Probe pin material including Ag—Pd—Cu-based alloy

Abstract

A probe pin material including a Ag—Pd—Cu-based alloy essentially including Ag, Pd and Cu, B as a first additive element, and at least any element of Zn, Bi and Sn, as a second additive element. A concentration of the first additive element is 0.1 mass % or more and 1.5 mass % or less, and a concentration of the second additive element is 0.1 mass % or more and 1.0 mass % or less. A Ag concentration, a Pd concentration and a Cu concentration in the Ag—Pd—Cu-based alloy are required as follows: a Ag concentration (S.sub.Ag), a Pd concentration (S.sub.Pd) and a Cu concentration (S.sub.Cu) converted as given that a Ag—Pd—Cu ternary alloy is formed from only such three elements all fall within a predetermined range in a Ag—Pd—Cu ternary system phase diagram. The probe pin material is excellent in resistance value and hardness/wear resistance, and also is enhanced in bending resistance.

Claims

1. A probe pin material comprising a Ag—Pd—Cu-based alloy comprising: Ag, Pd and Cu; B as a first additive element; at least any element of Zn, Bi and Sn as a second additive element, and unavoidable impurities, wherein the alloy contains no In; wherein S.sub.Ag is a ratio of a concentration of Ag in the alloy to a combined concentration of Ag, Pd and Cu in the alloy as mass %, S.sub.Pd is a ratio of a concentration of Pd in the alloy to the combined concentration of Ag, Pd and Cu in the alloy as mass %, S.sub.Cu is a ratio of a concentration of Cu in the alloy to the combined concentration of Ag, Pd and Cu in the alloy as mass %, wherein all values of the S.sub.Ag, the S.sub.Pd and the S.sub.Cu fall within a range of a polygon (A1-A2-A3-A4) surrounded with straight lines connecting respective points of a point A1 (Ag: 5.5 mass %, Pd:47.5 mass %, Cu:47 mass %), a point A2 (Ag: 5.5 mass %, Pd:58.5 mass %, Cu:36 mass % ), a point A3 (Ag: 18 mass %, Pd:49 mass %, Cu:33 mass %) and a point A4 (Ag: 18 mass %, Pd:45 mass %, Cu:37 mass %) in a Ag—Pd—Cu ternary system phase diagram, a concentration of the first additive element is 0.1 mass % or more and 1.5 mass % or less, and a concentration of the second additive element is 0.1 mass % or more and 1.0 mass % or less.

2. The probe pin material according to claim 1, wherein when one end of a wire rod comprising the Ag—Pd—Cu-based alloy is secured: and a first bending step of bending the wire rod at an angle of substantially 90° from a straight line state and a second bending step of bending the wire rod so as to return the wire rod from a bent state to the straight line state are alternately repeated, the first bending step and the second bending step being each defined as a single time of bending, and the number of times of bending until the wire rod is broken is counted, the number of times of bending counted is five or more.

3. A probe pin comprising the probe pin material defined in claim 1.

4. The probe pin material according to claim 1, wherein a Vickers hardness is 380 Hv or more and 580 Hv or less.

5. The probe pin material according to claim 4, wherein when one end of a wire rod comprising the Ag—Pd—Cu-based alloy is secured: and a first bending step of bending the wire rod at an angle of substantially 90° from a straight line state and a second bending step of bending the wire rod so as to return the wire rod from a bent state to the straight line state are alternately repeated, the first bending step and the second bending step being each defined as a single time of bending, and the number of times of bending until the wire rod is broken is counted, the number of times of bending counted is five or more.

6. The probe pin material according to claim 1, wherein all values of the S.sub.Ag, the S.sub.Pd and the S.sub.Cu fall within a range of a polygon (A1-A2-B3-B4) surrounded with straight lines connecting respective points of the point A1, the point A2, a point B3 (Ag: 13 mass %, Pd:52.8 mass %, Cu:34.2 mass %) and a point B4 (Ag: 13 mass %, Pd:46 mass %, Cu:41 mass %).

7. The probe pin material according to claim 6, wherein when one end of a wire rod comprising the Ag—Pd—Cu-based alloy is secured: and a first bending step of bending the wire rod at an angle of substantially 90° from a straight line state and a second bending step of bending the wire rod so as to return the wire rod from a bent state to the straight line state are alternately repeated, the first bending step and the second bending step being each defined as a single time of bending, and the number of times of bending until the wire rod is broken is counted, the number of times of bending counted is five or more.

8. The probe pin material according to claim 6, wherein all values of the Sa.sub.Ag, the S.sub.Pd, and the S.sub.Cu fall within a range of a polygon (C1-A2-C3-C4) surrounded with straight lines connecting respective points of a point C1 (Ag: 5.5 mass %, Pd:52 mass %, Cu:42.5 mass %), the point A2, a point C3 (Ag: 11 mass %, Pd:54.3 mass %, Cu:34.7 mass %) and a point C4 (Ag: 11 mass %, Pd:50 mass %, Cu:39 mass %).

9. The probe pin material according to claim 6, wherein a specific resistance after an aging heat treatment is 10 μΩ.Math.cm or less.

10. The probe pin material according to claim 6, wherein a Vickers hardness is 380 Hv or more and 580 Hv or less.

11. A probe pin comprising the probe pin material defined in claim 6.

12. The probe pin material according to claim 1, wherein all values of the S.sub.Ag, the S.sub.Pd, and the S.sub.Cu fall within a range of a polygon (C1-A2-C3-C4) surrounded with straight lines connecting respective points of a point C1 (Ag: 5.5 mass %, Pd:52 mass %, Cu:42.5 mass %), the point A2, a point C3 (Ag: 11 mass %, Pd:54.3 mass %, Cu:34.7 mass %) and a point C4 (Ag: 11 mass %, Pd:50 mass %, Cu:39 mass %).

13. The probe pin material according to claim 12, wherein a specific resistance after an aging heat treatment is 10 μΩ.Math.cm or less.

14. The probe pin material according to claim 12, wherein a Vickers hardness is 380 Hv or more and 580 Hv or less.

15. The probe pin material according to claim 12, wherein when one end of a wire rod comprising the Ag—Pd—Cu-based alloy is secured: and a first bending step of bending the wire rod at an angle of substantially 90° from a straight line state and a second bending step of bending the wire rod so as to return the wire rod from a bent state to the straight line state are alternately repeated, the first bending step and the second bending step being each defined as a single time of bending, and the number of times of bending until the wire rod is broken is counted, the number of times of bending counted is five or more.

16. A probe pin comprising the probe pin material defined in claim 12.

17. The probe pin material according to claim 1, wherein a specific resistance after an aging heat treatment is 10 μΩ.Math.cm or less.

18. The probe pin material according to claim 17, wherein a Vickers hardness is 380 Hv or more and 580 Hv or less.

19. The probe pin material according to claim 17, wherein when one end of a wire rod comprising the Ag—Pd—Cu-based alloy is secured: and a first bending step of bending the wire rod at an angle of substantially 90° from a straight line state and a second bending step of bending the wire rod so as to return the wire rod from a bent state to the straight line state are alternately repeated, the first bending step and the second bending step being each defined as a single time of bending, and the number of times of bending until the wire rod is broken is counted, the number of times of bending counted is five or more.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a diagram illustrating a Ag—Pd—Cu ternary system phase diagram, and a range (A1-A2-A3-A4) of S.sub.Ag, S.sub.Pd and S.sub.Cu as conversion values of the Ag concentration, the Pd concentration and the Cu concentration in the Ag—Pd—Cu-based alloy of the present invention;

(2) FIG. 2 shows a diagram illustrating a Ag—Pd—Cu ternary system phase diagram, and a preferable range (A1-A2-B3-B4) of S.sub.Ag, S.sub.Pd and S.sub.Cu as conversion values of the Ag concentration, the Pd concentration and the Cu concentration in the Ag—Pd—Cu-based alloy of the present invention;

(3) FIG. 3 shows a diagram illustrating a Ag—Pd—Cu ternary system phase diagram, and a more preferable range (C1-A2-C3-C4) of S.sub.Ag, S.sub.Pd and S.sub.Cu as conversion values of the Ag concentration, the Pd concentration and the Cu concentration in the Ag—Pd—Cu-based alloy of the present invention;

(4) FIG. 4 shows a diagram illustrating a Ag—Pd—Cu ternary system phase diagram, and S.sub.Ag, S.sub.Pd and S.sub.Cu as conversion values of the Ag concentration, the Pd concentration and the Cu concentration in each of Ag—Pd—Cu-based alloys in Examples 1 to 34 and Comparative Examples 5 to 12 examined in the present embodiment;

(5) FIG. 5 shows a diagram illustrating a Ag—Pd—Cu ternary system phase diagram, and S.sub.Ag, S.sub.Pd and S.sub.Cu as conversion values of the Ag concentration, the Pd concentration and the Cu concentration in each of Ag—Pd—Cu-based alloys in Comparative Examples 1 to 4 examined in the present embodiment; and

(6) FIG. 6 shows an illustrative drawing of a method for evaluating bending resistance of a Ag—Pd—Cu-based alloy produced in the present embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) Hereinafter, a suitable embodiment of the present invention is described. In the present embodiment, probe pin materials including Ag—Pd—Cu-based alloys having various compositions were produced, and the hardness and the specific resistance of each of the probe pin materials were measured and furthermore an evaluation test of bending resistance of such each probe pin material was performed.

(8) In the present embodiment, a base material where bare metal raw materials of Ag, Pd and Cu were mixed was produced, bare metal raw materials of a first additive element (B) and second additive element(s) (Zn, Bi and Sn) were added to the base material, thereafter the resulting mixture was subjected to melt casting, and thus a Ag—Pd—Cu-based alloy ingot was produced. In the present embodiment, twelve types of base materials (used in Examples 1 to 34 and Comparative Examples 5 to 12) were produced where Ag, Pd and Cu were mixed at a ratio falling within a range of A1-A2-A3-A4 in FIG. 1. In addition, four types of base materials were produced (used in Comparative Examples 1 to 4) where Ag, Pd and Cu were mixed at a ratio outside a range of A1-A2-A3-A4 in FIG. 1. After each additive element was added, a Ag—Pd—Cu-based alloy ingot was produced by vacuum melting and continuous casting. Herein, a Ag—Pd—Cu ternary alloy or Ag—Pd—Cu-based alloy ingot where both the first and second additive elements or one of the additive elements were/was not added was also produced in Comparative Example.

(9) The concentration of each constituent element in various alloy ingots produced was analyzed by ICP. The Ag concentration, the Pd concentration and the Cu concentration measured were converted into S.sub.Ag, S.sub.Pd and S.sub.Cu. The locations of the S.sub.Ag, the S.sub.Pd and the S.sub.Cu in each of the Ag—Pd—Cu-based alloys produced in the present embodiment, in a Ag—Pd—Cu ternary system phase diagram, are illustrated in FIG. 4 and FIG. 5.

(10) Next, alloy ingots of Ag—Pd—Cu ternary alloys having various compositions and Ag—Pd—Cu-based alloys having various compositions were each worked into a 4-mm square rod material, with cold groove rolling, and further subjected to cold wire drawing, to provide a wire rod having a diameter of 2 mm. Such an alloy wire rod was subjected to the first solution treatment involving heating at 800° C. for 30 minutes and then water cooling. Next, such an alloy wire rod was worked into a wire rod having a diameter of 1 mm, with cold wire drawing, and the wire rod was subjected to the second solution treatment involving heating at 850° C. for 30 minutes and water cooling. The wire rod was worked into a fine line having a diameter of 0.1 mm, with cold wire drawing, and then subjected to an aging heat treatment. The aging heat treatment was made with heating at 300 to 580° C. for 60 minutes.

(11) The respective fine lines produced of the Ag—Pd—Cu ternary alloys having various compositions and the Ag—Pd—Cu-based alloys having various compositions were each subjected to measurements of the hardness and the specific resistance. These measurements were performed with respect to both the respective fine lines before the aging heat treatment (after working) and after the aging treatment. The hardness measurement was performed with a Vickers hardness meter at a load of 200 gf for an indentation time of 10 seconds. The specific resistance measurement was performed with measurement of the electric resistance with an electric resistance meter, and the specific resistance was calculated from the cross-sectional area and the length of a sample.

(12) An evaluation test of the bending resistance of each of the fine lines was performed. The evaluation test was performed by a method based on the above evaluation method. As illustrated in FIG. 6, an alloy fine line (diameter 0.1 mm), one end of which was secured with a jig, was bent at an angle of 90° , and bent so that the fine line returned from such a bent state to a straight line state. Such working operations for bending at 90° and returning were again repeated alternately, and the number of times of bending until breakage occurred was counted and evaluated. Such bending resistance evaluation was also performed with respect to the fine lines before and after the aging heat treatment.

(13) Various measurement results about the respective fine lines of the Ag—Pd—Cu ternary alloys and the Ag—Pd—Cu-based alloys produced in the present embodiment are shown in Table 1.

(14) TABLE-US-00001 TABLE 1 Alloy constitution AgPdCu ternary Specific resistance Number of times Composition (mass %) alloy conversion Hardness (Hv) (μΩ .Math. cm) of bending (times) of AgPdCu-based alloy (mass %) After After heat After After heat After After heat Ag Pd Cu B Zn Sn Bi S.sub.Ag S.sub.Pd S.sub.Cu working treatment working treatment working treatment Example 1 10.60 53.50 35.25 0.15 0.5 — — 10.67 53.85 35.48 304 458 25.22 6.69 10 15 Example 2 14.95 49.17 35.23 0.15 0.5 — —  5.05 49.49 35.46 308 465 26.47 7.81 11 13 Example 3 10.17 50.20 38.98 0.15 0.5 — — 10.24 50.53 39.23 302 512 25.97 6.48 13 12 Example 4 12.72 47.68 38.95 0.15 0.5 — — 12.80 47.99 39.21 298 499 27.49 8.00 12 12 Example 5  6.99 53.89 38.52 0.1  0.5 — —  7.03 54.21 38.76 298 538 26.78 6.10 9 5 Example 6  6.96 53.67 38.37 0.5  0.5 — —  7.03 54.21 38.76 320 556 27.41 6.84 9 7 Example 7  6.89 53.15 37.96 1.5  0.5 — —  7.03 54.21 38.76 337 560 27.65 7.62 9 7 Example 8  7.01 54.07 38.67 0.15 0.1 — —  7.03 54.21 38.76 290 458 26.58 6.13 12 13 Example 9  6.98 53.86 38.51 0.15 0.5 — —  7.03 54.21 38.76 295 551 27.17 6.21 13 13 Example 10  6.95 53.59 38.31 0.15 1   — —  7.03 54.21 38.76 314 581 29.42 7.08 8 5 Example 11  7.01 54.07 38.67 0.15 — 0.1 —  7.03 54.21 38.76 285 451 28.44 6.21 13 13 Example 12  6.98 53.86 38.51 0.15 — 0.5 —  7.03 54.21 38.76 298 538 28.13 6.37 12 13 Example 13  6.95 53.59 38.31 0.15 — 1   —  7.03 54.21 38.76 324 573 29.25 7.09 8 6 Example 14  7.01 54.07 38.66 0.15 — — 0.1  7.03 54.21 38.76 284 447 27.64 6.09 12 12 Example 15  6.98 53.86 38.51 0.15 — — 0.5  7.03 54.21 38.76 295 514 28.90 6.19 13 12 Example 16  6.95 53.59 38.31 0.15 — — 1    7.03 54.21 38.76 326 570 28.97 7.14 8 7 Example 17 14.48 47.81 37.06 0.15 0.5 — — 14.57 48.12 37.31 290 472 26.83 7.98 10 13 Example 18  9.02 48.95 41.38 0.15 0.5 — —  9.08 49.27 41.65 288 501 26.59 7.45 13 13 Example 19 16.86 46.82 35.67 0.15 0.5 — — 16.97 47.12 35.91 315 398 27.09 8.28 11 12 Example 20  5.96 48.68 44.71 0.15 0.5 — —  6.00 49.00 45.00 285 380 25.40 7.58 13 13 Example 21  5.76 56.83 36.76 0.15 0.5 — —  5.80 57.20 37.00 312 478 25.98 6.28 12 11 Example 22 10.07 52.18 37.10 0.15 0.5 — — 10.14 52.52 37.34 317 384 26.23 6.04 11 12 Example 23 12.59 49.70 37.11 0.1  0.5 — — 12.67 50.00 37.33 312 418 26.14 7.04 11 6 Example 24 12.54 49.50 36.96 0.5  0.5 — — 12.67 50.00 37.33 379 456 28.99 7.55 9 11 Example 25 12.42 49.02 36.56 1.5  0.5 — — 12.67 50.00 37.33 388 509 30.24 8.00 8 11 Example 26 12.64 49.88 37.23 0.15 0.1 — — 12.67 50.00 37.33 320 442 25.32 7.68 10 11 Example 27 12.59 49.68 37.08 0.15 0.5 — — 12.67 50.00 37.33 324 442 26.50 7.38 12 12 Example 28 12.53 49.43 36.89 0.15 1   — — 12.67 50.00 37.33 330 484 26.94 7.94 8 6 Example 29 12.64 49.88 37.23 0.15 — 0.1 — 12.67 50.00 37.33 314 445 27.14 7.70 9 8 Example 30 12.59 49.68 37.08 0.15 — 0.5 — 12.67 50.00 37.33 319 453 27.48 7.85 9 8 Example 31 12.53 49.43 36.89 0.15 — 1   — 12.67 50.00 37.33 348 497 27.55 7.86 9 5 Example 32 12.64 49.88 37.23 0.15 — — 0.1 12.67 50.00 37.33 308 429 27.08 7.61 14 11 Example 33 12.59 49.68 37.08 0.15 — — 0.5 12.67 50.00 37.33 324 438 27.16 7.74 11 10 Example 34 12.53 49.43 36.89 0.15 — — 1   12.67 50.00 37.33 336 484 26.16 7.89 10 5 Comparative  3.97 53.65 41.73 0.15 0.5 — 1    4.00 54.00 42.00 285 422 25.77 10.08 14 8 Example 1 Comparative 19.87 51.10 28.38 0.15 0.5 — — 20.00 51.43 28.57 299 317 27.61 26.73 11 11 Example 2 Comparative 20.37 45.21 33.77 0.15 0.5 — — 20.50 45.50 34.00 313 486 29.10 11.40 9 3 Example 3 Comparative 12.89 45.12 41.34 0.15 0.5 — — 12.97 45.41 41.62 326 484 19.79 9.01 11 4 Example 4 Comparative  7.03 54.21 38.76 — — — —  7.03 54.21 38.76 273 289 29.10 5.06 10 10 Example 5 Comparative  7.02 54.16 38.72 0.1  — — —  7.03 54.21 38.76 313 364 26.43 5.78 11 6 Example 6 Comparative  7.00 53.94 38.56 0.5  — — —  7.03 54.21 38.76 324 368 26.81 6.84 9 8 Example 7 Comparative  6.93 53.41 38.16 1.5  — — —  7.03 54.21 38.76 322 375 27.14 7.52 9 8 Example 8 Comparative 12.36 48.78 36.36 2   0.5 — — 12.67 50.00 37.33 273 474 29.10 8.30 10 0 Example 9 Comparative 12.48 49.26 36.76 — 1.5 — — 12.67 50.00 37.33 279 477 29.70 7.85 13 0 Example 10 Comparative 12.48 49.26 36.76 — — 1.5 — 12.67 50.00 37.33 284 469 29.30 8.50 15 0 Example 11 Comparative 12.48 49.26 36.76 — — — 1.5 12.67 50.00 37.33 383 475 26.71 8.01 12 1 Example 12

(15) It can be seen from Table 1 that optimization of the composition ranges of Ag, Pd and Cu and addition of appropriate additive elements are necessary for a reduction in resistance and improvements in hardness (wear resistance) and bending resistance, as objects of the present invention. In other words, a Ag—Pd—Cu-based alloy having concentrations of Ag, Pd and Cu so that S.sub.Ag, S.sub.Pd and S.sub.Cu are outside a region of a polygon (A1-A2-A3-A4) in FIG. 1 is liable to be higher in specific resistance (Comparative Examples 1 to 4). Specifically, an alloy (Comparative Example 1) having a composition outside a line A1-A2, an alloy (Comparative Example 2) having a composition outside a line A2-A3, and an alloy (Comparative Example 3) having a composition outside a line A3-A4 each have a high specific resistance of more than 10 μΩ.Math.cm after the aging heat treatment. The alloy in Comparative Example 2 is also inferior in hardness (less than 380 Hv), and the alloy in Comparative Example 3 is inferior in bending resistance (number of times of bending: 3). An alloy (Comparative Example 4) having a composition outside a line A4-A1 exhibits a specific resistance value of 10 μΩ.Math.cm or less, but is liable to be higher in resistance. The alloy in Comparative Example 4 exhibits a number of times of bending of less than 5 (4) and is inferior in bending resistance. As described above, each of the alloys in Comparative Examples 1 to 4, although appropriately includes additive elements (B, and at least any of Zn, Bi and Sn) applied in the present invention, is inferior from the viewpoint of a reduction in resistance and is also sometimes insufficient in hardness and bending resistance.

(16) Additive elements are required to be appropriately added to a Ag—Pd—Cu-based alloy. A Ag—Pd—Cu ternary alloy including no additive elements is considered to have the lowest hardness and be inferior in wear resistance (Comparative Example 5). Addition of B in an amount outside an appropriate range results in a poor effect of enhancing hardness (Comparative Examples 6 to 8). Furthermore, excess addition of B can lead to clear deterioration in bending resistance (Comparative Example 9). Furthermore, if the amounts of addition of Zn, Bi and Sn being additive elements each having an effect of enhancing hardness are outside proper ranges, the number of times of bending is less than 5 and bending resistance is deteriorated (Comparative Examples 10 to 12).

(17) The Ag—Pd—Cu-based alloys (Examples 1 to 34), in which the concentrations of Ag, Pd and Cu are controlled so that S.sub.Ag, S.sub.Pd and S.sub.Cu fall within a range of a polygon (A1-A2-A3-A4) in FIG. 1 and furthermore to which B and at least any of Zn, Bi and Sn are added, have each been confirmed to exhibit excellent characteristics of all low resistance (specific resistance), wear resistance (hardness) and bending resistance (number of times of bending), as compared with the Ag—Pd—Cu-based alloys in Comparative Examples.

INDUSTRIAL APPLICABILITY

(18) As described above, the probe pin material of the present invention is low in resistance and excellent in wear resistance, and is also good in bending resistance. The probe pin material of the present invention is applied to a probe pin of a probe card for inspection in various electronic equipment, semiconductor devices, power devices, and the like. In particular, the probe pin material of the present invention, which is excellent in bending resistance, can also be usefully applied to a cantilever type probe pin, and a probe pin having a pogo pin shape.