# US 2019/0320536 A1 · Printing device and printing method for applying a viscous or pasty material

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- Number: US 2019/0320536 A1
- Document ID: US20190320536A1
- Status: Published application
- Kind: A1
- Application number: 16/343,436
- Filed: 2017-10-06
- Published: 2019-10-17
- Earliest claimed: 2016-10-21
- Assignees: Robert Bosch GmbH
- Applicants: Robert Bosch GmbH
- Inventors: Guenter Gera
- Web page: https://patentgrep.com/patent/US20190320536A1

## CPC

- H05K 3/1225: {Screens or stencils; Holders therefor}
- B23K 1/0008: {specially adapted for particular articles or work}
- H05K 1/0296: {Conductive pattern lay-out details not covered by sub groups H05K1/02 - H05K1/0295 (H05K1/11 takes precedence; lay-out adapted to mounted component configuration H05K1/18)}
- H05K 3/3485: Application of solder paste, slurry or powder (using printing techniques to form the desired conductive pattern of the printed circuit by applying conductive material H05K3/12)
- B23K 2101/42: Printed circuits
- H05K 2201/09845: Stepped hole, via, edge, bump or conductor
- H05K 2203/0121: Patterning, e.g. plating or etching by moving electrode
- H05K 2203/0139: Blade or squeegee, e.g. for screen printing or filling of holes
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM

## Abstract

The invention relates to a printing device for applying a viscous or pasty material onto a support substrate and molding a defined material geometry by means of a template. The template which is provided for application and molding purposes has at least one continuous opening, and the opening side facing the support substrate functions as an application opening surface. Furthermore, the opening, in particular the inner wall thereof, forms an outer border for the material geometry outer surface to be molded. As a whole, the template is designed such that an adhesive force of the viscous or pasty material acting on the inner wall of the opening is overcome by means of a relative movement, in particular a movement relative to the support substrate. The template is advantageously formed as a stack composite of at least two sub-templates adjoining each other in a connection region. Each of the sub-templates has at least one sub-opening, by means of which the inner wall of the opening is divided into proportional molding surfaces of the sub-template. Furthermore, sub-opening connection surfaces which correspond to one another are formed in the connection region, and each of the sub-templates can be reversibly separated in the connection region.

## Claims

### Claim 1

A printing device (100) for applying a viscous or pasty material (40) onto a carrier substrate (20) and shaping a defined material geometry (45) by means of a stencil, wherein the stencil has at least one continuous opening (55) with an application opening surface (50.1c) facing the carrier substrate (20) and the inner wall of the opening (55) forms an outer boundary for an outer surface (46) of the material geometry (45) to be shaped, wherein the stencil is configured to overcome an adhesive force of the viscous or pasty material (40) acting on the inner wall of the opening (55) by means of a relative movement,
characterized in that
the stencil is formed as a stack composite (50) of at least two sub-stencils (50.1, 50.2, 50.x) adjoining each other in a connection region (30), wherein the sub-stencils (50.1, 50.2, 50.x) each have at least one partial opening (55.1, 55.2, 55.x), by means of which the inner wall of the opening (55) is divided into proportional shaping areas (50.1a, 50.2a, 50.xa) of the sub-stencils (50.1, 50.2, 50.x), and wherein connection surfaces (50.1a, 50.1b) of the sub-openings (55.1, 55.2, 55.x) which correspond to one another are formed in the connection region (30), and the sub-stencils (50.1, 50.2, 50.x) can each be reversibly separated from one another in the connection region (30).

### Claim 2 (depends on 1)

The printing device (100) as claimed in claim 1, characterized in that for the stencil (50) an overall area ratio as the ratio of the area of the inner wall to the application opening surface (50.1c) is =<0.66.

### Claim 3 (depends on 1)

The printing device (100) as claimed in claim 1, characterized in that for a sub-stencil (50.1, 50.2, 50.x) a part-related area ratio as the ratio of the shaping area (55.1a, 50.2a, 55.xa) of the partial opening (55.1, 55.2, 55.x) to the connection surface area (50.1b, 50.2b) or to the application opening surface (50.1c) is >=0.66.

### Claim 4 (depends on 1)

The printing device (100) as claimed in claim 1, characterized in that for the stencil (50) an overall aspect ratio as the ratio of the smallest opening width of the opening (55) to the stencil thickness (h) of the stencil (50) is <1.5.

### Claim 5 (depends on 1)

The printing device (100) as claimed in claim 1, characterized in that the printing device (100) has a closed excess pressure blade (65′) for applying the viscous or pasty material (40) into the at least one continuous opening (55) of the stencil, wherein the closed excess pressure blade (65′) is formed by a printing head, which rests on the stencil and completely covers an entry opening surface (56) of the stencil facing away from the carrier substrate (20) and which is configured to introduce the viscous or pasty material (40) into the opening (55) under pressure.

### Claim 6 (depends on 1)

The printing device (100) as claimed in claim 1, characterized in that at least two partial openings (55.1, 55.2, 55.x) of a sub-stencil (50.1, 50.2, 50.x) or the partial openings (55.1, 55.2, 55.x) of at least two sub-stencils (50.1, 50.2, 50.x) in the stack composite (50) which form the at least one opening (55) are configured differently in geometry and/or size.

### Claim 7 (depends on 1)

The printing device (100) as claimed in claim 1, characterized in that the stencil (50) comprises a plurality of openings (55), wherein a center-to-center distance (pitch) of two immediately adjacent openings (55) is <=2 mm.

### Claim 8

A printing method for applying a viscous or pasty material (40) onto a carrier substrate (20) and for shaping a defined material geometry (45) using a stencil, wherein the stencil has at least one continuous opening (55) with an application opening surface (50.1c) facing the carrier substrate (20) and the inner wall of the opening (55) forms an outer boundary for the outer surface (46) of the material geometry (45) to be shaped, the method comprising
determining a maximum shaping area (50.1a, 50.2a, 50.xa) of the stencil for a circumferential outer surface section (46.1, 46.2, 46.x) of the material geometry (45), at which an adhesive force of the viscous or pasty material (40) acting on the shaping area (50.1a, 50.2a, 50.xa) can still be overcome under a relative movement of the stencil, and
at delayed intervals, beginning the removal of at least two outer surface sections (46.1, 46.2, 46.x) of the material geometry (45) from the mold, in each case having a surface area up to the size of the specified shaping area (50.1a, 50.2a, 50xa), by means of the stencil.

### Claim 9 (depends on 8)

The printing method as claimed in claim 8, characterized in that at least one of the outer surface sections (46.1, 46.2, 46.x) having an area up to the size of the specified maximum shaping area (50.1a, 50.2a, 50.xa) is completely demolded before the removal of at least one other outer surface section from the mold is begun.

### Claim 10 (depends on 8)

The printing method as claimed in claim 8, characterized in that after a sub-region of at least one outer surface section (46.1, 46.2, 46.x) has already been removed from the mold, at least one other outer surface region is then removed from the mold at the same time, wherein the simultaneous demolding is executed in such a way that at any subsequent time a surface area of the remaining areas of these outer surface sections yet to be demolded is present, which is smaller than the specified maximum shaping area.

### Claim 11 (depends on 8)

The printing method as claimed in claim 8, characterized in that the viscous or pasty material (40) is formed as a material deposit (26) on a bonding pad (25) on a circuit substrate (20).

### Claim 12 (depends on 8)

The printing method as claimed in claim 8, characterized in that a solder paste, a thermal conducting paste, a conductive paste or a conductive adhesive is printed onto the carrier substrate (20) as the viscous or pasty material (40).

### Claim 13

A circuit substrate (20) having at least one material deposit (26) applied by means of stencil printing and with a defined material geometry (45), wherein
the at least one imprinted material deposit (26) has a printable surface connecting to the carrier substrate (20) and the material geometry (45) has an outer surface (46) shaped by means of an inner wall of an opening (55) of the printing stencil (50), wherein a ratio of the outer surface (46) to the printable surface is <0.66.

### Claim 14 (depends on 13)

The circuit substrate (20) as claimed in claim 13, characterized in that the imprinted material deposit (26) has different cross-sectional areas and/or shapes in cutting planes parallel to the printable surface.

### Claim 15 (depends on 13)

The circuit substrate (20) as claimed in claim 13, having a plurality of material deposits (26) in the form of a pattern arrangement (27).

### Claim 16 (depends on 1)

The printing device (100) as claimed in claim 1, wherein the relative movement is a movement relative to the carrier substrate (20).

### Claim 17 (depends on 1)

The printing device (100) as claimed in claim 1, characterized in that for the stencil (50) an overall area ratio as the ratio of the area of the inner wall to the application opening surface (50.1c) is 0.3 to 0.5.

### Claim 18 (depends on 1)

The printing device (100) as claimed in claim 1, characterized in that for a sub-stencil (50.1, 50.2, 50.x) a part-related area ratio as the ratio of the shaping area (55.1a, 50.2a, 55.xa) of the partial opening (55.1, 55.2, 55.x) to the connection surface area (50.1b, 50.2b) or to the application opening surface (50.1c) is 0.66 to 2.

### Claim 19 (depends on 1)

The printing device (100) as claimed in claim 1, characterized in that for the stencil (50) an overall aspect ratio as the ratio of the smallest opening width of the opening (55) to the stencil thickness (h) of the stencil (50) is 0.6 to 1.0.

### Claim 20 (depends on 1)

The printing device (100) as claimed in claim 1, characterized in that the stencil (50) comprises a plurality of openings (55) in a pattern arrangement (27), wherein a center-to-center distance (pitch) of two immediately adjacent openings (55) is <=0.5 mm.

### Claim 21 (depends on 8)

The method as claimed in claim 8, wherein the relative movement is a movement relative to the carrier substrate (20).

### Claim 22 (depends on 8)

The printing method as claimed in claim 8, characterized in that the viscous or pasty material (40) is formed as a material deposit (26) on a bonding pad (25) on a circuit substrate (20), and in the form of a printed circuit board, a DBC, an LTCC, an IMC, a wafer or a solar cell, with the defined material geometry (45).

### Claim 23 (depends on 13)

The circuit substrate (20) as claimed in claim 13, wherein the at least one imprinted material deposit (26) is a solder paste or an adhesive deposit (26)