JP2009145069A - Probe apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe apparatus which does not require readjustment of needle contact during a test and ensures a contact with an electrode pad. <P>SOLUTION: A probe apparatus for electrically testing a semiconductor integrated circuit in a wafer state comprises a probe needle 4 having a rigid circular arc part, and a probe card substrate 3. The probe needle 4 is connected with the probe card substrate 3 so that an angle formed by an assumed straight line connecting both the ends of the circular arc part of the probe needle 4 and the probe card substrate 3 is adjustable, and that the electrode pad 2 provided in the semiconductor integrated circuit and the circular arc part of the probe needle 4 directly contact with each other when an overdrive amount is maximum. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor integrated circuit test apparatus, and more particularly to a probe apparatus that contacts a terminal of a semiconductor integrated circuit in order to perform an electrical test of the semiconductor integrated circuit in a wafer state.

  In the LSI manufacturing process, in order to test each of a plurality of LSI chips created on the wafer surface at the wafer stage, contact is made with electrode pads on the LSI chip with needle-like probe needles (hereinafter referred to as “probing”). Electrical connection.

  Patent Document 1 discloses a probe needle shown in FIG. Reference numeral 1 denotes a wafer (semiconductor chip), 2 denotes an electrode pad, and 3 denotes a probe card substrate. As a configuration, the contact needle 4 (hereinafter referred to as “probe needle”) is formed in a plate shape so that the contact surface of the tip portion 41 with the electrode pad 2 is rounded and the support portion 42 is bent in the vertical direction. To do.

  Further, the central axis of the portion close to the tip portion 41 is inclined with respect to the surface of the electrode pad 2. Or the wear resistance of the front-end | tip part 41 further improves by making the shape of the front-end | tip part 41 into a semicircle. Thereby, the pressure applied to the electrode pad 2 is relieved and the electrode pad 2 is prevented from being damaged.

  Patent Document 2 discloses a probe having an arcuate structure. The purpose of this is to secure a stable electrical continuity by securing a scrub length necessary for contact with miniaturization of the probe.

JP 63-169039 A JP 2005-265659 A

  Since there is a height difference in the wafer surface due to the warpage of the wafer and the degree of patterning, the probe needle pressure (hereinafter referred to as “overdrive”) is used as the reference height of the needle stand in the wafer test probing. "). Therefore, as shown in FIG. 10, the probe needle 4 is brought into contact with the electrode pad 2 on the surface of the wafer 1 until probing is performed until the determined overdrive is reached.

  However, excessive overdrive is applied to relatively high portions of the wafer surface. Where this excessive overdrive is applied, the probe needle 4 becomes a fulcrum at the contact point with the surface of the wafer 1 as shown in FIG. For this reason, there is a problem that the wafer test cannot be performed normally due to poor contact.

  The reason is that the probe needle 4 as shown in Patent Document 1 has a linear structure and is in contact with the electrode pad 2, so that the probe needle 4 is lowered by a force that pushes the probe card substrate downward at the time of excessive overdrive. This is because the downward movement is the movement of the probe needle 4 in the lateral direction as it is.

  The probe needle of Patent Document 2 has an arc-shaped portion. However, when the overdrive is applied, the arc-shaped portion is deformed flat, and the same problem occurs.

  As described above, because of the difference in height of the wafer surface that always occurs due to the convenience of wafer manufacture, a contact failure between the probe needle and the electrode pad occurs, and an accurate wafer test cannot be performed. As a result, LSIs that should be judged as non-defective products may be judged as defective products due to such poor contact at the time of measurement, and the yield rate decreases due to an increase in defective products and the environment due to material loss. The impact on is a problem. Further, in order to prevent this, needle contact readjustment generally performed during a wafer test leads to an increase in test time and an increase in cost due to an increase in development man-hours.

  In addition, since it is expected that the LSI chip size and electrode pads will be further miniaturized in the future, it is considered that the problem of such needle position deviation due to the conventional method will become more prominent.

  In view of the above problems, an object of the present invention is to provide a probe device that does not require readjustment of a needle contact during a test and can be reliably brought into contact with an electrode pad.

  In one aspect of the present invention, a probe apparatus for performing an electrical test of a semiconductor integrated circuit in a wafer state, comprising: a probe needle including a rigid arcuate portion; and a probe card substrate, The needle is an electrode pad provided in the semiconductor integrated circuit when the angle formed between the assumed straight line connecting both ends of the arc-shaped portion of the probe needle and the probe card substrate is variable and the overdrive amount is maximum And the arcuate portion are connected to the probe card substrate so as to be in direct contact with each other.

  In this probe apparatus, when the maximum height from the wafer surface to the probe card substrate is y and the difference between the maximum height and the minimum height from the wafer surface to the probe card substrate is D, the arc-shaped portion Is preferably set so that R = y− (D / 2).

  Further, when the horizontal distance from the connection position between the probe card substrate and the probe device to the electrode pad is x, the arc shape is such that the numerical value calculated by Rx is smaller than the size of the electrode pad. It is preferable that the radius R of the part is set.

  Moreover, it is preferable to have a spike-shaped protrusion at the tip of the probe needle.

  Moreover, it is preferable that the measurement position confirmation camera can be focused on the protrusion.

  Moreover, it is preferable that the arcuate portion of the probe needle further has a linear extension portion on the side connected to the probe card substrate.

  Moreover, it is preferable that at least a part of the extension portion is made of an elastically deformable material.

  In another aspect of the present invention, there is provided a test method for a semiconductor integrated circuit, wherein an angle formed between an assumed straight line connecting both ends of an arc-shaped portion of a probe needle and a probe card substrate is variable. The probe needle is connected, the arc-shaped portion of the probe needle is brought into contact with the electrode pad of the semiconductor integrated circuit to be tested by overdrive, and the relative height of the probe card substrate with the semiconductor integrated circuit The position of contact between the arcuate portion of the probe needle and the electrode pad is rotated and slid in accordance with the fluctuation of.

  By using the probe device according to the present invention, readjustment of the needle contact during the test is unnecessary, and the electrode pad can be reliably contacted, so that the yield of the wafer is improved, and the wafer test time can be reduced and the cost can be reduced. . In addition, since it is possible to cope with improvement of only the probe needle and the electrode pad, the conventional tester assets can be inherited. Furthermore, future LSI miniaturization can also cope with miniaturization of chips and electrode pads.

Example 1
FIG. 1 is a side view of a probe apparatus according to one embodiment of the present invention. As shown in FIG. 1, in one embodiment of the probe device according to the present invention, the entire shape of the probe needle 4 is an arc. The probe card substrate 3 is connected so that the angle α formed between the assumed straight line 7 connecting the both ends of the arc-shaped portion and the probe card substrate 3 is variable. The arc-shaped portion only has a change in angle α even when excessive overdrive is applied, and the arc-shaped portion itself has rigidity to such an extent that it does not substantially deform.

  If the radius R of the arc-shaped portion has a certain size compared to the height from the surface of the wafer 1 to be tested to the probe card substrate 3, the certain effect of the present invention can be obtained. That is, even if the relative height from the surface of the wafer 1 to be tested to the probe card substrate 3 slightly fluctuates and excessive overdrive is applied, as shown in FIGS. While the probe needle 4 maintains its shape, the probe needle 4 rotates and slides around its connection position to change the contact position with the electrode pad 2 of the semiconductor integrated circuit, whereby the arc-shaped probe needle 4 and the electrode pad 2 are It is possible to maintain contact at all times.

  2A shows a case where the point of the electrode pad 2 where the overdrive amount is minimized is probed, and FIG. 2B shows a case where the point of the electrode pad 2 where the overdrive amount is maximized is probed. .

However, the optimum radius R is preferably set to the size indicated by the following formula (1).
R = y-(D / 2) ... Formula (1)
Here, y is the maximum height of the probe card substrate, D is the difference between the maximum height and the minimum height of the probe card substrate, and R is the radius of the arc of the probe needle.

  This is because, as shown in FIG. 3, when the intermediate value between the maximum height and the minimum height of the probe card substrate is the radius R of the arc, the contact position deviation amount L can be minimized.

  By setting the arc radius R of the probe needle 4 in this way, the contact position deviation amount L is set to be smaller than the size of the electrode pad 2 even when the overdrive amount differs due to the height difference of the electrode pad 2. By using the probe needle 4 that has been made, it is possible to always keep the state in contact with the electrode pad 2.

  FIG. 3 shows a state where the overdrive amount is minimum, an intermediate state, and a maximum state on the same diagram when probing with the probe needle 4 having an arc shape. Note that the drawing of the probe needle 4 is changed for each state in order to easily understand the difference in position.

  When probing, the arc-shaped probe needle 4 is arranged so as to come into contact with the electrode pad 2. Using this probe needle 4, overdrive is applied until the probe needle 4 comes into contact with all of the electrode pads 2 provided on the LSI chip, and probing is performed. Therefore, as shown in FIG. 2, an electrode pad 2 having the largest overdrive amount and an electrode pad 2 having the smallest overdrive amount are generated.

  The amount of displacement of the contact position of the probe needle 4 with the electrode pad 2 (the range in which the contact position moves in the horizontal direction when the probe card substrate fluctuates between the maximum height and the minimum height) L is expressed by the following equation (2 ).

L = (x ² + (D / 2) ² ) ^1/2 −x = R−x Equation (2)
Here, L: amount of displacement of the contact position of the probe needle 4, x: horizontal distance from the connection position of the probe card substrate 3 and the probe needle 4 to the electrode pad 2, y: maximum height of the probe card substrate 3, D: The difference between the maximum height and the minimum height of the probe card substrate 3, R: radius of the probe arc.

  As described above, the probe needle 4 is formed in an arc shape, and the contact position deviation amount L of the probe needle 4 obtained from the equation (2) is reduced from the probe card substrate 3 to the electrode pad 2 so as to be smaller than the electrode pad 2. By setting the horizontal distance x to the pad 2 and the radius R of the probe arc, the arc-shaped surface of the probe needle 4 can always keep in contact with the electrode pad 2 even when the overdrive is maximized.

(Example 2)
FIG. 4 is a side view of the probe needle 4 according to the second embodiment of the present invention. As shown in FIG. 4, when it is difficult for the probe needle 4 to have a circular arc configuration due to the positional relationship between the probe card substrate 3 and the electrode pad 2, the connecting portion between the probe needle 4 and the probe card substrate 3 is extended. By providing the structure 5, the same effect can be obtained.

  The contact position deviation amount L of the probe needle 4 at this time is calculated by the formula (2) using the length including the portion 5 obtained by extending the connection portion between the probe needle 4 and the probe card substrate 3 as the radius R. As described above, the same effect as that of the first embodiment can be obtained only by extending the arc-shaped portion of the probe needle 4 and the probe card substrate 3.

(Example 3)
FIG. 5 is a side view of the probe needle 4 according to the third embodiment of the present invention. In this configuration, the tip 41 of the probe needle 4 has a shape with sharp small protrusions (hereinafter referred to as “spike shape”).

  By making the tip 41 of the probe needle 4 into a spike shape as shown in FIG. 5, the probe needle 4 slides on the electrode pad 2 during probing, but the spike portion of the probe pad 4 is made of the electrode pad 2 (for example, aluminum) when sliding. The oxide film 6 generated on the top can be removed.

  FIG. 5 shows a state (A) before the probe needle 4 is brought into contact with the electrode pad 2.

  FIG. 6 shows a state (B) in which the probe needle 4 is brought into contact with the electrode pad 2 and overdrive is weakly applied. The tip 41 of the probe needle 4 partially removes the oxide film 6.

  FIG. 7 shows a state (C) in which the probe needle 4 is brought into contact with the electrode pad 2 and overdrive is strongly applied.

  By forming the tip 41 of the probe needle 4 in a spike shape as shown in FIG. 5, even if the oxide film 6 is generated on the electrode pad 2, the oxide film 6 is removed by giving a weak overdrive as shown in FIG. As shown in FIG. 7, it is possible to obtain a good contact by giving a strong overdrive.

  Furthermore, this shape is also effective in recognition of the probe needle tip for confirming the measurement position, which is performed by actual probing.

  This is because the probing device detects the probe needle tip from the image of the measurement position confirmation camera attached to the device. At the time of this detection, the tip 41 of the probe needle 4 is focused, and the focused needle tip portion can be detected as the position of the probe needle 4. For this reason, if the tip 41 has a spike shape as described above, needle tip recognition can use a conventional camera focus mechanism, and no prober modification is required.

Example 4
FIG. 8 is a side view of the probe needle 4 according to the fourth embodiment of the present invention. As shown in FIG. 8, the probe needle 4 is shaped so that stress concentration occurs at point C in FIG. 8, which is an intermediate portion between the probe card substrate 3 on which the probe needle is fixed and the arcuate portion of the probe needle 4. design. If the material of the probe needle 4 is a material having flexibility such as a metal such as iron, the stress concentration portion will be broken, and the function of the arc-shaped probe needle 4 can be sufficiently exhibited. Further, in order to prevent the tip of the probe needle from being deformed in an excessive overdrive state, the inner side of the arc-shaped portion of the probe needle 4 and the portions A and B of FIG.

  With this configuration, when excessive overdrive is applied, bending occurs at point C in FIG. 8 where stress is concentrated. Further, by reinforcing the portions A and B of FIG. 8 so that the tip of the probe needle is not deformed due to excessive overdrive, the probe needle 4 is not deformed even in the portion in contact with the electrode pad 2, and the probe needle is designed as designed. The contact surface 4 and the electrode pad 2 slide (slide). As a result, the displacement between the probe needle 4 and the electrode pad 2 is minimized.

  For example, in the case where the needle base is fixed with a resin and the needle base is raised, it may be difficult for the needle base to be bent. In this case, there is a possibility that the card substrate resin-needle portion is not deformed and only the portion on the arc is subjected to weighting. Therefore, when the present invention is realized by using such a needle stand technique, if the shape of the needle is designed so that there is a portion where stress is concentrated and deformed as shown in FIG. Any bend can be realized.

  Although the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the configurations of the above-described embodiments, and various modifications that can be made by those skilled in the art within the scope of the present invention. Of course, including modifications.

It is a side view of the probe apparatus of Example 1 which concerns on this invention. It is a figure which illustrates the probing state of the probe apparatus of Example 1 which concerns on this invention. It is a side view explaining operation | movement of the probe apparatus of Example 1. FIG. It is a side view of the probe apparatus of Example 2. It is a side view of the probe apparatus of Example 3. It is a side view of the probe apparatus of Example 3. It is a side view of the probe apparatus of Example 3. It is a side view of the probe apparatus of Example 4. It is a side view of the probe apparatus of a prior art. It is a side view of the probe apparatus which shows the normal overdrive state of a prior art. It is a side view of the probe apparatus which shows the excessive overdrive state of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wafer 2 Electrode pad 3 Probe card board 4 Probe needle 5 Probe needle extension part 6 Oxide film 7 Assumption straight line 41 which connects both ends of circular arc part Tip part 42 Support part

Claims (8)

A probe device for conducting an electrical test of a semiconductor integrated circuit in a wafer state,
A probe needle including a rigid arcuate portion, a probe card substrate,
With
The probe needle is provided in the semiconductor integrated circuit when the angle formed between an assumed straight line connecting both ends of the arc-shaped portion of the probe needle and the probe card substrate is variable and the overdrive amount is maximum. A probe device characterized in that the electrode pad and the arcuate portion are connected to the probe card substrate so as to be in direct contact with each other. The maximum height from the wafer surface to the probe card substrate is y,
When the difference between the maximum height and the minimum height from the wafer surface to the probe card substrate is D,
2. The probe device according to claim 1, wherein a radius R of the arc-shaped portion is set to be R = y− (D / 2). When the horizontal distance from the connection position of the probe card substrate and the probe needle to the electrode pad is x,
The probe apparatus according to claim 2, wherein a radius R of the arc-shaped portion is set so that a numerical value calculated by R-x is smaller than a size of the electrode pad.   The probe apparatus according to any one of claims 1 to 3, wherein a spike-shaped protrusion is provided at a tip of the probe needle.   The probe apparatus according to claim 4, wherein a focus of a measurement position confirmation camera can be focused on the protrusion.   The probe device according to claim 1, further comprising a linear extension portion on a side where the arc-shaped portion of the probe needle is connected to the probe card substrate.   The probe apparatus according to claim 6, wherein at least a part of the extension part is made of an elastically deformable material.   The probe needle is connected to the probe card board so that an angle formed between an assumed straight line connecting both ends of the arc-shaped part of the probe needle and the probe card board is variable, and the arc-shaped part of the probe needle is tested. The electrode pad of the semiconductor integrated circuit that performs the overdrive is brought into contact with the electrode pad, and the arc-shaped portion of the probe needle and the electrode pad follow the fluctuation in the relative height of the probe card substrate with the semiconductor integrated circuit. A method for testing a semiconductor integrated circuit, wherein the contact position of the semiconductor is rotated and slid.

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