JP2007109899A - Method for inspecting semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inspecting a semiconductor device which enables an electric contact without forming a scribing mark, and corresponds even to an area array type electrode-pad constitution. <P>SOLUTION: A membrane type probe 5 brought into contact with electrode pads is contacted and operated on the whole surface of a wafer. The scribing mark is not generated on the electrode pads 4 by bringing a cantilever type probe needle 2 into contact with bump rear sections 5b, under the state in which bumps 5c are left as they are abutted and arranged on the top face of the wafer to the electrode pads 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for inspecting a semiconductor device, and relates to a technique for connecting a probe to an electrode pad in a step of inspecting electrical characteristics of a semiconductor device formed on a semiconductor wafer.

  Conventionally, in a semiconductor device manufacturing process inspection, a probe needle of a probe card is pressed against an electrode pad of a semiconductor device formed in a semiconductor wafer in the manufacturing process, and a test signal is applied to the semiconductor device from the semiconductor device tester. By detecting an output signal from the device, the operation of the semiconductor device is tested, and a semiconductor device that does not operate normally is separated as a defective one.

  Probe inspection is performed using a probe card in order to obtain electrical continuity with the electrode pad. A physical contact operation (such as scrubbing) is performed on the electrode pad by the probe needle of the probe card, and the probe is probed. Electrical characteristics are inspected after ensuring the connection between the needle and the electrode pad.

  By the way, in recent years, with the high integration and miniaturization of LSIs, the arrangement of electrode pads is becoming narrower and the pitch of multi-pins is becoming narrower. As a conventional electrode pad arrangement configuration, a peripheral type (peripheral arrangement terminal) has been widely used in consideration of easy wafer inspection and easy assembly process. In this peripheral type, electrode pads are arranged on the peripheral side of a semiconductor device.

  In response to the demand for more pins in recent years, an area array type (surface arrangement terminal) has been proposed in which electrode pads are arranged in a two-dimensional manner over the entire surface of the semiconductor device. A contact probe corresponding to an area array type arrangement has been proposed.

  In addition to the conventional cantilever system in which the probe needle is cantilevered, the probe card includes a vertical probe card (vertical system) in which probe needles are arranged in the vertical direction as corresponding to the area / array type arrangement design.

  However, in any electrode pad arrangement, a scrub mark generated on an aluminum electrode pad due to a contact operation at the time of probe inspection causes a shortage of a bonding area in a subsequent assembly process such as a wire bonding process. Alternatively, in the process of generating solder connection terminals directly on the electrode pads, a cleaning solution or the like is mixed into the scrub mark, which may cause molding defects in the solder ball process or cause corrosion over a long period of time. It was.

  In addition, the method of inspecting semiconductor devices by function has been generalized, and the number of inspections due to the division of the inspection process has increased, resulting in an increase in the area of the scrub mark generated on the aluminum electrode pad and frequent occurrence of rough electrode pad surfaces. Was.

  Patent Document 1 describes a contact probe in which a plurality of contact pins (probe terminals) protrude from one surface of an insulating layer. The insulating layer is formed by laminating a plurality of divided layers having different elastic moduli such that the elastic modulus decreases toward the one surface side, and the contact pin has a base end portion penetrating the insulating layer and is formed on the other surface of the insulating layer. The penetrating direction in the arranged divided layer and the penetrating direction in the divided layer arranged on one surface side are shifted from each other.

  In this contact probe, if overdrive is applied when the contact pin is brought into contact with the electrode pad, a force is generated to move the contact pin in a direction shifted in the penetrating direction, and the contact pin spontaneously slides and scrubs. Do.

In the contact probe using solder bumps called membrane type, the needle tip hardly slides and does not scrub. Therefore, high contact pressure is required to contact the aluminum electrode pad, and contact failure is likely to occur. It is described that there is an inconvenience.
JP 2002-277486 A

  In the prior art, there is no probe inspection method that can reduce the size of the scrub mark on the electrode pad aluminum while ensuring electrical contact. Although it is possible to reduce the scrub mark size by simply reducing the probe needle load, there is a problem that the electrical contact property at the time of probe inspection is lowered.

  Similarly, no probe inspection method can be found that can reduce the size of the scrub mark even when the electrode pad arrangement is an area array type. If a cantilever probe card is used for this area array type electrode pad, the closer the electrode pad is to the center of the semiconductor device, the greater the amount of movement of the probe needle during contact operation. There is a problem that the tip of the probe does not stay and the probe needle cannot contact the electrode pad.

  Furthermore, in recent years, it has been studied to dispose each transistor circuit of a semiconductor device under an aluminum electrode pad. However, due to normal contact operation, electrical characteristics fluctuate in the transistor circuit disposed under the electrode pad. Has been found to occur at about 7%. Even in this case, although it is possible to reduce the electrical characteristic fluctuation of the transistor circuit by reducing the probe needle load, there is a problem that the electrical contact property at the time of probe inspection is lowered.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an inspection method that does not cause a defect in an electrical probe inspection of a semiconductor device in a wafer state, and a scrub mark on an electrode pad that leads to a defect in an assembly process is downsized. It is an object of the present invention to provide a method for inspecting a semiconductor device that achieves both.

  In order to solve the above-described problems, a semiconductor device inspection method according to the present invention is a method for inspecting electrical characteristics of one or more semiconductor devices formed on a semiconductor wafer, and is an electrical device provided in a membrane probe. An alignment process that aligns and connects isolated bumps on each electrode pad of the semiconductor device on the entire surface of the semiconductor wafer, and a contact operation of a cantilever type or vertical type probe on the back side of each bump on the back side of the membrane type probe It is characterized by comprising a step of causing

  In this configuration, the membrane probe is aligned with each electrode pad of the semiconductor wafer before the probe inspection, and the probe load necessary to break the oxide film on the electrode pad of the semiconductor device is applied to the membrane probe. Applying at least once to enable electrical conduction, and in this state, the probe is brought into contact with the back surface of the bump to eliminate the occurrence of a scrub mark on the electrode pad.

  Further, the semiconductor device inspection method of the present invention makes contact between each bump of the membrane type probe and each electrode pad of the semiconductor device with only a probe load necessary for electrical inspection at the time of probe inspection performed after the contact operation. The semiconductor device disposed under the electrode pad is inspected by reducing a variation amount of electrical characteristics of the semiconductor element.

  In this configuration, the load required for the probe inspection includes a needle load value for contacting a cantilever type or vertical type probe needle to the back surface of the bump, and electrode pads 4 and bumps 5c of the semiconductor device capable of electrical conduction. Select a load that is greater of the probe load values required to maintain electrical contact with

  The semiconductor device inspection method of the present invention is characterized in that the back surface of the bump is formed in a different size so as to match the slip amount of the tip of the probe needle generated in the cantilever type probe. Furthermore, the sliding direction of the tip of the probe needle generated in the cantilever type probe is matched with the extension forming direction of the back surface of the bump.

  In this configuration, the longer the tip of the cantilever type probe needle, the more the contact with the back surface of the bump cannot be maintained, and the amount of slip cannot be controlled, but the back surface of the bump is adjusted according to the amount of slip of the probe needle. It is possible to maintain electrical contact between the probe needle and the back surface of the bump by forming the different sizes and matching the extension forming direction of the back surface of the bump with the sliding direction of the probe needle.

  The method for inspecting a semiconductor device of the present invention is a method for inspecting the electrical characteristics of one or a plurality of semiconductor devices formed on a semiconductor wafer, and a probe needle is directly applied to each electrode pad of the semiconductor device on the entire surface of the semiconductor wafer. When making contact, it is provided with a step of making contact operation with the probe needle load necessary to break the oxide film on the electrode pad and a step of reducing the probe needle load to the needle load value necessary for electrical inspection. It is characterized by inspecting the semiconductor element disposed under the electrode pad under a reduced probe needle load while reducing the amount of variation in electrical characteristics.

  With this configuration, in the contact operation process, after the probe needle breaks the oxide film on the electrode pad and the probe needle comes into contact with the aluminum, the probe needle does not move away from the electrode pad while maintaining the state where the contact surface is not exposed to the atmosphere. In addition, by performing inspection while reducing the needle load on the probe needle, even when the transistor circuit of the semiconductor device is placed under the electrode pad, the electrical characteristics fluctuation of the transistor circuit is reduced and probe inspection is performed. Can be implemented.

  According to the semiconductor device inspection method of the present invention, a scrub mark is not left on the aluminum electrode pad of the semiconductor device even after the probe inspection. Also, no matter how many times the cantilever type or vertical type probe is contacted to the back surface of the bump of the membrane type probe, the aluminum electrode pad surface of the semiconductor device is not scraped or the electrode pad surface is not roughened. Does not cause problems in the process. Further, even if there is a transistor circuit under the electrode pad, it is possible to reduce the variation in electrical characteristics and to perform inspection in the same wafer state as before.

  Embodiments of the present invention will be described with reference to the drawings. In FIG. 1, the cantilever type probe card is composed of a probe card substrate 1 and a plurality of probe needles 2 made of tungsten or the like, and the probe needle 2 is aligned with the position of the electrode pad 4 of the semiconductor device formed on the semiconductor wafer 3. Is arranged.

  Further, the membrane probe 5 includes a plurality of bumps 5c that form probe terminals, and the arrangement of the bumps 5c can be collectively connected to the electrode pads 4 of the semiconductor device on the entire surface of the semiconductor wafer 3. In the membrane probe 5, the bump 5 c disposed on the front surface side facing the electrode pad 4 is made of nickel, and the bump back surface portion 5 b disposed on the back surface side of the membrane probe 5 is formed by plating a copper pattern with gold. It is the best form.

  The scrub mark attached to the aluminum electrode pad 4 in the contact operation between the bump 5c of the membrane type probe 5 and the electrode pad 4 is about 25% smaller in area than when using a cantilever type or vertical type probe card. In addition, the depth is about 10% to 30% shallower in the depth direction, and the feature is that the scrub marks are evenly aligned because they are manufactured by etching.

  A commercially available wafer prober device or alignment device may be used for the alignment operation for collectively adjusting the positions of the electrode pads 4 of the semiconductor wafer 3 and the bumps 5c of the membrane probe 5. However, the probe card fixing portion (not shown) in the wafer prober apparatus or alignment apparatus has a manual or automatic exchange function of a membrane system and a cantilever system or a vertical system.

  In this alignment operation, the bumps 5c of the membrane probe 5 are positioned with respect to the electrode pads 4 on the entire surface of the semiconductor wafer 3, and the positions of the bumps 5c are matched within the range of all the electrode pads 4.

  Further, in this operation, in order to break the oxide film on the aluminum surface of the electrode pad 4, for example, a pressing operation for applying a probe load of 8 g or more per bump is also necessary. After this pressing operation, the bumps 5c of the membrane type probe 5 placed on the semiconductor wafer 3 are not changed in position so that the electrode pads 4 and the bumps can be used even under a probe load of 1 g or less per bump. Maintain the contact surface of 5c not exposed to the atmosphere.

  Thereafter, a cantilever probe card is mounted, and probe inspection is performed by bringing the probe needle 2 of the cantilever probe card into contact with the bump back surface portion 5b of the membrane probe 5 by a general prober operation.

  The load required for this probe inspection is 1.5 g or more in the needle load value to the bump back surface portion 5b by the probe needle 2 of the cantilever type probe card, and the electrode pad 4 that has already become electrically conductive The probe load value necessary for maintaining electrical contact with the bump 5c is 3 g even if the height variation of the electrode pad 4 and the bump 5c is taken into consideration, and the probe load set in the apparatus is about 3 g. As a result, the load at the time of probe inspection is 50% or less as compared with the load for the membrane probe 5 to break the oxide film on the aluminum surface of the electrode pad 4.

  The membrane type probe 5 shown in FIG. 1 has a bump of the membrane type probe 1 even if the probe inspection temperature is set to a high temperature of 120 ° C. because the thermal expansion of the ceramic ring 5 c matches the thermal expansion of the semiconductor wafer 3. 5c does not remove the contact surface with the electrode pad 4 on the entire surface of the semiconductor wafer.

  By the way, as shown in FIGS. 2A and 2B, when a cantilever type probe card is used via a membrane type probe 5 for the arrangement configuration of the electrode pads 4 of the area array type, the probe is used. The configuration of the needle 2 is three-dimensional and complicated as shown in FIG.

  As shown in FIG. 3A, the probe needle 2 of the cantilever type probe card arranged above the bump back surface portion 5b of the membrane type probe 5 is at the probe needle position 10 before the contact operation.

  As shown in FIG. 3B, when the probe needle 2 of the cantilever type probe card is lowered from the probe needle position 10 to a position in contact with the bump back surface portion 5b by the contact operation of the prober device, the scrub operation by the probe needle 2 is performed. And the tip portions 11, 12a, 12b of the probe needle 2 slide forward with respect to the fixed end 13 by at least 20 μm during the scrubbing operation.

  At this time, in order to prevent contact between the needles of the tip portions 11, 12a, 12b, the probe needles 2 of the cantilever type probe card have different lengths of the tip portions 11, 12a, 12b, and the shortest tip portion. 11, the longest tip 12a is three times as long.

  As a result, as shown in FIG. 3B, the longer tip portions 12a and 12b cannot be kept in contact with the bump back surface portion 5b, resulting in a separation distance B. Since this slip amount cannot be completely controlled by design, it is necessary to design the bump back surface portion 5b to a size including the above-mentioned separation distance B.

  Alternatively, as shown in FIG. 4, in order to make the needle loads of all the probe needles 2 that perform the contact operation as uniform as possible, the bump back surface portions 5b are made different in accordance with different slip amounts generated in each probe needle 2. Designed to keep contact by size.

  In FIG. 4, the interval between the bump back surface portions 5b is 200 μm or more, and the size of the bump back surface portion 5b is 50 μm or more in width and 100 μm or more in length in the sliding direction of the probe needle 2.

  In this case, in order to set a region 7 in which different scrubbing operations of each probe needle 2 are considered, and to further consider the scrub direction of the probe needle 2 in this region 7 at the design stage, the bump back surface portion 5b in the region 7 is set. Boundary lines 8 that determine different sizes and directions of extension formation are defined. In FIG. 4, two different scrub directions of the probe needle 2 are defined as indicated by arrows by the boundary line 8.

  Further, as shown in FIG. 5, the region 7 in which the scrub movement of the probe needle 2 is taken into consideration is divided into four blocks by the boundary line 9 to define four different scrub directions of the probe needle 2 so that the cantilever method can be used. The probe needle 2 can be rationally designed and manufactured.

  Further, the scrub direction of the probe needle 2 does not have to be the above-described two directions or four directions, and can be arbitrarily set for each probe needle 2. In this case, the probe needle 2 arbitrarily set is set. The extending direction of the bump back surface portion 5b is matched with the scrub direction.

  After the wafer inspection using such a cantilever type probe card and the membrane type probe 5 is completed, the membrane type probe 5 is used as a part of a wafer batch probe for performing wafer level burn-in as it is in a subsequent process. You can also.

  Furthermore, in the present invention, in the contact operation step, the bumps 5c of the membrane probe 5 are matched with the electrode pads 4 on the entire surface of the semiconductor wafer 3 to break the oxide film on the aluminum surface of the electrode pads 4, thereby Since the inspection is performed while reducing the probe load while keeping the contact surface between the bump 4c and the bump 5c in contact with the atmosphere, even when the semiconductor device is disposed under the electrode pad 4, the semiconductor device There is no significant variation in electrical characteristics of the transistor circuit (semiconductor element).

  FIG. 6 shows the electric characteristic fluctuation amount of the transistor circuit under the electrode pad 4 when the cantilever type probe needle 2 is used to directly contact the conventional electrode pad 4.

  As shown in FIG. 6, in order to apply a needle load of 2.4 to 3 g to the cantilever type probe needle 2 normally, an electric characteristic variation is about 5 to 5 in the transistor circuit (semiconductor element) under the electrode pad 4. 7% occurred. However, after this, when the needle load setting was reduced to 0.74 g and the change in the electrical characteristics of the transistor was measured, it was reduced to about 1.3%.

  That is, by reducing the needle load to a value necessary for maintaining the electrical contact between the electrode pad 4 and the probe needle 2 at the time of the probe inspection, it is possible to reduce the electric characteristic variation of the transistor under the electrode pad 4 by about 3%. / 4 (75%) can be reduced and probe inspection can be performed.

  FIG. 7 shows an example of verification of contact operation by the cantilever type probe needle 2. Here, in order for the contact resistance to be 1.5Ω, it is necessary to perform the contact operation with the needle load set to a minimum of 2.22 g. Further, when the contact operation was carried out by changing the setting of the needle load to 0.74 g, the contact resistance was about 2.4Ω.

  However, when the contact operation is performed with the needle load set at 2.22 g, and the needle load is reduced to 0.74 g while maintaining the contact state, the contact resistance increases by 0.2Ω. Even if the contact state is left for 50 hours or more, no increase in contact resistance is observed.

  That is, when there is a needle load sufficient to conduct the contact surface between the electrode pad 4 and the probe needle 2, oxidation does not proceed and stable probe inspection is possible.

  As described above, the method for inspecting a semiconductor device according to the present invention is compatible with a semiconductor device having an area / array type (surface-arranged terminal) electrode pad configuration, and even with a conventional probe, an electrode pad on a semiconductor wafer. This prevents the scrub mark from being scraped or roughened in the aluminum used in the process, eliminates problems in the assembly process of the semiconductor device due to the scrub mark, and ensures the stability of the probe contact performed in the electrode pad. This is a technique that can be used in the probe inspection of a semiconductor device because the fluctuation of the electrical characteristics of the transistor circuit disposed below the circuit is reduced.

The figure explaining the inspection method of the semiconductor device in the embodiment of the present invention 1 shows a cantilever type probe needle in the same embodiment, (a) is a cross-sectional view taken along line A-A ′ of (b), and (b) is a plan view of the cantilever type probe needle. (A), (b) is a figure explaining the operation | movement subject of a cantilever type probe, respectively. The figure explaining the case where the difference in movement amount and the scrub direction are defined in two directions The figure explaining the case where the difference in movement amount and the scrub direction are defined in four directions Relationship diagram between needle load value and contact resistance of cantilever type probe needle The figure which shows the electric characteristic fluctuation amount of the transistor circuit under the electrode pad at the time of probe inspection

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Probe card board 2 Cantilever type probe needle 3 Semiconductor wafer 4 Electrode pad 5 Membrane type probe 5a Ceramic ring 5b Bump back surface part 5c Bump 6 Semiconductor device 7 The area | region which considers a different needle movement 8 The scrub direction of 2 directions of a probe needle Boundary line to be defined 9 Boundary line to define four scrub directions of the probe needle 10 Probe needle positions 11, 12 a, 12 b before the contact operation Probe needle tip 13 Probe needle fixed end

Claims (7)

A method for inspecting the electrical characteristics of one or more semiconductor devices formed on a semiconductor wafer, wherein electrically isolated bumps provided on a membrane probe are positioned on each electrode pad of the semiconductor device on the entire surface of the semiconductor wafer A method for inspecting a semiconductor device, comprising: an alignment step of connecting together and a step of causing a contact of a cantilever type or vertical type probe to the back side of each bump on the back side of the membrane type probe. 2. The method for inspecting a semiconductor device according to claim 1, wherein in the alignment step, a probe load necessary for breaking the oxide film on the electrode pad of the semiconductor device is applied to the membrane type probe at least once. 2. The method for inspecting a semiconductor device according to claim 1, wherein the contact surface between the bump of the membrane probe and the electrode pad of the semiconductor device is not exposed to the atmosphere after the alignment step. A semiconductor element disposed under the electrode pad by contacting each bump of the membrane probe and each electrode pad of the semiconductor device with only a probe load necessary for electrical inspection at the time of probe inspection performed after the contact operation. 2. The method of inspecting a semiconductor device according to claim 1, wherein the inspection is performed by reducing the amount of fluctuation in electrical characteristics of the semiconductor device. 2. The method for inspecting a semiconductor device according to claim 1, wherein the back surface of the bump is formed in a different size in accordance with a slip amount of the tip of the probe needle generated in the cantilever type probe. 2. The method for inspecting a semiconductor device according to claim 1, wherein a sliding direction of a tip of a probe needle generated in a cantilever type probe is matched with an extension forming direction of a bump back surface portion. A method for inspecting the electrical characteristics of one or more semiconductor devices formed on a semiconductor wafer, wherein the probe needle is directly contacted with each electrode pad of the semiconductor device on the entire surface of the semiconductor wafer. The electrode pad includes a step of performing contact operation with a probe needle load necessary to break the oxide film, and a step of reducing the probe needle load to a needle load value necessary for electrical inspection, and the electrode pad under the reduced probe needle load. A method for inspecting a semiconductor device, comprising: inspecting the semiconductor element disposed under the semiconductor element while reducing an amount of fluctuation in electrical characteristics.

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