JP5083118B2 - Screen printing apparatus and method - Google Patents

Description

  The present invention provides a mask in which an opening is formed opposite to a workpiece and a paste-like printing material placed on the mask by moving in parallel while sliding in contact with the upper surface of the mask. The present invention relates to a screen printing apparatus including a squeegee that is applied onto the workpiece through a section, and a screen printing method using the same.

Conventionally, a mask in which an opening is formed opposite to a workpiece, and a paste-like printing material placed on the mask is moved through the opening by moving in parallel while sliding on the mask upper surface. A screen printing apparatus provided with a squeegee for coating on the workpiece is known.
When screen printing is performed by such a screen printing apparatus, the mask is pressed by a squeegee and bent toward the work side, and the mask at the place where the printing material is applied is brought into contact with the work.
As the mask, for example, there is a mask configured as a metal mask. In this metal mask, by applying the printing material with a squeegee while the mask is in contact with the workpiece, the printing material corresponding to the thickness of the mask is obtained. Since it is transferred onto the workpiece, a certain amount (thickness) of the printing material can be applied to the workpiece.

The screen printing apparatus described in Patent Document 1 is an apparatus for applying cream solder, which is a printing material, to a printed circuit board. The amount of cream solder applied to the printed circuit board is the amount of electronic components mounted on the printed circuit board. It is desirable to keep constant because it affects solderability.
Therefore, in Patent Document 1, the height of the stage on which the printed board is placed is positioned so that the gap between the upper surface of the printed board serving as a workpiece and the mask is constant.
In this way, by making the gap between the upper surface of the printed circuit board and the mask constant, there is a gap between the mask and the printed circuit board where the printing material is applied, or conversely, the mask exerts excessive pressure on the printed circuit board. The mask can be brought into contact with the printed circuit board with an appropriate pressure without being pressed.

  That is, in the conventional screen printing apparatus, as shown in FIG. 7, the mask 101 where the printing material is applied is always pressed by the squeegee 102 until it abuts against the work 110, and this causes the entire surface of the work 110 to be pressed. A certain amount of printing material can be applied.

As shown in FIG. 8A, even when there are irregularities on the surface of the workpiece 110, the mask 101 where the printing material is applied always comes into contact with the shape of the surface of the workpiece 110. As shown in FIG. 8B, the printing material is applied to the surface of the work 110 with a certain thickness according to the thickness of the mask 101.
JP-A-9-76455

As shown in FIG. 9, generally, a product 121 such as an inverter module on which a power semiconductor element as a heat generating component is mounted is provided with a heat radiating plate 111 for radiating heat. In order to improve adhesion and increase heat dissipation efficiency, grease 131 may be interposed between the product 121 and the heat dissipation plate 111.
The grease 131 is applied on the heat dissipation plate 111 by the above-described screen printing apparatus. However, since the grease 131 is applied with a constant thickness even when the surface of the heat dissipation plate 111 is uneven, the heat dissipation plate 111 having the unevenness. When grease 131 is applied to the product 121 and attached to the product 121, as shown in FIG. 10, only the convex portion of the heat sink 111 is in close contact with the product 121, and there is a gap between the concave portion of the heat sink 111 and the product 121. As a result, the adhesiveness between the heat radiating plate 111 and the product 121 is deteriorated and the heat radiating performance is lowered.

  Therefore, in the present invention, the printing material applied by the screen printing apparatus is a material such as grease interposed between the product and the heat radiating plate attached to the product, and the heat dissipation by which the printing material is applied. It is an object of the present invention to provide a screen printing apparatus and method capable of bringing a product and a workpiece into close contact with each other over the entire application range of a printing material even when irregularities exist on the surface of the workpiece such as a plate.

The screen printing apparatus and method for solving the above problems have the following characteristics.
That is, as described in claim 1, by moving in the mask surface direction while slidingly contacting the mask upper surface and pressing the mask toward the workpiece side, the mask is arranged facing the workpiece and formed with an opening. A screen printing apparatus provided with a squeegee for applying a paste-like printing material placed on the mask onto the workpiece through the opening, and a measuring means for measuring the uneven shape of the workpiece surface; Control means for controlling the amount of deflection of the mask at the sliding contact position of the squeegee when applying the printing material based on the measurement value of the measuring means, the control means at the time of applying the printing material The amount of deflection of the mask is controlled by changing the position of the squeegee with respect to the mask. Squeegee mask lower surface of the portion where sliding contact is performed so as not pushed to the workpiece side than the portion that is most prominent in the workpiece surface.
As a result, it is possible to apply the printing material as a whole in the range from the reference surface of the workpiece upper surface to a certain height width, and the upper surface of the applied printing material can be applied regardless of the uneven state of the workpiece upper surface. It becomes flat.
Therefore, for example, when the work is a heat sink attached to a product such as an inverter module on which a power semiconductor element is mounted and the printing material is grease interposed between the product and the work, the surface of the work Even if there are irregularities on the workpiece, when the workpiece is assembled to the product, the printing material (grease) is filled with no gap between the workpiece and the product so that the workpiece and the product are in close contact with each other. It is possible to improve heat dissipation from the product to the workpiece.
Further, the amount of deflection of the mask can be controlled with a simple configuration without adding a special member.
Furthermore, the mask does not come into contact with the shape of the surface of the workpiece, and it is possible to reliably apply a printing material having a certain width from the reference surface to the upper surface of the workpiece.

Further, as described in claim 2, the paste-like material placed on the mask is moved in parallel with the squeegee slidably contacted on the upper surface of the mask disposed facing the workpiece and having an opening. A screen printing method for applying a printing material on the workpiece through the opening, wherein the printing material is applied based on a measurement step for measuring the uneven shape of the workpiece surface and a measurement value in the measurement step. A deflection amount control step of controlling the amount of deflection of the mask at the sliding contact position of the squeegee at the time, and in the deflection amount control step, the position of the squeegee with respect to the mask during application of the printing material is changed. Thus, the deflection amount of the mask is controlled, and the position of the squeegee with respect to the mask in the deflection amount control step is controlled so that the squeegee is in sliding contact. Mask underside place is performed so as not pushed to the workpiece side than the portion that is most prominent in the workpiece surface.
As a result, it is possible to apply the printing material as a whole in the range from the reference surface of the workpiece upper surface to a certain height width, and the upper surface of the applied printing material can be applied regardless of the uneven state of the workpiece upper surface. It becomes flat.
Therefore, for example, when the work is a heat sink attached to a product such as an inverter module on which a power semiconductor element is mounted and the printing material is grease interposed between the product and the work, the surface of the work Even if there are irregularities on the workpiece, when the workpiece is assembled to the product, the printing material (grease) is filled with no gap between the workpiece and the product so that the workpiece and the product are in close contact with each other. It is possible to improve heat dissipation from the product to the workpiece.
Further, the amount of deflection of the mask can be controlled with a simple configuration without adding a special member.
Furthermore, the mask does not come into contact with the shape of the surface of the workpiece, and it is possible to reliably apply a printing material having a certain width from the reference surface to the upper surface of the workpiece.

According to the present invention, it becomes possible to apply the printing material as a whole in a range from the reference surface of the workpiece upper surface to a certain height width, and the upper surface of the applied printing material is in an uneven state on the workpiece upper surface. It can be flat regardless.
Therefore, for example, when the work is a heat sink attached to a product such as an inverter module on which a power semiconductor element is mounted and the printing material is grease interposed between the product and the work, the surface of the work Even if there are irregularities on the workpiece, when the workpiece is assembled to the product, the printing material (grease) is filled with no gap between the workpiece and the product so that the workpiece and the product are in close contact with each other. It is possible to improve heat dissipation from the product to the workpiece.

  Next, modes for carrying out the present invention will be described with reference to the accompanying drawings.

  The screen printing apparatus shown in FIG. 1 includes a stage 3 on which a workpiece 10 to be coated with a printing material 31 is placed, and a mask that is disposed above the workpiece 10 and has an opening at least at a location facing the workpiece 10. 1 and a squeegee 2 for applying a paste-like printing material 31 placed on the mask 1 onto the workpiece 10 through the opening.

The squeegee 2 is supported by a support member 7 movable along a rail 8 arranged in parallel with the mask 1, and can move in the horizontal direction (the surface direction of the mask 1) integrally with the support member 7. It is configured.
The support member 7 is configured to be moved up and down by an elevator 6 so that the squeegee 2 can move in a direction perpendicular to the surface of the mask 1.
The mask 1 is a metal mask.

Further, the screen printing apparatus includes a surface shape measuring device 4 for the workpiece 10. The surface shape measuring instrument 4 measures the surface shape of the workpiece 10 by, for example, irradiating the surface of the workpiece 10 with laser light from the laser irradiator 4a and imaging the reflected light on the surface of the workpiece 10 with the imaging device 4b. It consists of a laser displacement meter.
The surface shape measuring instrument 4 is configured to be movable in the same direction as the moving direction of the squeegee 2 and can measure the surface shape of the workpiece 10 over the entire range.
In this example, a laser displacement meter is used as the surface shape measuring instrument 4, but the present invention is not limited to this, and any measuring instrument capable of measuring the surface shape of the workpiece 10 can be used.

  When the printing material 31 is applied to the workpiece 10 by the screen printing apparatus, the squeegee 2 is pressed against the mask 1, and the squeegee 2 is bent toward the workpiece 10 by the squeegee 2. The paste-like printing material 31 placed on the mask 1 is applied to the surface of the workpiece 10 through the opening by the squeegee 2 slidably contacting the mask 1.

The squeegee 2 is pressed against the mask 1 by moving the squeegee 2 toward the mask 1 by the elevator 6. However, the screen printing apparatus is moved up and down to move the squeegee 2 as shown in FIG. A control device 5 for controlling the operation of the device 6 is provided.
That is, the elevator 6 lowers the squeegee 2 when moving the squeegee 2 toward the mask 1 when applying the printing material 31 to the workpiece 10, and raises the squeegee 2 after applying the printing material 31 to the workpiece 10. It is moved away from the mask 1 side.

The control device 5 receives the measurement value of the surface shape of the workpiece 10 measured by the surface shape measuring instrument 4. The control device 5 prints the measured value based on the input measurement value of the surface shape of the workpiece 10. The deflection amount of the mask 1 at the sliding contact position of the squeegee 2 when applying the material 31 is controlled.
That is, the control device 5 calculates an appropriate amount of bending of the mask 1 based on the measured value of the surface shape of the workpiece 10, and moves the squeegee 2 toward the mask 1 so that the mask 1 is bent by the calculated amount of bending. In order to move, the operation of the elevator 6 is controlled.

Specifically, in the control device 5, based on the measurement value of the surface shape of the workpiece 10 measured by the surface shape measuring instrument 4, the upper surface of the workpiece 10 is determined from the height position of the reference surface L on the upper surface of the workpiece 10. The dimension d1 up to the height position of the most protruding part is calculated as a convex dimension.
In this case, the convex dimension d1 is calculated, for example, by calculating the difference between the distance from the surface shape measuring instrument 4 to the reference plane L and the distance from the surface shape measuring instrument 4 to the most protruding portion on the upper surface of the workpiece 10. can do.
Further, the reference plane L can be set, for example, as a flat surface portion excluding convex portions on the surface of the workpiece 10, or can be set as a virtual plane consisting of an average value of height positions of the upper surface of the workpiece 10.

In the control device 5, the distance from the surface shape measuring instrument 4 to the lower surface of the mask 1 is stored in advance, and the gap between the lower surface of the mask 1 and the reference surface L is determined from the measured value of the surface shape of the workpiece 10. A dimension d2 is calculated.
Then, a difference dimension Δd between the gap dimension d2 and the convex dimension d1 is calculated, and the difference dimension Δd is obtained as a deflection amount of the mask 1.

  Further, the control device 5 that has calculated the difference dimension Δd that is the amount of deflection of the mask 1 pushes the mask 1 toward the workpiece 10 by the squeegee 2 so that the mask 1 bends by the difference dimension Δd when the printing material 31 is applied. That is, the amount of movement of the squeegee 2 toward the workpiece 10 by the elevator 6 is controlled.

  In this way, by controlling the amount of pressing of the mask 1 toward the workpiece 10 by the squeegee 2, the squeegee 2 moves in the mask surface direction (horizontal direction) while being in sliding contact with the mask 1, and is placed on the mask 1. When the placed printing material 31 is applied onto the workpiece 10, the lower surface of the mask 1 at the sliding contact position of the squeegee 2 is always separated from the reference surface L of the workpiece 10 by the convex dimension d1, as shown in FIG. It will be in the state pushed to the position.

  The amount by which the mask 1 is pushed into the workpiece 10 by the squeegee 2 is controlled by the control device 5 so that the lower surface of the mask 1 is always pushed to a position separated from the reference plane L of the workpiece 10 by the convex dimension d1. When the printing material 31 is applied to the workpiece 10 by moving the squeegee 2 in the mask surface direction, the printing material 31 is filled between the lower surface of the mask 1 and the upper surface of the workpiece 10 through the opening of the mask 1. As shown in FIG. 5, the printing material 31 is applied to the work 10 over the entire area in a range of a certain height width dp from the reference surface L.

That is, at the location where the lower surface of the mask 1 and the upper surface of the workpiece 10 are separated, the separated printing material 31 corresponding to the convex dimension d1 is filled in the separated location, and the printing corresponding to the thickness dimension dm of the mask 1 is performed. The material 31 will be applied.
Further, the most protruding portion on the upper surface of the workpiece 10 protrudes from the reference surface L by the convex dimension d1, and the lowermost surface of the mask 1 abuts at the most protruding portion when the printing material 31 is applied. The printing material 31 corresponding to the thickness dimension dm of the mask 1 is applied to the protruding portion.
As a result, the printing material 31 having a constant height dp from the reference surface L is applied to the work 10 as a whole regardless of the uneven state on the upper surface of the work 10.
That is, the printing material 31 is thickly applied to the concave portion on the upper surface of the work 10, and the printing material 31 is thinly applied to the convex portion. The upper surface of the applied printing material 31 is flat regardless of the uneven state of the upper surface of the work 10. Become.

Thus, in this screen printing apparatus, after measuring the uneven shape of the surface of the work 10 by the surface shape measuring instrument 4 in the measurement process, the surface of the work 10 in the measurement process is measured in the bending amount control process. Since the amount of deflection of the mask 1 at the sliding contact position of the squeegee 2 when applying the printing material 31 to the workpiece 10 is controlled by the control device 5 based on the measured value of the shape, the upper surface of the workpiece 10 is In addition, it is possible to apply the printing material 31 in a range of a certain height width dp from the reference surface L as a whole.
Thereby, for example, when the work 10 is a heat radiating plate attached to the product 21 such as an inverter module on which a power semiconductor element is mounted, and the printing material 31 is grease interposed between the product 21 and the work 10. As shown in FIG. 5, even when the surface of the workpiece 10 is uneven, when the workpiece 10 is assembled to the product 21, the printing material (grease) 31 is between the workpiece 10 and the product 21. Thus, the workpiece 10 and the product 21 can be brought into close contact with each other as a state of being filled without any gaps, and the heat dissipation from the product 21 to the workpiece 10 can be improved.

  Further, the amount of deflection of the mask 1 by the control device 5 changes the position of the squeegee 2 with respect to the mask 1 when the printing material 31 is applied to the workpiece 10, that is, the amount by which the squeegee 2 pushes the mask 1 toward the workpiece 10 side. Therefore, the amount of deflection of the mask 1 can be controlled with a simple configuration without adding a special member.

  Further, the control means controls the position of the squeegee with respect to the mask so that the lower surface of the mask 1 where the squeegee 2 is in sliding contact is not pushed into the workpiece 10 side than the most protruding portion of the workpiece 10 surface. As a result, the mask 1 does not come into contact with the shape of the surface of the workpiece 10 and the printing material 31 having a certain height and width dp can be reliably applied to the upper surface of the workpiece 10 from the reference plane L. It is possible.

  In this example, the amount of deflection of the mask 1 is the difference dimension Δd obtained by subtracting the convex dimension d1 of the most projecting part on the upper surface of the workpiece 10 from the gap dimension d2 between the lower surface of the mask 1 and the reference surface L, that is, Since the gap dimension between the most protruding portion on the upper surface of the workpiece 10 and the lower surface of the mask 1 is set, as shown in FIG. 6, if the convex dimension d1 of the workpiece 10 is small, the deflection amount (squeegee of the mask 1). 2), the amount of deflection of the mask 1 (the amount of movement of the squeegee 2 toward the workpiece 10) decreases as the convex dimension d1 of the workpiece 10 increases.

Further, in this example, the difference amount Δd, which is obtained by subtracting the convex dimension d1 of the most projecting portion on the upper surface of the work 10 from the gap dimension d2 between the lower surface of the mask 1 and the reference surface L, That is, the gap dimension between the most protruding portion on the upper surface of the workpiece 10 and the lower surface of the mask 1 is set, but the gap dimension (difference dimension Δd) between the most protruding portion on the upper surface of the workpiece 10 and the lower surface of the mask 1 is set. It is also possible to obtain a dimension obtained by subtracting a predetermined dimension from).
In this case, since the deflection amount of the mask 1 is smaller than the difference Δd, the mask 1 does not contact the upper surface of the workpiece 10 even when the printing material 31 is applied to the most protruding portion on the upper surface of the workpiece 10. .

  In this example, the amount of bending of the mask 1 is determined by moving the squeegee 2 in the direction orthogonal to the surface of the mask 1 by the elevator 6 so that the position of the squeegee 2 relative to the mask 1 when the printing material 31 is applied. Although it is controlled by changing, it is also possible to control using the contact pressure of the squeegee 2 against the mask 1 when the printing material 31 is applied.

It is a side view which shows a screen printing apparatus. It is a block diagram which shows the surface shape measuring device of a screen printing apparatus, an elevator, and a control apparatus. It is a side view which shows the lower surface position of the mask 1 in the sliding contact position of a squeegee. It is a side view which shows the printing material printed by the fixed thickness dimension from the reference plane of the workpiece | work. It is a side view which shows the state which assembled | attached the workpiece | work with which the printing material was printed on the product. It is a figure which shows the relationship between the convex dimension of the location which protrudes most on the workpiece | work surface, and the moving amount | distance of a squeegee. It is a side view which shows a mode that the mask bends at the time of apply | coating printing material to a workpiece | work in the conventional screen printing apparatus. (A) is a side view showing how a mask bends when a printing material is applied to a workpiece with a conventional screen printing apparatus when a convex portion exists on the workpiece surface, and (b) is a conventional screen. It is a side view which shows the printing material apply | coated to the workpiece | work with the printing apparatus. It is a side view which shows the grease interposed by the conventional screen printing apparatus and interposed between the product and the heat sink attached to a product. It is a side view which shows the grease interposed by the conventional screen printing apparatus when a heat sink has an unevenness | corrugation and interposed between the product and the heat sink attached to a product.

DESCRIPTION OF SYMBOLS 1 Mask 2 Squeegee 3 Stage 4 Surface shape measuring instrument 5 Control apparatus 6 Elevator 10 Work 31 Printing material

Claims (2)

A paste placed on the mask by moving in the mask surface direction while slidably contacting the mask upper surface and pressing the mask toward the workpiece side, with the mask disposed facing the workpiece and having an opening formed thereon A screen printing apparatus comprising a squeegee for applying a printing material in a shape on the workpiece through the opening,
Measuring means for measuring the uneven shape of the workpiece surface;
Control means for controlling the amount of deflection of the mask at the sliding contact position of the squeegee when applying the printing material based on the measurement value of the measuring means ;
The control means controls the amount of deflection of the mask by changing the position of the squeegee with respect to the mask when applying the printing material,
Control of the position of the squeegee with respect to the mask by the control means is as follows:
The lower surface of the mask where the squeegee is in sliding contact is performed so that it is not pushed into the workpiece side than the most protruding portion of the workpiece surface.
A screen printing apparatus characterized by that. The paste-like printing material placed on the mask is moved through the opening by moving in parallel with the squeegee slidably contacting the upper surface of the mask arranged facing the workpiece and having the opening formed. A screen printing method for applying on a workpiece,
A measurement process for measuring the uneven shape of the workpiece surface;
A deflection amount control step for controlling the deflection amount of the mask at the sliding contact position of the squeegee when applying the printing material based on the measurement value in the measurement step;
In the deflection amount control step, the deflection amount of the mask is controlled by changing the position of the squeegee with respect to the mask when the printing material is applied.
Control of the position of the squeegee with respect to the mask in the deflection amount control step is as follows.
The lower surface of the mask where the squeegee is in sliding contact is performed so that it is not pushed into the workpiece side than the most protruding portion of the workpiece surface.
A screen printing method.

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