DE112011100331T5 - A method of producing a tungsten-containing diamond-like carbon film on a base material of a contact probe pin for a semiconductor test apparatus - Google Patents

Abstract

It is a method for producing a tungsten-containing diamond-like carbon film on a base material of a contact probe pin for a semiconductor test device disclosed, characterized in that the tungsten-containing diamond-like carbon film on the base material by performing sputtering in a gas mixture of a hydrocarbon gas and argon gas using a tungsten carbide target is formed.

Description

Technical area

The present invention relates to a method for producing a tungsten-containing diamond-like carbon film on a base material of a contact probe pin for a semiconductor test apparatus. More particularly, it relates to a method of forming a tungsten-containing diamond-like carbon film on a base material having excellent tin adhesion strength such that adhesion of tin as a main component of a solder to a contact portion of the probe pin is prevented when the probe pin with the solder in Contact is, and also has excellent electrical conductivity.

State of the art

Since a contact probe pin for a semiconductor tester is repeatedly brought into contact with a solder as a probe material for a probe pin during a semiconductor test, tin as the main component of the solder sometimes adheres to the contact portion of the probe pin. If the adhered tin is oxidized, this increases the resistance, resulting in a drawback in the investigation. Accordingly, the adhesion of tin causes a reduction in the durability of the probe pin. In order to suppress the adhesion of tin on the surface of the probe pin and to improve the electrical conductivity, it has been proposed to form a tungsten-containing diamond-like carbon (DLC) film on the surface of the base material of the probe pin.

For example, Patent Literature 1 discloses the formation of a DLC film comprising a metal such as a metal. B. tungsten at least at the tip of a contact portion on the side of the upper end in a probe comprising tungsten or rhenium-tungsten. It is disclosed that a metal-containing DLC film is formed on the surface of a probe unit by performing sputtering using a carbon target and a metal target. Further, Patent Literature 2 proposes the formation of a carbon film in which a metal element such as. As tungsten, at least on the surface near the upper end of a contact terminal in a connecting device of a test apparatus of a semiconductor device, etc., before. It is disclosed that the carbon film in which the metal member is incorporated is preferably formed by a sputtering method using a carbon target and a metal target.

List of cited documents

patent literature

• Patent Literature 1: JP-A-2001-289874
• Patent Literature 2: JP-A-2002-318247

Summary of the invention

As a method of forming a DLC film on a base material, in addition to the sputtering method using a solid carbon source as the target as described above, there has been known a chemical vapor deposition (CVD) method in which a hydrocarbon gas in a plasma is decomposed. On the other hand, as a method of introducing a metal such. For example, tungsten, in a DLC film, not only a deposition method of performing sputtering by sharing a carbon target and a metal target as proposed in Patent Literature 1 and Patent Literature 2 are considered, but also a deposition method wherein sputtering is performed using a metal target while utilizing a CVD method of decomposing the hydrocarbon gas.

According to a study of the present inventors, the deposition rate of the DLC by the CVD method is higher than the deposition rate of the metal by the sputtering method and a difference in deposition rate is caused because the CVD method decomposes the gas in the latter method, so that the control of the composition of the metal in the DLC film was difficult.

Further, according to the study of the present inventors, it has been found that when a DLC film containing tungsten is formed by carrying out the sputtering process in a gas containing a hydrocarbon gas, the surface properties of the DLC film obtained are the metal target used is a tungsten target or a tungsten alloy target is different, resulting in an effect on tin adhesion resistance.

The present invention has been made in view of this subject matter and is intended to provide a method of forming a tungsten-containing DLC film on a base material of a contact probe pin for a semiconductor test apparatus in which a tungsten composition in the DLC film can be easily controlled and which is excellent in tin adhesion resistance, so that tin as a main component of a solder is prevented from adhering to the contact portion of the probe pin when the probe pin is in contact with the solder, and also excellent in electrical conductivity.

The present invention provides, in one aspect, a method for producing a tungsten-containing DLC film on a contact probe pin base material for a semiconductor testing apparatus, wherein the tungsten-containing DLC film is formed on the base material by performing sputtering using a tungsten carbide target in a semiconductor probe A gas mixture comprising a hydrocarbon gas and argon gas is formed.

The present invention, in another aspect, further provides a contact probe stylus for a semiconductor test device comprising a tungsten-containing DLC film obtained using the method described above.

Objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description.

Description of an embodiment

The present invention, in one aspect, provides a method for producing a tungsten-containing DLC film on a contact probe pin base material for a semiconductor test apparatus, wherein the tungsten-containing DLC film is formed on a base material of a contact probe pin by performing sputtering using a tungsten carbide target in a gas mixture comprising a hydrocarbon gas and argon gas.

The process for forming the tungsten-containing DLC film on the base material will be described for a preferred embodiment thereof.

[Target]

A target used in the sputtering method according to this embodiment is a tungsten carbide (WC) target. That is, tungsten (W) is introduced into a DLC film by performing sputtering using the WC target.

In the course of conducting a test for forming the tungsten-containing DLC film by performing sputtering in the gas containing the hydrocarbon gas, the present inventors have studied to compare the surface properties of the obtained DLC film between a case where for introducing tungsten into the DLC film as a target, a tungsten (W) target is used, and a case where a tungsten carbide (WC) target is used as the target. As a result, it has been found that a film having a smoother surface property than W-containing DLC film can be obtained in the case of using the WC target as compared with the case of using the W target. The present inventors further found that the tin adhesion resistance to the W-containing DLC film in the W-containing DLC film having a smooth surface compared with a W-containing DLC film having a rough surface considerably is improved.

In view of the reason why a W-containing DLC film having a smoother surface can be obtained in a case where the WC target is used as compared with the case where the W target is used , the present inventors are the following view. Deposition using the WC target tends to form a smooth amorphous surface the element carbon (C) bonded to the metal W reaches a base material. On the other hand, in the deposition using the W target while the surface is in an amorphous state, there may be a tendency for a cluster-like structure due to W particles to form during the formation of the film, form a fine unevenness due to the cluster. As a result, it is considered that the roughness of the film surface increases in the case of using the W target as compared with the case where the WC target is used.

As a WC target, superhard alloys can usually be used. For example, various types of superhard alloys that are used in JIS H 5501-1996 are indicated. In particular, type G and type D are of JIS H 5501-1996 preferably, since they substantially do not contain Ti, can suitably form a W-containing amorphous DLC film and can provide a W-containing DLC film having a low surface roughness. Various types of super hard alloys used in JIS H 5501-1996 Also, 2 atomic% or less of elements other than W, Co and C include.

[Process gas]

In the sputtering method according to this embodiment, a gas mixture of a hydrocarbon gas and argon gas is used as the process gas. That is, a DLC film is formed by introducing the gas mixture of the hydrocarbon gas and the argon gas into a vacuum chamber and performing reactive sputtering under predetermined conditions.

The hydrocarbon gas used is preferably methane (CH ₄ ) gas and / or acetylene (C ₂ H ₂ ) gas. In the W-containing DLC film formed by reactive sputtering, since W is introduced from the WC target into the DLC film, and on the other hand, carbon in the DLC film is not only introduced from the WC target but also of C in the hydrocarbon gas, the composition ratio of W to C in the W-containing DLC film is more easily controlled by using the CH ₄ gas and / or the C ₂ H ₂ gas as the hydrocarbon gas.

The concentration of the hydrocarbon gas with respect to the argon gas is preferably from 1 to 20% by volume, and more preferably from 2 to 10% by volume. The W content in the DLC film can be adjusted by changing the mixing ratio of the hydrocarbon gas to the argon gas, thereby adjusting the C content in the DLC film. When the concentration of the hydrocarbon gas relative to the argon gas is less than 1% by volume, there is a tendency that the deposition rate of the DLC is reduced as compared with the rate of introduction of W into the DLC. On the other hand, when the concentration exceeds 20% by volume, there is a tendency that the deposition rate of the DLC is relatively increased as compared with the rate of introduction of W into the DLC, whereby a difference in the deposition rate may be caused.

[Sputtering]

In this embodiment, the W-containing DLC film is formed on the base material of a contact probe pin by performing reactive sputtering in the mixed gas of the hydrocarbon gas and the argon gas using the WC target.

As sputtering, magnetron sputtering is preferable, and magnetron sputtering is more preferable in view of smoothing the surface of the W-containing DLC film. According to this method, the amount of Ar ions can be increased and the base material can be irradiated with Ar ions because a plasma space can be extended to near a substrate. By Ar ion irradiation, the kinetic energy of Ar ions contributes to improving the thermal energy of sputtered particles reaching the base material. The improvement of the thermal energy of the sputtering particles facilitates the movement of the particles on the substrate and the film can be densified to obtain a smooth film. To further enhance the effects, by applying a bias voltage to the substrate, the energy of the Ar ions can be controlled and adjusted, and the surface smoothness can be further improved.

[W-containing DLC film]

Since the W-containing DLC film formed on the base material of the contact probe pin according to the method of this embodiment has smooth surface properties, adhesion of tin in the solder to the contact portion of the probe pin can be prevented.

As the W-containing DLC film of this embodiment, it is preferable to form a W-containing DLC film having surface properties such that the surface roughness (Ra) of the outer surface is 0.2 nm or less in a 4 μm ² . Scanning range of an atomic force microscope (AFM) is. Within the range of surface roughness (Ra) described above, the adhesion of tin in the solder to the contact portion of the probe pin can be substantially completely prevented, as shown by an example to be described later.

The surface roughness (Ra) is determined by the arithmetic mean of the roughness determined according to JIS B0601 is set three-dimensional, and z. B. calculated as indicated below. That is, the arithmetic mean of the roughness is obtained by using image data obtained from an image in a 2 μm × 2 μm scanning region by an AFM device (SPI 4000, manufactured by SII Co.) and one averaged slant correction in both the X-direction and the Y-direction has been subjected by a surface processing software attached to the apparatus as image data and processing of the image data by a surface processing software (ProAna3D).

The content of W content in the W-containing DLC film is preferably 10 to 50 at% and more preferably 20 to 40 at%. W can improve the electrical conductivity of the DLC film, which is poor in the property of electrical conductivity, while limiting the adhesion of tin to a low level. If the W content ratio exceeds 50 at%, there is a tendency that the reliability of the semiconductor inspection is lowered since adhesion of tin is caused and the electrical resistance tends to be increased by the oxidation of the tin component. Further, if the proportion is less than 10 at%, the effect of providing the electric conductivity due to W tends to be lowered.

The thickness of the W-containing DLC film is preferably 50 to 1000 nm. When the thickness of the film exceeds 1000 nm, the unevenness on the outer surface tends to be increased, and if the thickness of the film is less than 50, on the other hand nm, there is a tendency that the film is subject to wear, so that the base material is exposed. More preferably, since the surface is smoothened and the internal strains are reduced so that the film peels less when the film is thinner, the thickness is more preferably 500 nm or less, and more preferably 300 nm or less.

The W-containing DLC film may be formed on the base material by means of an intermediate layer on the base material of the contact probe pin. The intermediate layer serves to enhance strong adhesion of the W-containing DLC film to the surface of the base material. The intermediate layer may contain W and C and have a gradient composition, wherein the ratio of the number of W atoms to the number of C decreases in the thickness direction from the surface of the base material to the W-containing DLC film. Alternatively, the intermediate layer may be a layer containing a pure metal, such as. Cr, Ti, W, Al, etc., or it may be a combination of a layer comprising a pure metal and a layer having the gradient composition. The thickness of the intermediate layer is preferably 5 to 400 nm, and more preferably 5 to 200 nm. Since the growth of W crystal grains contained in the intermediate layer is reduced to 400 nm or less, the unevenness on the outer surface of the W containing DLC film formed on the intermediate layer can be reduced. As a method for forming the intermediate layer on the base material of the probe pin, a sputtering method, in particular an unbalanced magnetron sputtering method, is preferably used. In this case, an intermediate layer may be formed in advance on a conductive substrate, and then the W-containing DLC film may be formed on the intermediate layer.

Further, the material for the base material is not specifically limited, and base materials of various metals or alloys may be used. The surface of the base material may also be plated. For plating, materials containing a pure metal or an alloy of two or more metals selected from the group consisting of chromium, cobalt, nickel, rhodium, palladium and gold may be used.

While a preferred embodiment of the present invention has been specifically described above, the description in all aspects is merely illustrative, and the present invention is not limited thereto. It should be noted that a number of unexemplated modified examples may be considered without departing from the scope of the present invention.

embodiments

Hereinafter, embodiments of the present invention will be described, but the invention is not limited to such embodiments.

(Formation of W-containing DLC film)

Deposition was carried out using an unbalanced magnetron sputtering system (UBM202) manufactured by Kobe Steel Ltd. has been made. As a target, a W target (99.9% purity) or a WC target (superhard alloy target, corresponding to a type G, No. 2 of U.S. Pat JIS H 5501-1996 Co is used as a binder) (see Table 1). A substrate was placed in parallel to a target on a substrate holder disposed on a substrate table, and deposition was performed while the table was rotated. As the base material, a glass substrate was used. After introducing the base material into the apparatus and evacuating the interior to 1 × 10 ^-3 Pa or less, deposition was performed.

A gas mixture of argon gas and a hydrocarbon gas was used as the process gas, and CH ₄ gas or C ₂ H ₂ gas was used as the hydrocarbon gas. Deposition was performed while the gas mixture of the argon gas and the hydrocarbon gas was introduced into the chamber. Table 1 shows the concentration of the hydrocarbon gas used in volume percent, based on the argon gas. The gas pressure during the deposition was set at a constant 0.6 Pa and the bias applied to the substrate during deposition was set at a constant -100 V. The W content in the DLC film was adjusted by changing the gas mixture ratio during the deposition, thereby adjusting the C content in the DLC film.

The power supplied to the W target or the WC target was set to 2.0 kW. The deposition time was adjusted so that the film thickness was constant at about 200 nm. The film thickness was measured by a probe-type surface roughness meter (DEKTAK6M).

(Analysis of W content in the DLC film)

The W content in the obtained DLC film was analyzed by SEM (Scanning Electron Microscope) -EDX.

While Co could be detected slightly as a binder component in the W-containing DLC film obtained by using the WC target, the W content was calculated so that the two elements W and C represented 100 atom% ,

(Measurement of resistivity)

The resistivity measurement of the obtained W-containing DLC film was carried out by a 4-probe measurement.

(Evaluation of tin adhesion)

To evaluate the tin adhesion, a sliding test was conducted by using a tin-plated ball. For the slip test, a rotation slip test was performed with a ball-on-disc tester (tribometer, manufactured by CSM Co.). The radius of rotation was 1.5 mm, the rotation speed was set to 0.2 cm / s, and the load was set to 0.2 N, and a ball made by applying a 10 μm tin plating to SUJ2 (diameter 9 , 5 mm) has been formed. The sliding distance was set to a constant 0.5 m, and the evaluation was carried out on the basis of the amount of tin deposition after the sliding test.

To evaluate the tin deposition amount, four points on a slip circle were measured by a profilometer. The deposition cross-sectional area at each of the positions was determined, and an average value for the four points is shown in Table 1. Those with a numerical value of zero show no deposition of tin.

(Evaluation of surface properties)

To evaluate the surface properties, the surface roughness was measured with an AFM device (SPI 4000, manufactured by SII Co.). The probe used was an attached SN-AF01 probe with a length of 100 μm.

The measurement was made in air for a 2 μm × 2 μm scanning area after it was confirmed that a 10 μm × 10 μm site was free from impurities. The roughness arithmetic mean (Ra) was used as a parameter for the surface roughness and image data obtained from an image for 2 μm × 2 μm and an average slant correction in both the X direction and the Y direction were subjected to a surface processing software (SP14000) attached to the apparatus, and the value calculated by a surface processing software (ProAna3D) is shown in Table 1.

(Result)

The result is shown in Table 1. [Table 1] Sample No. target Concentration of the hydrocarbon gas W amount in the film (atomic%) Specific resistance of the film (Ω · cm) Tin deposition amount (μm ² ) Surface roughness Ra of the film (nm) CH ₄ (% by volume) C ₂ H ₂ (% by volume) 1 W 18 - 29.4 6.9 × 10 ^-4 0.9 0,350 2 W 20 - 25.3 8.9 × 10 ^-4 0.5 0,300 3 W - 3 28.2 2.7 × 10 ^-4 1.2 0.445 4 W - 4 21.7 4.7 × 10 ^-4 0.5 0.303 5 WC 5 - 39.8 2.1 × 10 ⁴ 0 0,170 6 WC 8th - 23.9 5.0 × 10 0 0,160 7 WC - 2 25.2 4.6 × 10 ^-4 0 0.168 8th WC - 3 21.9 6.8 × 10 ^-4 0 0.113

Samples are W-containing DLC films obtained by performing reactive sputtering in a mixed gas of a hydrocarbon gas and argon gas using the W target for Samples Nos. 1 to 4 and WC targets for Samples Nos. 5 to 8 have been obtained.

In all W-containing DLC films, the W content ratio is set within a range of 20 to 40 atomic%. Further, the resistivity of all W-containing DLC films is 1 × 10 ^-3 Ω · cm or less.

With respect to the amount of tin deposition after the sliding test using the tin-plated balls, no tin deposition is generated for the W-containing DLC films obtained by using the WC target (Sample Nos. 5 to 8), while tin deposition is observed in the tin plating W-containing DLC films (Sample Nos. 1 to 4) obtained using the W target are produced.

Further, the surface roughness (Ra) is 0.3 nm or more in the W-containing DLC films (Sample Nos. 1 to 4) obtained by using the W target, while being 0.2 nm or less in W-containing DLC films (Sample Nos. 5 to 8) obtained by using the WC target. A correlation between the surface roughness and the tin deposition amount for Samples Nos. 1-4 are apparent, and it can be seen that the amount of tin deposition is smaller when the surface is smoother. Further, in the sample Nos. 5 to 8, the surface roughness (Ra) is 0.2 nm or less, and the deposition of tin is not generated at all.

As described above, in one aspect, the present invention provides a method for producing the tungsten-containing DLC film on the base material of a contact probe pin for a semiconductor test apparatus, wherein the tungsten-containing DLC film is formed on the base material by performing a Sputtering is formed in the gas mixture of the hydrocarbon gas and argon gas using the tungsten carbide target.

According to the method, since the tungsten-containing DLC film has a smooth-surfaced property, a tungsten-containing DLC film excellent in tin adhesion resistance which prevents tin from adhering to the contact portion of the probe pin on the base material of the Contact probe pin for a semiconductor tester are formed. Further, a tungsten-containing DLC film in which the tungsten composition in the DLC film can be easily adjusted and which is excellent in electrical conductivity can be formed on the base material of the contact probe pin for a semiconductor test apparatus.

Further, the hydrocarbon gas used in the method is preferable in view of the fact that the composition ratio of tungsten to carbon in the DLC film can be more easily adjusted, preferably methane (CH ₄ ) gas and / or acetylene (C ₂ H ₂ )-Gas.

Further, in view of that the tungsten content in the DLC film can be easily adjusted, the concentration of the hydrocarbon gas relative to the argon gas is preferably 1 to 20% by volume.

Further, in view of the property of a smooth surface of the tungsten-containing DLC film, sputtering is preferably an unbalanced magnetron sputtering.

Further, the surface roughness (Ra) of the formed tungsten-containing DLC film is preferably 0.2 nm or less in a 4 μm ² scanning region, measured by an atomic force microscope. Within this range, adhesion of tin to the contact portion of the probe pin can be substantially completely prevented.

Further, in another aspect, the present invention provides a contact probe pin for a semiconductor test device comprising a tungsten-containing DLC film obtained using the method described above. A contact probe pin for a semiconductor test apparatus comprising a tungsten-containing DLC film having improved durability can be produced by using the method described above.

Industrial Applicability

According to the method of the present invention, a tungsten-containing DLC film formed on the base material of the contact probe pin for a semiconductor test apparatus, in particular, a tungsten-containing DLC film in which the tungsten composition in the DLC film can be easily adjusted, and which is also excellent in tin adhesion resistance, in which adhesion of tin in a solder to the contact portion of the probe pin is prevented, and also excellent in electrical conductivity. Further, using the method described above, a contact probe pin for a semiconductor test apparatus having a tungsten-containing DLC film with improved durability can be manufactured.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• JIS H 5501-1996 [0017]
• JIS H 5501-1996 [0017]
• JIS H 5501-1996 [0017]
• JIS B0601 [0025]
• JIS H 5501-1996 [0032]

Claims (6)

A method of producing a tungsten-containing diamond-like carbon film on a base material of a contact probe pin for a semiconductor tester, characterized in that the tungsten-containing diamond-like carbon film is formed on the base material by performing sputtering in a mixed gas of hydrocarbon gas and argon gas gas using a tungsten carbide target , The production process of claim 1, wherein the hydrocarbon gas is methane (CH ₄ ) gas and / or acetylene (C ₂ H ₂ ) gas. The production method according to claim 1, wherein the concentration of the hydrocarbon gas relative to the argon gas is 1 to 20% by volume. The manufacturing method of claim 1, wherein the sputtering is an unbalanced magnetron sputtering. The manufacturing method according to claim 1, wherein the tungsten-containing diamond-like carbon film has a surface roughness (Ra) of 0.2 nm or less in a 4 μm ² scanning region of an atomic force microscope. A contact probe pin for a semiconductor testing apparatus comprising a tungsten-containing diamond-like carbon film obtained by using the manufacturing method according to any one of claims 1 to 5.