Method for the mask-etching of a piercing element

1. A method for the mask-etching of a piercing element comprising an elongate shaft, a distally protruding tip, a proximal holding part, and a laterally open collecting channel that collects bodily fluid and extends along the shaft as far as the area of the distally protruding tip, in which method a double-sided etching mask is applied to the two sides of a substrate and, under action of an etching agent, the piercing element is formed as a part made by chemical blanking, wherein a channel side of the double-sided etching mask is provided with a channel etching slit for unilateral etching of the collecting channel, wherein the channel etching slit has a proximal end portion and a distal end portion located opposite the proximal end portion, wherein the proximal and/or distal end portion of the channel etching slit is configured to taper toward the end of the channel etching slit, wherein the double-sided etching mask is provided with a flange-forming area, which adjoins the channel etching slit in the proximal direction, and the flange-forming area is undercut to form a flange edge forming a mouth of the collecting channel.

2. The method of claim 1 wherein the proximal and/or distal end portion of the channel etching slit tapers linearly, such that the etched collecting channel extends in the direction of the taper with a constant or continuously decreasing cross-sectional area.

3. The method of claim 1 wherein the channel etching slit in a proximal region of the double-sided etching mask is positioned such that the etched collecting channel opens out at the front end of the proximal holding part.

4. The method of claim 1 wherein the double-sided etching mask comprises, on both sides of the substrate, a tip-forming area in order to form a tip contour, wherein the tip forming area on the channel-side is arranged distally in front of the tip-forming area lying on a side opposite the channel-side.

5. The method of claim 1 wherein the channel etching slit is extended so far into a distal tip-forming area of the etching mask that the collecting channel terminates at a distance of 150 to 400 μm before the distal end of the distally protruding tip.

6. The method of claim 1 wherein the proximal and/or distal tapered end portion of the channel etching slit is reduced in width, by 0.4 to 0.6 times its initial width, toward a blunt end edge.

7. The method of claim 1 wherein the channel etching slit, at its proximal and/or distal end portion, is tapered toward the slit end along a length in the range of between 100 and 300 μm.

8. The method of claim 1 wherein the flange edge is configured for flanging a test element onto the proximal holding part.

9. The method of claim 8 wherein the flange-forming area comprises a mask bridge extending transversely with respect to the channel etching slit across a proximal slit end thereof.

10. The method of claim 1 wherein the double-sided etching mask comprises a sacrificial continuation, which is arranged at the proximal end portion downstream of the channel etching slit and which is used to screen an etching agent effect in the mouth area of the collecting channel.

11. The method of claim 10 wherein the sacrificial continuation protrudes freely on a mask edge and is defined by an arc shape in an edge area directed away from a proximal slit end of the channel etching slit.

12. The method of claim 10 wherein the dimensions of the sacrificial continuation are adapted to an undercutting width of the substrate in response to the etching agent, such that the sacrificial continuation is completely etched off to its proximal base.

13. The method of claim 1 wherein the double-sided etching mask, on its opposite side directed away from the channel etching slit, comprises an auxiliary opening which serves to avoid making of undercut edges in the area of the distally protruding tip.

14. The method of claim 13 wherein the auxiliary opening is arranged in a tip-forming area of the double-sided etching mask at a lateral distance from a mask edge.

15. The method of claim 13 wherein the auxiliary opening comprises two auxiliary opening limbs extending toward each other in a V shape in a distal direction.

16. The method of claim 13 wherein the auxiliary opening is Y-shaped and comprises opening limbs extending toward each other, and wherein a connection point of the opening limbs is arranged distally from the tip contour to be formed on a side opposite the channel-side.

17. The method of claim 13 wherein the auxiliary opening has a distal auxiliary opening continuation which extends in a distal direction.

18. The method of claim 17 wherein a proximal end of the auxiliary opening continuation, as viewed in the proximal direction, is arranged behind a distal end of the distally protruding tip to be formed.

19. The method of claim 17 wherein the auxiliary opening is designed as a slit or series of holes.

20. A method for the mask-etching of a piercing element comprising an elongate shaft, a distally protruding tip, a proximal holding part, and a laterally open collecting channel that collects bodily fluid and extends along the shaft as far as the area of the distally protruding tip, in which method a double-sided etching mask is applied to the two sides of a substrate and, under action of an etching agent, the piercing element is formed as a part made by chemical blanking, wherein a channel side of the double-sided etching mask is provided with a channel etching slit for unilateral etching of the collecting channel, wherein the channel etching slit has a proximal end portion and a distal end portion located opposite the proximal end portion, wherein the proximal and/or distal end portion of the channel etching slit is configured to taper toward the end of the channel etching slit, wherein the double-sided etching mask, on its opposite side directed away from the channel etching slit, comprises an auxiliary opening which serves to avoid making of undercut edges in the area of the distally protruding tip.

21. The method of claim 20 wherein the auxiliary opening is arranged in a tip-forming area of the double-sided etching mask at a lateral distance from a mask edge.

22. The method of claim 20 wherein the auxiliary opening comprises two auxiliary opening limbs extending toward each other in a V shape in a distal direction.

23. The method of claim 20 wherein the auxiliary opening is Y-shaped and comprises opening limbs extending toward each other, and wherein a connection point of the opening limbs is arranged distally from the tip contour to be formed on a side opposite the channel-side.

24. The method of claim 20 wherein the auxiliary opening has a distal auxiliary opening continuation which extends in a distal direction.

25. The method of claim 24 wherein a proximal end of the auxiliary opening continuation, as viewed in the proximal direction, is arranged behind the a distal end of the distally protruding tip to be formed.