JPS5873129A - Method and apparatus for inspection of semiconductor element - Google Patents

Abstract

PURPOSE:To eliminate remedy after mounting and to practice high-density mounting by a method wherein heating is applied from the rear of a probe card and projected electrodes at the upper face are abutted to solder balls on the electrodes of a semiconductor element for melting and connection and after inspection, the solder balls are again melted for partial fusion. CONSTITUTION:Projected electrodes 12 of W with Ni plating of an alumina ceramic made probe card 11 are positioned to the electrodes of a semiconductor substrate 7 and the temperature of the projected electrodes 12 is risen by applying heating from the rear of the card and after exceeding solder melting point, the projected electrodes 12 are abutted to the solder balls 9 on the electrodes of the substrate 7 for connection and heating is stopped. The solder balls will not be melted as far as the bases. A predetermined inspection is performed through a power wire 13 and signal wires 14 contained in the card and heating is done again and heating is stopped when the solder around the electrodes is melted and separated each other. Therefore, the solder on an element will scarcely be decreased and the bases of the solder balls do not melt and undesired heat hysteresis will not be given to the element. In this way, when a substrate like practically used wiring substrate is used for the prober, high-speed inspection is available and with the length of the electrodes 12, tip shape and solder ball diameter selected, solder correction after mounting becomes unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for inspecting semiconductor elements to be subjected to solder fusion bonding.

Semiconductor devices go through several electrical property tests before they are actually mounted on a board. These include the stage where electrodes are formed on the wafer, dicing, die bonding, wire bonding, and packaging. When used, a semiconductor element 5 is usually used as shown in FIG.
is mounted on the printed circuit board B.

However, when mounted on a printed circuit board and in Figures 1 and 2,
The electrical characteristics of the wafers shown in the figure are generally different at one stage.

That is, in FIGS. 1 and 2, a wafer 1 on which a semiconductor element is formed is brought into contact with an electrode thereon by a probe 4 made of tungsten or the like coming out of a probe card 2, and its electrical characteristics are tested. Note that 3 in FIGS. 1 and 2 is a probe card hole.

However, due to the shape of the probe 4, the lumped inductance there is large, and there is a limit to inspection using high-speed signals. That is, if the characteristic impedance of the signal line on the probe card is R, and the lumped inductance of the probe is L, then
The time constant is L/R, R=50Ω, L=50n
In the case of H, it is 1 nS, and when handling such a high-speed signal, the waveform becomes dull and accurate inspection cannot be performed. Therefore, direct current characteristic testing is usually the main method.

Next, when such a semiconductor element is packaged as shown in FIG. 6, the electrodes inside the semiconductor element 5 are connected to the pattern on the printed circuit board 6 via wirebond wires, wiring inside the package 5, and leads. Ru. Therefore, even if high-speed signal characteristics can be tested on Ueno, when it is actually packaged, the effects of lead inductance and capacitance will appear.

On the other hand, in chip connection by melting solder, as shown in FIG. The distance between the electrodes, that is, the solder height is 100 μm to 300 μm, and the concentrated inductance in this portion is extremely small. Therefore, as in the package shown in FIG. 3, there is almost no influence from leads or other factors, and the original characteristics of the semiconductor element are exposed on the substrate surface electrode. Furthermore, since this connection method is suitable for high-density packaging and one-shot bonding with a high yield, its application is expanding. However, a blower similar to that shown in FIGS. 1 and 2 is used to test this semiconductor device.

FIG. 5 is an enlarged view showing the state in which the tip of the prober 4 is in contact with the solder ball 9 formed on the electrode on the semiconductor element Z.

Therefore, high-density mounting, high-yield bulk bonding,
Although the solder fusion bonding method has the advantage of not affecting the high-speed characteristics of the package, the high-speed characteristics can still be measured in the chip state by using the conventional blower used for wire-bonding semiconductor devices as a prober. Can not. Therefore, it becomes necessary to mount them on a board and repair those with poor characteristics.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device testing method and testing device that eliminates the drawbacks of the prior art described above and enables high-speed electrical characteristic testing of semiconductor devices for solder fusion bonding. .

This eliminates the need for repairs after the elements are mounted on the board, and contributes to the practical application of high-density packaging using solder fusion connections.

In order to achieve the above object, the present invention, in principle,
A board similar to the wiring board actually used is used as a prober, and a heat source is provided on the back side of the board to melt the solder balls on the semiconductor element. Furthermore, the electrodes on the substrate are protruded in order to not change the amount of solder on the semiconductor element and to absorb warpage of the substrate. -Furthermore, in order to accurately test high-speed electrical characteristics, it is necessary to wire with a constant characteristic impedance to each signal electrode to prevent reflection noise.

Therefore, unlike conventional probes, probes to all electrodes are not treated equally, but signal electrodes are connected to signal wiring, and power supply electrodes are connected to a power supply layer that is a reference layer for the signal wiring.

In FIG. 6, the present invention will be explained in detail with reference to the drawings. In FIG. 6, reference numeral 11 denotes a probe card consisting of a multilayer wiring board having signal wiring and a power supply layer therein, and is usually made of alumina ceramics.

Reference numeral 12 denotes a projecting electrode projecting from the glove card at a substantially right angle, and is connected to the internal signal wiring 14 and power supply layer 16, as shown in the sectional view of FIG. Here, the signal wiring 14 is a strip line or a microstrip line with the power supply layer 16 as a reference layer, and has a constant characteristic impedance. Therefore, unlike conventional probes, it does not have lumped inductance, and although there is a delay depending on the signal wiring length, the waveform does not become rounded. Further, the electrode corresponding to the power source is directly connected to the power layer. In order to make the board general-purpose, the power supply electrodes are connected to the power supply layer with a constant impedance wiring in the same way as the signal wiring, and if they are connected to the power supply layer outside the board or at the end surface, the DC The results are the same, but with high-speed pulses, signals are induced in this wiring, resulting in reflection noise and the like, making it impossible to test high-speed electrical characteristics.

Note that when alumina ceramics is used as the substrate, a conductor such as tungsten is used for these signal wiring layers and power supply layers. Therefore, it is preferable to use the same tungsten for the protruding electrodes.

However, since tungsten alone does not wet the solder, nickel plating is performed which is relatively wettable with the solder and has high reliability even after repeated use. This protruding electrode has three purposes. One of these is that when testing a single semiconductor device on a large wafer 7, the probe card board needs to be long enough to prevent it from touching the solder balls of other devices on the wafer. It is. Second, if the electrode is made to be the same size as a normal electrode on a board, the opposing area is needs to be made smaller. Thirdly, the solder balls on the semiconductor element are heated and connected, and the heat is transferred to the solder balls via the protruding electrodes. Therefore, by forming the solder ball into a protruding shape, the heat capacity of the solder ball is reduced to prevent it from melting to the bottom side of the solder ball, thereby preventing unnecessary heat history from being imparted to the semiconductor element. In order to meet these six objectives, it is preferable that the diameter of the tip is 1/3 or less of the maximum diameter of the solder ball, and the length is greater than or equal to the height of the solder ball. Such protruding electrodes can be formed not only from the sintered tungsten described above but also from copper plating. 1
0 is a heat source that applies heat from the back side of the probe card 11, and hot jet, infrared irradiation, or heat conduction from a normal heating element is possible, but for the purpose of the present invention, the former two are preferable. .

Hereinafter, the inspection method using the apparatus of the present invention will be explained step by step.

First, the protruding electrode and the semiconductor element electrode are aligned,
Probe card 11 is heated by heat source 10 . As a result, the temperature of the protruding electrode 12 of the probe card rises,
After this exceeds the solder melting temperature, the Ueno probe card is brought close to the solder ball, the protruding electrode is pressed against the solder ball to melt the solder, and after all the electrodes are brought close to a predetermined distance where a connection can be established, heating is stopped. As a result, the bottom of the solder ball does not melt. In this state, after a predetermined electrical characteristic test is performed, it is heated again by a heat source. At this time, by applying a slight force in the direction of separating the Ueno 7 and the probe card 11, the solder around the protruding electrodes will be separated when it melts, reducing the amount of solder on the semiconductor element. Since the bottom surface of the solder ball does not melt even at this time, unnecessary heat history is not imparted to the semiconductor element.

As described above, in the present invention, a board that is almost the same as the wiring board that is actually used is used as a probe, so it is possible to test high-speed electrical characteristics in a form that is close to the actual mounting.
The protruding electrodes can reduce the loss of solder in the semiconductor element. As a result, when the semiconductor element for solder fusion connection is used in a high-speed pulse circuit or the like, there is no need for repairs after mounting, and reliability regarding the amount of solder can be ensured.

[Brief explanation of the drawing]

Figures 1 and 2 show a conventional inspection prober; Figure 3 shows a conventional DIL semiconductor device mounted; Figure 4 shows a solder-fused semiconductor element mounted; and Figure 5 shows a solder-fused semiconductor element mounted. 6 is a diagram showing the state of probing, FIG. 6 is a cross-sectional view of the inspection device according to the present invention, and FIG. 7 is a sectional view of the probe card of the present invention. 1...Semiconductor element wafer 2...Probe card 4...Probe 9...Solder ball 10...Heat source 12...Protruding electrode 1st episode

Claims (1)

[Claims] 1. In the inspection of a semiconductor element having a solder pole on the electrode for solder fusion connection, a multilayer substrate having a protruding electrode at a position corresponding to the electrode is used, and the surface having the protruding electrode is Heat is applied from the opposite side, the protruding electrode is pressed against the solder ball, at least a portion of the solder is melted, and conduction is established between the semiconductor element electrode and the protruding electrode, and the wiring in the multilayer board is connected to the protruding electrode. A method for testing a semiconductor device, characterized in that, after transmitting and receiving a test signal and testing the semiconductor device, the multilayer substrate is heated again to melt the solder and separate the semiconductor device and the protruding electrodes. 2. The protruding electrode to be connected to the power supply electrode of the semiconductor element is connected to the corresponding power conductor layer in the multilayer board without going through the signal line in the multilayer board, and the protrusion corresponding to the other signal electrode The electrode is connected to a signal conductor wiring in the substrate, and the signal conductor wiring is a line having a constant characteristic impedance with the power supply conductor layer as a reference layer, and is connected to the signal conductor wiring on the same substrate, or 2. A test device for testing a semiconductor device according to claim 1, wherein the test device is connected to a test circuit connected by a connector or the like. 3. The inspection device according to claim 2, wherein the protruding electrodes are made of tungsten and nickel plated thereon. 4. Claim 2, characterized in that the protruding electrode has a shape in which the diameter of the tip thereof is one-third or less of the maximum diameter of the solder ball, and the length is longer than the height of the solder ball. Inspection equipment as described.