JPH06268035A - Micro prober - Google Patents

Abstract

PURPOSE:To enable simultaneous probing to pad portions of a plurality of specimens formed on a semiconductor substrate. CONSTITUTION:Electric circuits consisting of a conductive material film or conductive layer is formed on a prober substrate 1 consisting of semiconductor such as silicon and materials which assure good reproducibility to stress and have small thermal expansion coefficient such as ceramic or metal with coating of insulating film. A comb-teeth portion having the layout and size accurately corresponding to a pad portion 8' of an IC (semiconductor integrated circuit) element which is formed on the surface of a silicon substrate as an inspection sample obtained by processing the prober substrate 1 is also provided and a projected metal part is also formed on the electric circuit at the end part of the comb-teeth portion as a contact for the pad portion 8' of the specimen Moreover, the probing with a plurality of inspection samples can be made simultaneously by providing a plurality pairs of probing.portions through modification of thickness, size, shape, composition and property in the pitch matching with the arrangement of the specimen in order to give necessary mobility to the comb-teeth portion and the periphery thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aging device for inspecting and aging characteristics of an IC (semiconductor integrated circuit) element formed on the surface of a semiconductor substrate such as silicon, which is an object to be inspected, and an inspection apparatus for such characteristics ( Both of them are collectively referred to as a main body device hereinafter), and a probe unit or a microprober for the purpose of contacting the bonding pad portion (hereinafter abbreviated as a pad portion) of the subject with high accuracy and reliability. Since it is possible to expand to a structure that can simultaneously probe multiple test objects or many test objects grown on the entire wafer at the same time because of the structure, the characteristics at the initial stage of the manufacturing process by combining with the main unit Inspection and aging processing can be performed at the wafer stage to detect and eliminate defective products, and prevent them from flowing to the subsequent lines. At the same time the efficiency of bad IC production line yield may greatly improve, the IC element demand has become more recently it is possible to cope with a so-called chip sales sold in the state of pellets.

[0002]

2. Description of the Related Art Probing a wafer deformed by a complicated IC manufacturing process with high reliability is extremely difficult. Conventionally, a mechanism mainly using a long metal needle is used. However, in this method, the area occupied by the probing mechanism is much larger than the area of one subject, and it is very difficult to configure the mechanism to perform probing simultaneously with a plurality of subjects. Difficult, let alone targeting a large number of subjects.

Further, since accelerated aging is performed by a heating / cooling cycle from room temperature to about 125 ° C., it is impossible to maintain contact if there is a difference in thermal expansion coefficient between the subject and the prober mechanism, especially in recent years. Wafers are getting bigger 8
Since the size of inches is the mainstream, the dimensional error due to the thermal expansion is so large that it is impossible to perform probing with a large number of specimens at once.

[0004]

To solve this problem, 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 solved. Regardless of having a structure that can maintain complete contact with the pad of the subject, and even with aging, there is a probe and mechanism with the same coefficient of thermal expansion as the subject in order to maintain complete contact with the subject. You will need it.

[0005]

In order to solve the above-mentioned problems, the structure of a conventionally used metal needle or the like is stopped, and the ratio of the area occupied by the probing mechanism to the area of one IC element is equal. It is necessary to develop a prober with a probe section that has the possibility of maintaining the perfect contact with the pad section in spite of the following distortion of the semiconductor substrate that occurs during the IC manufacturing process. is there.

As a result of various studies to solve the above-mentioned problems, the present inventor has found that the semiconductors such as semiconductors such as silicon, glass, ceramics, metal with an insulating coating, etc., have good resilience to stress and the coefficient of thermal expansion. And an IC (semiconductor integrated circuit) element formed on the surface of a semiconductor substrate, which is an object to be inspected, by forming an electric circuit composed of a conductor coating or a conductive layer on a prober substrate made of a small material Providing a comb-tooth-shaped portion having an exact corresponding arrangement and dimensions, forming a metal convex portion on the electric circuit at the tip of each comb-tooth to form a contact with the pad portion of the subject, and further In order to give the comb-shaped part and its surroundings the necessary flexibility,
Probing with multiple subjects can be performed at the same time by providing multiple sets of probe parts that are formed by taking measures such as changing thickness, size, shape, composition, and properties at a pitch that matches the array of subjects. The structure was made as possible.

Further, in order to maintain contact with the wafer on which the specimen is grown even during the heating / cooling cycle of aging, it is necessary to use a material having a thermal expansion coefficient substantially the same as that of the wafer as the material of the prober substrate. , A structure in which a prober substrate is made of a material such as glass, ceramics, or a semiconductor, and if necessary, a structure made of a metal material having a coefficient of thermal expansion close to the backing is used to increase the strength. Using a semiconductor substrate with the same crystal orientation as the wafer as the material of the substrate,
By aligning the crystal direction with the wafer when forming the probe or wiring structure, the position error between the contact point on the prober substrate and the test object pad caused by thermal expansion / contraction or distortion of the dimension due to temperature is reduced. I devised what can be done.

[0008]

In general, semiconductors such as silicon, glass, or ceramics having a large thickness are easily cracked by external stress, but as it becomes thinner, it becomes more difficult to break even if it is bent considerably. Therefore, it is suitable for the purpose of probing by processing the substrate made of the above material into a comb shape and changing the thickness, size, shape, composition or property of the comb shape part or its vicinity. It can be set to have a possibility, and a metal having a small coefficient of thermal expansion coated with an insulating film can be given similar properties.

Regarding the problem of thermal expansion, a prober substrate or mechanism is formed with a thermal expansion coefficient substantially the same as that of the semiconductor substrate on which the subject is grown, or if necessary, the prober substrate is substantially the same as the semiconductor substrate. The coefficient of thermal expansion can be corrected and the strength can be increased by backing a structure made of a material having a coefficient of thermal expansion, and the same crystal orientation as that of the subject is used as the prober substrate for accurate correction. By using a semiconductor substrate having, by further aligning the formation direction of the probe portion and the electric wiring with the crystal direction of the subject, the prober contact point and the subject pad portion caused by thermal expansion and contraction or distortion of dimensions due to temperature It is possible to reduce the position error of.

[0010]

EXAMPLE The present invention is an IC formed on the surface of a semiconductor substrate.
(Semiconductor integrated circuit) A prober attached to an aging tester device (hereinafter, referred to as a main body device) for the purpose of characteristic inspection and aging of a device as a subject, and which comes into contact with the pad portion of the subject with high reliability Is.

That is, a conductor coating or a conductive layer is formed on a prober substrate made of a material such as a semiconductor such as silicon, glass or ceramic, or a metal having an insulating coating, which has a good resilience to stress and a small coefficient of thermal expansion. A comb-tooth shape having an arrangement and dimensions accurately corresponding to a pad portion of an IC (semiconductor integrated circuit) element formed on the surface of a semiconductor substrate which is a subject by processing the prober substrate And a metal convex portion is formed on the electric circuit at the tip of each comb tooth to form a contact point with the pad portion of the subject, and there is a possibility that the comb tooth portion and its vicinity may be necessary. Thickness, size, shape, composition,
It is characterized by having a plurality of sets of probe sections formed by taking measures such as changing properties, at a pitch that matches the arrangement of the subject, and with such a configuration, probing with a plurality of subjects at the same time can be performed. You can

In this case, the structure and processing of the comb-teeth portion of the probe portion are carried out by a photographic method and a chemical treatment, or by electric discharge machining or the like, and mechanical processing which has become more accurate in recent years can be used together. However, in the case of electric discharge machining of a semiconductor substrate, it is necessary to increase the impurity concentration in advance to give conductivity.

The conductive coating or conductive layer on the prober substrate can be formed by plating a conductor such as metal with a means such as plating, coating, pasting or vapor deposition. It can also be produced by diffusing impurities.

The contact at the tip of the probe can be formed by applying a related technique such as printed circuit board or IC manufacturing, or plating or electroforming technique. To form a basic pattern, and then form a metal such as platinum, rhodium, or nickel, which is a material with high hardness against abrasion, by thick plating, or form a photoresist after attaching the metal foil. It is formed by a method such as a photographic method using.

FIG. 1 shows a prober substrate 1 according to an embodiment of the present invention.
Is formed with four sets of probe portions each having a comb-tooth-shaped portion on four sides having an arrangement corresponding to the number of pads of the subject and the number of teeth, and each lead 2 constituting the comb-tooth is as shown in FIG. It has a circuit 3 made of a conductive layer and a contact 4.

The circuit 3 is assembled on the prober substrate 1 by the through-hole structure 3'to form a data bus, an address bus and the like. A bus buffer 5 is inserted to strengthen the bus and a decoder 6 is used. By decoding the external probe section designation code and selecting and designing each probe section, the bus can be made common, and the number of wires related to the connecting means 7 between the circuit 3 and another external circuit can be reduced. It can also be done.

Although a considerable thickness is required to maintain the strength or rigidity of the entire prober substrate 1, the leads 2 are formed on the wafer related to the subject by means of changing the thickness, size, shape, composition and properties of the leads 2. It is necessary to have a possibility to follow unevenness due to strain, and if more possibility is required, similar means can be used near the lead 2.

In order to further increase the overall strength, it is possible to increase the strength by backing the prober substrate 1 with a substrate or a structure made of a material having substantially the same thermal expansion coefficient as the material of the prober substrate 1.

In recent years, the density of integrated ICs has increased, and the number of IC elements having a complicated pad arrangement shape and a large number of pads has been increasing. In such a case, as shown in FIG. This can be dealt with by arranging the comb-tooth-shaped portions according to the purpose, such as arranging the tooth-shaped portions alternately to form a probe.

As the material of the prober substrate 1, a semiconductor such as silicon, glass, ceramic, or a metal having an insulating coating and a small coefficient of thermal expansion can be applied. When a semiconductor is used, an IC is formed on the surface. It is possible to make the density high by forming the circuit 3 by the conductive layer by the same means as described above, and further, as the prober substrate 1, a semiconductor substrate having a crystal orientation similar to that of the wafer to be inspected is used. By arranging the crystal orientation in line with the wafer, it is possible to cancel thermal expansion / contraction and distortion in the X and Y directions.
It is possible to minimize the positional deviation between the pad portion of the subject and the contact 4.

Further, as the material of the prober substrate 1, a metal or the like having substantially the same coefficient of thermal expansion, resilience and flexibility as the subject is used, and the surface thereof is coated with an insulator or an insulating thin film is applied. By forming the insulating film, the stray capacitance related to the circuit 3 becomes large and the operating speed is lowered, and there are drawbacks such as difficulty in processing.

During the actual measurement and aging of various characteristics of the wafer, the pad portion of the object to be inspected on the wafer and the contact point 4 to the prober substrate 1 are aligned, and then the prober substrate 1 is pressed against the wafer. The pad portion of the subject is brought into contact with the contact 4 by means of the probe 8. When the pressure contact pressure is further increased, the pressure receiving portion 1'other than the probe portion of the prober substrate 1 is related to the wafer 8 as shown in FIG. It is possible to limit the pressure applied to the probe portion and prevent the probe portion from being broken by pressing the portion other than the pad portion 8 ′ of the subject.

In this case, the structure of the subject and the circuit 3 are not affected by means such as forming the pressure receiving portion 1'with an insulating layer, an insulating film or an elastic film, or combining them with the pressure receiving portion 1 '. It is also possible to protect it.

The alignment of the pad portion 8'of the subject and the contact 4 relating to the prober substrate 1 necessary for performing probing is usually performed by optical means, so that the prober substrate 1 is transparent. And convenient.

In the present invention, the prober substrate 1 can be made of a material such as glass or ceramic which is transparent to visible light, ultraviolet rays, infrared rays and the like, and since there is a void near the probe portion, By using them, the alignment can be easily performed, and if necessary, the opening 9 can be formed in a place other than the circuit 3 as shown in FIG.
The purpose can be achieved by providing.

[0026]

According to the present invention, since it is possible to perform probing simultaneously with a plurality of specimens, it is possible to extend this over the entire wafer and at the same time to configure the main body device so as to perform aging and characteristic inspection at the same time. Since defective products can be found and eliminated by performing aging and characteristic inspection at the stage of growing the defective products, it is possible to prevent defective products from flowing to the subsequent line, and especially for the production line of ICs with poor yield. The efficiency can be greatly improved, and at the same time, it is possible to deal with so-called chip sales in which IC elements, which are in high demand in recent years, are sold in a pellet state.
Further, since only the operation check needs to be performed in the final process, the process can be greatly simplified, and it is expected to have a great effect of reducing the product cost.

[Brief description of drawings]

FIG. 1 is a front view showing a configuration example of a prober substrate.

FIG. 2 is a back view showing a configuration example of a probe.

FIG. 3 is a cross-sectional view showing a structural example of a lead.

FIG. 4 is a cross-sectional view showing a pressed state of a subject and a probe.

[Explanation of symbols]

 1 Prober Board 7 Connection Means 2 Lead 8 Wafer 3 Circuit 9 Opening 4 Contact 5 Bus Buffer 6 Decoder

Claims (7)

[Claims] 1. A conductor coating or a conductive layer on a prober substrate made of a material such as a semiconductor such as silicon, glass, ceramic, or a metal with an insulating coating, which has a good resilience to stress and a small coefficient of thermal expansion. A comb-tooth-shaped portion having an arrangement and dimensions accurately corresponding to a pad portion of an IC (semiconductor integrated circuit) element formed on the surface of a semiconductor substrate which is a subject by processing the prober substrate In addition to forming a metal convex portion on the electric circuit at the tip of each comb tooth to form a contact point with the pad portion of the object to be examined, the possibility of forming the comb tooth-shaped structure and its vicinity can be improved. Probing with a plurality of subjects by providing a plurality of pairs of probe sections with a pitch that matches the arrangement of the subjects by taking measures such as changing the thickness, size, shape, composition, and properties in order to have At the same time A microprober characterized by being configured to be able to perform 2. The microprober according to claim 1, wherein the comb-tooth-shaped portions are arranged facing each other or alternately in order to correspond to an IC element having a large number of pads. 3. The microprober according to claim 1, wherein a semiconductor such as silicon is used as a material for the prober substrate, and an insulating layer and an electric circuit are formed on the surface thereof by the same means as that for forming an IC. 4. When the prober substrate is pressed out and the contact point and the pad portion of the subject are sufficiently contacted and then further pressed out, the prober substrate is provided on a portion other than the probe portion. The pressure sensing part is configured to limit the pressure by contacting the surface of the subject and protect the probe from damage, and the pressure sensing part is buffered to avoid affecting the structure and circuit of the subject. The microprober according to claim 1, wherein a layer, an insulating layer, an insulating film, or the like is formed. 5. A semiconductor plate having the same material and crystal orientation as that of the object to be inspected is used as the prober substrate, and the crystal orientation is aligned with that of the object to be inspected or wiring structure is formed. 2. The microprober according to claim 1, wherein the position error between the contact point of the prober and the object pad portion caused by the thermal expansion / contraction or distortion of the dimension due to is reduced. 6. The method of applying an encoder or a decoder to an electric circuit formed on the surface of the prober board, thereby reducing the number of wirings of a connecting means between the prober board and another circuit. The microprober according to claim 1. 7. The prober substrate is made of a material such as glass or ceramic which is transparent to visible light, ultraviolet rays, infrared rays, or the like, or is necessary for facilitating alignment with a subject during probing. The microprober according to claim 1, wherein a means such as an opening is provided at a place.