JP5134221B2 - Manufacturing method of semiconductor device - Google Patents

Description

  The present invention relates to a manufacturing method and a semiconductor device that can stably move a semiconductor device having bumps onto a semiconductor substrate.

  In recent years, semiconductor devices have complicated functions, the number of connection terminals such as bumps has increased, and they have been highly integrated and have been remarkably miniaturized. On the other hand, in order to connect the semiconductor device stably and reliably on the semiconductor substrate, the connection terminals such as bumps need to have a certain size. Therefore, the size of connection terminals such as bumps is very large compared to the size of the semiconductor device.

Therefore, when a semiconductor device is handled for movement or inspection, as shown in FIG. 3, the surface on which the bump is formed is sucked with a suction collet, and a method of bringing the jig into contact with the bump is performed. (For example, see patent literature)
JP-A-11-274205

  However, the bump material is often a noble metal such as gold, or a low melting point metal material such as solder, but these materials are relatively soft and often prone to scratches and deformation. Therefore, a relatively soft material such as a resin is often used for the adsorption collet. With the above configuration, when the bump part of the semiconductor device is picked up by the suction collet and the semiconductor device is moved or inspected, the suction collet and the bump are held in close contact when the semiconductor device is removed from the suction collet. In some cases, it is difficult to ensure the withdrawal. This is because, when the suction collet is used repeatedly, a concave portion is formed in a part of the suction collet made of a soft material due to contact with the bump, and the contact area between the suction collet and the bump becomes large and cannot be removed smoothly. (FIG. 3B). This problem not only makes it difficult to reliably move the semiconductor device, but further, the first semiconductor device that has not been detached from the adsorption collet after the movement is placed on the second semiconductor device to be moved next. As a result, the semiconductor devices are likely to be accidentally damaged. These defects tend to increase in frequency as semiconductor devices become smaller and lighter.

  An object of this invention is to provide the manufacturing method and semiconductor device which can move the semiconductor device which has a bump stably on a semiconductor substrate.

  By roughening the surface of the bump, the contact area between the suction collet and the bump is reduced and the adhesion is lowered. The first method for roughening the bump surface is a method of pressing a jig having a rough surface with fine irregularities on the surface and transferring the irregularities on the jig surface to the bumps. The second method for roughening the surface of the bump is a method for producing irregularities on the bump surface by heating and melting the bump to a temperature equal to or higher than the melting point.

  By using the means as described above, the suction collet and the semiconductor device can be reliably detached when the semiconductor device having bumps is moved onto the semiconductor substrate, and the efficiency of the movement and inspection of the semiconductor device is improved. .

  The reason why the suction collet and the semiconductor device cannot be reliably detached is because the contact area between the bump and the suction collet is large and the contact is easy. By reducing the area, the adsorption collet and the semiconductor device can be prevented from remaining in close contact with each other, and the semiconductor device can be reliably detached from the adsorption collet.

  First, an embodiment of the present invention will be described with reference to FIG.

On the upper surface of the semiconductor device 1, a bump surface roughening jig 4 having an uneven shape formed on the surface and harder than the bump material is disposed (FIG. 1A). Next, the bump surface roughening jig 4 and the bump 2 of the semiconductor device 1 are brought into contact with each other to press the bump surface to transfer the uneven shape of the jig surface onto the upper surface of the bump 2 to form the bump 2A having an uneven surface. To do. Since a relatively soft material is often used for the bump, the transfer with the jig 4 is easy (FIG. 1B). By doing so, the contact area between the bump 2A and the suction collet 3 is reduced, and the semiconductor device 1 can be reliably detached from the suction collet 3. (Fig. 1 (c))
As a material for the bump, it is desirable that the surface portion or the entire material is tin or a metal material containing tin as a main component. In addition, a material containing one or more of silver, copper, bismuth, and zinc is desirable. Alternatively, an alloy having a composition ratio other than the eutectic point is desirable.

  Next, a second embodiment of the present invention will be described with reference to FIG. When the bump is a solder bump, the constituent material is a low melting point metal, and the bump 2B having unevenness on the surface can be formed by heat-treating it to a high temperature. The method is as follows.

  In the case of a solder bump formed by a plating method or a printing method, first, the solder is melted by a high-temperature heat treatment called a wet back, and then molded into a ball shape by the surface tension of the melted solder. Next, by performing wet back treatment again, fine irregularities are formed on the surface, and the surface is roughened. Wet-back processing of solder bumps formed by plating is usually performed with flux applied, but a larger effect can be achieved by performing wet-back processing without applying flux during the second wet-back processing. Can be obtained.

  Here, the method of the present invention requires that the alloy composition of the solder bumps does not coincide with the so-called eutectic point. Even if the deviation of the composition from the eutectic point is about 10% of the ratio of each alloy component, it is sufficient.

  For example, in the case of a Sn—Cu alloy, Cu = 0.7 wt% is the eutectic point, but the above method can be used even when the composition ratio is Cu = 0.6 wt%. The temperature condition during the second wet-back process varies depending on the composition ratio of the solder material, but in the case of a solder material mainly composed of Sn, after being heated to a temperature approximately at least 20 ° C. higher than the melting point of the solder material. It is desirable to cool at a rate of about 100 ° C. for 30 seconds.

Schematic cross-sectional view showing a method for manufacturing a semiconductor device according to the first embodiment of the present invention (a) Schematic cross-sectional view before formation of rough surface (b) Schematic cross-sectional view during formation of rough surface (c) Collet adsorption Schematic cross section of the hour Schematic sectional view of a semiconductor device according to a second embodiment of the present invention Schematic sectional view showing pick-up operation of conventional semiconductor device (a) Schematic sectional view before collet adsorption (b) Schematic sectional view at the time of collet adsorption

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Bump 2A Bump 2B with the surface of the roughening jig on the surface Bump 3 with bumps formed on the surface by heat treatment 3 Adsorption collet 3A Adsorption collet with concave portions on the contact surface with the bump by repeated use 4 Bump surface roughening jig

Claims (2)

A method of manufacturing a semiconductor device having bumps formed thereon,
Forming solder bumps;
A first wet-back process in which a flux is applied to the solder bump and then a high-temperature heat treatment is performed;
A second wet-back process for performing high-temperature heat treatment without flux;
A method for manufacturing a semiconductor device comprising: The solder bump is mainly composed of Sn, and the second wet back process is performed under a temperature condition in which the solder bump is heated to a temperature 20 ° C. higher than the melting point of the solder bump and then cooled at a rate of 100 ° C. for 30 seconds. A method for manufacturing a semiconductor device according to claim 1.

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