1. A printed circuit board (PCB) comprising:
a first metal film;
a polymer film formed on one surface of the first metal film; and
a second metal film, interposed between the first metal film and the polymer film, having a first surface facing the first metal film and a second surface facing the polymer film, wherein the second surface is rougher than the first surface.
2. The PCB of claim 1, wherein the first metal film is formed of copper or a copper alloy.
3. The PCB of claim 1, wherein the second metal film is formed of nickel or a nickel alloy.
4. The PCB of claim 1, further comprising a third metal film interposed between the polymer film and the second surface.
5. The PCB of claim 4, wherein the third metal film is formed of nickel, palladium, gold, or an alloy thereof.
6. The PCB of claim 1, wherein the second metal film is formed on the first metal film before the polymer film is formed on one surface of the first metal film.
7. The PCB of claim 1, wherein the second surface has a roughness measured in gloss units in a range between 0.2 and 0.8.
8. The PCB of claim 1, wherein the second metal film has a thickness in a range between 0.1 and 0.5 microns.
9. A method of manufacturing a printed circuit board (PCB), the method comprising:
preparing a first metal film;
forming a second metal film on one surface of the first metal film using electroplating, the second metal film having a first surface contacting the first metal film and a second surface opposite to the first surface, wherein the second surface is rougher than the first surface; and
forming a polymer film on the second surface of the second metal film.
10. The method of claim 9, wherein the first metal film is formed of copper or a copper alloy.
11. The method of claim 9, wherein the second metal film is formed of nickel or a nickel alloy.
12. The method of claim 9, wherein the electroplating is performed for 3-20 seconds at a current density of 10 Adm2 or greater.
13. The method of claim 9, wherein in the forming of the second metal film by using electroplating, a plating bath including 2.5-3.5 gl of nickel sulfate or nickel chloride is used.
14. The method of claim 9, further comprising forming a third metal film on the second surface of the second metal film before the forming of the polymer film, wherein the polymer film is formed on the third metal film.
15. The method of claim 14, wherein the third metal film is formed of nickel, palladium, gold, or an alloy thereof.
16. The method of claim 9, wherein the second metal film is formed on the first metal film before the polymer film is formed on the second metal film.
17. The method of claim 9, wherein the second surface of the second film has a roughness measured in gloss units in the range between 0.2 and 0.8.
18. The method of claim 9, wherein the second metal film has a thickness in a range between 0.1 and 0.5 microns.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A device for measuring bulk unconfined strength of powder material, comprising:
a test cell having a cavity with a top opening and a bottom opening;
a removable top cover and a removable bottom cover configured to retain powder with the cavity and between the bottom and top openings;
a rotation arm having an axis of rotation, the test cell attached to the rotation arm a radial distance from the axis of rotation, the cavity oriented with the cavity center axis perpendicular to the axis of rotation;
a light source for directing light in a direction through the cavity;
a light detector configured to detect light from the light source after the light passes through the cavity; such that,
a powder material may be deposited within the cavity and the cavity rotated about the axis of rotation to first consolidate the powder in the cell and then, after removing the top and bottom covers, rotating the cavity again until the event of the powder being forced out of the cavity, the event detected by detecting the light passing through the cavity.
2. A method of measuring bulk unconfined strength of powder material, comprising;
confining a powder material in a cavity having an end opening;
consolidating the powder toward the opening while preventing powder from passing through the opening;
applying increasing acceleration forces to the powder in a direction toward the opening while allowing powder to pass through the opening;
detecting the condition of powder leaving the cavity;
determining the acceleration applied at the time the powder leaves the cavity; and
determining a powder strength from the acceleration applied and the cavity geometry and powder physical characteristics.
3. A method, according to claim 2, and wherein:
the step of detecting the event of powder leaving the cavity comprises detecting light passing through the cavity
4. A method, according to claim 2, and wherein:
the step of applying increasing acceleration forces to the powder comprises rotating the cavity containing powder about a vertical axis of rotation that is perpendicular to a cavity center axis.
5. A device for measuring bulk unconfined strength of powder material, comprising:
a conical cavity having a center axis and having a top opening and a smaller bottom opening;
a retention means for removably covering the top and bottom openings;
an acceleration means for rotating the cavity about an axis of rotation perpendicular to the cavity center axis;
a detection means for detecting when powder disposed in the cavity is then forced out of the cavity by the rotation of the cavity about the axis of rotation;
a speed measuring device configured to determine the rotational speed of the cavity when the powder is forced out of the cavity.
6. A device, according to claim 5, and wherein:
the detection means comprises a light source and a light sensor together configured to detect light passing through the cavity.
7. A device, according to claim 5, and wherein:
the speed measuring device comprises a tachometer.