JPH0774216A - Prober - Google Patents

Abstract

PURPOSE:To probe even many objects, to be inspected, at a time, with high accuracy and with high reliability by a method wherein a probing part is provided in the central part of a prober substrate whose coefficient of thermal expansion is substantially the same as that, of a semiconductor substrate and lead parts for the probing part are formed so as to be extended to the outer circumferential direction from the central part of the prober substrate. CONSTITUTION:A prober substrate 1 whose coefficient of thermal expansion is substantially the same as that of a semiconductor substrate is provided, an opening part 13 is formed in the central part of the prober substrate 1, and a probing part 2 including a plurality of lead parts 5 which are extended to the outer circumferential direction from the inside is installed at its circumference. Contacts 6 which are used to come into contact with pad parts for an IC element are formed near outside end parks of the individual lead parts 5, and conductive layers 4 one end of which is connected to the individual contacts 6 and the other end of which is terminated near the outer peripheral edge of the prober substrate 1 are formed. Thereby, the area of the IC element as an object to be inspected can be made equal too, or smaller than, an area occupied by a probing mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prober used for performing characteristic inspection and aging of a semiconductor integrated circuit (IC) element (inspection object) formed on the surface of a semiconductor substrate such as silicon.

[0002]

2. Description of the Related Art Demands for a prober capable of simultaneously probing a plurality of specimens or a large number of specimens formed on one wafer due to their structure are becoming stronger from the following points. ing. For example, it is possible to detect and eliminate defective products by performing characteristic inspection and aging treatment at the wafer stage before cutting, and to pass only good products to the post-treatment stage. At the same time, it can be greatly improved, and at the same time, it has a great advantage that it can be applied to so-called chip sales in which IC elements, which have been in high demand in recent years, are sold in a pellet state.

However, it is extremely difficult to simultaneously perform probing with high precision and high reliability on a plurality of specimens or wafers that have been deformed by undergoing a complicated IC manufacturing process. Probing was performed from the periphery of the subject using a long metal needle or the like, and a prober in which metal needles combined with springs were arranged in the shape of a sword was used.

[0004]

In the conventional one using a long metal needle, the size of the probing mechanism is very large as compared with the arrangement size of one object, and a plurality of objects are simultaneously probed. Was impossible to configure. In addition, a prober with metal needles combined with springs arranged in a sword-like shape requires high precision in processing, so it is difficult to manufacture a probe that can probe a large number of objects at the same time without defects. In addition, it is not suitable for mass production and has the drawback of being extremely expensive.

Accelerated aging is carried out from room temperature to 125
Since it is performed by a heating and cooling cycle of about ° C,
If there is a difference in thermal expansion coefficient between the subject and the prober mechanism, it is difficult to maintain the contact state with the conventional prober structure. Particularly, in recent years, the size of wafers has become large and the size of about 8 inches has become the mainstream, so that the dimensional deviation due to the thermal expansion becomes very large, and in the conventional prober configuration, a large number of specimens on the large wafer can be detected. It was nearly impossible to probe at once.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a large number of test objects such as IC elements.
It is to provide a prober that can perform probing at once with high accuracy and high reliability.

[0007]

According to the present invention, a prober used for testing the performance of a semiconductor integrated circuit device formed on the surface of a semiconductor substrate has a coefficient of thermal expansion substantially the same as that of the semiconductor substrate. A prober substrate having, wherein the prober substrate has a probe portion having a plurality of lead portions corresponding to respective pad portions of the semiconductor integrated circuit element in a central portion thereof, and the lead portion, When mounting the prober substrate on the surface of the semiconductor substrate,
Contact points are provided in contact with the respective corresponding pad portions, and further, a conductive layer is formed on the prober substrate, one end of which is connected to each of the contact points and the other end of which is terminated near the outer peripheral edge of the prober substrate. It is characterized by having done.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the accompanying drawings.

First, the principle of the present invention will be described before describing specific examples of the present invention. In order to solve the problems of the conventional techniques as described above, first, the unit occupying area of the probing mechanism is equal to or less than the unit area of the object to be tested, and the distortion of the semiconductor substrate generated during the IC manufacturing process is also considered. Regardless, it has a flexible structure such that it can maintain complete contact with the pad part of the subject, and it has the same coefficient of thermal expansion as the subject substrate to maintain perfect contact with the subject even during aging. You will need a prober board and mechanism.

For this purpose, the ratio of the area occupied by the unit probing mechanism to the area of the IC element alone is equal or less, and the pad portion and the pad portion are completely formed in spite of the distortion of the semiconductor substrate generated during the IC manufacturing process. It is necessary to develop a prober with a probe that has the elasticity and flexibility necessary to maintain contact, that is, the adaptability.

Therefore, as a result of various studies to solve such a problem, the present inventor found that a prober is required to maintain contact with the wafer on which the sample is formed even during the aging heating and cooling cycles. Since it is necessary to use a material having the same coefficient of thermal expansion as that of the wafer as the material of the substrate,
Prober substrate is made of materials such as glass, ceramics, or semiconductors, and the structure is backed by a structure made of a metal material having a thermal expansion coefficient close to that of the prober to increase strength. By using a semiconductor substrate with a crystal orientation and aligning the crystal direction with the wafer to form the structure required for probing, the contact point on the prober substrate and the object to be inspected caused by thermal expansion, contraction or distortion of the dimension due to temperature. We focused on reducing the position error with the pad.

Then, the prober substrate is provided with a comb-tooth-shaped portion having an arrangement and dimensions exactly corresponding to the pad portion of the IC element formed on the surface of the semiconductor substrate which is the subject,
The individual tooth-like portions of the comb-tooth-like portion, that is, the lead portion and its vicinity are provided with necessary adaptability by means of changing the thickness, size, shape, composition, etc., and further, the conductor is provided on the prober substrate. An electric circuit composed of a coating film or a conductive layer is formed, and a metallic convex portion is formed as a contact point with the pad portion on the electric circuit at the tip of each lead portion to form a probe portion.

Generally, semiconductors such as silicon and glass,
Alternatively, when a material such as ceramic has a large thickness, it is easily cracked by an external stress, but as it is made thinner or thinner, the flexibility becomes larger, and the elasticity becomes larger by the operation such as quenching. . Therefore, the present inventor processes a substrate made of these materials into a comb-teeth shape, and changes the thickness, size, shape, composition, etc. of the comb-teeth-shaped portion (lead portion) or the vicinity thereof by means such as
Although it can be set so as to have properties suitable for the purpose of probing, it was noted that a metal with a small coefficient of thermal expansion coated with an insulating film can be used for the same purpose. .

In this case, the structure and processing of the comb-teeth-shaped portion (lead portion) of the probe portion are determined by photographic method and chemical treatment.
Alternatively, it is possible to use mechanical processing that is performed by electric discharge machining or the like and has become more accurate in recent years. However, a portion of the semiconductor substrate to be electric discharge machined has a high impurity concentration in advance to have conductivity. There is a need.

The conductive coating or conductive layer on the prober substrate can be formed by plating a conductor such as a metal by means such as plating, coating, sticking or vapor deposition. When the substrate is a semiconductor or the like, it is formed on the surface. It can also be produced by diffusing impurities, etc., and the conductive film or conductive layer is processed by applying a related technique such as printed circuit board or IC manufacturing, or plating or electroforming technique to form a circuit. .

Furthermore, the contact is also applied to the tip of the lead portion of the probe by applying the related technology such as printed circuit board or IC manufacturing or the plating or electroforming technology. The convex portion is formed of a metal such as nickel.

Next, a detailed configuration example of the prober as a specific embodiment of the present invention based on such a principle will be described. FIG. 1 of the accompanying drawings is a plan view showing a configuration example of a unit prober as one embodiment of the present invention. The unit prober of this embodiment is used for probing an IC device having a large number of pad portions 8 formed on a substrate 7 which is a subject as shown in the plan view of FIG. 3 and along the periphery of the substrate 7. It is a thing.

The prober is composed of a plate-like prober substrate 1 as a whole, and the central portion of the prober substrate 1 is
A rectangular opening 13 is formed for facilitating alignment with a subject as described later. And
A probe having a comb-like structure including a plurality of lead portions 5 extending from the inner side to the outer periphery in the central portion of the probe substrate 1 around the opening 13 and cut out by a plurality of C-shaped or U-shaped voids 1A. A section 2 is provided. The number and arrangement of these lead portions 5 correspond to the number and arrangement of the pad portions 8 of the IC element which is the subject to which this probe is applied.

Near the outer ends of the lead portions 5, contacts 6 are provided for making contact with the pad portions 8 of the IC element which is the subject. Furthermore, the prober board 1 is formed with a plurality of conductive layers 4 each having one end connected to each contact 6 and the other end terminating at each corresponding terminal 4 arranged near the outer peripheral edge of the prober board. In addition, an electric circuit for connecting to an external circuit for performing a performance test of the subject is configured.

FIG. 2 is an enlarged view showing a cross section of the lead portion 5 of the probe shown in FIG. 1. As is clearly understood from FIG. 2, in this embodiment, the thickness of the lead portion 5 depends on the probe. It is thinner than the other parts of the substrate 1. This requires a considerable thickness to maintain the strength or rigidity of the entire prober substrate 1, but the lead portion 5
The reason is that it is necessary to have an adaptability that can follow the unevenness due to the distortion of the wafer related to the subject, and it is necessary to have greater elasticity and flexibility. In this embodiment, the thickness of the lead portion 5 is thin, but it is also possible to change the other dimensions and shape of the lead portion.
Similar goals can be achieved. The same purpose can be achieved by changing the composition of the lead portion 5 from that of other portions.

On the other hand, by backing the prober substrate 1 with a reinforcing means made of a material such as metal or ceramics having a coefficient of thermal expansion substantially the same as that of the prober substrate 1, the strength of the entire mechanism relating to probing is increased. May be.

The unit prober having such a structure is
Connect the lead portion 5 of the probe unit 2 from the inside of the subject to the outer peripheral direction,
That is, since the prober substrate 1 is formed so as to extend from the central portion toward the outer peripheral direction, even if the area required for an electric circuit including the conductive layer 4 is included, the area occupied by the probing mechanism with respect to the area of the IC element alone is reduced. Since the ratio can be made equal to or less than that, it is possible to form a plurality of unit probers on the prober substrate 1 at the same pitch as the arrangement of the subject on the wafer. FIG. 4 is a plan view showing a prober of another embodiment of the present invention when a plurality of unit probers are formed on the prober substrate as described above. Components similar to those of the prober of FIG. 1 are designated with the same reference numerals as used in FIG. 1 and will not be described in detail again here.

In the prober of the embodiment shown in FIG. 4, an electric circuit including a large number of conductive layers 4 on the prober substrate 1 has a data bus and an address bus connected to each unit prober formed on the prober substrate 1. However, the number of wirings to an external circuit (not shown) for testing is obtained by using bus strengthening means such as a bus buffer or by applying the decoder 9 or the encoder 10. Can be reduced. In the embodiment of FIG. 4, the decoder 9 and the encoder 10 are mounted on one end of the prober board 1 to decode the designated code of the probe unit 2 transmitted from the external circuit for the test, and By encoding the data output from the unit prober, the number of connection terminals 11 which are connection means between a large number of conductive layers 4 and external circuits is reduced, and the number of wirings is reduced.

Further, in recent years, the integration density of ICs has increased,
ICs with complicated pad array shapes and many pads
Although the number of elements is increasing, in such a case, the shape of the probe 2 should be made uniform, or the probe 2 should be arranged in a zigzag pattern, etc. It can be dealt with by performing according to.

When a semiconductor is used as the material of the prober substrate 1, the density of the prober substrate 1 can be increased by forming an electric circuit by the conductive layer 4 on the surface by the same means as the IC formation, and further, the prober substrate can be formed. As a substrate 1, a semiconductor substrate having a crystal orientation similar to that of a wafer related to a subject is used, and its crystal direction is aligned with the wafer to cancel thermal expansion, contraction, strain, etc. in the X and Y directions. This makes it possible to minimize the positional deviation between the pad portion 8 and the contact 6 of the subject due to heat.

As the material of the prober substrate 1, a metal or the like having substantially the same coefficient of thermal expansion, resilience and adaptability as the subject is used, and an insulator is applied to the surface thereof or an insulating thin film material is attached. Although it can be used by forming an insulating film by the means described above, there are drawbacks such that the stray capacitance associated with the electric circuit including the conductive layer 4 increases, the operating speed decreases, and the processing becomes complicated.

When actually measuring and aging various characteristics relating to the wafer and the pellet, the prober substrate 1 is used.
After the position of the prober 1 is aligned with the subject, the prober substrate 1 is brought into pressure contact with the subject to bring the pad portion 8 and the contact 6 into contact with each other. This may result in destruction of the subject. FIG. 5 is a sectional view showing a prober of another embodiment of the present invention capable of preventing such a situation.

FIG. 5 shows a state in which the prober of another embodiment is mounted for probing on a semiconductor substrate on which an IC element as an object is formed, and the cross-sectional position of the prober is shown in FIG. In the case of the prober of the example, it is a position corresponding to the cross-sectional position along the line AA. In FIG.
The same reference numerals are used for components corresponding to those shown in FIGS. 1 to 3. As can be seen from FIG. 5, in the prober of this embodiment, the pressure receiving portion 12 which is slightly thinner than the thickness of the contact 6 is provided in the portion other than the lead portion 5 of the prober substrate 1 and the contact 6 of the lead portion 5 is When the lead portion 5 is elastically slightly displaced upward by being pressed against the pad portion 8 of the subject substrate 7, the pressure receiving portion 12 thereof should be in pressure contact with a portion other than the pad portion 8 of the subject substrate 7. As a result, no further deviation force is applied to each lead portion 5 of the probe portion 2. Therefore, each lead portion 5
Can be prevented from being damaged due to an excessive shift force, or can be prevented from being damaged due to excessive pressure applied to the subject substrate 7, the contact point 6 or the pad portion 8.

In this case, the structure of the subject and the electric circuit including the conductive layer 4 are affected by means such as forming the pressure receiving portion 12 with an insulating layer, an insulating film, or an elastic film, or combining it with the pressure receiving portion 12. It is also possible to protect it from reaching.

Regarding the alignment of the contact pad 6 and the pad portion 8 of the subject, which is necessary for probing,
In the above-described embodiment, the opening 13 for the prober substrate 1 is provided at the center of the prober substrate 1. However, since such alignment is usually performed by optical means, the prober substrate 1 is made of a transparent material. If formed, the alignment can be easily performed without forming such an opening. Further, according to the present invention, the prober substrate 1 can be made of a material such as glass or ceramic that is transparent to visible light, ultraviolet rays, infrared rays, etc.
Since the void 1A exists in the vicinity of, the alignment can be easily performed by utilizing them.

However, when probing a large number of specimens formed on the same specimen substrate 7 such as wafers at one time, the area of the prober substrate 1 and the specimen substrate 7 becomes large. The influence of distortion of both substrates also increases, and in a method that simply depends only on the adaptability relating to the lead portion 5 of the probe portion 2, a large number of contact points 6 and pad portions 8 are formed.
It may be difficult to obtain a proper contact pressure between
It may be difficult to perform reliable probing. In such a case, each lead part 5 of the probe part 2 of the prober is positively and elastically displaced so that the contact point 6 is pressed against the corresponding pad part 8 of the subject substrate 7. It is possible to do so.

FIG. 6 is a sectional view similar to FIG. 5, showing yet another embodiment of the present invention as described above. In the prober of the embodiment shown in FIG. 6, a magnetic substance 14 such as permalloy is attached to the surface of each probe 5 of the probe 2 opposite to the surface on which the contact 6 is provided. On the other hand, the excitation coil 16 is arranged below the base 15 on which the subject substrate 7 is installed. With such an arrangement configuration, a current is applied to the exciting coil 16 during probing to attract the magnetic body 14 by the generated magnetic field, thereby attracting the lead portions 5, thereby forming the contact points 6 and the pad portions 8. Can be surely brought into contact with each other.

According to such an embodiment, the exciting coil 1
An appropriate contact pressure can be obtained by controlling the current flowing through 6. Moreover, if a mixture of alternating current and pulsating current components is used as the current flowing through the exciting coil 16, the lead portion 5 can be vibrated, whereby the oxide film generated on the surface of the pad portion 8 by the contact 6 can be prevented. The effect of being able to destroy is also obtained.

As a method of attaching the magnetic body 14 to the back side of the lead portion 5 as described above, vapor deposition, plating, electrodeposition,
Various methods such as application, sticking, and the like can be considered. Further, the base 15 made of a magnetic material is more convenient because the magnetic field near the prober substrate 1 is averaged and the exciting current is smaller.

Further, when probing a large number of whole objects such as wafers at one time, if defective portions are mixed, it becomes difficult to perform inspection and aging. For example, for each individual object, It is also possible to install the exciting coils 16 and select and drive the exciting coils 16 corresponding to those other than those corresponding to the defective portion. Further, by configuring the lead portion 5 to have a bimorph structure and applying a voltage to only the necessary lead portion 5 to activate the lead portion 5, it is possible to selectively move the individual lead portions 5 of the probe portion 2. By adopting such a configuration, when probing a large number of test objects at once such as when a wafer is targeted, it is possible to perform probing while avoiding a defective portion.

In addition to the above, it is possible to apply to the lead portion 5 and the like of the probe portion 2 a technique relating to a so-called micromachine, which has made rapid progress in recent years.

[0037]

Since the prober according to the present invention can make the ratio of the area occupied by the probing mechanism to the area of the IC element or the like which is the subject to be equal to or less than that, it is not limited to the probing of each subject, It is also possible to simultaneously perform probing on a plurality of test objects and further on the entire wafer by means of a prober formed by collecting a plurality of probers.

When the main body apparatus using the prober of the present invention is introduced into an IC manufacturing line, the I
Aging and characteristics inspection are performed at the stage of forming the C element, and if the found defective product is eliminated, only the operation check need be performed in the final process.
There is also an effect that the efficiency of the C production line can be greatly improved, and at the same time, so-called chip sales, in which IC elements, which have been in great demand in recent years, are sold in a pellet state, can be dealt with.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration example of a unit prober as an embodiment of the present invention.

FIG. 2 is an enlarged view showing a cross section of a portion of a lead portion 5 of the probe shown in FIG.

FIG. 3 is a plan view showing an example of a subject substrate on which an IC element is formed.

FIG. 4 is a plan view showing a prober of another embodiment of the present invention when a plurality of unit probers are formed on a prober substrate.

FIG. 5 is a cross-sectional view showing a prober according to another embodiment of the present invention in a probing state.

FIG. 6 is a sectional view similar to FIG. 5, showing yet another embodiment of the present invention.

[Explanation of symbols]

 1 Prober Board 1A Gap 2 Probe 3 Terminal 4 Conductive Layer 5 Lead 6 Contact 7 Contact Substrate 8 Pad 9 Decoder 10 Encoder 11 Connection Terminal 12 Pressure Receptor 13 Opening 14 Magnetic Material 15 Base 16 Excitation Coil

Claims (8)

[Claims] 1. A prober used for testing the performance of a semiconductor integrated circuit device formed on a surface of a semiconductor substrate, comprising a prober substrate having a coefficient of thermal expansion substantially the same as that of the semiconductor substrate. The substrate has a probe section in the center of which a plurality of lead sections corresponding to the respective pad sections of the semiconductor integrated circuit device are formed, and the probe section is provided with the prober substrate in the semiconductor section. When placed on the surface of the substrate, contacts are provided for contacting the respective corresponding pad portions, and further, the prober substrate has one end connected to each of the contacts and the other end outside the prober substrate. A prober, characterized in that a conductive layer terminated near the periphery is formed. 2. The prober substrate has probe portions equal in number to the semiconductor integrated circuit elements formed on the surface of the semiconductor substrate, corresponding to the arrangement positions of the semiconductor integrated circuit elements formed on the surface of the semiconductor substrate. The prober according to claim 1, which is provided at a different position. 3. The lead portion is made thinner than the thickness of the probe substrate thereof, and the probe substrate has a thickness on the same surface side of the lead portion as the contact surface on which the contact portion is provided. The prober according to claim 1 or 2, wherein a pressure receiving portion having a slightly thin thickness is provided. 4. The prober substrate is formed of the same semiconductor material as that of the semiconductor substrate, and the relationship between the crystal orientation of the prober substrate and the probe section is defined by the crystal orientation of the semiconductor substrate and the semiconductor integrated circuit element. Claim 1 or 2 which has the same relationship as
Or the prober described in 3. 5. The lead portion, in a state where the prober substrate is placed on the surface of the semiconductor substrate, receives a force from the outside in a non-contact manner so that its contact point becomes the corresponding pad portion. The prober according to any one of claims 1 to 4, which is provided with a shift means for ensuring positive contact with the prober. 6. A prober according to claim 6, wherein said shifting means is adapted to be selectively actuated. 7. The prober substrate comprises visible light, ultraviolet light,
Alternatively, the prober according to any one of claims 1 to 6, which is formed of a material transparent to infrared rays. 8. The prober substrate according to claim 1, wherein an opening for alignment with a semiconductor integrated circuit element formed on the surface of the semiconductor substrate is formed in the prober substrate. Prober.