KR101079369B1 - Fabricaiton method of probe pin for probe card - Google Patents

Abstract

According to an embodiment of the present invention, there is provided a method of forming a recessed area corresponding to a probe pin on a mold substrate, reducing the roughness of at least the surface of the recessed area so that the surface of the recessed area becomes smooth; It provides a method for manufacturing a probe pin comprising the step of forming a release layer on the surface of the region, and forming a probe pin corresponding to the intaglio region by applying the plating process. Preferably, after the plating process, after placing the mold substrate on which the probe pin is formed on a circuit board, connecting the probe pin to a desired position on the circuit board, and maintaining the mold substrate as it is. The method may further include separating the mold substrate from the. In addition, the separated mold substrate may be recycled.

Description

Probe pin manufacturing method for probe card {FABRICAITON METHOD OF PROBE PIN FOR PROBE CARD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to probe pins for probe cards, and more particularly, to a method for manufacturing probe pins, which enables a simple process and enables recycling of molds used for manufacturing pins.

Recently, a probe card is an inspection apparatus that determines whether an electrical characteristic or a defect of a semiconductor chip on a wafer is used by using electrical contact with a probe pin. The probe card may implement a circuit board such as a ceramic substrate on which a circuit is implemented and a plurality of fine probe pins electrically connected to the circuit.

Since the probe pin for the probe card is in mechanical contact with the wafer, the pin body must have a high yield strength and have excellent restoring force. Therefore, excellent mechanical elasticity is required, and the chip has to have low electrical resistance since the chip is electrically tested.

In addition, the tip portion of the pin in mechanical contact with the chip requires abrasion resistance and low contact resistance. In recent years, the probe inspection apparatus needs to improve the integration of probe pins in order to collectively inspect high-density memory semiconductor chips at the wafer level. Therefore, it is desirable to form fine probe pins collectively using MEMS processing technology to improve the integration of the pins. It is a general trend.

In general, a probe pin forms an electrode on one surface of a ceramic substrate, and a probe pin is formed by performing a MEMS process on a semiconductor wafer such as silicon, followed by a bonding process between the ceramic substrate and the wafer. Here, the probe pins are formed on the ceramic substrate by removing the silicon wafer used as the mold to provide the desired probe card.

Conventional manufacturing methods for probe pins used herein can be broadly summarized into two.

The first method is to manufacture a mold for a probe pin using a polymer material on a ceramic substrate, and then fill the mold by plating to form a pin, and then remove the mold material to leave the probe pin on the ceramic substrate.

Another method is to process the mold into a desired mold by using the substrate itself, which can be selectively removed, as a mold material, form a probe pin using a plating process in the processed space, and then perform a bonding process with a ceramic substrate. It is a method to selectively remove the substrate.

The conventional method for manufacturing a probe pin has a problem in that a mold forming step for fabricating a pin is complicated and finally, a structure used as a mold is removed, so that a mold needs to be formed for each probe pin production. For example, in the case of manufacturing a mold using a polymer, the body of the probe pin (or probe beam) is formed by using the process of exposure → development → forming → plating, and the above steps are repeated to form a tip portion, and bonding is performed. → Probe pins are manufactured through the process of removing the mold, and pretreatment processes such as cleaning, surface treatment, polymer coding, and drying are required even in consideration of the general exposure process, which increases manufacturing time and repair time in the event of a failure of the probe card. In practice, in the field, the decrease in inspection efficiency causes the chip productivity to decrease.

The present invention is to solve the above-mentioned problems of the prior art, the object of which is to facilitate the separation of the prop pin and the mold structure to simplify the probe pin manufacturing process and the manufacture of the probe pin for the probe card that the mold structure can be recycled To provide a method.

In order to achieve the above technical problem, the present invention,

Forming an intaglio area corresponding to the probe pin on the mold substrate, reducing at least the roughness of the intaglio area surface to smooth the surface of the intaglio area, and releasing it on the intaglio area surface of the mold substrate It provides a method for producing a probe pin comprising the step of forming a layer, and forming a probe pin corresponding to the intaglio area by applying a plating process to the mold substrate.

The mold substrate may be a silicon substrate. The probe pin may have a structure having a probe beam and a probe team provided at one end of the probe beam.

Preferably, reducing the roughness of the surface of the intaglio region includes forming an oxide film on the surface of the intaglio region and removing the oxide layer.

In this case, the oxide film formed on the surface of the intaglio region may be a thermal oxide film.

Preferably, the release layer may be copper (Cu) or a copper-containing alloy.

Preferably, before the forming of the release layer, the method further comprises the step of forming a mask layer on the surface of the mold substrate except for the intaglio area. In this case, the method may further include removing the mask layer after the plating process.

In a particular example, the probe pin may be selected from the group consisting of Ti, Ni, Co, and combinations thereof.

In a preferred embodiment, after the plating step, after placing the mold substrate on which the probe pin is formed on a circuit board, connecting the probe pin to a desired position on the circuit board, and maintaining the mold substrate as it is. The method may further include separating the mold substrate from the probe pin.

In the present embodiment, the separating of the mold substrate may be performed by using a thermal expansion coefficient of the probe pin and the mold substrate.

In particular, the separated mold substrate can be recycled. That is, the mold substrate separated from the probe pin may be used again in the surface modification process for reducing the roughness, the release layer forming process, and the plating process for forming the probe pin.

The method of manufacturing a probe pin according to the present invention simplifies the mold forming process for manufacturing the pin and continuously recycles the mold in the probe pin manufacturing process. As a result, not only can the manufacturing time of the probe pins be greatly shortened, but also the productivity can be greatly improved through the recycling of the mold. In particular, as in the case of the MEMS probe card, the repair time in case of pin failure is shortened, resulting in chip inspection efficiency. Improvement can be aimed at.

Hereinafter, with reference to the accompanying drawings will be described a specific embodiment of the present invention.

1A to 1F are cross-sectional views of processes illustrating a process of forming a probe pin in a method of manufacturing a probe pin according to an exemplary embodiment of the present invention.

As shown in Fig. 1A, a mold substrate 11 used in the present probe pin manufacturing method is provided.

The mold substrate 11 may be a silicon wafer, but is not limited thereto, and may be another known semiconductor substrate having easy processability. In particular, any substrate that can have a desired negative structure through an anisotropic etching process such as a reactive ion etching (RIE) process can be advantageously used.

Subsequently, as shown in FIG. 1B, an intaglio region P corresponding to a desired probe pin is formed on the mold substrate 11.

The intaglio region P may be formed to have a region 11b corresponding to the probe beam and a region 11a corresponding to the probe tip to correspond to a desired probe pin structure. Although an intaglio area P for one probe pin is shown in the present example, it can be understood that in an actual process, the engraved area P for a plurality of probe pins is formed in a large area silicon wafer.

As mentioned above, the process may be implemented by known anisotropic etching processes such as RIE processes. In particular, when the negative region P is formed by anisotropic etching, the etching surface of the mold substrate made of silicon has a constant inclined surface (eg, 11a) based on a horizontal plane according to a desired probe shape. Etching surfaces can improve mold release.

Meanwhile, the surface of the intaglio region P, that is, the surface to which the anisotropic etching is applied, may be damaged during the etching process and thus have a high surface roughness. Since this high surface roughness is an obstacle to ensuring release property, the present invention includes a process for improving the surface. That is, the present invention employs a step of reducing at least the roughness Ra of the surface of the intaglio area P so that the surface of the intaglio area P is smooth.

For example, the surface may be improved by applying simple wet etching after anisotropic etching such as RIE etching is applied, but the process of improving the surface roughness for the intaglio region P which may be preferably employed in the present invention is illustrated in FIG. 1C. And by the process illustrated in FIG. 1D.

That is, as shown in FIG. 1C, a thin oxide film 12 is formed on the surface of the intaglio region P. FIG. The oxide film 12 may be a silicon oxide film when a silicon substrate is used as the mold substrate 11. The oxide film 12 formed on the surface of the intaglio region P may be a thermal oxide film. Subsequently, as shown in FIG. 1D, a smoother surface can be obtained by removing the oxide film 12 formed on the surface of the intaglio region P. FIG. This removal process may be performed using a known wet etching process.

The smooth surface of the intaglio area obtained through the oxide film formation / removal process can ensure high release property.

In addition, as shown in FIG. 1E, a process of forming the release layer 15 on the surface of the intaglio region P is performed.

The release layer 15 employed in the present invention may be preferably used as long as it is a material having electrical conductivity and capable of adding high releasability between the metal used in the subsequent plating process and the substrate material for the mold.

For example, prior to forming the seed layer, a material such as Ti or Cr was formed to increase adhesion to silicon, but in the present method, Ti or Cr may not be preferable to secure release property of the probe pin.

The release layer 15 preferably employed in the present invention may be copper or a copper alloy. The copper release layer 15 can increase current density to improve the efficiency of subsequent plating processes and achieve high release properties. The adhesion between the release layer 15 and the substrate 11, which is silicon, may be controlled to a desired level through the thickness of the release layer 15.

This process can be easily realized by forming a mask layer 16 such as a photoresist pattern on the surface of the mold substrate 11 except for the intaglio region P before forming the release layer 15. Can be. In this case, the mask layer 16 is maintained until the plating process, and the mask layer 16 will be removed after the plating process.

Next, as shown in Figure 1f, by applying the plating process to form a probe pin 17 corresponding to the intaglio area.

In a particular example, the probe pin 17 may be selected from the group consisting of Ti, Ni, Co, and combinations thereof. The probe pin 17 realized by the plating process may have a structure having a probe beam 17b and a probe tip 17a formed at one end of the probe beam 17b according to a previously engraved area. As described above, the release layer 15 such as copper, which is employed in the present invention, can ensure a high current density, and thus provides an advantage of easily performing an electroplating process.

Many of the advantageous advantages and effects of the present invention can be more clearly understood through the process of transferring to a circuit board for a probe card such as a ceramic substrate. 2A through 2C are cross-sectional views of processes illustrating a transfer process in a method of manufacturing a probe pin according to an exemplary embodiment of the present invention.

As shown in Fig. 2A, a substrate 21 for a probe card having a circuit is provided. The substrate 21 may be a multilayer ceramic circuit board.

As shown, a metal junction 27 is formed in one circuit region 22 of the substrate 21. The metal junction 27 may be formed to have a predetermined height and may be formed as part of a probe pin.

Subsequently, as shown in FIG. 2B, after the mold substrate 11 on which the probe pin 17 is formed is disposed on the circuit board 21, a part of the probe pin 17 is disposed on the circuit board 21. To the desired location of the

Specifically, as shown, the probe pin 17 is connected to the circuit board 21 by connecting one end of the probe beam 17b corresponding to the end opposite to the end where the tip 17a is formed on the metal joint 27. Can be transferred to.

Next, as shown in FIG. 2C, the mold substrate 11 is separated from the probe pin 17 so that the mold substrate 11 is maintained as it is.

Useful advantages of the present invention are evident in the present process. That is, the separation process of the mold substrate 11 of the present invention is not made by removing the mold structure, unlike the prior art, the mold substrate is separated from the probe pin 17 on the basis of high releasability while maintaining the shape thereof. do. This release can be realized by employing a conductive release layer 15, such as copper, with improved surface roughness, as described above.

In particular, the separated mold substrate 11 can be recycled. If necessary, the mold substrate 11 separated from the probe pin 17 may be repeatedly used several times through a surface modification process for reducing roughness, a release layer forming process, and a plating process for forming a probe pin. .

This separation process can be easily realized using the difference in thermal expansion coefficient between the constituent material of the probe pin 17 (strictly including the release layer 15) and the mold substrate 11. In general, the bonding process is carried out at a high temperature, after which only the probe pin 17 and the mold substrate 11 are locally cooled at a low temperature, thereby increasing the interfacial stress due to the difference in thermal expansion rate between silicon and metal, for example. The probe pin 17 is released along the introduced metal layer. In fact, since silicon and ordinary metals have a difference in thermal expansion of about 4.4 times, a separation process using a thermal expansion coefficient such as local low temperature cooling can be easily realized.

As such, the invention is not limited by the embodiments described above and the accompanying drawings, but is defined by the appended claims. Therefore, it will be apparent to those skilled in the art that various forms of substitution, modification, and alteration are possible without departing from the technical spirit of the present invention described in the claims, and the appended claims. Will belong to the technical spirit described in.

1A to 1F are cross-sectional views of processes illustrating a process of forming a probe pin in a method of manufacturing a probe pin according to an exemplary embodiment of the present invention.

2A through 2C are cross-sectional views of processes illustrating a transfer process in a method of manufacturing a probe pin according to an exemplary embodiment of the present invention.

Claims (12)

Forming an intaglio area corresponding to the probe pin on the mold substrate; Reducing the roughness of the surface of the intaglio area at least so that the surface of the intaglio area is smooth; Forming a release layer on a surface of the intaglio region of the mold substrate; And And forming a probe pin corresponding to the intaglio area by applying a plating process to the mold substrate. The method of claim 1, The mold substrate is a probe pin manufacturing method, characterized in that the silicon substrate. The method of claim 1, The probe pin is a probe pin manufacturing method, characterized in that having a probe team and a probe team provided on one end of the probe beam. The method of claim 1, Reducing the roughness of the surface of the negative area, And forming an oxide film on the surface of the engraved region, and removing the oxide film. 5. The method of claim 4, The oxide film formed on the surface of the intaglio region is a probe pin manufacturing method, characterized in that the thermal oxide film. The method of claim 1, The release layer is a probe pin manufacturing method, characterized in that the copper (Cu) or copper containing alloy. The method of claim 1, And forming a mask layer on the surface of the mold substrate except for the intaglio area before forming the release layer. The method of claim 7, wherein And removing the mask layer after the plating process. The method of claim 1, The probe pin is a probe pin manufacturing method, characterized in that selected from the group consisting of Ti, Ni, Co and combinations thereof. The method of claim 1, wherein after the plating process, Placing the mold pin on which the probe pin is formed on a circuit board, and then connecting the probe pin to a desired position on the circuit board; And separating the mold substrate from the probe pin so that the mold substrate is kept intact. The method of claim 10, Separating the mold substrate, the probe pin manufacturing method, characterized in that performed using the thermal expansion coefficient of the probe pin and the mold substrate. The method of claim 10 And reducing the roughness of the surface of the intaglio area by using the mold substrate having the probe pin separated therefrom, and separating the mold substrate from the probe pin.

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