JP4089261B2 - Free-cutting ceramics, manufacturing method thereof, and probe guide parts - Google Patents

Description

【００５４】
表１から分かるように、本発明にかかる焼結体からなるセラミックス材料を用いると、割れや欠けを生じることなく高精度な微細加工を行うことができる。またこの材料の熱膨張係数は従来の結晶化ガラス系セラミックス材料に比べて小さく、シリコンの熱膨張係数に近い値を示すことがわかる。
【００５５】
【発明の効果】
本発明によれば薄い壁厚みで幅または直径の小さい深いスリットまたは貫通穴を精度良く形成できるので高密度に多数のプローブを所定位置に保持でき、かつ測定温度による位置ずれが小さく、その結果、LSI の高密度化に対応可能な半導体素子の検査装置が実現できる。
【図面の簡単な説明】
【図１】 プローブ案内部品の模式的説明図であり、装置図１(A) はプローブカードの断面を示す略式説明図、図１(B) はブローブ案内部品を備えたプローブカードの断面を示す略式説明図、図１(C) はプローブ案内部品の貫通穴の略式平面図、および図１(D) は略式断面である。
【図２】 図１の別の変形例を示すので、スリットを備えたプローブ案内部品の略式説明図である。
【図３】 実施例で形成したスリットの形状の説明図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-strength free-cutting ceramic whose thermal expansion coefficient is controlled in a range suitable for the intended use, a method for manufacturing the same, and a processed part such as a probe guide part.
[0002]
The high-strength free-cutting ceramic according to the present invention has a thermal expansion coefficient close to that of silicon, that is, the thermal expansion coefficient at 25 ° C. to 600 ° C. is in the range of 3 to 5 × 10 ⁻⁶ / ° C. Because it is controlled, the thermal expansion coefficient of silicon is close to 4 × 10 ⁻⁶ / ° C., and when used as a probe guide component (probe guide) for a semiconductor inspection apparatus in which slits and / or holes are formed, the semiconductor element to be inspected Does not cause misalignment.
[0003]
[Prior art]
Ceramic materials are attracting attention as structural members for semiconductor manufacturing equipment because of their excellent mechanical characteristics and high temperature characteristics. However, ceramics have a large shrinkage during sintering, and grinding is necessary to obtain a desired shape and dimensions with high accuracy. In this case, the inherent difficulty of ceramics becomes a problem.
[0004]
Therefore, in order to improve the workability, a ceramic or another ceramic having a cleavage property in a glass matrix, for example, a material in which mica or boron nitride is dispersed is used. These are generally called free-cutting ceramics and are used for semiconductor inspection equipment members that require high-precision fine workability and insulation, but they have the high strength and excellent strength required for high-precision fine processing. There are few products that have both workability and thermal expansion coefficient close to that of silicon.
[0005]
For example, in an inspection apparatus for inspecting the electrical characteristics of a semiconductor element such as an IC or LSI, a probe card having the same number of measurement probes as many electrode pads formed on the semiconductor element to be inspected is used. An inspection is performed by simultaneously contacting the electrode pads.
[0006]
FIG. 1 is a schematic diagram illustrating a state in which a semiconductor element is inspected using a probe guide provided with a measurement probe.
As shown in FIG. 1 (A), the probe card 1 is formed of an insulating material such as ceramics, and has an opening 10 at substantially the same size or larger than the semiconductor element to be inspected. As shown in the figure, the opening 10 is generally shaped like a morning glory that opens upward. On the upper surface of the probe card 1, as many measuring probes 2 as electrode pads of semiconductor elements to be inspected are attached by, for example, an adhesive.
[0007]
The measurement probe is made of a conductive material such as metal, and the tip thereof is bent into an approximately L shape, and is attached to the upper surface of the card 1 so as to protrude from the lower surface of the card 1 through the opening 10. Although not shown, the other end of the probe is electrically connected by solder to a conductive pattern formed on the upper surface of the card 1. The periphery of the probe except the tip may be covered with a heat resistant resin so that the probes do not contact each other.
[0008]
The probe card 1 is placed on and pressed against a semiconductor element to be inspected, and the tip of the measurement probe 2 protruding from the opening 10 comes into contact with an electrode pad (not shown) of the semiconductor element, so that the electrical characteristics of the semiconductor element are obtained. Is inspected. For this purpose, all of the multiple measurement probes must be in reliable contact with the electrode pads of the semiconductor element placed under them simultaneously. However, the probe is usually a thin metal material, and the position of the tip tends to shift due to the holding when pressed, making it difficult to reliably contact the electrode pad.
[0009]
As shown in FIG. 1 (B), as a means for facilitating precise positioning of the measurement probe, a probe guide component 3 in which a through hole 12 through which the probe passes is provided in the same pattern as the electrode pad on a plate of an insulating material. It may be placed so as to close the opening 10 of the probe card 1. Thereby, since the tip of each probe 2 protrudes through the through hole 12 of the probe guide part 3, the lateral movement due to the bending is limited, and the electrode pad can be more reliably brought into contact.
[0010]
The probe guide part 3, it is necessary to form the through hole 12 of slightly larger diameter than the measurement probe 2 at the same pitch as the electrode pads. Recent LSIs have dramatically increased in density, and it is not uncommon for electrode pad pitches to be 100 μm or less.
[0011]
For example, as shown in FIGS. 1 (C) and (D) in the plan view and the cross-sectional view, when the electrode pad pitch is 70 μm, the wall thickness between the through holes (between the holes) when the diameter of the through holes 12 is 60 μm. The minimum distance) is 10 μm and the wall thickness is very thin. Thus, it is necessary to form a fine and thin through-hole with high accuracy in the probe guide component by, for example, drilling.
[0012]
FIG. 2 is a schematic explanatory view of a probe guide component that has been slit by a grinding wheel. In this case, the probe 2 is supported by the slit 14 instead of the hole.
[0013]
Conventional probe guide parts are made of plastic or free-cutting crystallized glass ceramic materials such as Al ₂ O ₃ , SiO ₂ , K ₂ O, etc., and recently boron nitride-based free-cutting ceramics. It was. However, plastic cannot be used when it is necessary to inspect at a high temperature, and sufficient dimensional accuracy of a through hole or a slit cannot be obtained.
[0014]
On the other hand, when crystallized glass ceramic materials are used, it is possible to cope with high temperature inspection, but there is a problem that the thermal expansion coefficient is larger than that of semiconductor elements, and there is a problem of positional displacement depending on the measurement temperature. Since the strength is low, chipping and cracking are likely to occur during drilling, and sufficient dimensional accuracy cannot be obtained. See Japanese Patent Application Laid-Open No. 58-165056.
[0015]
Further, the composite material of aluminum nitride and boron nitride has a thermal expansion coefficient close to that of silicon and little misalignment due to the measurement temperature, but is not suitable for high-precision fine processing because of poor workability. See JP-A-60-195059.
[0016]
A high-strength, free-cutting silicon nitride / boron nitride composite material has also been proposed, but its thermal expansion coefficient is smaller than that of silicon, so there is a problem that misalignment occurs depending on the measurement temperature when used in a jig for semiconductor inspection. There is. See JP 2000-327402 A.
[0017]
[Problems to be solved by the invention]
The object of the present invention is to provide ceramics having both high strength and excellent workability required for high-precision micromachining and a thermal expansion coefficient close to that of silicon, a method for producing the same, and a probe guide component produced therefrom. Is to provide.
[0018]
Furthermore, a specific problem of the present invention is that by adding high thermal expansion zirconia and controlling the thermal expansion coefficient to a range close to that of silicon, the dimensions due to temperature change when used in other combination parts or inspection jigs. It is to provide a high-strength free-cutting ceramic suitable for microfabrication and a method for manufacturing the same, which can match the change with an object to be inspected.
[0019]
[Means for Solving the Problems]
As a result of repeated studies to solve the above problems, the present inventors have a strength of 240 MPa or more, and as a measure of machinability, the wear flank wear width by turning for 5 minutes with a carbide K-10 type tool. High-strength free-cutting ceramics with a VB of 0.2 mm or less and a work surface roughness Rmax of 5 μm or less enable micron-level microfabrication and is close to the thermal expansion coefficient of silicon among such materials. Paying attention to the effectiveness of the material, the main component is composed of 30 to 50% by mass of boron nitride, 50 to 70% by mass of zirconia and 0 to 10% by mass of silicon nitride , and further 1 to 15% by mass with respect to this main component It has been found that this can be realized by a free-cutting ceramic sintered body characterized in that it contains a sintering aid component .
[0020]
According to the present invention, novel ceramic processed parts such as the following (1) and (2) having a thermal expansion coefficient of 25 to 600 ° C. and a thermal expansion coefficient close to silicon of 3 to 5 × 10 ⁻⁶ / ° C. are provided. The
[0021]
(1) A machined part made of a free-cutting ceramic sintered body having a plurality of slits formed by grinding, wherein the wall thickness between the slits is 5 μm or more and less than 20 μm, and the slit depth / wall thickness ratio 15 or more and the pitch accuracy between the slits is within ± 4 μm.
[0022]
(2) A machined part made of a free-cutting ceramic sintered body having a plurality of holes formed by drilling, wherein the hole diameter is 65 μm or less, the wall thickness between the holes is 5 μm or more and less than 20 μm, A ceramic processed part having a depth / hole wall thickness ratio of 15 or more, and the hole diameter and hole pitch accuracy are both within ± 4 μm.
[0023]
Here, “wall thickness between holes” means the minimum distance between holes.
These ceramic processed parts may be probe guide parts having a plurality of slits and / or holes through which the probe passes.
[0024]
These processed parts according to the present invention are a process for obtaining a ceramic sintered body by sintering raw material powder containing boron nitride, zirconia, silicon nitride and an appropriate sintering aid under high temperature and pressure (hot pressing or HIP). And a method including a step of processing the ceramic sintered body with a grinding wheel or a drill.
[0025]
Here, it is preferable that the raw material powder of boron nitride and zirconia has an average particle size of less than 1 μm. By adding boron nitride, high thermal conductivity is imparted in addition to the original free machinability, both of which provide excellent workability.
[0026]
Moreover, since zirconia has high strength and large thermal expansion, it also serves as a thermal expansion adjusting material.
Although addition of silicon nitride is not essential, low thermal expansion and high strength can be realized by adding silicon nitride, so it may be added as an adjustment component for obtaining desired thermal expansion and strength.
[0027]
The ceramic according to the present invention has a high strength of 240 MPa or more and is free-cutting, and can perform fine machining with high accuracy. Furthermore, since the coefficient of thermal expansion at 25 ° C to 600 ° C is 3 to 5 x 10 ^-6 / ° C, which is close to that of silicon, the temperature when used for probe guide components (probe guides) used in semiconductor inspection equipment Even if there is a change, there is no misalignment with the semiconductor element to be inspected.
[0028]
When the constituent phase of this free-cutting ceramic was examined by X-ray diffraction, it was found that cubic zirconia was precipitated. Zirconia has three crystal forms of monoclinic, tetragonal, and cubic in order from the low temperature side. Tetragonal, cubic, or both are stabilized at room temperature. FSZ (stabilized zirconia → cubic) PSZ (partially stabilized zirconia → cubic + tetragonal) and TZP (tetragonal). In general, PSZ and TZP are tougher than FSZ.
[0029]
The reason why both high strength and free-cutting ability were achieved in the present invention is considered to be that free-cutting ability was expressed mainly by precipitation of FSZ, which is relatively easy to process than PSZ and TZP.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention example, a raw material powder is prepared by adding a sintering aid component to a main raw material powder composed of 30-50 mass% boron nitride, 50-70 mass% zirconia, and 0-10 mass% silicon nitride. This mixing can be performed by, for example, a wet ball mill.
[0031]
Boron nitride may be hexagonal (h-BN). From the viewpoint of obtaining the high strength required for fine processing, the main raw material powder, particularly boron nitride powder, having an average particle size of less than 1 μm is suitable. Similarly, the desired high-strength free-cutting ceramic can be obtained by using zirconia having an average particle size of less than 1 μm.
[0032]
The sintering aid used in the present invention can be selected from those conventionally used for sintering silicon nitride and boron nitride. Preferred sintering aids are one or more obtained from complex oxides such as aluminum oxide (alumina), magnesium oxide (magnesia), yttrium oxide (yttria), and oxides and spinels of lanthanoid metals, More preferred is a mixture of alumina and yttria, or a mixture obtained by further adding magnesia.
[0033]
The amount of sintering aid component is 1 to 15 by weight% of the main raw material powder, it is desirable that the particular ranging from 3 to 10 wt%. If the blending amount is too small, sintering becomes insufficient, the strength of the sintered body is lowered, and stabilization of zirconia is insufficient, resulting in insufficient precipitation of cubic zirconia. If the blending amount is too large, the grain boundary glass layer having a low strength increases and the strength of the sintered body is reduced.
[0034]
The raw material powder is sintered at high temperature and pressure. As the high-temperature pressure sintering method, there is a hot press, which may be performed in a nitrogen atmosphere or in pressurized nitrogen. The hot press temperature is preferably in the range of 1400-1800 ° C. If the temperature is too low, sintering becomes insufficient, and if it is too high, problems such as elution of the sintering aid component occur.
[0035]
An appropriate pressure is in the range of 20 to 50 MPa. The duration of hot pressing is usually about 1 to 4 hours although it depends on temperature and dimensions. High-temperature pressure sintering can also be performed by HIP (hot isostatic press). The sintering conditions in this case can also be set as appropriate by those skilled in the art.
[0036]
A sintered body obtained in this way, by appropriately selecting the type and amount of sintering aid, the thermal expansion coefficient at 25 ° C. to 600 ° C. is 3~5 × 10 ^-6 / ℃. Further, when the microstructure of the sintered body was observed with a scanning electron microscope (SEM), the average particle diameter of boron nitride, zirconia, and silicon nitride was 5 μm or less.
[0037]
Since this sintered body has excellent machinability and high strength, it can perform fine slit processing or hole processing with high accuracy, and exhibits a thermal expansion coefficient close to that of silicon. When used for (probe guide), it has a feature that it does not cause a positional deviation with respect to the semiconductor element to be inspected even if the temperature changes.
[0038]
The ceramic processed part according to the present invention is generally plate-shaped and has a plurality of slits formed by slitting with a grinding wheel and / or a plurality of through holes formed by drilling with a drill. is there.
[0039]
Since the wall thickness or the wall thickness between the holes is thin and can be processed with high accuracy, when the processed component according to the present invention is used as a probe guide component, the probe can be held at a high density and the positioning accuracy of the probe This improves the reliability of the inspection device.
[0040]
Accordingly, thus the thermal expansion coefficient produced find use high strength machinable ceramic close to silicon is not particularly limited, for example, probe guide elements to be mounted on a probe card used in the inspection apparatus of the semiconductor element described above It is useful as a processed part.
[0041]
Next, the effects of the present invention will be described more specifically with reference to examples.
[0042]
【Example】
The Example in this invention and the comparative example with respect to it are described, and a result is shown in Table 1. Unless otherwise specified, “%” and “parts” in Examples and Comparative Examples are “% by mass” and “parts by mass”.
[0043]
(Examples 1-8)
A hexagonal boron nitride (h-BN) powder having an average particle size of 0.9 μm and a purity of 99%, a zirconia powder having an average particle size of 0.1 μm and a silicon nitride powder having an average particle size of 0.1 μm were mixed in the ratio shown in Table 1. To this mixed powder (main raw material powder), 2% by mass of alumina and 6% by mass of yttria were added as sintering aids, and ball mill mixing was performed using ethyl alcohol as a solvent. At this time, a polyethylene pot was used, zirconia balls were used as a mixing medium, and the obtained slurry was dried by a vacuum evaporator to obtain a raw material powder.
[0044]
This raw material powder was filled in a graphite die and hot press sintered at 1600 ° C. for 2 hours while applying a pressure of 30 MPa in a nitrogen atmosphere to obtain a ceramic sintered body of 65 × 65 mm and a thickness of 10 mm.
[0045]
A test piece was cut out from the sintered body, and the fracture strength was measured by a three-point bending test to obtain the bending strength.
In addition, in order to evaluate the machinability, a turning test was conducted using a carbide K-10 type tool at a grinding speed of 18 min, a feed rate of 0.03 mm / rev, and a cutting depth of 0.1 mm. The surface roughness and the flank wear width of the tool (indicating the degree of tool wear) were measured.
[0046]
Furthermore, the thermal expansion coefficient of this sintered body was measured in the range of room temperature (25 ° C.) to 600 ° C.
These results are summarized in Table 1.
A slit having the shape shown in FIG. 3 (width = 40 μm, wall thickness = 15 μm, depth = 300) is obtained by slitting the sintered body using a grinding wheel (resin bond diamond wheel # 200, thickness 40 μm, outer diameter 50 mm). 100 μm) were formed at a pitch of 55 μm. Although slitting is possible, if the accuracy is insufficient (pitch accuracy exceeds ± 4μm) or cracking and / or chipping (chipping) occurs, slitting can be performed with sufficient accuracy. The case where no chipping occurred was evaluated as ◯.
[0047]
In addition, after cutting the obtained sintered body into a thin plate with a thickness of 300 μm, using a carbide drill with a diameter of 50 μm (material SKH9), as shown in FIG. Drilling was performed in 20 rows (total 200 pieces) at 70 μm. The hole diameter is 60 μm and the depth is 300 μm.
[0048]
Measure the accuracy of hole diameter and hole pitch of the obtained through-hole, ○ when this accuracy is within ± 4μm and there is no crack or chipping, drilling is possible, but accuracy is insufficient, The case where chipping occurred was evaluated as Δ.
[0049]
The results are shown in Table 1.
Example 9
Hexagonal boron nitride (h-BN) powder with an average particle size of 0.9 μm and purity of 99%, zirconia powder with an average particle size of 0.8 μm and silicon nitride powder with an average particle size of 0.5 μm are mixed in the proportions shown in Table 1. The other conditions were the same as in Examples 1 to 8, and a sintered body was produced and a characteristic test was performed. The results are shown in Table 1, and a decrease in bending strength was observed.
[0050]
(Comparative Examples 1 and 2)
Sintered bodies were produced in the same manner as in Examples 1 to 9 except that the mass ratio of boron nitride, zirconia, and silicon nitride was outside the scope of the present invention.
[0051]
(Comparative Example 3)
The conventional free-cutting crystallized glass-based ceramic material was slit and drilled in the same way as in the examples. However, the strength of the material was weak, and chipping occurred when fine processing was performed. I couldn't. Various characteristics and processing results of this ceramic material are also shown in Table 1.
[0052]
(Comparative Example 4)
When a conventional free-cutting ceramic material made of a composite material of aluminum nitride and boron nitride was subjected to slitting and drilling similar to the examples, the workability of the material was poor and it was not possible to drill accurately and cleanly. It was. Various characteristics and processing results of this ceramic material are also shown in Table 1.
[0053]
[Table 1]

[0054]
As can be seen from Table 1, when a ceramic material made of a sintered body according to the present invention is used, high-precision fine processing can be performed without causing cracks or chips. Moreover, it can be seen that the thermal expansion coefficient of this material is smaller than that of a conventional crystallized glass-based ceramic material, and shows a value close to that of silicon.
[0055]
【The invention's effect】
According to the present invention, a deep slit or a through hole having a small wall thickness and a small width or diameter can be formed with high accuracy, so that a large number of probes can be held at a predetermined position at a high density, and displacement due to measurement temperature is small. It is possible to realize a semiconductor device inspection system that can cope with higher density LSIs.
[Brief description of the drawings]
Figure 1 is a schematic illustration of a probe guide elements, Device FIG. 1 (A) is simplified explanatory diagram showing a cross-section of the probe card, FIG. 1 (B) a probe card of the cross-section having a blow blanking guide elements simplified illustration showing, FIG 1 (C) is probe guide schematic plan view of a through hole of the component, and FIG. 1 (D) is a simplified cross-section.
FIG. 2 is a schematic explanatory view of a probe guide component having a slit, showing another modification of FIG. 1;
FIG. 3 is an explanatory diagram of a shape of a slit formed in an example.

Claims (7)

The main component is composed of 30 to 50% by mass of hexagonal boron nitride and 50 to 70% by mass of cubic zirconia, and further includes a sintering aid component of 1 to 15% by mass with respect to the main component, and a bending strength of 240 MPa or more. Free-cutting ceramics characterized by   The free-cutting ceramics according to claim 1, wherein the hexagonal boron nitride and cubic zirconia each have an average particle size of 5 µm or less. The main component is composed of 30 to 50% by mass of hexagonal boron nitride, 50 to 70% by mass of cubic zirconia and 10% by mass or less of silicon nitride, and further comprises 1 to 15% by mass of a sintering aid component based on the main component. A free-cutting ceramic comprising a bending strength of 240 MPa or more.   The free-cutting ceramics according to claim 3, wherein the hexagonal boron nitride, cubic zirconia and silicon nitride each have an average particle size of 5 µm or less. The free-cutting ceramic according to any one of claims 1 to 4, which has a thermal expansion coefficient of 3 to 5 x ^10-6 / ° C at 25 ° C to 600 ° C.   A step of obtaining a raw material powder by mixing a main component raw material powder containing hexagonal boron nitride and zirconia, and optionally silicon nitride, and 1 to 15% by mass of a sintering aid of the main component raw material powder, and 6. A hot press sintering of the raw material powder mixture at a temperature of 1400-1800 ° C. and a pressure of 20-50 MPa, wherein the zirconia has an average particle size of less than 1 μm. A method for producing machinable ceramics.   A probe guide component comprising a plurality of slits and / or holes through which a probe passes, the probe guide component comprising the free-cutting ceramic according to claim 1.

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