. It is a figure which shows the state on a stencil when forward printing is started. (C) It is a figure which shows the state on the stencil in the middle of outward printing in the printing apparatus, (d) It is a figure which shows the state on stencil when outward printing is complete | finished by the printing apparatus.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a printing apparatus 1 according to an embodiment of the present invention. A printing apparatus 1 shown in FIG. 1 prints a printing material P on a substrate W. Here, as the substrate W, a wiring board on which a semiconductor chip is mounted, a wiring board having a through hole and / or a non-through hole (mainly a multilayer wiring board), or the like is used. As the printing material P, a liquid resin such as an epoxy resin mixed with a filler, a conductive paste in which metal fine particles are dispersed using an epoxy resin as a binder, a solder paste, or the like is used.

  In the printing apparatus 1, a vacuum chamber 2, a printing material supply means 3, a forward squeegee 4, a backward squeegee 5, a stencil 6, a stencil holder 7, a table 8, a squeegee travel shaft 9, a vacuum pump 10, a valve 11, and a control device 12. It has. FIG. 2 shows a state in which the inside of the vacuum chamber 2 of the printing apparatus 1 is viewed from above (the squeegee traveling shaft 9 is not shown).

  In the following description, the direction in which the forward squeegee 4 and the backward squeegee 5 move is the X-axis direction, and the direction perpendicular to the X-axis in the plane formed by the stencil 6 is the Y-axis direction. The linear direction is described as the Z-axis direction.

  The vacuum chamber 2 forms a sealed space in which the printing material supply means 3, forward squeegee 4, return squeegee 5, stencil 6, stencil holder 7, table 8, and squeegee running shaft 9 can be accommodated. The vacuum chamber 2 is made of a structure and material that can withstand a pressure difference between the inside and outside when the inside is in a vacuum state, but preferably has a window made of a transparent resin or glass that allows the inside to be visually observed. .

  The printing material supply means 3 supplies the printing material P onto the stencil 6, and includes a storage tank that stores the printing material P, a pump that pumps the printing material P in the storage tank, and the printing material P that is pumped. 1 is shown in FIG. 1. Note that the syringe of the printing material supply means 3 has a shape as shown in FIG. 2 when viewed from above, and moves in the Y-axis direction while discharging the printing material P from the syringe. The printing material P is supplied in such a range.

  The forward squeegee 4 and the backward squeegee 5 have a function of pushing the printing material P on the stencil 6 into the hole 6H of the stencil 6 (see FIG. 2). The forward squeegee 4 places the printing material P on the stencil 6 The step of pushing the hole 6H into the hole 6H is the forward pass printing, and the step of pushing the printing material P into the hole 6H of the stencil 6 by the return pass squeegee 5 is the return pass printing. The forward printing and the backward printing are performed along the same X-axis direction, but the traveling direction is different by 180 degrees between the forward printing and the backward printing. In this specification, the direction in which the printing material P supplied by the printing material supply means 3 at a predetermined position is pushed into the hole 6H of the stencil 6 is defined as the forward printing direction. Further, the printing apparatus 1 has a function of retracting to a height at which the return squeegee 5 does not contact the printing material P in forward printing, and retracting to a height at which the outward squeegee does not contact the printing material P at backward printing. Yes.

  The materials of the forward squeegee 4 and the return squeegee 5 are both selected according to the properties such as the viscosity of the printing material P, but the hardness is in the range of 60 to 90 degrees.

  As shown in FIG. 2, the width of the portion in contact with the stencil 6 in the forward squeegee 4 is equal to or larger than the maximum Y-axis direction component EW in the region where the hole 6H is formed, and both ends are at the time of forward printing. Bent toward the direction of travel.

  As shown in FIG. 2, the return squeegee 5 is wider than the forward squeegee 4 in the width of the portion in contact with the stencil 6, and both ends are bent in the traveling direction during the return pass printing. That is, the portion where the return squeegee 5 contacts the stencil 6 is a straight line in each direction perpendicular to the traveling direction at least in the range corresponding to EW in FIG. It has a shape that tilts. The reason why the width of the return squeegee 5 is larger than the width of the outward squeegee 4 is that the printing material P can be recovered and reused during the return pass printing even if the printing material P spreads beyond the width of the squeegee.

  The stencil plate 6 is made of a metal thin plate having a thickness of 0.05 mm to 2 mm made of a metal such as stainless steel, and includes a hole 6H corresponding to a target printing pattern.

  The stencil holder 7 is made of a metal such as stainless steel and is attached to the stencil 6 so as to form a weir having a height of about 1 cm to 2 cm, and the stencil 6 is fixed on the substrate W to be printed.

  The table 8 has a placement surface on which the substrate W is placed horizontally, and the placement surface is processed to have sufficient flatness. Further, if necessary, a large number of minute suction holes for sucking and holding the substrate W may be provided.

  The squeegee travel shaft 9 regulates the moving direction of the forward squeegee 4 and the backward squeegee 5 in the X-axis direction, and is made of a highly rigid material. Further, the forward squeegee 4 and the backward squeegee 5 move in the X-axis direction along the squeegee travel axis 9 and also move up and down by a drive mechanism (not shown).

  The vacuum pump 10 is a device for evacuating the inside of the vacuum chamber 2, and when the vacuum pump 10 is operated and the valve 11 is opened, the inside of the vacuum chamber 2 is depressurized to be in a vacuum state.

  The control device 12 includes an input / output device such as a touch panel, hardware mainly including a memory chip and a microprocessor, a hard disk device incorporating a computer program for operating the hardware, and an interface for performing data communication. Is done. The control device 12 is connected to the printing material supply means 3, a drive unit that moves the forward squeegee 4 and the backward squeegee 5, a vacuum pump 10, a valve 11, and the like, and performs each control.

  Hereinafter, the stencil printing process by the printing apparatus 1 will be described with reference to FIGS. 3 to 5. 3 to 5 are views of the inside of the vacuum chamber 2 of the printing apparatus 1 as viewed from the Z-axis direction, and are views showing the state of the surface portion of the stencil 6. That is, the forward squeegee 4 in FIGS. 3 and 4 shows a portion in contact with the stencil 6. Similarly, the return squeegee 5 in FIG. 5 also shows a portion in contact with the stencil 6. For this reason, the return squeegee 5 during forward printing and the forward squeegee 4 during backward printing that are not in contact with the stencil 6 are not shown.

  FIG. 3A shows a state where the forward squeegee 4 is in a standby state and the printing material P is not supplied onto the stencil 6. From this state, the syringe of the printing material supply means 3 moves in the Y-axis direction while discharging the printing material P, whereby the printing material P is supplied onto the stencil 6 (FIG. 3B). The area in the Y-axis direction for supplying the printing material P is equal to or greater than the Y-axis direction component maximum value EW of the area where the holes 6H on the stencil 6 are formed. In addition, the amount of the printing material P to be supplied needs to be larger than that for filling all the holes 6H. After the printing material P is supplied onto the stencil 6, the forward squeegee 4 moves to the printing material P side (FIG. 3C). Here, after supplying the printing material P onto the stencil 6, it is desirable to leave the printing material P for a predetermined time to defoam the defoaming (defoaming by being in the vacuum chamber).

  FIG. 4 is a diagram showing the forward printing process, and the forward squeegee 4 moves in the X-axis direction (to the right in the figure) while pressing the resin P with the lower end in contact with the surface of the stencil 6 (FIG. 4). 4 (d) to FIG. 4 (f)). During this time, the printing material P is embedded in the holes 6H in the stencil 6 after the forward squeegee 4 has passed (FIG. 4E). On the other hand, the printing material P that has not been embedded in the hole 6H moves in the X-axis direction while being pushed by the forward squeegee 4. Here, both ends in the width direction (Y-axis direction) of the forward squeegee 4 have a shape bent toward the traveling direction. For this reason, even if a part of the printing material P tries to move to both ends of the forward squeegee 4, the speed component is converted to the traveling direction side of the forward squeegee 4. It hardly spreads outward in the direction. As a result, the forward printing is completed in a state where most of the printing material P excluding the portion buried in the hole 6H is held (FIG. 4F).

When the forward printing is finished, the forward squeegee 4 is raised, and the backward squeegee 5 is lowered instead. Here, when the differential pressure filling is performed before the return pass printing is started, the pressure in the vacuum chamber 2 is increased (close to the atmospheric pressure), and the void generated in the printing material P filled in the holes 6H in the forward pass printing. Reduce.

  FIG. 5 is a diagram showing return pass printing. FIG. 5G shows a state in which the return pass squeegee 5 brings the lower end into contact with the surface of the stencil 6 and starts return pass printing. In the return pass printing, the printing material P is filled by moving the return pass squeegee 5 in the X-axis direction (left side in the figure) into the hole 6H that has not been sufficiently filled with the print material P in the forward pass printing (see FIG. 5 (h)). Here, since the width of the return squeegee 5 is larger than the width of the outward squeegee 4 as described above, even if there is a printing material that protrudes in the width direction of the outward squeegee 4 during the outward print, the return squeegee 5 Can be recovered. Further, since both ends in the width direction (Y-axis direction) of the return path squeegee 5 have a shape facing the traveling direction, the printing material P hardly spreads outward in the width direction of the return path squeegee 5. Return pass printing is terminated (FIG. 5 (i)). Further, if the printing material P is not sufficiently filled in the hole 6H even after the return pass printing, the forward pass printing may be performed again, or the combination of the forward pass printing and the return pass printing may be performed a plurality of times. In any case, stencil printing that effectively uses the printing material P supplied by the printing material supply means without waste can be performed in the vacuum chamber.

  As a modification of the embodiment of the present invention, the forward squeegee may be of a conventional type. That is, even if the forward printing is performed using the conventional forward squeegee 204 as shown in FIG. 11, if the backward squeegee 5 is used, the printing material protruding in the width direction of the forward squeegee 204 is collected. However, it is possible to perform return pass printing (FIGS. 6A to 6C).

  As described above, the printing material P can be used effectively by using the present invention. For this reason, it is also possible to suppress the usage amount of the printing material P to the minimum necessary. For example, when printing materials P are applied to a plurality of substrates W using the same stencil 6, the printing material supply unit 3 then determines the amount of the printing material P remaining on the stencil 6 after completion of printing by using a sensor. By adjusting the amount of printing material P to be supplied, waste is eliminated. Moreover, you may supply the printing agent P of the quantity corresponding to the some to-be-printed material W. As shown in FIG. By supplying the printing material P corresponding to the plurality of printing materials W, the printing material P can be defoamed once and printing on the plurality of printing materials W can be performed, which is effective in reducing the tact time.

  The printing apparatus of the present invention may be a printing apparatus 100 that includes a front chamber 102 that is adjacent to the vacuum chamber 2 and that is used for loading and unloading the substrate W. In the printing apparatus 100, the inside of the front chamber 102 is decompressed by the vacuum pump 10 and the valve 111. The inside of the front chamber 102 is set to atmospheric pressure when the substrate W is carried from the outside, and when the substrate is moved into the vacuum chamber 2, the vacuum chamber is set to atmospheric pressure when the substrate W is loaded and unloaded. There is no need to do it.

DESCRIPTION OF SYMBOLS 1 Printing apparatus 2 Vacuum chamber 3 Printing material supply means 4 Outward squeegee 5 Return squeegee 6 Stencil 7 Stencil holder 8 Table 9 Squeegee running shaft 10 Vacuum pump 11 Valve
12 Control device

Claims (8)

A printing apparatus that prints a printing material on a substrate using a stencil,
Printing material supply means for supplying the printing material on the stencil;
An outward squeegee for outbound printing;
A return squeegee having a width perpendicular to the moving direction for performing return pass printing, which is larger than the forward squeegee;
A printing apparatus comprising: a vacuum chamber configured to block a space area including an area where the forward squeegee and the area where the return squeegee moves from outside air and to vacuum the space area. The printing apparatus according to claim 1,
The printing apparatus according to claim 1, wherein both ends of the return path squeegee have a shape that is bent in a traveling direction during return path printing. The printing apparatus according to claim 2,
A printing apparatus, wherein both ends of the forward squeegee have a shape that is bent in a traveling direction during forward printing. The printing apparatus according to any one of claims 1 to 3,
The printing apparatus, wherein the printing material supply unit supplies an amount of the printing material corresponding to a plurality of printed materials at a time. A printing method for printing a printing material on a substrate using a stencil under a vacuum atmosphere,
Supplying resin onto the stencil;
A process of performing forward printing using an outward squeegee;
A printing method comprising a step of performing return path printing using a return path squeegee having a width that is perpendicular to the moving direction than that of the forward path squeegee. The printing method according to claim 5, wherein
A printing method characterized in that both ends of the return path squeegee have a shape that is bent in the direction of travel during return path printing. The printing method according to claim 6, comprising:
A printing method, wherein both ends of the forward squeegee have a shape that is bent in a traveling direction during forward printing. A printing method according to any one of claims 5 to 7,
In the step of supplying a resin onto a stencil, a printing method characterized by supplying an amount of the printing material corresponding to a plurality of printing materials at a time.

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